This PDF file contains the front matter associated with SPIE Proceedings Volume 7544, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

Form error in-process optical measurement is to provide feedback during a machining process for precision control. Based on the method of water beam assisted form error in-process optical measurement, a new air beam approach was proposed to solve the problems of coolant dilution and optical transmittance through multiple media. In order to identify key parameters to reduce the workload of experimental tests, a factorial test was conducted on transparent window size A_t and stability est. Calibration and assessment of A_t and e_st were introduced. Factorial test design was also examined. Results of the study show that v_t, v_a, and d_a are the key parameters on A_t. Although all 6 main parameters are not significant, vt is relatively more important on est. When v_t increases, A_t will decrease. When v_a or d_a increases, A_t will increase. The findings agree with our understanding of the physical process of fluid flow. When v_t decreases, the transparent window size stability e_st will be better. Consider both stability e_st and air velocity v_a, Run 11 should be the best choice of conditions for A_t. A larger transparent window size At typically gives better transparent window size stability e_st. To achieve a balance between e_st and v_a, a suitable size of transparent window at A_t=~30 mm² should be a good choice. Further studies are necessary to confirm the findings.

Workspace Measurement Position System (wMPS) is a newly developed laser based measuring system for large scale metrology. Initially, theoretical definition of metrology process models of wMPS is described and uncertainties are propagated from internal parameters using Monte Carlo simulation in which uncertainty decreases with sampling duration. Angular uncertainty is affected by internal parameters pointed out by mathematical model and experiments are then carried out to determine the actual uncertainty in the azimuth and elevation in order to select appropriate parameters to design the measuring system. Experiment results reveal that wMPS has the ability of accurate measurement for large volume and the uncertainty is less affected by the working volume. Measuring results shows wMPS designed based on the parameters achieves relative high measuring precision.

An optical method is proposed for in-situ measurement of angles of space elements separated at a distance of several or several tens of meters. When it is necessary to measure large objects or geometrical elements within a large scale space, it is not always possible to bring these workpieces to conventional coordinate measuring machines (CMMs) which are widely used in industries. Mobile measuring systems provide ideal solutions for these applications. The basic idea of the presented research work is to set up the multiple common optical references through which the dimensional inspections of separation angles of bifacial lines in a large scale space can be fulfilled. The angles between the projection light and each element can be captured through a machine vision system, and thereafter the angles between those corresponding elements can be determined using the geometrical principles. The method and the calibration approach have been validated on our designed work station.

Using the house-made transmission grating (3300 l/mm) and IRDAXUV100G (USA) photodiode detector, higher order harmonics contributions have been measured in the spectral radiation standard and metrology beamline at NSRL and the contributions of the different orders have been analyzed. In order to accurately calibrate the performance of optical elements, higher order harmonics must be efficiently suppressed. Selecting the suitable filter in different wavelength, the higher order contributions can be efficiently suppressed. In wavelength region between 5 nm and 12 nm with proper Zr filters, the contributions of higher order intensity are less than 1.25%, after modified by quantum efficiency of the detector , the higher order contributions are restricted to less than 0.62 %. In wavelength region between 13 and 17 nm with Si filter, the higher order contributions are almost zero. In wavelength region between 18 nm and 34 nm with proper Al filter, the contributions of higher order intensity are less than 8.06%, after modified by quantum efficiency of the detector, the higher order contributions are restricted to less than 3.08 %.In wavelength region between 35 and 40nm with Al/Mg/Al filter, the higher order contributions are restricted to less than 10.00 % after modified by quantum efficiency of the detector.

In order to develop an on-line optical lens measurement system, a dual autofocusing algorithm consisting of coarse autofocusing and fine autofocusing is proposed to realize the accurate and automatic image grabbing. In the procedure of coarse autofocusing, variance function on the whole image is selected as sharpness evaluation function (SEF), and mean comparison method is applied to realize the hill-climbing algorithm for focal plane searching. A 3-point method is used to initialize the searching direction. In the procedure of fine autofocusing, a conditional dilation method based on mathematical morphology is used to extract the region of interest (ROI), namely, the target images, and a shape factor is employed to eliminate the disturbance regions. Brenner function within ROI is selected as SEF, and single-point comparison method is used to find the focal plane accurately. Compared to the traditional methods, this dual autofocusing algorithm not only can realize high precision focusing, but also has large autofocusing range. The experiment results show that the dual autofocusing technique can guarantee that the focusing position locates in the depth of field. The proposed algorithm is suitable for the on-line optical lens measurement.

The relationship between subjective ride comfort in a vehicle seat and human whole-body vibration can be modeled using frequency weightings and rms(root mean square) averaging as specified in ISO2631. However, recent studies indicate that, there are some flaws in the relationship between subjective response and objective vibration given by the ISO2631.This paper presents an alternative approach based on neural network model. Time-domain vibration acceleration signals are processed as neural network inputs, subjective evaluation results are quantified as outputs, and the weights of neural networks are used as frequency weighting coefficients to evaluate the vehicle ride comfort. The method has been used to evaluate the ride comfort on a number of conditions with good results achieved.

Symmetricom's Multi-channel Measurement System (TSC MMS) is a phase measurement device based on the measurement principle of dual mixer time difference method (DMTD). TSC MMS is purchased by Time and Frequency measurement laboratory in National Time Service Center of Chinese Academy of Sciences. In order to evaluate the measurement capability of DMTD and research the improved method of performance, in this paper, the TSC MMS performance test platform is set up. We ensure the test signals have better stability than system, and the invariant environment to reduce the effect of measurement produced by external environment as much as possible. Under the same condition, three-day data are collected to measure the noise floor of a system. Finally, we analyze the reasons attributing to the measurement results and proposed a improving method in detail. The measured results demonstrate that the Allan deviation stability will reach 3E-13 per second when the frequency of the input signals is 10MHz.

This paper presents two various methods of transmission delay measurement for converter. One is group delay measurement method for multi-lever converter by means of high performance vector network analyzer. The other is envelope method used to determine the absolute delay of a converter using fast sampling scope. A scheme and key technologies of group delay measurement are described. A good measurement example is given and measurement results and their uncertainty are analyzed. It can not represent the real delay when modulation signals pass though the converter, Because the group delay curve measurement is performed by a vector network analyzer which needs the input of sweep frequency stimulation signal. Therefore, the characterization of BPSK modulation signal is analyzed. Transmission delay measurement method of BPSK modulation signal which passes though the converter is researched. Finally, the two measurement results obtained using two methods mentioned above are compared.

In order to effectively detect and remove abnormal data during dynamic measurement of discontinuous surfaces, this paper presents an effective method based on the dynamic GM(1,1). The dynamic GM(1,1) is used to implement modeling for the primary measurement data. The model based on the dynamic GM(1,1) can be a good approximation to normal data, while insensitive to abnormal data. Through comparing the model with the primary measurement data, abnormal data can be effectively detected according to a certain criterion. An experiment is carried out to verify the proposed method for detecting and removing abnormal data. A gross error is artificially introduced into the mesh errors of a hob at the ninth cutting. For the ninth cutting edge, the residual error between the mesh error and the modeling value is 3.2077 and greater than 2.5S. The mesh error of the ninth cutting edge is abnormal and replaced by the corresponding modeling value. The experimental result shows that the proposed method can effectively detect and remove abnormal data during dynamic measurement of discontinuous surfaces.

According to the operation and operator theory in the new generation geometrical product specification (GPS), the verification operator of cylindricity errors is an ordered set of several feature operations, including partition, extraction, filtration, association, and so on. Each feature operation contains some uncertainty due to the variability of measurement process and the incompleteness of ISO specification, and the uncertainty in previous operation can be transferred to the subsequent operation, resulting in cylindricity errors with high uncertainty. To ensure accurate evaluation of cylindricity errors, a method is proposed for estimation of uncertainty propagation in verification operators of cylindricity errors based on the new generation GPS. By investigating the propagation model of the uncertainty of cylindricity errors, the calculation formulas for the uncertainty propagation of key feature operations in operator, such as association operation and filtration operation, are proposed. The uncertainty calculation expression is developed for the choice of verification operators of cylindricity errors. The effects of filtration operation and association operation on the uncertainty of cylindricity errors are further verified through a case study. Test results indicate that the proposed method can not only improve the veracity of evaluation, but also provide helpful guidance for the reasonable choice of verification operators of cylindricity errors.

In order to increase the speed of photoelectric conversion, a linear CCD is applied as the photoelectric converter instead of the traditional photodiode. A white LED is used as the light source of the system. The color information of the urine test strip is transferred into the CCD through a reflecting optical system. It is then converted to digital signals by an A/D converter. The test results of urine analysis are obtained by a data processing system. An ARM microprocessor is selected as the CPU of the system and a CPLD is employed to provide a driving timing for the CCD drive and the A/D converter. Active HDL7.2 and Verilog HDL are used to simulate the driving timing of the CPLD. Experimental results show that the correctness rate of the test results is better than 90%. The system satisfies the requirements of the color information collection of urine analyzer.

This paper presents a dual magnetic circuit magnetic bead method and corresponding system for testing human blood coagulation. The system is composed mainly of a dual magnetic circuit magnetic beads test assembly, a signal modulation and demodulation module, a digital filter as well as a waveform processor. Smart hardware design together with subsequent software algorithm is presented for the system to overcome the defects of traditional dual magnetic circuit magnetic bead method. Experiments for verifying the system are carried out in comparison with an ACL200 coagulometer from Coulter Co. USA. Experimental results indicate that the system features excellent precision, repeatability better than 2.10%, and show that the dual magnetic circuit magnetic bead system suppresses external interference factors effectively.

New generation Geometrical Product Specifications (GPS) consist of a series of standard drafted by ISO/TC 213, which relate to drawing indication, definition of tolerance and values of specifications, characteristic, parameters and definitions of actual features, comparing verification, measuring instrument, and calibration of size, distance, radius, angle, form and position of geometrical features, roughness profile, waviness profile, primary profile, surface imperfection and edges. The characteristics of the GPS, e.g. chain matrix model in each standard, a lot of new and mathematical terms, the size system, indications of dimensions other than linear sizes by using geometrical tolerances, uncertainty series and etc., are introduced in this paper. Based on the characteristics above, some challenges in the implementation of the GPS are analyzed. Therefore, a lot of in-depth adaptive studies of GPS in indications of the sizes and the dimensions other than linear sizes in the drawings, the evaluation models of uncertainties, the measuring techniques and instruments and etc. should be done, and the matching user manual should be provided to designers, manufactures, inspection personnel for the wide application of the GPS.

Stimulated emission depletion (STED) microscopy exploits nonlinear saturable optical transition of fluorescent molecules, allowed to overcome Abbe's diffraction-limit and provides diffraction-unlimited resolution in far-field optical microscopy. We elaborate the mechanism of STED and the conditions of depletion. The formula of STED microcopy resolution is deduced through effective point spread function (E-PSF). The STED system resolution is mainly dominated by the quality of the fluorescence depletion patterns in the focal plane. The depletion pattern is mainly affected by STED beam intensity, polarization, phase plate, primary aberrations, STED pulse shape, pulse duration and delay time. In this paper, we found related models and simulate the relationship between the depletion patterns and the parameters, and put forward effective approach to enhance the system resolution.

Molten salts (sodium and potassium nitrides) are going to be used in many different plants as heat transferring fluids, e.g. concentration solar plants, nuclear power plants, etc. In fact they present may important advantages: their absolute safety and non toxicity, availability and low cost. But their use, e.g. in the energy receiving pipe in the focus of the parabolic mirror concentrator of the solar thermodynamic plant, requires the accurate knowledge of the thermophysical properties, above all thermal conductivity, viscosity, specific heat and thermal linear expansion, in the temperature range 200°C÷600°C. In the new laboratory by ENEA Casaccia, SolTerm Department all these properties are going to be measured. Thermal conductivity is measured with the standard probe method (linear heat source inserted into the material) manufacturing a special probe suited to the foreseen temperature range (190-550°C). The probe is made of a ceramic quadrifilar pipe containing in different holes the heater (Ni wire) and the thermometer (type J thermocouple). The thermal linear expansion will be measured by a special system designed and built to this end, measuring the sample dilatation by the reflection of a laser beam by the bottom of the meniscus in the liquid solid interface. The viscosity will be evaluated detecting the start of the natural convection in the same experiment as to measure thermal conductivity. In the paper the construction of the devices, the results of preliminary tests and an evaluation of the obtainable accuracy are reported.

The paper describes the manufacturing and dimensional measurements of high precision work-pieces by PTB, which shall act as test masses (TM) for the satellite-based experiment MICROSCOPE. The manufacturing involves turning of Ti alloys and PtRh10. The measurements were made by in-process tactile probing, coordinate metrology, and form measurement. The high geometrical demands of the project could be fulfilled on both the manufacturing and the measurement sub-projects.

A high-precision optical scale called LDGI (Linear Diffraction Grating Interferometer) has been developed for long stroke measurement to nanometer accuracy. This study presents the principle of newly developed LDGI and its possible waveform errors of output signals. Mathematical methods for waveform error correction, pulse counting, signal subdivision and displacement calculation are proposed. All the digital processes are carried out by software. Experimental results show that the system has high tolerance to geometrical errors of the moving stage. The standard deviation of measured values is within 20nm even up to 18mm long stroke.

Single crystal diamond micro-cutting tools, which are used for fabrication of precision micro-parts, have very sharp tool edges with radii in the range of tens of nanometers or even nanometers. Although there are many types of tools, the tools with a rounded nose are treated in this paper. They can be used for fabrication of very smooth and accurate surface with 3D micro structures such as micro-lens arrays, diffractive optical elements and so on. The machined quality is highly depending on the tool edges' states and it is desired to manage them. This paper presents a measuring instrument based on atomic force microscope (AFM), which is designed and constructed for on-machine measurement of the cutting edge profile. It is a combination of an AFM probe unit for 3D edge profile measurement and an alignment system with an optical sensor for aligning the probe-tip with the tool's edge top so that the measurement can be carried out in a short time. Measurement experiments of micro-tools with (nominal) nose radii of 8 μm and 0.2 mm are summarized to show the performance of the instrument. And the nose radii were evaluated as 7.2 μm and 0.188 mm, respectively.

This study aims at the development of a less reflective electromagnetic pneumatic actuator often used in the anechoic chamber. Because a pneumatic actuator on the market is not appropriate for use in such a chamber and a metallic one has high dielectric constant which generates reflective electromagnetic waves to influence test parameters in the chamber. The newly developed pneumatic actuator is made from low dielectric constant plastics with less reflective of electromagnetic. A turbine-type air motor is used to develop the pneumatic actuator and a employ Prony tester is used to run the brake horsepower test for the performance test of pneumatic actuator. Test results indicate that the pneumatic actuator in the minimal starting flow is 17 l/min, and it generates a brake horsepower of 48 mW; in the maximum flow is 26 l/min, it generates a brake horsepower of 108 mW. Therefore, it works with a torque between 0.24 N-m and 0.55 N-m, and such a torque will be sufficient to drive the target button.

The Differential Interference Contrast approach (DIC) which is frequently used for image enhancement to increase the contrast between transparent object and its background is adopted for the dimensional measurement of a transparent structure. With the phase difference image retrieved using the DIC technique, the phase map of the examined object can be approximated by integrating the phase difference. Experimental results show the feasibility of using the transmitted DIC for transparent object measurement. The results show that the height of a transparent structure measured using the DIC method is quite close to those measured using AFM while those measured using the white light interference method results in much larger measurement than all others. However, when a structure is no longer a simple geometry, adopting this method directly might results in wrong results. In this paper, we would like to present the work had been done, discuss the challenge ahead, and possible approach can be adopted.

In-process form error measurement provides feedback for precision control. There many existing studies on in-process roughness and size measurement but few on in-process form error measurement. Water beam based in-process form error measurement is proposed to solve the opaque problem of the commonly used coolant in precision machining. Factorial test results show that the water flow rate Q_w is one of the five important parameters to give a reasonably acceptable transparent window size A_t for the in-process form error measurement. In this project, both experimental and computational studies were conducted and the results show that transparent window size A_t will increase with the water flow rate Q_w and will decrease with the height of medium hm, coolant concentration c_c, table velocity v_t, and water channel diameter Φ_w. Based on the results of A_t(Q_w,h_m) and the results of A_t(Q_w,v_t), the ranges of Q_w∈[0.65,0.75] ml/s, h_m∈[0.5,0.55] mm, and v_t∈[120,150] mm/s would give a transparent window size A_t∈[20,40] mm², which is reasonably acceptable for the laser measurement currently for the tests. The results will be useful for design of the in-process sensor.

This study presents a reflective-type optical encoder based on fractional Talbot self-image effect using a phase grating. An amplitude grating image is produced by the phase grating at a quarter or three quarters of Talbot distance. The encoder has the advantages of a large gap and more light efficiency. This work use a 850nm Light-Emitting Diode (LED) as light source, the light source will be collimated by a collimator ,and incident on a phase grating by 45° angle. The fractional Talbot self-image of phase grating is produced and projected on an amplitude index grating. The Moiré interference is occurred when the both gratings displaced from each other. The encoder includes a reflective-type phase-grating scale with period 20 μm and an index-amplitude grating. The gap between the phase index grating and mail scale was increased to three quarters of Talbot distance. The tolerance of gap between the index and main grating is 0.1 mm. The tolerance of yaw motion is ± 0.25°.

The conventional angular measurement method based on moiré fringe is only competent to measure one-dimensional angle. The grating is replaced by combined horizontal and vertical gratings, therefore the yaw and pitch angles can be measured at the same time by figuring out the displacement of the vertical and horizontal moiré fringe. Moreover, when the main grating is adhered to the mirror which is rigidly attached to the measurement target, the roll angle can be measured by obtaining the width change of the moiré fringe. To validate this improved method, an experimental verification system is set up. The moiré fringe images are captured by a CCD detector, and then the width change and displacement of moiré fringe are obtained using image processing technology. Experimental results indicate that in a view field of ±30' the yaw and pitch angles measurement precision reaches 0.5" and the roll angle measurement precision reaches 1.5".

This paper presents the measurement of the slide error of a large-scale ultra-precision lathe with an effective fabricating length of 2000 mm. A cylinder workpiece with a diameter of 320 mm and a length of 1500 mm was mounted on the spindle of the lathe with its rotational axis along the Z-direction. Two capacitive displacement probes with a measurement range of 100 μm were mounted on the slide of lathe with its moving axis along the Z-direction. The displacement probes were placed on the two sides of the cylinder workpiece over the horizontal plane (XZ-plane). The cylinder workpiece, which was rotated by the spindle, was scanned by the displacement probes moved by the slide. The X-directional horizontal slide error can be accurately evaluated from the probe outputs by using a proposed rotatingreversal method through separating the influences of the form error of the cylinder workpiece and the rotational error of the spindle. In addition to the out-of-straightness error component, the parallelism error component with respect to the spindle axis, can also be evaluated. The out-of-straightness error component and the parallelism error component of the slide error were measured to be 3.3 μm and 1.68 arc-seconds over a slide travel range of 1450.08 mm, respectively.

Rail track geometric parameters, such as gage, level, twist, longitudinal irregularity, and alignment irregularity, etc., have much influence on the operation safety of train vehicles. GJ-4 track inspection car is a large scale dynamic measurement equipment for measuring track geometric parameters precisely and efficiently. It is useful to find track defects, guide track maintenance, and eliminate potential safety problems of track. However the device of measuring gage and alignment irregularity of this track inspection car is installed on a hanging beam, which is not suitable for rapid inspection and has higher failure rate. Hence this sub-system is replaced by the laser-camera method. The rebuild car is named GJ-4G. It greatly eliminates the measurement errors caused by the existing subsystem and increases the measuring stability. The feasibility of this track inspection car has been proven by the practical experiments carried out by Beijing Railway Administration.

Predictive measurement method was proposed for the circular position of time grating CNC rotary table. To reduce the dynamic prediction error and achieve high precision position feedback, this paper analyzes the characteristics of the dynamic prediction error caused by multi-factors of space and time quantity, and then proposes a discrete standard quantity interpolation method for real-time error correction. A dynamic prediction error correction model is established for the circular position of time grating rotary table, and the measured values of time grating are adopted as the standard of predicted values. The last prediction error is corrected in real-time with the current measured values of time grating after current position predicting is conducted. An experimental positioning system is designed to confirm the validity of the proposed methods. The dynamic error of time grating CNC rotary table is ±2", which proves precise prediction is achieved.

An oblate solid cylinder damping material specimen is used to construct three damping systems with three different additional masses. The specimen is excited by an electromagnetic shaker in the vertical direction, and the specimen excites the additional mass vibrating. The damping properties of the damping material change as the additional mass and the exciting magnitude change. Not only the traditional damping properties, such as the damping ratio, the vibration transfer rate from excitation to additional mass, and resonant frequency, but also the nonlinear properties of the damping system with different masses are measured to evaluate the damping specimen. The magnitude-frequency characteristics of vibration transfer rate with different additional masses are measured under constant stable excitation and linear vibration state over a frequency range which includes the resonant frequency of the fundamental mode. The nonlinear vibration transfer properties with different additional masses are measured and investigated under higher vibration magnitude. Experiment results indicate that both linear and nonlinear damping properties of the damping system change as the exciting magnitude and the additional mass change.

A method to accurately measure landmarks of Hanjiangfish fossil based on computer vision is presented. Hanjiangfish is a deracinated vertebrate ever lived on the earth four million years ago. The geometric morphometry of the ichthyolite based on the landmark measurement is fundamental in the vertebrate palaeontology. The landmark measurement is based on digital model of the fossil. The Hanjiangfish fossil is measured fast and accurately by using the structured-light scanning method. The digital model of the fossil then is made from the cloudy data through the acquisition, align, merge, and edit processes. The local least-square method is used to fit two lines near the measured landmark. The landmark is the point of intersection of the two fitting lines, which is unique and accurate. The distance between all pairs of landmarks and interior angles from a triangulation of the landmarks can be measured fast and accurately by the digital model. Other important geometric parameters of the fossil, such as curvature and surface area can also be measured by the digital model. The Hanjiangfish fossil is also measured accurately by a universal tool microscope, which is used as a measuring standard with higher accuracy to validate the proposed method. The experiment shows that the measured errors of the distance and angle are less than 0.1 mm and 1' respectively, which are good enough for geometric morphometry of palaeontology.

An on-line monitoring system for controlling the thickness and the flatness of NdFeB (Neodymium Ferrite Boron) laminate components during the skiving process is reported. The on-line monitoring system mainly consists of a non-contact eddy-sensor, a preamplifier, an A/D conversion card and a computer. The detailed description of the system with respect to the connection between the probe and the grinder is provided. Practical on-line measurement and data acquisition experiments are carried out. Experimental results indicate that the system principle is feasible and the accuracy is up to μm order. The monitoring system can be used to improve conventional grinders that are widely employed currently in China.

This paper describes a computer vision method for reconstruction of three-dimensional object which is capable of reconstructing the profile of the object real time and achieving high accuracy. The approach makes use of the light-section projecting a line-laser beam on the surface of an object. This work is distinguished by three key contributions. The first is the introduction of the light-section method and laser triangulation method. The space coordinates of points in the bright stripe which are considered as the first bright stripe outlining the measured object can be figured out by way of the laser triangulation method. The second contribution is algorithms of coordinate restoration, involved camera calibration and calibration of the central axis of turntable, which restores the space coordinates of the original points in the original bright stripe from that of being considered as the first bright stripe. The third is the profile reconstruction method for plotting the profile of the measured object using the OpenGL. In this paper, an experiment on a small disposal paper cup has been carried out and the three-dimensional profile of the paper cup has been obtained. The results meet the requirement of high accuracy and simplicity of computation.

Rotary parts are used commonly in the field of precision machinery and their roundness error can affect installation accuracy greatly which determines the performance of machine. It is essential to establish a proper method for evaluating roundness error to ensure accurate assessment. However, various evaluation algorithms are time-consuming, complex and inaccuracy which can not meet the challenge of precision measurement. In this paper, an improved area hunting method which used minimum zone circle (MZC), minimum circumscribed circle (MCC) and maximum inscribed circle (MIC) as reference circle was proposed. According to specific area hunting rules of different reference circles, a new marked point which was closer to the real center of reference circle was located from grid cross points around previous marked point. Searched area was decreasing and the process of area hunting terminated when iteration accuracy was satisfied. This approach was realized in a precision form measurement instrument developed in NIM. The test results indicated that this improved method was efficient, accurate and can be easily implemented in precision roundness measurement.

Common profilometers cannot be used to measure the complex surfaces with large range. A cantilever profilometer with large range and high accuracy is presented in this paper. The profilometer is composed of inductive sensors, gratings and angle measurement structure, which are used to measure surface profile, movement displacement and angle of the cantilever beam separately. The angle measured by the invariant light-distance structure based on auto-collimation principle is used to compensate the Abbe error to ensure high measurement accuracy. For counting accurately, a method of resistance chain subdivision is designed to process the grating interference fringe signal. Experiment results show that the Abbe error can be compensate through the invariant light-distance structure based on auto-collimation principle. The designed profilometer can be used to measure complex morphology.

The shape and size of a pocket influences the pressure distribution on the working face of an aerostatic bearing and causes the vibration in normal direction of air gap. In order to analyze the pressure distribution on the working face of an aerostatic bearing caused by the shape of a pocket, an aerostatic bearing restrictor with multi-loop coupling pocket is proposed and double-loop and tricycle forms are taken as examples to illustrate the arrangements of a pocket and analyze the pressure-impedance relationship of a throttle system in different situations. Simulation is done using FLUENT, a computational fluid dynamics (CFD) software, to obtain the pressure distribution on the working face of an aerostatic bearing and the static performance curve with respect to the diameter of an orifice. The comparison between restrictors of aerostatic bearing with or without double-loop coupling pocket shows that the addition of a multi-loop pocket on the working face of an aerostatic bearing contributes to the improvement of surface pressure-averaging effect and static load carrying capability, and the reduction of air film vibration, thereby improving the measurement accuracy. These results are of practical significance for the design of key aerostatic bearing components.

Three kinds of TCC (transmission cross coefficient) calculation algorithms used for partially coherent imaging simulation, including the integration algorithm, the analytical algorithm, and the matrix-based fast algorithm, are reviewed for their rigorous formulations and numerical implementations. The accuracy and speed achievable using these algorithms are compared by simulations conducted on several mainstream illumination sources commonly used in current lithographic tools. Simulation results demonstrate that the integration algorithm is quite accurate but time consuming, while the matrix-based fast algorithm is efficient but its accuracy is heavily dependent on simulation resolution. The analytical algorithm is both efficient and accurate but not suitable for arbitrary optical systems. It is therefore concluded that each TCC calculation algorithm has its pros and cons with a compromise necessary to achieve a balance between accuracy and speed. The observations are useful in fast lithographic simulation for aerial image modeling, optical proximity correction (OPC), source mask optimization (SMO), and critical dimension (CD) prediction.

This paper discusses the influence of ambient temperature and relative air humidity on pepper blade thickness, and establishes theoretical model of these two ecological factors with the changes of pepper blade thickness, on the basis of experiment data of pepper blade thickness, ambient temperature and relative air humidity in 24 hours. The vivo measurement of plant blade thickness with high accuracy is realized using a self-developed precision plant blade monitor instrument. The correlation of the influence of ambient temperature and relative air humidity with the changes of pepper blade thickness is established, analyzed and modeled by controlling other ambient variables. Test results show that the changes of pepper blade thickness and ambient temperature vary inversely, and there is a significant negative correlation between them. However, the change of blade thickness and air humidity show the same trend, and there is a significant positive correlation between them. According to the correlation analysis, the influence model of ambient temperature and relative air humidity with pepper blade thickness is established using multiple linear regression method. Significant test results show that in the period of 0:00A.M.~7:00P.M., pepper blade thickness was significantly influenced by ambient temperature and relative air humidity, while during 7:00P.M.~0:00A.M., the influence was weaker, probably due to the inertia of environment factors and plant's physiological activities. The model of pepper blade thickness can be used to guide the establishment of water-saving irrigation system controlled by blade thickness monitoring.

Planar cross diffraction grating can be adopted to measure displacement as scale. In this paper, Planar grating interferometer configuration for precise displacement measurements is introduced, and the principle of interferometer based on polarization optics is deduced. According to 2-D grating interferometer structure, error sources are analyzed, and the pitch and yaw of 2-D grating guide caused by planar guide's non-linearity is the main factors to decrease the measurement system's accuracy. With grating interferometer error sources analysis, precise planar stage is proposed to integrate with the gating interferometer, the stage is compact and can minimize abbe error in structure. The methods of calibration and error compensation are employed to improve the position accuracy of the stage. As experiments show, the stage position repeatability is less than 0.1um.

In order to solve the contradiction between wide scope and high precision of coordinate measurement, a new coordinate measurement method based on coding target and vision measurement is proposed. According to the holographic characteristic of coding target, the position and orientation information of coding target can be obtained by any section of coding image on the target, then the position of the target probe can be obtained and coordinate measurement is realized. Two CCD cameras gather target coding image from two right-angled orientations and measurement model is established according to the spatial geometric relation. Special coding target is designed and the parameters acquisition method of coding target is studied. Experiments testify the coding target is designed rationally, and the coordinate measurement method based on coding target is established credibly. The system enlarges the measurement range with the measurement accuracy satisfied.

With the development of the machinery industry and the enhancement of the components precision, the large internal micrometer with three-point contact broadens its field of application. However, the calibration method for large internal micrometer with three-point contact has not been solved completely. In order to solve all the calibration problems for large internal micrometer with three-point contact of 100mm and above, this paper proposes a new calibration method. Different from that of the calibration criterion JJF1091-2002 in Micrometer for Measuring inside Dimension, this method mainly uses the high precision CMM to calibrate the internal micrometer with three-point contact. The procedures are as follows. First, use the CMM to scan and measure the internal micrometer with three-point contact. Next, make the evaluation of scanning point with the method of the maximum circumcircle to get the CMM measurements of the internal micrometer with three-point contact in different diameter positions. Second, use the internal micrometer with three-point contact to measure any standard ring gauges within its measuring range to get the indicating value which is also named as reference point indicating value. Third, analyze the diameter value got by using the CMM to measure the internal micrometer with three-point contact in different positions and the reference point indicating value. After data processing, the error of indication in different positions can be got. Last, analyze the uncertainty of measurement to test its feasibility.

In accordance with the principle of Three-Line, this paper analyze the correlation of every main parameter of internal screw thread, and then designed a device to measure the main parameters of internal screw thread. Internal thread parameters, such as the pitch diameter, thread angle and screw-pitch of common screw thread, terraced screw thread, zigzag screw thread were obtained through calculation and measurement. The practical applications have proved that this device is convenience to use, and the measurements have a high accuracy. Meanwhile, the application for the patent of invention has been accepted by the Patent Office (Filing number: 200710044081.5).

An image segmentation method is proposed to locate the position of laser spots reflected by corner-cube array during relative attitude determination between aircrafts. First, the laser spots image acquired by CCD camera is transformed to a grayscale gradient distribution image by the Roberts operator. Then the image is divided into several small pieces according to the distribution of both energy and grayscale gradient. Each piece is segmented based on watershed algorithm individually to detect the margin of laser spots. Seeds of watershed segmentation are selected by using prior knowledge of appearance and energy of laser spots predicted when the laser measure system is designed. A binary image which contains the edge information of the laser spots is acquired after all segmented pieces is merged together. Then expansion and erosion algorithm is used to reduce the effect of over segmentation. The method can effectively remove the system noise or the disturbance brought by the reflection of the other optical antenna near the corner-cube array on the client terminal. Experimental results indicate that location of laser spots calculated by centric method is exactly limited in the anticipated area. The uncertainty of the center location is no more than 1 pixel.

This paper presents a measurement method used to precisely measure the diameter of water jet. A He-Ne laser is coupled into the water jet as the light source, and the image of the water jet is captured by a CCD. The diameter of water jet can be thus measured from the captured images by such processing as sharpening, filtering, subpixel locating and fitting. Experimental results indicate that the proposed method can be used to make real-time measurement of the diameter of water jet with a simple and low-cost set-up. The method can also be used to measure the break-up length of water jet by introducing a microstage along the direction of water jet.

A novel micro-tribometry system has been developed specifically for investigating whether the limited dynamic response of conventional instruments might hide functionally important materials behaviour. It is based on a universal measuring head, suitable for use with a wide range of specimen stages, that incorporates a relatively stiff elastic sensing element and actively-controlled electromagnetic force actuation in both axes. This paper first reviews the rationale for the new design and then explains the critical design features. Characterization and calibration are discussed: the prototype unit is aimed primarily at use in the 10 - 50 mN, with a bandwidth of at least 100 Hz. The basic operation and capabilities of the micro-tribometer head are presented by means of demonstration experiments on smooth and relatively rough surfaces.

This paper discusses the aspects that influence the interaction between a probe tip and a work piece during tactile probing in a coordinate measuring machine (CMM). The trend of component miniaturization results in a need for 3- dimensional characterization of micrometer sized features to nanometer accuracy. As the scale of the measurement decreases, the problems associated with the surface-probe interactions become increasingly apparent. The aspects of the interaction that are discussed include contact forces, surface forces, tip rotations, finite stiffness effects and probe repeatability. These aspects are investigated using the Gannen XP 3D tactile probing system developed by Xpress Precision Engineering using modeling and experimental verification of the effects. The Gannen XP suspension consists of three slender rods with integrated piezo resistive strain gauges. The deformation of the slender rods is measured using the strain gauges and is a measure for the deflection of the probe tip. It is shown that the standard deviation in repeatability is 2 nm in any direction and over the whole measurement range of the probe. The probe has an isotropic stiffness of 480 N/m and a moving mass below 25 mg. Finally, the TriNano CMM will be discussed. This novel coordinate measuring machine is designed for measuring three dimensional micro features with nanometer uncertainty. The TriNano has a kinematic and highly symmetrical design based on three parallel axes and obeys to the Abbe principle in its entire measurement volume.

A novel method to observe pH distribution by dual wavelength fluorescent ratiometric pH measurement by scanning near-field optical microscopy (SNOM) is developed. In this method, in order to investigate not only the pH of mitochondrial membrane but also its distribution in the vicinity, a pH sensitive fluorescent reagent covers mitochondria instead of injecting it to mitochondria. This method utilizes a dual-emission pH sensitive dye and SNOM with a themally-pulled and metal-coated optical fiber to improve the spatial resolution. Time-dependence of Fluorescent intensity ratio (FIR) under acid addition is investigated. As the distances between the dropped point and the SNOM probe becomes closer, the time when FIR changes becomes earlier. The response of mitochondria under supplement of nutrition is studied by using this method. While the probe is near to mitochondria, the ratio quickly becomes to increase. In conclusion, it was confirmed that the temporal variation of pH can be detected by this method, and pH distribution in the vicinity of mitochondria is able to be measured by this method.

Micro cavities with high aspect ratio are widely used in different fields including aerospace and defense industries with the development of manufacturing technology. So how to measure the dimension of these cavities has become one of the major research subjects in the field of measurement and instrument. This paper describes some activities of the precision micro cavity measurement technique in Center of Ultra-precision Optoelectronic Instrument (UOI), Harbin Institute of Technology (HIT). The key issue of micro cavity measurement in UOI is called touch-trigger measurement method. The first scheme is double optical fiber coupling, in which light coming from the incident optical fiber is transmitted in the reversal direction via the optical fiber coupling into the effluent optical fiber, the lateral displacement of the touch-trigger sensor is transformed into the deflexion of light coming out from the effluent optical fiber, and the deflexion is transformed into an image signal by the object lens and CCD capturing system. And the second scheme is micro focal-length collimation, in which a fiber stem with a ball mounted on its end is used as a probe and a small segment of it is used as a cylindrical lens to collimate a point light source and image it to a camera, the deflection of the fiber stem can be inferred from the change in image acquired by the camera with ultrahigh displacement sensitivity. Experiments for these activities will be given with a focus on the measurement results and repeatability uncertainty.

In order to improve the small range and poor dynamic performance of a flexible tilting mirror system for rapid compensation of laser beam directional stability offset error, a direct adjustment method is constructed by means of a translational spectroscope, which fixed on a piezoelectric actuator, to steer the laser beam to the collimating state, and to compensate for the displacement offset and angular offset of laser bean respectively. This method reduces the flexible rotation link in-between, avoids the backlash and lags error of friction and elastic deformation, and simplifies their control modes for the compensation process, thereby improving the control accuracy and dynamic performance of adjustment system. Experimental results show that, the tilted reflecting plane of the spectroscope can be used to steer the laser beam to the valid positions within the adjustment range up to 100μm, to compensate the offset error of the laser beam, or to compensate the vibration of laser source and the tilt error of detector installation, its control bandwidth above 100Hz. These results suggest this method can provide an effective solution for rapid precision collimation and compensation.

Phase-locked frequency multiplying technology is utilized to amplify 10MHz signal to 640MHz. Pulse inhibition method is then exploited to make high-frequency signal have a phase shift of 2π. 20MHz signal with 2π / 32 phase shift is output after 5 times flip frequency division. In order to optimize electromagnetic compatibility, signal integrity and power integrity of a high-speed circuit, system simulation is performed using HyperLynx, a specially EDA simulation software. A whole printed circuit board (PCB) was made under the guide of optimized simulation results. Phase-shift experiments show that the output of high-frequency phase-shifting circuit system is two-way signals with a frequency of 20.0001 MHz with 1.8ns time difference, i.e. two signals with 12.96°phase difference are obtained.

We have been developing a new technique for measuring urine glucose concentration using near infrared spectroscopy (NIRS) in conjunction with the Partial Least Square (PLS) method. In the previous study, we reported some results of preliminary experiments for assessing feasibility of this method using a FT-IR spectrometer. In this study, considering practicability of the system, a flow-through cell with the optical path length of 10 mm was newly introduced. Accuracy of the system was verified by the preliminary experiments using urine samples. From the results obtained, it was clearly demonstrated that the present method had a capability of predicting individual urine glucose level with reasonable accuracy (the minimum value of standard error of prediction: SEP = 22.3 mg/dl) and appeared to be a useful means for long-term home health care. However, mean value of SEP obtained by the urine samples from ten subjects was not satisfactorily low (53.7 mg/dl). For improving the accuracy, (1) mechanical stability of the optical system should be improved, (2) the method for normalizing the spectrum should be reconsidered, and (3) the number of subject should be increased.

The design of optical and electronic parts of multimatrix measuring modules is presented. Four optical channels in optical scheme are used. Correction algorithms for sensitivity and mutual declination of matrix photo detectors are presented. The practical realization of multimatrix measuring module is presented.

According to the durability testing principle, an open, high intelligent and practical durability testing system was designed. In this system, various sensor signals and executive loads of the engine are provided to simulate the on-line environment of a real vehicle for ECU. Though the CAN based communication network, the monitor card sends the testing data to the management software, and the durability testing report is automatically generated for developers. This system greatly reduces the testing cost and shortens the development cycle.

Accurate calculation of the moment of inertia of an irregular body is made difficult by the large number of quantities. A popular method is to use a trifilar suspension system to measure the period of oscillation of the body in the horizontal plane. In this paper, an instrument for measuring the moment of inertia based on trifilar pendulum is designed; some sources of error are discussed; three metal disks with known moments of inertia are used to calibrate the instrument, the other metal disks with known moments of inertia are used to test the accuracy of the instrument. The results are consistent when compared with calculated moment of inertia of the metal disks. In addition, the instrument could be used to measure the moment of inertia of other irregular objects. The period of oscillation is acquired by the capture mode of MSP430 microprocessor, the mass is obtained by the Electronic Balance and the data is transferred to the MSP430 via serial port.

Magnetic-levitation (maglev) positioning stage is a system with complex nonlinear, strong coupling and low damping. This research focused on the control algorithm and the effect of eddy current damper applied to the system which consists of a moving table, four Halbach permanent magnetic arrays, four stators and displacement sensors. All of the magnetic arrays are fixed to the bottom of the moving table. To avoid the occurrence of oscillation while the stage is being positioned, a permanent magnet set which served as an eddy current damper was added to the system; and it is proved through theoretical analysis that the damping force generated by the eddy current damper is proportional to the movement speed of the table. A motion control mathematical model including the segment of an eddy current damper was built, and the nonlinear controller of the system was given based on the theory of differential geometry decoupling. Simulation results show that decoupling control of movement the moving parts can be realized in horizontal and vertical directions.

This paper presents a novel piezodriven X-Y stage utilizing flexure hinges. Levers of high amplifying rate were adopted to magnify the output displacement of the piezoelectric actuator and a complex parallel four-bar mechanism was used to guide the mobile platform. In order to describe the static and dynamic behaviour of the stage, an analytical model was built and a series of formulae were deduced. Based on mathematical analysis, the configuration of the stage was optimized. Then Finite Element Analysis was applied to analyze travel ranges, natural frequencies and stress distribution. The simulation computation results demonstrate that the stage could reach a motion range of 200mby 200m and has a first order natural frequency of 265 Hertz, which is of good concordance with the theoretical estimate. Now a prototype is being fabricated.

To break through the limitations of static and dynamic characteristics of conventional step motor driven open-loop positioning devices, a two-dimensional precision positioning system with a travel range of 100mm×100mm has been developed. This paper presents its structure, control principle and performance experiments. This system, equipped with cross roller guides working as linear guiding elements, is driven by step motors through ball screw transmission. A threeaxis dual-frequency laser interferometric measurement system is established for real-time measurement and feedback of system's movements in three degrees of freedom (DOF) and an intelligent Fuzzy-PID controller is implemented for this system's motion control. In the controller, the PID module calculates the output from motor drivers and its initial parameters are tuned through expansion of critical proportioning method; the Fuzzy module optimizes PID parameters to fulfill specific requirements of different movement stages. A dead zone control mechanism is developed in this controller to minimize the oscillations around target position. Experimental results indicate that system with Fuzzy-PID controller shows faster response than that with ordinary PID controller. Moreover, with this controller implemented, the developed precision positioning system achieves better repeatability (±2μm) and accuracy (±2.5μm) within the full range than open-loop system using step motor.

This paper presents a DSP and FPGA based 4-axis motion controller, which use host PC as the platform. By adopting the strategy of two stage interpolation, the proposed motion controller supports 2-axis circular interpolation and 3-axis linear interpolation, and its maximum output pulse frequency of each axis can be up to 8 MHz. The controlling algorithms, such as improved coarse interpolation based on the time division principle, T-curve and S-curve velocity profile generation and the error compensation for the position loop, are implemented by DSP to ensure the high performance of the proposed motion controller. Meanwhile, the FPGA integrates PCI bus controller, dual port RAM, second-stage interpolation, encoder feedback logic circuit etc., which allows a flexible, compact, low-cost solution for various applications. Experimental results demonstrate that the presented motion controller features the merits such as the good real-time performance and high machining precision, and it can be used for a wide range of applications in numerical control system.

A precise translation stage is important for surface topography measurement based on scanning method, for it provides precise measurement datum and accurate positioning of scanning points. In this paper, a 2-D coplanar translation stage with synchronous XY position metrology is developed for surface scanning measurement. The mechanical structure of this stage is designed to translate along X and Y directions based on a common plane, which improves the movement flatness of the sample table. For higher precise 2-D positioning metrology, a novel double cross diffraction grating measurement system is proposed, by which the XY position of the sample table can be measured synchronously.

A multi-component Fourier Transform InfraRed (FTIR) gas analyzer with a low spectral resolution (8cm^-1) is described in this paper. The hardware of this analyzer is consisting of a rugged Fourier Transform Spectrometer (FTS), an uncooled pyroelectric Deuterated L-Alanine TriGlycine Sulfate (DLATGS) detector, a glass body long-path gas cell and relevant sampling devices. The transplantable software and algorithms include the building of spectral library from the free sources such as EPA, NIST, HITRAN etc, identification of spectrum components and a modified classical least square regression with automatic baseline compensation. In order to validate this system, we implemented a continuous on-line experiment using the 55 μmol·mol^-1 methane and 28 μmol·mol^-1 nitrous oxide standard mixtures. The experimental results show this low resolution analyzer has accuracy and robust analysis abilities. The description in this paper is helpful to facilitate the development of a FTIR multi-component gas analyzer.

An operational amplifier-based micro eddy current sensor circuit is developed for improvement of sensitivity, reduction of power consumption and application in small mounting space. An eddy current sensor is designed on the optimized parameters in this circuit. Meanwhile, an eddy current sensor static calibration system is built by comparing to the measurement unit of Switzerland TESA Inductance Sensor TT80 of high resolution. Simulation and experimental results show that the eddy current sensor has a high sensitivity, low power consumption and is capable of measuring a limited space. Also, the eddy current sensors are mounted in the honing head, and the feasibility of in-process inspection of parts being honed on the inner diameter have been verified in the Abrasive Machining (Honing).

A resonance frequency of 8.9MHz copper Interdigital Transducer (IDT) is fabricated on a 127.8°YX type LiNbO₃ substrate by lift-off process and the rapid droplet mixing is experimentally realized using the surface acoustic wave(SAW). The droplet mixing principle and the manufacturing process of the mixer are illustrated in detail. The droplet generates one swirl when only portion of the droplet is located on the saw propagating surface. The droplet generates two swirls when the whole of droplet is located on the saw propagating surface. The mixing between red particles with an average diameter of 1.5μm and a droplet with a volume of 3 μl is successfully implemented. No matter the droplet covers whole or just partly the saw propagating surface, the mixing process can be completed in one second when the applied driving power is 9W. The applications of SAW micro fluidics should be greatly enhanced using the rapid mixing process proposed in this paper.

In order to enlarge the measurement range of the monocular vision measurement system, enhance its measurement precision in depth direction, and realize the accurate measurement of large-scale equipement, a 3D mosaic method based on assistant target is proposed in this paper. By using the image of an assistant target in two adjacent measuring positions, on the basis of matching the images of feature points and epipolar constraint, it quickly computes the orientation and translation transform between the two adjacent measuring positions through linear algorithm and LM iteration method, and the scale factor of the translation is calculated from the distances between the feature points on the assistant target. At last, the measurement data in the local coordinate systems of different measuring positions can be transformed to the global measurement coordinate system with the transformation between the two adjacent measuring positions, and the three-dimensional mosaic of the measurement data is realized. This method overcomes the problem that the precision of the feature point three-dimensional coordinates in different coordinate systems seriously affects the mosaic accuracy. The experiment result proves that the proposed method is flexible and valid, and not only enlarges the measurement scope, but also raises the measurement precision for large-scale equipement.

A new technique is demonstrated for measurement of modulation transfer function (MTF) on image sensor arrays. Fourier analysis of a low frequency bar target pattern is used to extract MTF at odd harmonics of a target pattern frequency up to and beyond Nyquist. The technique is particularly useful for linear image arrays (either conventional linescan or time-delay- integration devices) where conventional slanted-edge technique is not always applicable. The technique is well suited to simple implementation and can provide live presentation of the MTF curve, which helps to ensure optimal alignment conditions are achieved. Detailed analysis of the technique and demonstration of experimental results are presented.

Electrical capacitance tomography (ECT) is a new technology for testing parameters of solid-air two-phase flow during the past decades. The key technique of ECT is the fast and accurate image reconstruction. In this paper, the principle and measuring process of ECT were elaborated, the reconstruction algorithm called generalized vector sampled pattern matching (GVSPM) method was used in two-phase flow particle concentration visualization. GVSPM method achieves accurate reconstruction by using an objective function that is calculated as the inner product calculation between the experimental capacitance and the reconstructed image capacitance. Mathematica simulation results showed that this method proved superior in the three parameters of capacitance residual, image error and image correlation, compared with the linear back projection (LBP) method. Using the GVSPM method, the "soft-field" effect and the ill-posed inverse problem in ECT technology can be effectively conquered, meanwhile, the reconstructed image has the advantages of high spatial resolution and low distortion.

A method based on white-light Michelson interferometer for measuring the retardation of multiple-order wave plates is presented. The linear polarized white-light splits into o-beam and e-beam by the test multiple-order wave plate which introduces retardation between the two beams, and then they are divided by a beam splitter and reflected by two plane mirrors in the Michelson interferometer respectively. Finally three white-light interference packets are formed. According to the optical path between the center packet and one of the side packets, the retardation can be obtained. The retardation of a multiple-order wave plate is measured in the experiment, whose result (2990.6nm) coincides with the one obtained by spectroscopic method (2992.8nm).

Start-stop torque is one of the key parameters of valve's capacity. In China, a torque spanner is used to measure the small-bore torque, but the accuracy is not very high. In the large-bore situation, the previous method can not be used to measure the torque, so the torque is determined by the design calculation result. Sometimes this result is far from the practical one, and the difference will impact the apolegamy of the actuating device of a valve. Some other methods, such as inductance type transducer valve torque sensor, strain gauge valve torque sensor, appeared. They both have the advantage of high accuracy, but their automatic level is low and their measuring equipments are complex. In this paper, a new style torque measuring device which is based on theory of mechanics of materials and measuring principle of strain gauge is designed. The maximal torque is 2000Nm. The measuring device is easy for installation, accurate on results, and is able to meet the actually online measuring demands.

The wavelength readout system reported in this paper is chiefly constructed of fiber Fabry-Perot tunable filter (FFP-TF), data acquisition card and a virtual instrument with programmable NI Labview. By combining the dynamic scanning of FFP-TF in C waveband (1520nm-1570nm) with 50nm free spectral range (FSR) and 4000 standard finesse value, the wavelength of a tested laser diode (LD) could be detected accurately, while the spectrum is displayed on line with the help of a virtual instrument to make the spectroscopy quick analysis possible. Furthermore, the scheme can also be applied for wavelength interrogation in fiber Bragg grating (FBG) sensing system. Considering the practibility and economical efficiency of such a system, it will be of great significance to adopt such a wavelength readout system in fiber sensors used for construction, mining, aerospace,etc.

Electro-magnetic acoustic detection technique has become a new development trend of nondestructive testing because of its high detection efficiency, accurate detection results, etc, so it now has been widely adopted in the railway department of our country. When the signal is detected using electro-magnetic acoustic detection technique, the influence of the poor condition of wheel surface, the existing electromagnetic interference and other factors will enable different levels of noise to exist in the detected signal, which will affect the signal quality, thereby reducing the detection accuracy. After introducing the structure and principle of electro-magnetic acoustic detection system, this paper has put forward two noise suppression algorithms for the noise problem of the detection signal, namely, phase difference algorithm and adaptive filtering algorithm. On the premise of reserving the necessary signal waveform of system, the algorithms can effectively suppress the noise of a detected signal, improve the quality of a data waveform, and obtain good detection results. The paper also compares two algorithms and points out that the better detection accuracy can be obtained if combining the two algorithms. This work has certain inspiration to raise the accuracy of electro-magnetic acoustic detection results.

The surface topography of automotive steel plate is decisive to its stamping, painting and image clarity performances. For measuring this kind of surface topography, an instrument has been developed based on the principle of vertical scanning white light microscopy interference principle. The microscopy interference system of this instrument is designed based on the structure of Linnik interference microscopy. The 1D worktable of Z direction is designed and introduced in details. The work principle of this instrument is analyzed. In measuring process, the interference microscopy is derived as a whole and the measured surface is scanned in vertical direction. The measurement accuracy and validity is verified by templates. Surface topography of textured steel plate is also measured by this instrument.

Low frequency time-code timing service is an important mode in the modern timing system, and it is actively commended by International Telecommunications Union (ITU). Low frequency time-code timing radio station (BPC) is built by National Time Service Center in China. The BPC broadcasts are used by millions of people to synchronize consumer electronic products like wall clocks, clock radios, and wristwatches. In addition, BPC is used for high level applications such as network time synchronization and frequency calibrations. Based on the modern signal characteristic of low frequency time-code of BPC, the additional spread spectrum modulation timing method in idle carrier wave is presented. A new structure of signal modulation is expatiated. The rationale of the additional spread spectrum modulation timing method in BPC is researched. The performance of a new system error is analyzed. The research results indicate that the anti-jamming performance can be improved by the additional spread spectrum modulation timing method in BPC, and low frequency time-code timing service can then be used broadly.

Electrical tomography (ET) aims at the study of the conductivity/permittivity distribution of the interested field non-intrusively via the boundary voltage/current. The sensor is usually regarded as an electric field, and finite element method (FEM) is commonly used to calculate the sensitivity matrix and to optimize the sensor architecture. However, only the lumped circuit parameters can be measured by the data acquisition electronics, it's very meaningful to treat the sensor as a multi terminal network. Two types of multi terminal network with common node and common loop topologies are introduced. Getting more independent measurements and making more uniform current distribution are the two main ways to minimize the inherent ill-posed effect. By exploring the relationships of network matrixes, a general formula is proposed for the first time to calculate the number of the independent measurements. Additionally, the sensitivity distribution is analyzed with FEM. As a result, quasi opposite mode, an optimal single source excitation mode, that has the advantages of more uniform sensitivity distribution and more independent measurements, is proposed.

with emphasis on the process of design and development method for the intelligent flexible structure distributed with orthogonal Fiber Bragg Grating sensor array, a fitting and reconstruction method based on orthogonal curvatures for three-dimensional curve and a method to make discrete curvatures continuous are analyzed with detailed algorithm processes and implementation steps in this paper. On the basis of the experimental calibration analysis with FBG model structures, a real-time apperception and reconstruction platform of intelligent flexible structures for analyzing and verifying the methodology and processes of the algorithm is developed with the technology of Visual C++ and OpenGL. The academic methodology and implementation technique are analyzed experimentally in the visualization platform. It reflects more accurately the real-time changes of intelligent flexible structures by employing an intelligent structure based on FBG as an experiment model. Experimental results prove the feasibility of the model design and the effectiveness of the three-dimensional reconstruction algorithm.

With the improvement of living standard, the incidence of diabetes increases year by year. Minimally invasive blood glucose monitoring is an effectively way to control diabetes, and it is achieved by measuring the glucose concentration of interstitial fluid in human body. This paper presents a portable minimally-invasive human glucose detection instrument which is based on a miniature integrated surface plasmon resonance (SPR) sensor. D-galactose/D-glucose Binding Protein (GGBP) which can specifically absorb glucose moleculars is used to modify the gold surface of SPR sensor for higher sensitivity and stability. The instrument includes an interstitial fluid extraction unit, a liquid flow unit, a SPR sensor unit and a circuit control unit. Interstitial fluid is extracted from human body using the interstitial fluid extraction unit, and it is then transported to the SPR sensor by the liquid flow unit, and the SPR sensor can detect the glucose concentration in the interstitial fluid. The acquisition and process of data is controlled by the circuit control unit, which controls the operation of the whole system as well. The glucose detection resolution could reach 6.25mg/L, and the experiment result has good linearity when the glucose concentration ranges from 6.25mg/L to 50mg/L.

The Long Trace Profiler (LTP) is a precision surface slope error measurement instrument used in synchrotron radiation optics for many years. By making some modifications to the LTP system, we developed a co-path scanning LTP (CSLTP) system to test the cylindrical aspherical surface which used in X-ray space optics. To reduce the mistake caused by air turbulence and manufacture faults of optical elements used, the CSLTP is designed with the least difference between the testing beam path and the reference beam path. Also, it uses multiple-beam interference but double beam interference to reduce the width of beam fringe. This improves the position precision of the beam fringe on the image plane.

To better understand the response and damage characteristics of structures under earthquakes, a great number of intelligent seismic sensors with high performance were needed to be installed distributed in the whole country. The intelligent seismic sensor was a cost-sensitive application because of its large number of usages. For this reason, a low cost intelligent seismic sensor was put forward in this paper. This kind of intelligent seismic sensor cut down the cost without sacrificing performance by introducing two three component MEMS accelerometers. It was composed by a microprocessor, two three component MEMS accelerometers, an A/D converter, a flash memory, etc. The MEMS accelerometer has better structure and frequency response characteristics than the conventional geophones'. But one MEMS accelerometer tended to be unreliable and have no enough dynamic range for precision measurement. Therefore two three component MEMS accelerometers were symmetrically mounted on both sides of the circuit board. And their measuring values were composed to describe the ground motion or structure response. The composed value was the in-phase stacking of the two accelerometers' measuring values, which enhanced the signal noise ratio of the sensor and broadened its dynamic range. Through the preliminary theory and experiment analysis, the low cost intelligent seismic sensor could measure the acceleration in accuracy.

A new kind of 3D measurement system has been developed to achieve the 3D profile of complex object. The principle of measurement system is based on the triangular measurement of digital fringe projection, and the fringes are fully generated from computer. Thus the computer-generated four fringes form the data source of phase-shifting 3D profilometry. The hardware of system includes the computer, video camera, projector, image grabber, and VGA board with two ports (one port links to the screen, another to the projector). The software of system consists of grating projection module, image grabbing module, phase reconstructing module and 3D display module. A software-based synchronizing method between grating projection and image capture is proposed. As for the nonlinear error of captured fringes, a compensating method is introduced based on the pixel-to-pixel gray correction. At the same time, a least square phase unwrapping is used to solve the problem of phase reconstruction by using the combination of Log Modulation Amplitude and Phase Derivative Variance (LMAPDV) as weight. The system adopts an algorithm from Matlab Tool Box for camera calibration. The 3D measurement system has an accuracy of 0.05mm. The execution time of system is 3~5s for one-time measurement.

An Offset Generator with low noise floor has been developed by Time & Frequency Measurement & Control Department, NTSC. The Offset Generator is designed with Phase Lock Loop, and the +100Hz offset is generated in the output stage. The Allan deviation noise floor of the Offset Generator is 1x10^-12 at 1 second. The Offset Generator has been installed in "Digital Multi-Channel Frequency Stability Analyzer" (DFSA), developed by Time & Frequency Measurement & Control Department, NTSC, too, and the Allan deviation noise floor of DFSA using current Offset Generator is about 4x10^-14 at 1 second and <1x10^-15 at 1000 second.

The rapid development of electronic products today, it is a very important part of that electric shock prevention remains the safety design of electronic products. When unplug the electrical equipment, the voltage in each pin of the plug is residual voltage. If residual voltage is too large, it may cause harm to human body, must attach importance to it and precisely measure it. Load of different electrical products lead to different transient voltage changes in sudden power-down, namely the changes in the residual voltage. In this paper, the load on the electrical equipment on the basis of type classification, focusing on the design of their corresponding capacitive load and peak power detection circuit link was simulated, thus arrive at the variation discipline of residual voltage, in order to better protect human safety.

A novel method for measurement and evaluation of cylindricity error is presented. The surface data of a workpiece can be measured from different views using digital fringe projection profilometry, and these data can be connected accurately using multi-aperture overlap-scanning connection technique. Thus all surface data of a workpiece can be obtained. The proposed method offers such advantages as non-contact, high efficiency and whole-field information. It can also be used to effectively overcome the axial undersampled problem with reference to the existing cylindricity measurement method. On the basis of new GPS, verification operators used for cylindricity error evaluation are constructed. The accuracy and reliability of cylindricity error evaluation can be ensured with the standard and optimal operation process. The validity and performances of cylindricity error measurement have been investigated through experiments.

With the increase of the number of IP cores integrated in SOC, the functions of SOC are becoming more complexed. Test time and test cost grow rapidly, therefore it becomes bottleneck of SOC test. Test scheduling is one of the efficient approaches to solve the forenamed question. Cross-entropy method, which is based on probability density function, has been used to solve the SOC test scheduling problem. Experimental results on ITC'02 benchmarks show that the proposed method provides better test time results compared to the Linear-Programming.

In order to analyze the resolution of variable fiber optic attenuator (VOA) instrument using digital micromirror device (DMD) precisely, the optical system of VOA is optimized and analyzed using Zemax to obtain the effective distributions of incident Gaussian beam (inside 1/e² Gaussian beam waist region) on the DMD. The beam is then divided into three power attenuation zones P₁, P₂ and P₃ using two cutoff normalized weight levels W₁ and W₂ for the DMD spatial samplers to arrive the desired high power attenuation resolution. C-Lens is also used as collimator to improve the working distance and decrease the insertion loss. Numerical simulation results indicate that the average power attenuation resolution is 5.072mdB, 3.811mdB and 0.674mdB respectively when the power attenuation percentage is 34.70%, 31.46% and 33.76% for P₁, P₂ and P₃ respectively. The study can be used to VOA test instrument applications.

In order to measure the attitude angles of our ultrasonic motor, a compact single stator multi-degree-of freedom (DOF) ultrasonic motor with a cylindrical stator and a spherical rotor is designed with one OEM encoder and 2D PSD (Position Sensitive Detector) sensor. The spherical rotor is rotated around three perpendicular axes by three natural vibrations excited on the stator. The OEM encoder disc is fixed on the rotor output shaft to measure the rotational angle of the output shaft. The PSD sensor is installed in loading sphere, and one LED is installed in the LED house, the line light emitted by the LED transmits along the output shaft axis and passes through the center of the spherical rotor, and then projects on the PSD surface, and the PSD and LED comprise the device to measure the pitch and roll of the rotor. The output current signals of the PSD sensor are changed into voltages, amplified by measuring circuits, converted into digital signals, and are transmitted to MCU. The attitude angles of the motor are calculated out using the proposed algorithm. The compact structure design of the motor makes the measurement of the attitude angles of the multi-DOF ultrasonic motor more practical and convenient.

A laser beam with an ideal wavefront passes through a random amplitude mask to produce speckle fields. The speckle fields then illuminate the measured lens and are modulated by its shape to further scatter the speckle fields. The shape of the lens can be measured from the sequential intensity measurements of volume speckle field and phase retrieval based on angular-spectrum propagation technique. The curvature radius of the lens is directly derived from the shape function. In comparison with the existing measurement methods, the method proposed has a simple set-up, a strong environmental anti-interference capability and a low cost. Experimental results indicate that the proposed method is an effective approach which can be used for the measurement of radius at low cost.

In this paper, a precision measuring device is developed for obtaining characteristic curve of tire profile and its geometric parameters. It consists of a laser displacement measurement unit, a closed-loop precision two-dimensional coordinate table, a step motor control system and a fast data acquisition and analysis system. Based on the laser trigonometry, a data map of tire profile and coordinate values of all points can be obtained through corresponding data transformation. This device has a compact structure, a convenient control, a simple hardware circuit design and a high measurement precision. Experimental results indicate that measurement precision can meet the customer accuracy requirement of ±0.02 mm.

This paper presents the absolute measurement of free form surface based on the use of interferometric technique to obtain the absolute height of surface, which utilizes the interference fringe obtained with an interferometric microscope to locate the points of surface and obtain the height information through a three-dimensional displacement stage. A theoretical model is established for this method based on the response of interference microscope to identify the main influence factors through analysis. A measurement system is developed based on a three-dimensional stage and a Linnik interference microscope. As the key operative part, the stage has two-grade positioning accomplished by a vertical scanning displacement function mechanism with a laser interference measuring system and driven by a servo-motor and a piezo-electronic transducer respectively. Performance tests show the stage meets the requirements for the measurement of large range surface according to the zero-order interference fringe tracing measurement method. Experimental results show that the measurement system has a vertical range of 8mm, vertical resolution of 0.002μm, and a repeatability error of less than 5%.

Double parallel-joints coordinate measuring machine (CMM) is a new type of coordinate measuring devices. In this paper, measuring principle and basic structure of double parallel-joints CMM are introduced at first and then total error sources that influence the measuring accuracy are analyzed. The possible accuracy of error sources correction is analyzed and the total error of the instrument is calculated. The error distribution is presented on the basis of accuracy design of the instrument. The error distribution is simulated and the error distribution law of the instrument is summarized. The accuracy analysis and the structure design of the instrument are guided by the research in the paper, and the solid theoretical basis is provided by the error correction to achieve the accuracy indicators of double parallel-joint CMM. The tasks accomplished in this thesis will be provided as a solid foundation for developing double parallel-joint CMM with our own intellectual properties and it will be accuracy higher and cost lower than the currently existing imported CMM.

In the article, an in-situ 3-D microscopic surface profilometer employing novel lateral confocal scanning principle, also called V-scan lateral confocal microscopy (VLCM), was developed to achieve in-field measurement with an effective vibration-resistance capability. The developed methodology combines digital structured fringe projection, lateral confocal scanning, shape from focus (SFF) and anti-vibration technique to perform lateral scanning for in-situ 3-D surface measurement. For microstructures having low reflectivity and high-slope surfaces to be measured within in-field process environment, it has been recognized as a great challenge for achieving accurate 3-D surface inspection. To overcome this, the presented method employing a new lateral confocal scanning strategy in combining a Z-axis vertical scanning with a horizontal X-axis scanning simultaneously, in which the scan pattern is similar to a V-shape. Meanwhile, to detect potential environmental vibration, a laser fiber interferometric positioning sensor based on heterodyne interferometry is employed to detect potential vibratory displacement between the optical probe and a tested surface for minimizing environment disturbance encountered in a real factory. A depth response curve is constructed by a series of images detected from successive depths during the V-scan lateral scanning. Potential vibration errors can be effectively detected by a fiber optic interometric positioning sensor and compensated simultaneously. A standard step-height target and several industrial V-groove microstructures have been measured to attest the measurement accuracy and feasibility of the developed approach. From the experimental results, it is confirmed that the depth resolution can reach 0.1 μm and the maximum measurement error can be controlled within 3% of the overall measuring height.

The axial beam scanning in confocal microscopy has been implemented using liquid crystal spatial light modulator (LC-SLM). A zoom illuminating lens is realized by introducing LC-SLM into the confocal illumination light path, and thus it shifts the focus of the objective lens axially. The axial optical sectioning in a conventional confocal microscope is hereby achieved by beam scanning rather than mechanically moving the objective lens. The axial focus shift of the objective lens is realized by changing the modulation phase bitmaps of LC-SLM. By electrically controlling LC-SLM, it has been demonstrated that the focus can shift in the axial direction continuously over a 100μm range, while the FWHM of the focal spot keeps the same as that without LC-SLM. Experimental results further show that the axial intensity curves shift axially in confocal microscopy and confocal axial beam scanning replacing mechanical scanning can therefore be implemented.

The resolution of the current length grating measuring system can reach micron level, sub-micron level and nanometer level. Researching and producing the high-resolution and high-preciseness length grating measuring system is the development tendency of measuring technology, while the high-preciseness length grating measuring system also has wide application prospects. In the practical application of the grating system, the error correction technology directly affects the measurement preciseness of the length grating measuring system. Therefore, launching the research on the error correction technology of the length grating measuring system is the important. The correction method of the length grating measuring system is discussed. In the method, the displacement length is traced back to the laser wavelength via the photoelectric microscope, line scale, laser Interferometer and data-fitting tool. The error correction method of the length grating measuring system mentioned in this article is simple in principle, more convenient to be implemented, provides high correction precision, and also can be implemented in real-time automatic correction. For some instruments, based on the length grating measuring such as three-coordinate measuring machine, length measuring machine and so on, the method is of important reference and consultation value.

Phase-shifting interference microscopy is a very important technique for precision surface topography measurement. In this paper, polarization phase-shifting interference microscopy is proposed for ultra-precision surface topography measurement. The principle of the microscopy is described and analyzed in details, a system based on the principle is constructed, and series of experimental testing are conducted on the system. The experimental results show that the measurement accuracy is better than 1.5nm, and high accuracy is verified.

Real-time test is one of the important parts in digital holographic interferometry researches. In this paper, taking advantage of electrically addressed liquid crystal display(EALCD) features of real-timely writing in and reading out images, the digital holographic interferometry system for real-time measurement of displacement is designed. In order to raise the contrast of the holographic hologram, the image enhancement based on the Laplacian operator has been used to process holograms. Based many advantages of CCD and EALCD, the holographic interferogram with high contrast can be obtained quickly, which can realize the precise measurement of small deformation and displacement of objects. Moreover, the measurement efficiency and precision is raised greatly.

Based on Michelson interferometer principle and controlled via an elaborately designed computer program, the variation of interference order, which contains the information of refractive index and its variation, can be detected by an optical power meter and a CCD camera. According to the relation between the increment of interference order and the change in optical path difference, the refractive index of photopolymer samples can be calculated in an accurate way. Typical measurements of the refractive index of our photopolymer samples are 1.547 and 1.583 at wavelength 532nm and 457 nm, respectively.

Traditionally extensometer has been used to measure the tensile strain to determine mechanical properties such as elastic modulus, yield and tensile strength. But it can only measure the average strain within the gauge length and can not produces the information on the strain distribution inside two knife point. This paper presents a novel method which uses digital speckle correlation technique, and produces whole-field strain for a better understanding of material behavior. It offers a significant advantage over conventional techniques with an extensometer in tensile test. The measurement results are presented with a comparison of the traditional method, and the data evaluation method is discussed in detail. This paper demonstrates the capabilities of technique for both quantitative and qualitative strain measurement in a whole field environment, which is almost impossible with the traditional method.

In manufacturing of precise miniature devices, automatic assembly is the trend to replace manual work for better quality and higher yield. Precise measurement is a critical issue during assembly process because the parts are often complicated and quite different in size, shapes, surface condition, etc. The position and orientation error must be determined precisely before assembly. In the developed automatic assembly system, microscopic machine vision and precise linear stages were integrated in the measurement system for higher detection resolution and larger measurement range in working space. As to the extract of contour of parts with different surface condition, dynamic illumination control and different combination of feature detection algorithms were applied. The errors brought by non-perpendicularity among precision linear stages were compensated and the movement errors were reduced with effective measurement strategy. The measuring accuracy was validated with a special fabricated precise template. Assembly tests were done with the developed system and results indicate that the required position and orientation accuracy can be met successfully and consequently the assembly task can be fulfilled.

This paper puts forward a kind of measuring method, double right-angle prisms imaging technique and video graduation technology have been adopted in inspecting laser beam levelness, and realized the measurement and adjustment of laser level. In this article, optic inspection technology, video graduation technology as well as the measuring error analysis and the efficient way of designing regularizing calibrating inspection are discussed in detail. Compare with the traditional way that testing and measuring in an area of fifteen square meters, this instrument can inspect the laser beam levelness error in a smaller test position (500mm), it can be adjusted and assembled easily. Installing and adjusting can be more easy and convenient in this relative smaller space. The instrument accuracy of this paper excels 3', can fully satisfy the requirement of laser level for the levelness of ± 15'. This instrument has been applied in measuring tools enterprise of our country.

The paper introduces the white-light spectral scanning interferometry for surface measurement. This interferometry can be used to measure the roughness of both smooth surfaces and those with large step heights. This real-time surface measurement can be achieved using acousto-optic tuneable filtering (AOTF) technique without mechanical scanning. At first, the structure and principle of this interferometry is introduced. Then the algorithm of the surface roughness measurement is proposed. What's more, the experiment with standard test piece is conducted. Compared with the traditional laser-light interferometry, the data shows that the proposed method has a higher accuracy which is proved to be nano-scale. A conclusion is given at last in which the superiorities and the limitations of the proposed system were discussed.

We propose a dew condensation sensor which combines surface plasmon resonance (SPR) and quartz crystal microbalance (QCM) to measure both refractive index change and mass loading caused by dew condensation simultaneously. In order to excite SPR and enhance water vapor sorption, a periodic silver nanostructure is fabricated on an AT-cut quartz crystal oscillator by template deposition. A self-assembled membrane (SAM) which consists of polystyrene spheres with the diameter of 202 nm was used as the template, and silver thin film with the thickness of 45 nm was deposited on the SAM by vacuum evaporation. Sensitivities of the sensor for detection of dew condensation were evaluated as the shifts of the SPR extinction peak wavelength and the resonant frequency of quartz crystal. The sensor is cooled down with the chilling rate of -0.5°C/min in the environment-controlled chamber with relative humidity and the temperature of 43.2%RH and 25.0°C, respectively. The proposed hybrid sensor was able to measure both the wavelength shifts of SPR and the additional mass caused by dew condensation simultaneously. Furthermore, the QCM response of the sensor achieved the sensitivity higher than the under detection limit (3 μg/cm²) of conventional optical detection method such as chilled mirror surface dew point hygrometer.

There is a need of measuring distributed pressure on the aircraft engine inlet with high precision within a wide operating temperature range in the severe environment to improve the efficiency of aircraft engine control. The basic solutions and principles of designing high-temperature (to 523K) microelectromechanical pressure sensors based on a membrane-type SOI heterostructure with a monolithic integral tensoframe (MEMS-SOIMT) are proposed in accordance with the developed concept, which excludes the use of electric p-n junctions in semiconductor microelectromechanical sensors. The MEMS-SOIMT technology relies on the group processes of microelectronics and micromechanics for high-precision microprofiling of a three-dimension micromechanical structure, which exclude high-temperature silicon doping processes.

Launchers of digital television have already built in many cities of our country as one of fundamental establishments of metropolis. The sent signal from launchers is powerful in power, low in frequency and wide in bandwidth, and it also covers absolutely entire city including many building dense areas. In this paper the signal frame structure of digital television terrestrial broadcasting (DTMB) standard of our country named GB20600-2006 is analyzed. Then the scheme measuring the distance with the special discontinuous PN code in the DTMB signal is designed. At last the new method measuring pseudo-range with DTMB signal is approved considered with DTMB signal own characteristics and tested by the data gathered at many spots in Xi'an. It provides technique method and supplement on positioning and navigation in complex circumstance of city.

There are many relationships between ocean and human life, and it's vital for our survival and development. Ocean observation is of great importance because it enables the prediction of specific global atmospheric changes. And ocean buoy is the core of marine monitoring system. In this paper, we propose a new method based on principle of electromagnetic induction coupling to realize non-contact signal transmission and power feeding for underwater sensors through mooring cable. Sufficient power feeding and data transmission are confirmed by experiments. It can be expected that the proposed system allows easier attachment and detachment of sensors to mooring wires and finally leads to miniaturization of the whole sensor body due to battery-free sensor operation.

Magnetic stress sensor has been considered as the most suitable sensor for measurement of steel cable stress because of its simple structure, low cost and long service life. However, the theoretical foundation for sensor design has never been reported, so it is necessary to study the theory and method of sensor design. Following the magneto-mechanical principle, a theoretical model of magnetic stress sensor is developed. The model indicated that the output of sensor is the function of structural parameters, excitation parameters and stress applied, respectively. A sensor is designed for an engineering steel cable and experiments are done to verify the optimization. Experimental results are in good agreement with the theoretical predictions. Compared to the previous results, the sensor sensitivity is improved by about 4 times, which shows that this model is rational and feasible and the theoretical foundation for optimization is truly of great importance for optimizing the characteristic properties of a sensor.

Today aircraft attitude measurement technology plays an important role in an aircraft system because it can provide orientation for aircraft in action. Lately star sensor technology used in aircraft attitude measurement has become more and more popular because of its high accuracy, light weight, without attitude accumulation errors and other advantages. There are three main steps for star sensor to measure aircraft attitude, star image locating, star identification and attitude tracking. The latter two steps are based on the accuracy of star image locating. So it's critical to make efforts to advance the accuracy of star image locating. Some imaging errors, such as spherical aberration or coma aberration, also have negative effect on the accuracy of star image locating, of which the effect is necessarily reduced as well. At the beginning of this article, the structure of star sensor hardware is introduced. Secondly three methods for star image locating are described specifically, which are traditional centroid method, Gauss quadric fitting method and improved Gauss quadric fitting method. Subsequently an imaging calibration method is described for the purpose of reducing the effect of imaging errors. Finally the experiment shows that the accuracy of the star sensor is 2-arc-second.

The high-order even-modes of high-aspect-ratio rectangular diaphragms are further exploited in this paper to excite Lamb waves. Thus the capacitive Lamb wave transducer (CLWT) can be excited by not only the second-order mode but also higher order even-modes, so that we can obtain higher operation frequencies, and make the CLWTs operate at several different frequencies for different applications. An optimized design with a 3μm thick silicon plate and submicrometer thick conducting silicon diaphragms is given according to the characteristics of the lowest order Lamb wave (i.e. A₀ wave) and the TDK model for capacitive micromachined ultrasonic transducers (CMUT) with high-aspect-ratio rectangular diaphragms. Such a CLWT with multiple even-modes is significant and attractive for gas and liquid sensing in the field of biochemical measurements.

In this paper, an edge filter demodulation of fiber Bragg grating (FBG) displacement measuring scheme using long period grating (LPG) is reported and demonstrated. The system consists of a 3dB coupler, a sensing FBG, a LPG and a photo-detector. As the sensing element, FBG can convert the displacement information into the shift of the Bragg wavelength, and then the wavelength information is converted into power using edge filter demodulation. The experimental results show that there is good linear relation between the output power detected by the photo-detector and the displacement in the measurable ranges 0-3.6mm. The displacement sensitivity is 9.24pw/mm.

The adsorption technology is one key technology of wall-climbing robot. The research actuality of adsorption technology at home and abroad was introduced, and the characteristics of adsorption technology were analyzed. The magnetic absorption of underwater wall-climbing robot was used as an example, and the materials of magnetic circuit which included yoke iron, magnet, separated magnetic material and armature were chose, and the law that magnetic force changes with the magnetic gap was analyzed, and that the packaging rubber thickness of magnetic sucker impacts on the magnetic force was proved by experiment, and a magnetic adsorption device was developed, and a new magnetic adsorption body was provided for underwater wall-climbing robot .

This paper presents the development of piezoelectric energy harvesting from ultrasonic vibration in fluid environments. The ultrasonic is emitted by the transducer in the ultrasonic cleaner and propagated in fluid environments which causes the piezoelectric bimorph bending up and down, thus the PZT layer generates electrical charges. Some preliminary experiments including output voltages in different fluid environments and in draft angles of the piezoelectric device relative to the level surface have been investigated. The experimental result shows that the output voltages vary with the fluid environment, the maximum voltage is generated in clean water and then physiological saline and sea water. Additionally, different draft angle lead to various output voltages with the maximum voltage been present at 45°to 60°or 105°to 120°region and the minimum value at 90°in the same fluid environment. Some possible causes about this phenomenon are also analyzed.

This paper presents a method to study and design a fully pre-stressed double-layer six-component force/torque sensor. The structure characteristic of the fully pre-stressed sensor is analyzed. In order to achieve the best performance, the static mathematical model is built by using screw theory. Based on the task ellipsoid, the task model of the pre-stressed force sensor is built. The relationship between the sensor and the task is studied systematically. And the mathematic description of task-oriented performance evaluation of the fully pre-stressed sensor is proposed. The key parameters of the fully pre-stressed force sensor satisfying the purpose of the task are obtained. The research results of this paper are useful for the further research and practical application of the six-component force sensor.

A kind of sun sensor is designed based on the optical fiber. This project consists of three parts: optical head, photoelectric sensor and signal processing unit. The innovation of this design lies in the improvement of traditional sun sensor, where multi-fibers, used as a leader, are symmetrically distributed on the surface of a spacecraft. To determine the attitude of a spacecraft, the sun sensor should measure the direction of the sun. Because the fiber length can be adjusted according to the fact, photoelectric sensor can be placed deeply inside a spacecraft to protect the photoelectric sensor against the damage by the high-energy particles from outer space. The processing unit calculates the difference value of sun energy imported by each pair of opposite optical fiber so as to obtain the angle and the orientation between the spacecraft and the sun. This sun sensor can suit multi-field of view, both small and large. It improves the accuracy of small field of view and increases the precision of locating a spacecraft. This paper briefly introduces the design of processing unit. This sun sensor is applicable to detect the attitude of a spacecraft. In addition, it can also be used in solar tracking system of PV technology.

A hydraulic square pressure generator with a unique spool valve has been developed for use in a system to calibrate and evaluate the dynamic characteristics of pressure sensors. This hydraulic square pressure generator generates a hydraulic square pressure with a rapid transient response in the time domain and with abundant harmonics in the frequency domain at low fundamental frequencies, rather than square pressure with poor harmonics at high fundamental frequencies. Its rise time and fundamental frequency are around 32.0 μs and 5 Hz, respectively, supporting a wide range of dynamic calibration of hydraulic square pressure generators. The sensing cavity in the hydraulic square pressure generator constrains the pressure transient produced by the fluid in the valve and maintains the generated hydraulic square pressure for both tested and reference pressure sensors. Three pressure sensors are calibrated using the hydraulic square pressure produced by the system with an auto-regressive exogenous model. Their transfer functions are obtained by applying the common pole-zero principle to describe their dynamic characteristics in the frequency domain.

In order to solve the difficulties of the measurement of one-dimensional and bi-direction flow by a hot-wire probe, a test method and the model experiment are presented in this paper. Based on the exiting hot-wire sensor, another same sensor is added. The two sensors are installed in parallel whose distance is 6 times their diameters, and they are separately connected to the controller. If the flow goes around two circular cylinders in tandem with the low Reynolds number, an obvious velocity drop between free-stream and gap flow can be found. Consequently, the velocity detected by the upstream sensor is higher than that by the downstream one. Because the relatively fixed position of the pair of sensors has been determined beforehand, the direction of the one-dimensional flow can be deduced from the plus and minus of velocity drop detected by the two sensors.

Broadband wavelength converters based on difference frequency generation (DFG), single-pass and double-pass cascaded second harmonic generation and difference frequency generation (SHG+DFG), single-pass and double-pass cascaded sum and difference frequency generation (SFG+DFG) are fulfilled by utilizing segmented grating structure in lithium niobate waveguide. Under the small-signal approximation, the effects of the waveguide length and the response flatness on DFG-based wavelength conversion are investigated by use of matrix operator, and then a feasible scheme to enhance the bandwidth and stability of signal and pump wave is proposed. For single-pass/double-pass SHG+DFG wavelength conversion scheme and single-pass/double-pass SFG+DFG wavelength conversion scheme, the effect of segmented grating structure on conversion bandwidth is studied theoretically and numerically, the results show that the signal conversion bandwidth can be broadened by optimizing the aperiodic grating. Moreover, the influence of "balance condition" on double-pass SFG+DFG-based wavelength conversion is analyzed, one can achieve enhanced conversion efficiency and conversion bandwidth by adjusting the power and wavelengths of pump sources according to the "balance condition". In the end, a reasonable suggestion is presented to achieve broadband wavelength conversion under different requirements.

Precise low speed motion control is important for the industrial applications of both micro-milling machine tool feed drives and electro-optical tracking servo systems. It calls for precise position and instantaneous velocity measurement and disturbance, which involves direct drive motor force ripple, guide way friction and cutting force etc., estimation. This paper presents a comparison study on dynamic response and noise rejection performance of three existing disturbance estimation techniques, including the time-delayed estimators, the state augmented Kalman Filters and the conventional disturbance observers. The design technique essentials of these three disturbance estimators are introduced. For designing time-delayed estimators, it is proposed to substitute Kalman Filter for Luenberger state observer to improve noise suppression performance. The results show that the noise rejection performances of the state augmented Kalman Filters and the time-delayed estimators are much better than the conventional disturbance observers. These two estimators can give not only the estimation of the disturbance but also the low noise level estimations of position and instantaneous velocity. The bandwidth of the state augmented Kalman Filters is wider than the time-delayed estimators. In addition, the state augmented Kalman Filters can give unbiased estimations of the slow varying disturbance and the instantaneous velocity, while the time-delayed estimators can not. The simulation and experiment conducted on X axis of a 2.5-axis prototype micro milling machine are provided.

The technique of Phase Diversity (PD) is widely adopted to measure the wavefront error caused by atmosphere turbulence and system error. PD solves the Zernike coefficients of the wavefront by utilizing two images obtained with different defocus value. In this paper, we propose a method to restore the image and estimate the wavefront error of an imaging system. And we use present white noises to verify the robustness of the algorithm. We design an experiment system and implement it in our laboratory. The proposed algorithm is validated by computer simulations and experimental results. To use a broadband white object in experimental system a reasonable simplification for the system model is done. Our results show that the robustness against Gaussian white noises of the method is better then the case when the variance value is 0.03. The proposed method can be used as a wavefront sensor and restore the degradative images by photoelectric image system.

Joint Transform Correlator (JTC) is a more advanced optical pattern recognizer. Compared with computer correlation matched method, it has many advantages, such as parallel processing, high speed and more sampling points. The bottleneck technique of JTC is how to recognize the distorted targets in cluttered scene. The Maximum Average Correlation Height (MACH) algorithm applied in JTC is presented. The MACH algorithm has powerful capability of recognition for distorted targets (rotation and scale etc.). Through optimizing MACH frequency domain filter and projecting it to space domain, the MACH reference image can be obtained. This MACH reference image clearly records various distortions of a target. Based on the basic principle of JTC, the distorted targets in cluttered scene can be detected. Optical experiments with JTC show that the edge features of detected image should be extracted, the correlation calculation of MACH reference image and detected target can be performed accurately and the bright correlation peaks can be obtained. In the process of optical correlation recognition, the performance of MACH reference image is used sufficiently. The energy of correlation peaks is greatly enhanced, the cluttered scene can be suppressed effectively and the MACH reference image has high distortion tolerance. To demonstrate the feasibility of MACH reference image, the scale distorted car in cluttered scene is successfully detected.

This paper presents a unique two-stage image restoration framework especially for further application of a novel rectangular poor-pixels detector, which, with properties of miniature size, light weight and low power consumption, has great value in the micro vision system. To meet the demand of fast processing, only a few measured images shifted up to subpixel level are needed to join the fusion operation, fewer than those required in traditional approaches. By maximum likelihood estimation with a least squares method, a preliminary restored image is linearly interpolated. After noise removal via Canny operator based level set evolution, the final high-quality restored image is achieved. Experimental results demonstrate effectiveness of the proposed framework. It is a sensible step towards subsequent image understanding and object identification.

The noise interference and end effect is irritating in the HHT processing of strong noise signals. In view of this situation, an improved HHT method based on the wavelet denoising and wave characteristic matching is proposed. Firstly, according to the analysis of the noise interference in wave characteristic matching extension and HHT itself, the paper adopts the wavelet threshold denoising to make a pretreatment of strong noise signal that can wipe off noise interference effectively. Then, extends and reconstructs data at both ends of signal to restrain end effect during EMD and Hilbert transform with the wave characteristic matching. Lastly, obtains the early fault feature of four-way valve from HHT time-frequency spectrum accurately. Simulation and instances show that the improved HHT method is able to reduce the false components resulted from decomposing useless noise, restrain the end effect, enhance the accuracy and timeliness of HHT, and thus make HHT arithmetic more practical.

Moving object detection from moving camera sequences is an important subject in field of computer vision. This paper presents a new approach for moving object detection in sequences taken from moving camera, key idea of which is to compensate the camera motion by estimate affine transformation parameters of the background using a combined method of Scale Invariant Feature Transform (SIFT) algorithm and Random Sample Consensus (RANSAC) algorithm. Feature points are detected in consecutive frames by SIFT detector and matched according to Euclidean measure, which is the initial matching step. In order to eliminate incorrect feature correspondences and the correctly matched features in the image region of moving object, RANSAC algorithm is applied to rectify the initial matching results and the affine transformation parameters are estimated accurately. Followed by inter-frame difference and morphology operations, moving object is detected successfully. Tracking of features is robust by using SIFT and the computational complexity is significantly reduced by performing the RANSAC estimation algorithm. The effectiveness of the proposed method is demonstrated using real video sequences from moving cameras.

Due to high speed requirement of real-time online inspection, and disturbances in industrial scene such as illumination and vibration, the captured image of piston ring by CCD is not very distinct, interfering following image procedures greatly. Therefore, in this paper, two models of dimensional measurement and damage defect recognition for piston rings are both established and wavelet transform is added in the process to analysis the edge image to ensure the precision and accuracy of detection results. A series of detection algorithms are elaborated in detail. The first step in the algorithms is to make image-preprocess to original images of piston rings by extracting interested area, image-filtering, and image erosion, with the aim of obtaining precise edge of piston rings' images for defect recognition. In the next step, wavelet transform method is used to calculate accurate edge of piston rings, thus dimension parameters of piston rings could be calculated after calibration of pixel. Then the least squares method is applied to fit a relative datum curve of the edge of piston rings. Based on defect recognition algorithm model and the procedures above, the detection algorithm can distinguish the upper and lower surface of piston rings, recognize piston rings' breakages and justify whether piston rings are conforming or not. The application of detection algorithm has been used to actualize non-contact automatic online inspection system.

To achieve high location accuracy, a sub-pixel location method based on Zernike moment is proposed for the location of the center of target. Original images are preprocessed to weaken the effect of noise. Sub-pixel edge detection is implemented using Zernike moment. The center of target is located using an ellipse fitting algorithm. Some criterions such as grayscale, area and circular degree of the objects are used to recognize the target simultaneously. Experiments are carried out with synthetic image and real image to verify the accuracy and noise immunity of the proposed method. Experimental results show that the accuracy is better than 1/25 pixel. It can therefore be concluded that the method can be used to meet the requirement of high-accuracy measurement.

Measurement points are obtained using a CMM. Lyite rule is used to optimize the data. The algebra relationship between independent parameters and Cartesian coordinate system is built using parametric equations of Archimedes helicoid surface and the error equations about the parameters are constructed. The parameters are acquired use least square method. Experimental results show that the proposed method can be used to make the values of parameters close to the theoretical values, and so, it can be used to do other kinds of parameters fitting of helicoid surface.

For a projectile with slots at the base, the index of amplitude modulation in Doppler radar echo reflects the information of angular motion. According to our research, the procedure to obtain the index can be divided into two steps, i.e., 1) separating the envelope from radar echo and 2) estimating the index from the acquired envelope. Here we assume that the envelope has already been achieved. To obtain the index from the envelope so as to extract the motion information, we investigated first the signal model of the envelope. A constant envelope model of echo is modified as an amplitude modulation and frequency modulation signal to express the amplitude modulation. The envelope is simplified as the combination of DC, the component of spin rate, and the second harmonic of spin. To restrain long-range and short-range spectral leakages and improve the index estimation accuracy, an interpolated FFT method that iterates in frequency domain and time domain alternately is proposed to. It adopts the interpolation algorithm in frequency domain to alleviate short-range leakage effect, uses the time window and the iterative CLEAN technique to realize long-range leakage correction. The influences of such parameters, as modulation frequency, value of the index, and SNR are simulated. The results of simulation and experiment prove the rationality of the model and the validity of the proposed method.

In order to improve the precision of gravity matching aided navigation, a gravity correlation coefficient is selected to study the gravitational field intrinsic features using the method of normalized standard deviation firstly. Some statistics laws are identified from the random gravitational field through the statistical analysis of gravity correlation coefficient. So that series of gravity matching conclusions can be drawn. Secondly, a gravity intrinsic features threshold matching algorithm of gravitational field is proposed based on these findings. Finally, the simulation results obtained using the gravity matching algorithm in a gravity aided navigation system show that the threshold can be used to find the better gravity matching areas, enable the integrated navigation system to diverge effectively and increase the accuracy of gravity aided navigation system.

As the main objects, imagoes have been researched in quarantine pest recognition in these days. However, pests in their larval stage are latent, and the larvae spread abroad much easily with the circulation of agricultural and forest products. It is presented in this paper that, as the new research objects, larvae are recognized by means of machine vision, image processing and pattern recognition. More visional information is reserved and the recognition rate is improved as color image segmentation is applied to images of larvae. Along with the characteristics of affine invariance, perspective invariance and brightness invariance, scale invariant feature transform (SIFT) is adopted for the feature extraction. The neural network algorithm is utilized for pattern recognition, and the automatic identification of larvae images is successfully achieved with satisfactory results.

This paper presents a real-time navigation system in a behavior-based manner. We show that autonomous navigation is possible in different rooms with the use of a single camera and natural landmarks. Firstly the intelligent wheelchair is manually guided on a path passing through different rooms and a video sequence is recorded with a front-facing camera. A 3D structure map is then gotten from this learning sequence by calculating the natural landmarks. Finally, the intelligent wheelchair uses this map to compute its localization and it follows the learning path or a slightly different path to achieve the real-time navigation. Experimental results indicate that this method is effective even when the viewpoint and scale is changed.

Metal magnetic memory is a novel NDT method that can be used to detect residual stress distribution of ferromagnetic components.Wavelet decomposition and entropy theory are used and wavelet singular entropy is introduced to extract characteristic from abnormal signals of defect. Furthermore, RBF neural network is utilized to identify defect character. Experimental results showed that, compared to the traditional gradient value, the proposed new method can be used to effectively reflect defect character and it is immune to the effect of noises.

It is obvious character that the chopper must be used in Uncooled pyroelectric imaging system. At present, three mainly type chopper which are linear chopper, Archimedean spiral chopper and Fresnel zone plate array (FLA) chopper. The FLA has some advantages than the others, which used diffraction solution. The paper report pyroelectric focal plane binary optics chopper which was processed by laser direct writing etched Fresnel zone plate array shape, and draw the test results: the sub-beam ratio of 1.2 x 10³; diffraction efficiency more than 40%; non-uniformity: multi-point test better than 10% in the FLA chopper.

According to the deficiency of SIFT algorithm for matching multi-source remote sensing image feature points, this paper provides a multi-sensor image registration algorithm of window segmentation based on SIFT point and line feature vector. Firstly, we roughly matched the remote sensing images, and then we divided the remote sensing images into several separate temporary windows based on their characteristics. In the sub-window, we extracted SIFT feature point of remote sensing images and selected the eight directions points with the same name around the feature points to build line feature vectors. Finally, we ended up match point set by constraining the initial point of the SIFT algorithm. Tests show that this method achieved a high matching accuracy.

In order to improve the matching accuracy and the level of automation for image mosaic, a matching algorithm based on SIFT (Scale Invariant Feature Transform) features is proposed as detailed below. Firstly, according to the result of cursory comparison with the given basal matching threshold, the collection corresponding SIFT features which contains mismatch is obtained. Secondly, after calculating all the ratio of Euclidean distance from the closest neighbor to the distance of the second closest of corresponding features, we select the image coordinates of corresponding SIFT features with the first eight smallest ratios to solve the initial parameters of pin-hole camera model, and then calculate maximum error σ between transformation coordinates and original image coordinates of the eight corresponding features. Thirdly, calculating the scale of the largest original image coordinates of the eight corresponding features to the entire image size, the scale is regarded as control parameter k of matching error threshold. Finally, computing the difference of the transformation coordinates and the original image coordinates of all the features in the collection of features, deleting the corresponding features with difference larger than 3kσ. We can then obtain the exact collection of matching features to solve the parameters for pin-hole camera model. Experimental results indicate that the proposed method is stable and reliable in case of the image having some variation of view point, illumination, rotation and scale. This new method has been used to achieve an excellent matching accuracy on the experimental images. Moreover, the proposed method can be used to select the matching threshold of different images automatically without any manual intervention.

In order to increase the efficiency of filling area, a novel declining scanning-line filling algorithm for filling area is proposed, in which the boundaries of image are traced through the adjacent connection, and their locations of the image edges are recorded at the same time. The direction of scanning-line is determined by the relative position between the seed point and the boundary point, and all the points in the adjacent field of scanning-line are filled only once. The vertical distance between the scanning-line is depended on the connected domain. The number of crossing points between the scanning-line and boundary is used to estimate the state of filling or ending. The algorithm can be used to fill the 4-adjacent or 8-adjacent fields, to settle the problem of deep recursion and iterative stack, and to solve the defect of repeated scanning and filling in traditional algorithm. By using the proposed algorithm, the filling result is accurate, the calculation of the algorithm is decreased, and the filling efficiency is enhanced.

The fabrication methods of binary and continuous-relief diffractive optical elements (DOE) by direct laser writing and lithography are analyzed. Laser metrology often requires the precision forming of a probe laser beam. This problem is solved optimally by application of DOEs. A number of scientific and practical applications require the fabrication of DOEs to create highly accurate aspherical wavefronts. This paper reviews the research directed toward the creation of equipment and technologies for DOEs with a binary, multilevel, and continuous profile. The results of the practical applications of DOEs (fabricated in Institute of Automation and Electrometry SB RAS) in optical measuring systems are presented.

According to the theory of self-mixing interference (SMI) in fiber ring lasers (FRLs), Fourier Transform method is adopted for vibration measurement. The harmonic components increase with the increase of the amplitude of vibration. According to the theory of self-mixing speckle effect (SMSE) in FRLs, the similarity to Gaussian form of probability density distribution increases as the velocity increases. A method based on the fractal boxes of a section of speckle waveform is adopted for demodulation. The relationship between the numbers of boxes and velocities of the object is linear. Dual-channel SMI is presented demonstrating the potential for multiplexing in FRLs. The dual wavelengths of the FRL are selected by two fiber Bragg gratings (FBGs). The output power in one channel is modulated by that in the other channel, which is resulted in the mode competition between the two channels. The experimental results show a good agreement with the simulation results, and indicate that SMI with parallel dual-channel is an efficient approach for multiple displacement measurement.

The researches in the millimetre wave range require the high accuracy for position of the mirror components. A mirror weight is the cause of the roll deformation of the elevation axle relatively the bearing. At result the elevation angle of a parabolic mirror axis orientation is not equal to the set values. For the measuring these roll angular deformations the new type of the anamorphic based system are used. The new method for roll angles measuring is developed. Optical scheme for the measurement system and anamorphic element is proposed. Equation for the static characteristic of the system and its graphical representation are shown.

In this research, an electron emission method which combines field emission and plasmon resonance is proposed and examined. Electron field emission properties of a sharp gold tip under continuous-wave laser irradiation at the plasmonresonant wavelength are investigated. Due to the application of plasmon resonance, the electric field in the vicinity of the emitter is strongly enhanced, resulting in the decrease of emission threshold voltage and the increase of emission current. The emission-area is strongly confined under illumination when the optical electric field is parallel to the emitter shank, and the optical modulation of the emission current is demonstrated.

The main mirror construction of the radiotelescope for the millimetre wave range requires to measure the line deformation of mirror's surface and shifts of the secondary mirror relatively main mirror. There is a necessity to construct the new radio-telescope RT-70 Suffa (Russia). The 3-D parabola main mirror of this radio telescope has a diameter 70 meters, and the elliptical secondary mirror with the diameter 3 meters are placed on the distance 21 meter relatively main mirror. Following issues dealing with this problem are described in this article: 1) the possibility of the design of deformation measurement system based on triangular method 2) the new scheme of optic-electronic measurement system. The great attention during the research was paid to the experimental approval of the theoretical results. The experimental setup of the described system had the following characteristics: infrared emission diode AL107B by power 15 mWt as sources of radiation; the objective by the focal length 450 mm as aperture of receiver video-camera, the CMOS matrix receiver by type OV05620 Color CMOS QSXGA with 2592*1944 pixels and one pixel size (2.2*2.2) μm² produced OmniVision as image analyzer . The computer simulation error and the experimental error measurement was 0.1 mm at the

We describe the use of Near Infrared Spectroscopy (NIRS) for the non-invasive investigation of changes in haemodynamics and oxygenation of human peripheral tissues. The goal was to measure spatial variations of tissue NIRS oxygenation variables, namely deoxy-haemoglobin (HHb), oxy-haemoglobin (HbO₂), total haemoglobin (HbT), and thereby to evaluate the responses of the peripheral circulation to imposed physiological challenges. We present a skinfat- muscle heterogeneous tissue model with varying fat thickness up to 15mm and a Monte Carlo simulation of photon transport within this model. The mean partial path length and the mean photon visit depth in the muscle layer were derived for different source-detector spacing. We constructed NIRS instrumentation comprising of light-emitting diodes (LED) as light sources at four wavelengths, 735nm, 760nm, 810nm and 850nm and sensitive photodiodes (PD) as the detectors. Source-detector spacing was varied to perform measurements at different depths within forearm tissue. Changes in chromophore concentration in response to venous and arterial occlusion were calculated using the modified Lambert-Beer Law. Studies in fat and thin volunteers indicated greater sensitivity in the thinner subjects for the tissue oxygenation measurement in the muscle layer. These results were consistent with those found using Monte Carlo simulation. Overall, the results of this investigation demonstrate the usefulness of the NIRS instrument for deriving spatial information from biological tissues.

To monitor the whole Shanghai Expo Park, a vehicle tethered aerostat optoelectronic monitoring platform with the characteristic of time-sensitive and all-weather monitoring is described in detail in this paper, which is hung beneath the tethered balloon and equipped with a variety of payloads, including visible light monitoring system, infrared monitoring system, hyperspectral monitoring system, GPS/INS system, monitoring and control system and so on. These equipments can be used for real-time monitoring, environmental monitoring, and ground target location of Shanghai Expo Park. The output High Definition (HD) image of Shanghai Expo Park from visible light monitoring system is clear and stable, and the stabilization accuracy of visual axis is 0.07°(3δ). The optoelectronic monitoring platform system uses the target location technology based on Global Position System/Inertial Navigation System (GPS/INS) system to output real-time location data compatible with Geographic Information System (GIS). Test results show that the maximum errors between the location results (latitude and longitude) solved by the target location program and the reference target are 0.2 0/00(latitude) and 2 0/00(longitude). Now the whole system has been used for surveillance the Shanghai Expo Park since April 2010.

A new approach of Fabry-Perot (F-P) filter, where the optical length of cavity is tuned by using linear electro-optic (EO) effect of crystals, is demonstrated with the numerical analysis. For achievement of polarization-independent tunability of this filter, directions of light propagation and the external field applied are illustrated by means of the index ellipsoid. An example of the F-P filter using LiNbO₃ crystal is discussed and its tunability is analyzed.

White cotton lint trash can not be effectively detected by white light imaging method. It becomes a serious problem in textile industry. Ultraviolet (UV)-induced fluorescence imaging method is based on the principle that different materials have different spectral excitation and emission characteristics. The fluorescence spectroscopy experiment gave reliable evidence that most white trash had much stronger fluorescent effect than that of lint. In order to simultaneously discriminate several kinds of white lint trash, an Optimal Wavelength Selected Model for describing cotton/trash discrimination was developed. It was determined that 342-388 nm was the optimal detection waveband for white trash detection. Imaging results and analysis clearly showed that for both uncovered and covered situation, the gray differences between white trash and lint were significantly improved when illuminated by a type of UV light. It was concluded that UV-induced fluorescence imaging method is a feasible way to detect most white trash. This method can also be used in white trash detection in seed cotton, wool, tealeaf, and tobacco leaf.

In this paper, based on the extended coupled nonlinear Schrödinger equations including exponential saturable nonlinearity (ESN) in optical fibers, the linearized coupled nonlinear Schrödinger equations are derived. Subsequently, the corresponding condition and gain spectra of cross-phase modulation induced modulation instability (MI) are deduced and calculated. And the variations of the critical perturbation frequency and the peak gain with the input powers are calculated and compared with the case of conventional saturable nonlinearity (CSN) in both the normal and anomalous dispersion regions. The results show that, the critical perturbation frequency and the peak gain increase with the input power, reach a maximum value, and then decrease. Moreover, in comparison, when the other parameters are the same, the varying rates will be faster than those of CSN. These features lead to a unique value of peak gain and critical frequency for two different input powers. This work may be beneficial to further study of new types of bistable or multistable optical solitons.

Polarization fluctuation caused by polarization coupling in polarization maintaining fiber (PMF) resonator is one of the major noise sources in resonant fiber optic gyroscope. Polarization axis 90-degree docking is an effective way to overcome the polarization fluctuation, but the 90-degree docking error has a major affect to the gyroscope noise suppression effect. In this paper, a fiber Michelson interferometer testing system of polarization coupling in doublecoupler polarization maintaining fiber resonator based on white-light interferometer is designed to realize 90-degree docking error control and obtain a good result of 0.37 degree experimental docking error. Then the detection method of sawtooth scanning is used to analyze the resonance characteristics and polarization characteristics of double-coupler polarization maintaining fiber resonator experimentally and obtains the response curve with 24 finesse and 179.65 degree phase interval of the two polarization eigenstates.

The analysis models of Zernike aberrations of precision conformal aspheric optical windows are built, and the influences on Zernike aberrations of different aspheric optical window shapes and the variation laws of Zernike aberrations of precision conformal optical windows at different gimbal angles are analyzed using the multi-configuration capability techniques of Zemax software. The results of analysis show that the astigmatism of conformal aspherical optical windows is the largest, coma is followed, and spherical aberration is smaller in the range of 45° gimbal angles, and the Zernike aberration coefficients of paraboloid and hyperboloid conformal optical windows are higher than that of ellipsoid conformal optical windows. Therefore the ellipsoid surface function is more suitable for the design of precision conformal aspheric optical windows from the point of view of optical system designs and aberration correction techniques.

Based on the appearance of infrared dual-band device and the technical parameters of infrared seeker, a new-type Cassegrain optical system is designed. The main advantages of the system are large field-of-view, infrared dual-band common path and compact structure. In the Cassegrain optical system, the working wavelengths are 3.7μm~4.8μm and 8μm~12μm, the field-of-view 4° and the aperture 240mm. The paraboloidal primary mirror and hyperboloidal secondary mirror are all replaced by spherical surfaces. So the problems of high machining accuracy and alignment become much easier. In order to balance the aberrations, two compensating lenses are used in the system. The amounts of compensating lenses are much less than other optical systems. So the new optical system becomes much more economy, light and compact. The total length of system is 170mm. The ratio of total length to focal length is 0.62. So it can meet the operating requirement of seeker in limited space. Moreover, the system has a good performance of athermalization between negative 40°c and positive 50°c. The design results of the system show that the MTF value of each field is greater than 0.7 when the cut-off frequency is 11 lp / mm. Wavefront aberration is less than 0.038λ.

Generally, the theoretical analysis of the fluorescent life time temperature measurement is based on the assumption of the exponential life time characteristic, but in practice, the actual curve of the fluorescence are different from exponential. This is the key-influence on the stability of the high precision fluorescent measurement system. The differences are analyzed base on the theoretical mechanism of fluorescent, and a cutting and normalized method is given to describe the degree of the non-exponent of the actual fluorescent curve defer from the exponential curve. Several kinds of typical fluorescence materials spectrum and its cutting and normalized experiment results verify this theoretical analysis. Some effective measures to improve the non-exponent of the system are taken and are applied to a temperature measurement system based on actual fluorescent curve analysis with resolution 0.1°C, precisions ±0.2°C, and real-time calibration is carried on. Based the theory base and the actuality of fluorescence optical fiber temperature sensor, two methods about fluorescence decay time constant are proposed. In the mean time, the mathematic model has been formed and analysis, so that the different schemes are selected in different situation.

Off-axis illumination (OAI) technology is widely used to enhance resolution for deep ultraviolet lithography. The realizing methods of OAI include geometrical optics method and physical optics method. However, the former has the disadvantage of weak intensity distribution controlling ability, and the latter introduces simulation errors evidently when dealing with near field diffraction propagation. A diffractive optical element (DOE) designing method using plane wave angular spectrum theory is presented in this paper. Several kinds of OAI modes at near field away from DOE can be realized, and simulation errors and the size of illuminator are also reduced. According to studying the relationships of the sampling point distance of DOE, light beam propagation distance, and the structure of the beam shaping unit, a method of determining the designing parameters is discussed. Using this method, several illumination modes are realized, and simulation results show that all diffraction efficiencies reach up to 84%. The method of DOE manufacturing is analyzed at last, and it is proven to be feasible.

To quickly measure the trace concentration of the single component toxic gas (e.g. sarin), a micro-array toxic gas detector is designed. A 3 x 3 gas sensor array with metalloporphyrins as sensitive materials is introduced. A micro-capsule that can be easy to be loaded and unloaded is designed for the gas reaction. A fiber-array optical path is designed, which is based on the principle that gas sensors will show different colors after reaction with the toxic gas. The tricolor information about the concentration of gas is collected by the color liner CCD. A control handling system with C8051F021 MCU as the core is implemented and embedded into the detector to perform the functions of gas sampling, data collection and analysis calculation. Data acquisition experimental results show that the proposed scheme can effectively collect the color information after gas reaction. Moreover, the system has many important advantages, such as small size, compact structure, high degree of automation, fast detection speed and high performance-cost ratio, etc.

This paper presents a new idea that designing a high speed telescope system with freeform surface. The system is designed based on the relation that between the coefficient of Zernike polynomial and Seidel aberration, so that we can control the aberrations of every field of view and alternation optimize with a specific aim. The primary mirror is freeform surface, and others are conicoid. It is telecentric in the image space. Its F-number is 2.0, its focal length 360mm, and its field of view 4 degrees. This system is compact and diffraction-limited. It's unique in that the chief ray on the 0 field of view traces along the line between every vertex of elements, so that its assembly difficulty is greatly reduced, the working distance is long and good to place the color filters.

More attention is paid to on-line monitoring of biofouling in industrial water process systems. Based on optical fiber sensing technology, biofouling detection mechanism is put forward in the paper. With biofouling formation, optical characteristics and the relation between light intensity and refractive index studied, schematic diagram of optical fiber self-referencing detecting system and technological flowchart are presented. Immunity to electromagnetic interference and other influencing factors by which the precision is great improved is also remarkable characteristic. Absorption spectrum of fluid medium molecule is measured by infrared spectrum and impurity is analyzed by character fingerprints of different liquid. Other pollutant source can be identified by means of infrared spectrum and arithmetic research of artificial neural networks (ANN) technology. It can be used in other fields such as mining, environment protection, medical treatment and transportation of oil, gas and water.

A novel underwater fiber laser vector hydrophone is presented. Theoretical and experimental analyses are carried out to test the performance of the hydrophone, which shows a sensitivity of 25 pm/g and a flat frequency response in the range of 5 Hz~200 Hz are achieved. Field demonstration shows that the vector hydrophone has good directivity.

This paper investigates theoretically the suppression of relaxation oscillation (RO) in strong optical injection-locked semiconductor laser diode (SLD). The theoretical model is based on external injection locking (IL) in a SLD. In our simulation, an adaptive fourth-order Runge-Kutta algorithm is used to solve the rate equations of injection-locked SLD, the temporal evolution of the carrier and the light intensity in the SLD are obtained. Compared with previous reports of weak optical IL, where IL in SLD will experience a RO and finally come to a steady state, it is found in our study that this RO can be suppressed very well when employing strong optical IL, and the settling time in SLD becomes shorter with high intensity of injection; we also find that the suppression level is almost the same with the same injection ratio while different injection detune. And we believe our results of IL in the SLD with dc excitation can contribute to increase the modulation bandwidth of SLD.

The production of large components, e. g. in aerospace industries, requires flexible and yet highly precise measurement techniques to determine absolute lengths of up to one hundred metres. Two different approaches are presented in this paper. One is based on a time-of-flight measurement, using a femtosecond frequency comb as an advanced modulator. By the combined phase analysis of lines of different distinct frequencies in the Mega- and Gigahertz frequency range, a measurement distance of one hundred metres with a relative measurement uncertainty of 1x10^-7 was achieved in laboratory conditions. In a second approach to long distance measurements, two standard interferometric measurement techniques, i.e. variable synthetic and fixed synthetic wavelength interferometry, were combined. The two interferometry techniques were realised within a single set-up, using two external cavity diode lasers as sources. Experimentally, lengths of up to twenty metres could thus be determined with relative uncertainties below 1x10^-6, in good agreement with theoretical analysis. Both techniques, femtosecond fibre laser-based time-of-flight and diode laser-based multiwavelength interferometry, are therefore capable of absolute, guidance-free long distance measurements and have achieved demonstrated relative measurement uncertainties below 1x10^-6 for distances over ten metres.

Traceable calibrations of various micro and nano measurement devices are crucial tasks for ensuring reliable measurements for micro and nanotechnology. Today metrological AFM are widely used for traceable calibrations of nano dimensional standards. In this paper, we introduced the developments of metrological force microscopes at PTB. Of the three metrological AFMs described here, one is capable of measuring in a volume of 25 mm x 25 mm x 5 mm. All instruments feature interferometers and the three-dimensional position measurements are thus directly traceable to the metre definition. Some calibration examples on, for instance, flatness standards, step height standards, one and two dimensional gratings are demonstrated.

This paper presents a two-modality laser diode (LD) interferometer which combine as two-wavelength sinusoidal phase modulating (SPM) interferometer with a wavelength scanning interferometer (WSI) for measurement of distance over long range with high accuracy. Moreover, the intensity modulation due to power changes of LD is suppressed by appropriately choosing the modulation amplitude of injection current (IC) of LD. Triangle wave is used to modulate the IC of one LD with that of the other LD being constant at first. Thus the interferometer works as a wavelength scanning interferometer. An initial estimate of the distance can be obtained from the phase change of the interference signal. Then sinusoidal wave is used for modulating IC of both LDs to realize a two-wavelength SPM interferometer. However, the modulation of the IC of two LDs results in not only the wavelength modulation but also the intensity modulation. This intensity modulation will cause a measured phase error. To eliminate this error, SPM depths are appropriately chosen, therefore the distance to be measured can be accurately obtained with synthetic-wavelength algorithm. Experimental results indicate that an absolute distance measurement accuracy of 1μm can be achieved over the range of 40mm to 100mm.

In nature, insects and plants have evolved ways of living and reproducing themselves using the least amount of resource. This involves both efficiency in metabolism and optimal mechanisms and materials for life functions. Human beings have long tried to learn from and mimic nature. The study of biological materials has received increasing interest in recent years due to the often extraordinary mechanical properties and unusual structures exhibited by these materials. Micro-structure biomaterials exhibit important local variations of elasticity due to the complex and anisotropic composition. In this paper, a specially developed multi-function tribological probe microscope (TPM) has been used to map the mechanical properties of some special micro-structured biomaterials. Results of the mapped surface topography and elastic modulus on specimens of elytra cuticle of dung beetle, nacre of shell and bovine horn have shown some significant lateral variations of elasticity across the surface area.

The establishment and use of precision measurement technology and system become an important part to understand and to effectively control the materials, structures or installations in nano-scale. In this paper, a system based on the multiple beam interferometry, multi-matrix method and fast spectral correlation method is developed to measure the thickness and refractive index of thin film. Primary study to analyze the FECO images obtained from symmetrical three-layer (micaair- mica) with film thickness over 200nm and non-symmetrical interference (mica- air- LDPE-mica) was made. The results show that the fast spectral correlation formula can be applied to both symmetric and non-symmetric three-layer interference, and the film thickness measurement is applicable to over 200nm.

Glasses with different Er³⁺-doped concentrations were fabricated, and J-O theory, F-L theory and MC theory have been used to calculate the spectral characteristics of Er³⁺ -doped glasses. The influences of Er³⁺ -doped concentration and the composition of matrix glass material on the physical properties and spectral properties were analyzed and the best doping concentration was obtained. The results confirmed that a strong Near-infrared fluorescence emission at the wavelength of 1534 nm was obtained with the pumped wavelength of 488 nm, 532 nm and 800 nm, respectively, in Er³⁺ -doped cadmium silicate glass. The results obtained have confirmed that the sample was an excellent candidate for preparation of doped photonic crystal fiber material.

The conventional vertical-cavity surface-emitting lasers (VCSELs) are designed to have a very short resonant cavity. Therefore, the longitudinal mode of the VCSELs is intrinsically single; and the VCSELs are expected to be an excellent instrument for many precision measurements that demand high-purity single-wavelength light sources. However, the laser facet of the conventional VCSELs is relatively large, around 10 μm, which admits the emission of multi-transverse modes. Accordingly, conducting a single transverse mode from VCSELs is an important research topic. In this research, the beam-profile-adapted optical feedback (BPAF) method was investigated by a single-mode fiber cavity (SMFC), in which the beam profile of the multimode-VCSEL's output was adapted to the fundamental-transverse mode of an optical fiber to feedback into the laser's cavity. The operational principle and performance of BPAF will be presented. The experimental results successfully demonstrated that BPAF can efficiently conduct multimode VCSELs to stably lase the fundamental transverse mode with a wide tuning range of about 1090 GHz, or 2.62 nm, and a spectrum purity around 20 dB. Some precision spectrum measurements will be exhibited. These results will help to extend the application of the VCSELs in many precision measurements.

This paper presents a rapid inspection technique used for the evaluation of structures with line-width below sub-wavelength and diffraction limit. Inspections are carried out with an optical microscope via a vertical scanning and through-focus measurement, where the intensities of reflection light from different focal positions of the specimen are transferred into a series of numeric data through the use of an Entropy algorithm. A through-focus focus metric (TFFM) profile is then obtained for the inspection of line-width. The secondary peak in TFFM profile is related to the distance of 180° phase difference of the grating image according to the Talbot effect. This characteristic can be used to determine the pitch of grating specimen. Based on the variance of the secondary peak for different line-width, the line-width of a grating can be obtained from the comparison of simulated and measured data. Experimental results show that the Entropy algorithm can be used to achieve more reliable and fast evaluation in line-width inspection. Furthermore, as through-focus measurement is a non-destructive inspection method, it can be used as another positive element which equals to a traditional nano-scale inspection methods, such as AFM and SEM.

The main study purpose is to develop a device capable of translating exercise energy into hot or icy drinkable water. This device can accurately measure energy consumption during exercise, transform it, and apply it to a heating and refrigerating system. Traditional energy measurements were based on the amount of exercise load from the human body. The research tapped into this non-electric form of energy transmission to run a heating and refrigerating system. The energy requirement was 50.6 kcal. When compared to 57.9 kcal, which the body consumes based actual calorie test, the difference was within a 15% striking range. In terms of energy comparisons, this study demonstrates potential R & D value with this innovative design. It complied with carbon emission requirements by producing 2,000 cc of energy at 47°C of hot water and 1,300 cc of energy at 6.6°C of ice water, all without the use of conventional energy sources. As the paper shows, this device is an innovative and environmentally conscious design. In an upcoming low-carbon emissions future, its research potential is definitely worth evaluating.

In a typical homodyne interferometer with 4-channel detectors, the nonlinearity resulting from beam power drifting couldn't be thoroughly suppressed by Heydemann correction. This study presents an analysis of the nonlinearity resulting from beam power drifting. From a theoretical approach, the nonlinearity model before and after conventional Heydemann correction is built. And a fine correction method involving Heydemann correction with partial data is introduced. The experimental results indicate that, the proposed method suppresses the nonlinearity in a homodyne interferometer to 0.18 nm, which would be 1.49 nm with conventional Heydemann correction.

This paper presents the measurement of the carbon monoxide concentration in industry field by scanning absorption spectrum. In the measurement, the frequency of DFB laser is stabilized in the central frequency point of absorption peak in 1.57μm absorption band of carbon monoxide by a control system with a standard CO gas chamber, fiber loop, TEC controlled by MCU and its temperature stability is 0.01°C at long time to stabilize the central frequency. In the process of measurement, at first, the CO absorption spectrum will be determined by a standard gas camber to choose a maximum CO absorption peak in its frequency band and its frequency point will be stabilized. The parameters of the operation frequency and environment will be stored in the NV memory in MCU as next operation condition. The concentration can be calculated in a composite algebra operation by first and second harmonic intensity passed through test gas chamber. It has very high measurement precision and real time. The experiment result is consistent with actual gas concentration. It shows that the measurement scheme is valuable for fast, real-time and efficiency measurement.

Based on the principle that the distance from the axle of an inspected long shaft to the two laser planes is unique, the method used image processing to get the coordinate of the cross point and the angle of the horizontal line of the laser image, and calculated the straightness parameters with distance position information along the long shaft. The image processing of the cross laser was carried out by a local maximum intensity. With a camera (640x480 pixels and 0.0973mm/pixel as resolution of target), 50 samples were taken at each distance of 1m, 9m and 18m. The standard deviation was 0.00937mm, 0.0342mm and 0.0860mm for polar radius, 0.843', 1.26' and 1.57' for angle, respectively. Experimental results indicate that the straightness inspection system for long shaft is simple in structure, easy to operate and precise in inspection results.

Because of the practical applications, there has been increasing interest in obtaining information of turbid media by use of a Stokes vector/Mueller matrix approach. Much progress has been achieved in recent research using a Monte Carlo technique and Sphere queue model. However, the intrinsic characters restrict their applications. This paper presents a detail comparison of the two methods used for calculating backscattering Mueller matrix. To implement the comparison, several elements of Mueller matrix are calculated when photons propagate in different kinds of media, which varies in particle sizes and concentrations. Numerical results reveal that these two methods accord with each other well when particle sizes are about 2.04μm or concentrations are higher than 9.6x10¹¹cm^-3. In other situations, the Monte Carlo method has a better performance than the Sphere queue model since it takes multiple-scattering into account.

The optical error of a cat's eye retro-reflector is a major factor which affects the measuring accuracy of a laser tracking 3D coordinates measuring system based on multi-beam principle. A measuring apparatus is constructed with a Talyrond roundness tester and a HP laser interferometer to measure the optical error of a cat's eye retro-reflector CER75. In the process of measured data processing, non-linearity fitting arithmetic including 2D interpolation arithmetic is used to obtain the optical error in different directions and to eliminate the measuring error. Experiment results indicate that the maximum optical error of a cat's eye retro-reflector is about 4μm. After error correction, 3D coordinates measuring accuracy of the laser tracking system have been improved to some extent.

Several static tests indicate that the Ring Laser Gyro (RLG) bias inside of the Strap-down Inertial Navigation System (SINS) varies remarkably as long time working. Further experiments and analyzing results show that the SINS external metal shell could insure the inside temperature rising gently and evenly, and the RLG drifts could be viewed mainly affected by RLG inside temperature field. In order to achieve better RLG stability characteristic within full temperature range, investigated the BP and RBF Artificial Neural Networks (ANN) nonlinear modeling and compensation technology. Firstly, introduced two typical structures for BP and RBF neural networks, and then, take a set of static tests data from 25 °C to 55 °C as training samples, separately built up four-layer BP and two-layer RBF neural networks for RLG drifts. In order to compare the compensation effects, first-order and second-order piecewise Least Square (LS) fitting technologies are also implemented here. Four new experimental data were adopted to check the modeling validity. The compensation results show that the RLG drifts stability could be improved by 20%-40%; the precision of BP network modeling method is better than that of first-order linear piecewise LS fitting, and the precision of RBF is better than that of second-order piecewise LS fitting.

In this paper the mechanical model of measuring rod of traditional stylus profilometer is established and the analysis results show that the measuring force is changed with rotation angle of the measuring rod. The impact on profile measurement of unsteady measuring force and the necessity of measuring surface of different materials with different constant measuring force are also discussed. The mechanical relations between the measuring rod and the surface are simplified by the structural change of measuring rod and a gravity center adjustment device. A voice coil motor (VCM) is added into the measuring system to control the measuring force. By adjusting the current in the coil of the VCM in real time, the measuring force can be controlled. With the controllable force, different workpieces can be measured by using different constant measuring force and the measurement results of different workpieces are given.

Methane absorption properties under the pressure from 0.01 MPa to 4 MPa are studied with infrared spectrometer at normal temperature. Gas concentration of methane remains unchanged and nitrogen is gradually added to increase the pressure. Test results show that the absorbance changes a little, almost like a straight line at the beginning. When the pressure continues to increase, absorbance significantly decreases. While the pressure increases to a definite value, absorbance enters into another stable region. No frequency shift appears in absorption line shape but the pressure broadening effect can be observed. So, when high pressure methane in pipeline is measured by absorption spectroscopy, the effect of absorption properties brought about by pressure must be considered, and pressure correction is then needed.

The pulsed time-of-flight laser scanner can be used to detect intrusions of humans or foreign objects into user-defined zones, give alarm or shut down hazardous equipment whenever the pre-defined zone is intruded. Working principles and system components of the laser scanner are introduced, and pulsed time-of-flight laser scanning techniques including laser transmitting, receiving, arrival time discrimination and time interval measurement are discussed in detail. High-repetition-frequency, narrow pulse semiconductor laser transmitting circuit is designed and realized to generate pulsed laser. Wide bandwidth and fast response time receiving circuit using avalanche photodiode is designed and realized to receive pulsed laser echo. Three time discrimination methods including leading edge, constant fraction and peak are discussed, and time discrimination circuits are designed. Experiment results indicate that constant fraction and peak time discrimination are not affected by changes in pulse amplitude. High resolution time interval and distance measurement is realized using integrated time-to-digital converter. By Comparing distance measurement value with distance setting value, the laser scanner can be used to realize both alarm and protection of user-defined zones.

To investigate the propagation of Surface Acoustic Waves (SAWs) in the heated region of Polymethyl Methacrylate (PMMA), through the thermoelastic mechanism, a finite element model is put forward to simulate laser inducing SAWs in PMMA. Meanwhile, the propagation of SAWs through the heated region of PMMA is investigated experimentally: a Nd:YAG laser is used to excite SAWs and a polyvinylindene fluoride (PVDF) transducer is used to detect SAWs. The simulation and experimental results are in good agreement. SAWs have a significant attenuation when they propagate through the heated region of PMMA.

As the damage region of a sensor can be regarded as some sort of anomalistic aperture diaphragm, the reflectivity model of the sensor can be established, where the optical path of a surface damage detection system can be taken as a propagation process for a plane wave through a defocused optical lens and is reflected back to the return place. Based on the theory of angular spectrum diffraction, the diffraction transmission formulas for a plane wave through the cat-eye system can be derived by taking two-dimensional discrete Fourier transfer. The regulations on the variation of the intensity distribution of the cat-eye reflected light with different damage conditions of the sensor can then be given, and the effect of the focal shift can be analyzed. Experiment results show the intensity distribution of cat-eye reflected light has a direct relationship with the profile of the damage region and the amplificatory effect for the small damage region is of direct ratio with the focal shift. Moreover, the proposed method can be straightforwardly utilized for the surface damage effect detection of a sensor in optical lens without disconnecting it.

Telescope coupling efficiency is one of the important parameters for a lidar system because of the use of single-mode fiber Bragg grating, which seriously affects the signal-to-noise ratio of lidar. A newly developed telescope coupler of lidar based on single-mode fiber array is designed to enhance the coupling efficiency and signal power. By analyzing the coupling mathematic expression between the free space plane-wave and single-mode fiber, the relationship between the numerical aperture and the alignment tolerance, especially the relation between lateral offset and tilt angle error, is established, and then the system parameters are optimized to improve the coupling efficiency. For further improvement of the signal-to-noise ratio of a lidar system, seven single-mode fibers array structured as a telescope coupler is considered to receive the lidar returning signal, and its configuration feature is analyzed using the Gaussian beam propagating matrix. Simulation results show that this coupler may provide optimum coupling efficiency and signal power for all-fiber Raman lidar, and then the coupling efficiency of backscattering signal stimulated by near-field beam is given for the case of considering telescope focal length and central obscuration.

This paper presents the design of the 2D laser distance sensor based on the laser triangulation principle. The hardware structure of the sensor and the signal processing circuit based on DSP and FPGA are designed. A CMOS image sensor is used to grab the laser light image of the laser line on the object. The pixel positions of the laser line in the grabbed image are extracted by image processing methods. In order to improve measuring precision, the geometric distortion of the original image is corrected and the system parameters of the sensor are calibrated. Experimental results demonstrate that the devised sensor can work at high-speed with high precision.

The laser output power stability is one of the most important parameters to evaluate a laser performance. Both the operation principle and the structural features of a laser-diode (LD) end-pumped single-frequency Nd:YAG laser at 1064nm are described, the main factors that affect the stability of Nd:YAG laser output power are recieved, and a control scheme has been proposed and experimentally studied for the stabilization Nd:YAG laser output power. Because the output power of Nd:YAG laser is proportional to the injection current LD when the temperature of LD and Nd:YAG crystal rod is stable, the control scheme requires firstly that the temperature of LD and Nd:YAG crystal rod be strictly controlled, then LD's injection current be adjusted throng a negative feedback control system when Nd:YAG laser output power fluctuates. Experimental results indicate the laser output power stability is better than 1.3% within a period of 130 minutes by use of the designed control system when the output power of LD-pumped single-frequency Nd:YAG laser at 1064nm is about 11.5mW,

The internal optical feedback effect in fiber ring lasers is similar to self-mixing interference, and the former has same phase sensitivity with the later: one fringe shifting corresponds to a target displacement of half optical wavelength λ. The optical feedback effect presented in this paper is achieved inside the laser cavity. So the feedback part becomes part of the fiber ring laser, and makes the laser not only a light source, but also a sensitive element. The similarities and differences between optical feedback in fiber ring lasers and self-mixing interference in semiconductor lasers are analyzed, which offers the theoretical foundation and experiment technology for fiber active sensing applications. The internal optical feedback system based on fiber ring lasers satisfies the need of microminiaturized sensing device and the interrogation demand of optical fiber. This system can easily perform noncontact and remote measurement of velocity, vibration, displacement, etc.

Metal tanks are generally used for the measurement of liquid petroleum products for fiscal or custody transfer application. One tank volume precise measurement method based on data cloud analysis was studied, which was acquired by laser scanning principle. Method of distance measurement by laser phase shift and angular measurement by optical grating were applied to acquire coordinates of points in tank shell under the control of a servo system. Direct Iterative Method (DIM) and Section Area Method (SAM) were used to process measured data for vertical and horizontal tanks respectively. In comparison experiment, one 1000m³ vertical tank and one 30m³ horizontal tank were used as test objects. In the vertical tank experiment, the largest measured radius difference between the new laser method and strapping method (international arbitrary standard) is 2.8mm. In the horizontal tank experiment, the calibration result from laser scanning method is more close to reference than manual geometric method, and the mean deviation in full-scale range of the former and latter method are 75L and 141L respectively; with the increase of liquid level, the relative errors of laser scanning method and manual geometric method become smaller, and the mean relative errors are 0.6% and 1.5% respectively. By using the method discussed, the calibration efficiency of tank volume can be improved.

Energy metabolism is one of the basic life activities of cellular in which lactate, O₂ and CO₂ will be released into the extracellular environment. By monitoring the quantity of these parameters, the mitochondrial performance will be got. A continuous measurement system for the concentration of O₂, CO₂ and PH value is introduced in this paper. The system is made up of several small-sized fiber optics biosensors corresponding to the container. The setup of the system and the principle of measurement of several parameters are explained. The setup of the fiber PH sensor based on principle of light absorption is also introduced in detail and some experimental results are given. From the results we can see that the system can measure the PH value precisely suitable for cell cultivation. The linear and repeatable accuracies are 3.6% and 6.7% respectively, which can fulfill the measurement task.

We measured the transient wavelength and line width of distributed feedback (DFB) diode laser by the short fiber delayed self-heterodyne (FDSH) interferometer. Experimental results have shown that the beat frequency signal and power spectrum were consistent with the theory. The beat frequency was measured from 20mA to 120mA injection current. The emission wavelength and linewidth dependence on injection current where the laser heat sink temperature, T, was held constant at temperature T=-5 degress Celsius, namely, tuning characteristics of transient were obtained. We compared the transient characteristics with the static one of the DFB diode laser. The results showed that the deviation was about 0.4nm. This meant that, in most cases the transient wavelength and line width of diode laser could not be substituted by the static one of the diode laser. This innovative feature was helpful to improve the accuracy of laser systems based on multi-gas sensing.

The wide variety of shapes, functions, and operational parameters of microelectromechanical systems (MEMS) moving into production requires high flexibility for any measurement instrument. A computer-controlled stroboscopic interferometer system is described in the paper for measuring out-of-plane motions of MEMS structures with nanometer resolution. This system introduces five-step phase-shifting interferometric measurement method with high accuracy and differential measurement mode by choosing a fixed area on the device as the reference point, which eliminates the effect of random errors efficiently and improves the measurement repeatability of the system. The repeatability of 10 measurements is 3.17 nm. The study on the dynamic behavior of a micro-resonator illustrates the powerful capabilities of the system.

In recent years, the reliable method to obtain absolute phase has been studied more and more widely in the field of structured light. A 3D profile measurement using heterodyne dual-frequency phase shift method is proposed in this paper. The method has three parts: phase shift, heterodyne dual-frequency and binocular stereo vision. The four-step phase shift technique is used to obtain wrapped phase map. The wrapped phase map is arctangent values between -π and π. To get the absolute phase map, wrapped phase map must be unwrapped. The traditional phase unwrapping methods, such as Gray code, produces wrong unwrapping results easily on image code boundary or break points. To solve this issue, firstly we project two spatial frequency fringes separately onto the object and obtain two wrapped phase maps by four-step phase shift technique. Secondly, by superimposing one wrapped phase map upon the other produces another phase map with a lower frequency according to heterodyne dual-frequency principle. This phase map is the absolute phase map. Finally, the binocular stereo vision accomplishes stereo matching according to the absolute phase map and 3D point reconstruction. Experimental results show that accurate and reliable phase result can be obtained on phase map boundaries and break points, which proves its feasibility in industry measurement.

This paper research the effect of scale using in reconstruction of industry close-range photogrammetry. The two major factor of scale using, deviation of scale reconstruction and calibration, are analyzed. Based on the analysis, the equation of deviation in scale using is obtained and verified by the experiment. According to this equation, some requests of scale using to improve the reconstruction accuracy are studied, and a new scale using method, close scale model, is proposed. Using close scale model, it can be reduced the effect of scale using deviation in reconstruction, the accuracy of industrial close-range photogrammetry is improved.

Slider/disk clearance, also known as flying height, is one of the most critical parameters when designing a hard disk drive (HDD). Flying height is supposed to be lower and lower with the increase of magnetic recording areal density in order to maintain sufficient signal amplitude and hence high signal-to-noise. In this paper, a symmetrical common-path heterodyne interferometry (SCPHI) is introduced and utilized to measure the clearance of commercial slider/disk. A high-speed phase measurement technology is employed and the symmetrical common-path configuration can effectively compensate the errors induced by spinning disk distortion, disk runout and some environment disturbances. Theoretical analysis indicates the resolution of SCPHI is better than 0.1 nm when the resolution of phase measurement is 0.1⁰. On the other hand, the method was employed to measure the height of an etched groove, and the results agree well with these by a commercial white light interferometric surface profiler, verifying its sub-nanometer resolution. Furthermore, clearances of commercial slider/disk interface under different rotation speeds were successfully obtained by the proposed method.

In order to obtain the output of tunable dual-frequency laser with large frequency difference, a scheme has been designed for diode-pumped two-cavity dual-frequency Nd:YAG laser, which is based on the principle of laser longitudinal mode selection by use of intra-cavity birefringent filter. The feasibility of simultaneously oscillated dual-frequency Nd:YAG laser output has been experimentally verified when a novel birefringent filter consisting of a polarizing beam-splitter and a half wave-plate (i.e. PBS-λ/2) as a laser longitudinal mode selector. The advantages and disadvantages of the dual-frequency Nd:YAG laser have been analyzed and an optimum design scheme of dual-frequency Nd:YAG laser at 1064nm has been proposed and experimentally investigated. In the optimum scheme, both output couplers of the straight and right angle standing-wave cavities have been chosen to be made from calcite crystal plates, and such birefringent output couplers together with the intra-cavity common piece of PBS element constitute two independent birefringent filters acting as laser axial mode selectors. The p-and s-component of 1064nm laser light can therefore be forced to oscillate simultaneously in single longitudinal mode in the straight and right angle cavities, respectively, and the frequency difference of dual-frequency laser can be tuned by changing each cavity-length. The experimentally obtained results indicate that the tuning range of frequency difference of dual-frequency laser at 1064nm has been expanded from the previous range of 27~113.4GHz to the present range of 11.9~148.4GHz when an optimum scheme is used.

A new method based on laser-generated ultrasound and piezoelectric transducer (PZT) is proposed to measure the velocity distribution on welded metal structure. High-frequency Rayleigh waves are excited by the Nd: YAG pulsed laser and probed by self-made transducer. A serial of ultrasonic pulses can be detected on the surface of the sample by the transducer through the scan of the line source with translation stage. The waveform cross-correlation technique is applied to compute the propagation velocity of Rayleigh waves. Then analogically, a series of wave velocities at different positions are detected, by which the distribution of velocities is obtained. It is found that high frequency wave signals excited by laser line pulse can be probed effectively using the PZT, and results indicate that this method can provide the basis for precision detection with quick scanning and the reliable measurement of velocity distribution.

Blue-green laser communication has many advantages over traditional VLF radio communication especially to a submerged subject. An experimental blue-green laser communication system employing optical pulse position modulation (PPM) is developed. The principle of PPM modulation method is analyzed, and the corresponding frame format is presented. Then the detailed design of PPM modulator and demodulator are separately described, and the practical implementation of the transmitting and receiving systems are realized. Results show that the whole communication system is compact, efficient, reliable and inexpensive. It has achieved a high-speed rate communication up to 5M bits/s and a reasonably low error rates to 10^-4. Further research of this PPM modulated system will provide advantageous reference to underwater, space and other optical communication.

Modern manufacturing in the globally networked economy with exchange of components, sub-assemblies and final products is based on internationally accepted procedures and standards for production control which in turn require a system which guarantees globally comparable measurements, traceable to the international system of units, the SI. This paper describes some of the activities of the precision engineering division of the PTB, the national metrology institute (NMI) of Germany, to support and further develop the necessary metrology infrastructure for production control. In general, these activities are concentrated on the following aspects: research and development in the field of prototype measurement instrumentation especially adapted to the needs of a metrology institute, modelling of the signal contrast of measurement tools, design and development of suitable calibration standards, determination of calibration uncertainties, e.g. by use of so-called virtual instrumentation models, dissemination of the unit of length to the manufacturing industry as well as science and society by means of calibrated dimensional standards, organization of and involvement in international comparison measurements between NMIs and cooperation in national and international standardization work. Examples for these different activities will be given in this paper with a focus on the support of nanomanufacturing processes.

Invasive and non-invasive measurement sensors and systems perform vital roles in medical care. Devices are based on various principles, including optics, photonics, and plasmonics, electro-analysis, magnetics, acoustics, bio-recognition, etc. Sensors are used for the direct insertion into the human body, for example to be in contact with blood, which constitutes Invasive Measurement. This approach is very challenging technically, as sensor performance (sensitivity, response time, linearity) can deteriorate due to interactions between the sensor materials and the biological environment, such as blood or interstitial fluid. Invasive techniques may also be potentially hazardous. Alternatively, sensors or devices may be positioned external to the body surface, for example to analyse respired breath, thereby allowing safer Non-Invasive Measurement. However, such methods, which are inherently less direct, often requiring more complex calibration algorithms, perhaps using chemometric principles. This paper considers and reviews the issue of calibration in both invasive and non-invasive biomedical measurement systems. Systems in current use usually rely upon periodic calibration checks being performed by clinical staff against a variety of laboratory instruments and QC samples. These procedures require careful planning and overall management if reliable data are to be assured.

Dynamic error measurement methods of force sensors toward the dynamic calibration and correction are reviewed. The methods are based on the Levitation Mass Method (LMM). In the LMM, the inertial force of a mass levitated using a pneumatic linear bearing is used as the reference force applied to the objects under test, such as force transducers, materials or structures. The inertial force of the levitated mass is measured using an optical interferometer. In this paper, software for correcting the dynamic error of force sensors has been proposed.

The NB fan is placed in the center of the seismic platform. The commercial DVD pick-up head is used as the sensor to measure the vibration of the NB fan. We use the automatic positioning program to control the micro stage, and let the DVD displacement sensor to position the zero-point of S-curve automatically. Experimental results indicate that the standard deviation is less than 5%, which indicates that the displacement senor has an excellent stabilization. Furthermore, the commercial DVD pick-up head is used as the sensor, so this system not only reduces the cost but also obtains good vibration measurement results.

Four beams laser rangefinder with possibility to determinate an angle between the main axis of the space vehicle and the normal to the plate ground was designed. The testing unit for fixing optical axis and measuring main characteristics of receiving module is described. The unit allows to measure the focal plane position of main lens, detector chanel detectivity, level of nonaxis sun scattering light, transmittance of optical system and dynamic range of receiving channel.

An independent distortion correction algorithm based on equidistance is proposed in this paper. Two entirely different procedures of distortion correction and parameter calibration are isolated. Distortion correction is firstly realized to provide the basis for linear calibration to improve calibration accuracy. In the independent algorithm, the difference between ideal and actual pixel coordinates is defined as distortion amounts for all imaging points, which are calculated by finite "reference photopoints", mobile pitches and straight slopes in x and y directions of the feature-point lattice. Then distortion amounts for all non-imaging feature points are computed by making use of bilinear interpolation. Finally, a higher-precision reference table is set up which applies to all kinds of calibration or measurement images. The imaging center point (principal point) is the position with the smallest distortion amount in the reference table. The experimental results demonstrate that the independent algorithm could effectively correct lens distortion and it has benefit for improving the calibration accuracy of machine vision systems.

Developing the ac low voltage standard source need the technology of low-noise digital synthesis sine wave. In this article, we analysed the frequency spectrum characteristic of the digital synthesis sine wave. Considering the ac low voltage had the strict requirement for harmonic wave, we put forward the "harmonic wave counteraction method", and found this function to counteract harmonic wave, and made it come true from the mathematics and electrocircuit. By the strict calculating of the numerical value and testing verification, we testified the feasibility of the method. By using "harmonic wave counteraction method ", every harmonic wave noise was reduced several order of magnitude, and the total noise voltage was less than 4μV in the 50Hz~10kHz frequency range, the uncertainty for the effective value of output voltage was 0.001%.

This paper presents the findings about performance of the fuel system of a diesel engine at different diesel temperature obtained through simulation and experiment. It can be seen from these findings that at the same rotational speed of fuel pump, the initial pressure in the fuel pipe remain unchanged as the fuel temperature increases, the peak pressure at the side of fuel pipe near the injector delays, and its largest value of pressure decreases. Meanwhile, at the same temperature, as the rotational speed increases, the initial pressure of fuel pipe is also essentially the same, the arrival of its peaks delays, and its largest value of pressure increases. The maximum fuel pressure at the side of fuel pipe near the injector has an increase of 28.9 %, 22.3%, and 13.9% respectively than the previous ones according to its conditions. At the same rotational speed, as the temperature increases, the injection quantity through the nozzle orifice decreases. At the same temperature, as the rotational speed increases, the injection quantity through the nozzle orifice increases. These experimental results are consistent with simulation results.

In order to identify accelerometer error model coefficients more accurately on indexing table, the relationship between the calibration accuracy of accelerometer and the errors of indexing table is determined. At first, the attitude matrix between accelerometer coordinate system and geographical coordinate system is established based on consideration of various error sources. Then the accelerometer output expressions are analyzed based on the established error model. After that, according to the output of an accelerometer, the relationship among calibration errors of accelerometer model coefficients, indexing table errors and alignment errors is analyzed through Fourier analysis. Finally, an accelerometer is calibrated on indexing table and the angular errors are measured, modifications of bias K_F and scale factor K_I are analyzed before and after compensating for the angular errors. Experiments show that, to make relative calibration accuracys of K_F/K_I and ▵K_I/K_I achieve relative accuracy of 10^-6, the first and the second order term of Fourier series of the angular errors of the indexing table should be less than 0.15" and 0.4" separately, random error and angular rotary error of the axis system should be limited to 1" level.

This paper gives a way which utilizes the PTC (Positive Temperature Coefficient) material to preheat diesel fuel in the injector in order to improve the cold starting and emissions of engine. A new injector is also designed. In order to understand the preheating process in this new injector, a dynamic temperature testing system combined with the MSP430F149 data acquisition system is developed for PTC material heating diesel fuel. Especially, the corresponding software and hardware circuits are explained. The temperature of diesel fuel preheating by PTC ceramics is measured under different voltages and distances, which Curie point is 75 °C. Diesel fuel is heated by self-defined temperature around the Curie point of PTC ceramics. The diesel fuel temperature rises rapidly in 2 minutes of the beginning, then can reach 60 °C within 5 minutes as its distance is 5mm away from the surface of PTC ceramics. However, there are a lot of fundamental studies and technology to be resolved in order to apply PTC material in the injector successfully.

The factors that effect the surface temperature measurement of planes using infrared thermography were analyzed based on the theory of infrared radiation. The blackbody is normally used as a measurement standard to calibrate the infrared thermography. Because the atmosphere has an affect of absorption on the infrared ray, while all the measurement as well as blackbody can not avoid transmitting through the atmosphere, so that the affect brought by the atmospheric transmittance becomes a main factor that effects the measurement on blackbody. And the influence caused by the atmospheric transmittance was mainly discussed. Meanwhile, a set of experimental taking blackbody as measured target has been done to discover the principle of error during the measurement. And the atmospheric transmittance can be calculated through the experiment results. Furthermore, the calculated value was used to compensate the error caused by the atmosphere. Compare the calibrated results with before, the measurement errors significantly reduced. Then the accuracy of measurement has been improved. Finally, a way of setting blackbody as a measurement standard was proposed to compensate the error brought by atmosphere.

Rolling bearing is a very important comment for mechanical system. The traditional measurement method is using time domain analysis and frequency domain analysis with mechanical vibration theory. However, these methods are very difficult to precisely diagnose the rolling bearing fault. Demodulated resonance technology is an effective method to diagnose bearing fault. In this paper, the realization of demodulated resonance technology is described in detail. It includes three important aspects: design of filter, envelope demodulation and spectrum zooming. Hilbert transform is an effective solution to envelope demodulation. Based on this theory, the PC controlled experimental device for fault diagnosis was built up. The ball bearing of type 6201 was measured on the experimental device, and the applications software was programmed by VC++, which had the functions of real-time monitoring, spectral analysis (FFT), digital filtering and zoom-FFT etc. So this system can get fault characteristic from the vibration speed signal with big noise and automatically identify the type of fault. The types included the fault of inner ring, outer ring and rolling element. Results showed that it has a remarkable effect on bearing fault diagnosis, and it had many advantages such as high precision, high degree of automatic measurement.

Blade tip timing is a non-intrusive technique used for detection, measurement and analysis of blade vibration in rotating blade assemblies. The main recent focus in the application of blade tip timing system has been the determination of blade vibration frequencies. Although the fundamentals of the technique are fully developed, the analysis of data obtained in the presence of simultaneous excitation response is problematic. A number of methods have been introduced for the analysis of blade tip timing data from assemblies undergoing synchronous excitation or asynchronous vibration, each of them has its inherent limitation in practice. The approaches to the analysis of blade tip timing data were presented with its theoretical principle and application requirement. Several of the techniques were found to perform effectively on asynchronous resonances or synchronous resonances, with accurate vibration frequency estimates yielded.

The parameters of the robot have been changed due to the rising of machine temperature and the external environment variances during the continuous moving of the robot, which greatly enlarge the error of the robot coordinate measurement system, therefore the changes of the parameters must be compensated. This paper compares two techniques used in robot parameters rapid calibration: based on measurement space fixed-point real-time robot parameters rapid calibration technology and based on space constant distance real-time robot parameters rapid calibration technology. Both of the techniques realize with the same method. First, we should solve out the robot model parameters in reversal after changing based on the relationship of the robot motion model, parameters and fixed-point coordinate (constant distance).Then figure out the measuring results variation caused by the change of robot parameters by forward calculation with these parameters. At last, amend the final measuring results to realize real-time robot parameters rapid calibration. Experiments prove that techniques based on measurement space fixed-point real-time robot parameters rapid calibration can improve system accuracy from 0.5mm to 0.2mm above, while those based on space constant distance real-time robot parameters rapid calibration can reduce the system error from 0.5mm to 0.18mm. So, the accuracy compensate ability of the latter one is slightly higher than that of the former one by 0.02mm.

In order to improve the accuracy of an instrument by reducing or correcting the error of a sensor system, a calibration device which can be used to trace the laser wavelength is used to calibrate the static and dynamic characteristics of dual sensor system. Based on the accurate calibration data of the sensor, the nonlinearity error and the coherence error are corrected and compensated using least-square approximation model and interpolation method. Test results indicate that the nonlinearity of each sensor can be within 0.15% in the range of ±10μm and the incoherence is less than 0.2 % in the range of ±5μm after corrected. Meanwhile, the cause and effect of a misalignment error between dual sensors are analyzed.

This paper presents a planar projective transformation based method for fully automated exterior and interior calibration of a three-dimensional laser scanning system. The calibration is crucial for applications that attempt to produce accurately registered or fused three-dimensional sensor data. A key contribution of the method lies in the derivation of transformation relations that describe the same point in three defined coordinate systems with respect to the rotating characteristic of two scanning planes and its calibration target object whose geometric feature can be reliably recognized from a single observation. The transformation relationship can be converted to the closed-form solution to the constraint equations of the system parameters in the form of intrinsic and extrinsic matrices. By deriving the relationship between a single two-dimensional range scan and the point location presentation in the absolute frame, the interior and exterior calibration can be accomplished simultaneously and the algorithm of the 6 DOF pose improves the identification precision. Finally, this paper reports the performance and stability of this method on real data sets, and demonstrates the accuracy within ±0.1 degree of the orientation precision and 8mm of position precision in a realistic configuration.

This paper presents a photoelectric autocollimator, which consists of an optical autocollimator and an area CCD and is calibrated using a dual-frequency laser interferometer HP5528A. The positional precision of a NC motorized stage is detected automatically and quickly by applying the photoelectric autocollimator calibrated and an optical polyhedron to finish the error compensation of the stage. According to GB/T 17421.2-2000, when the polyhedron and the stage both revolve with the same axis, the positional error of the stage is measured by the photoelectric autocollimator. Experimental results show that an angle can be measured by the photoelectric autocollimator whose standard deviation is less than 0.5" and the calculated position accuracy agrees with the specification of the stage.

Articulated Arm Coordinate Measuring Machine (AACMM) is a kind of portable coordinate measuring equipment with a flexible structure, which employs a series of rotating components around generally perpendicular axes. As a portable device, the probe parameters of AACMM will change after probe switching or dismounting and reassembling the same probe during shipping AACMM from one place to another to carry out measurement tasks. As incorrect coordinates will be given without the correct probe parameters, the probe parameters must be re-identified. By analyzing the identifiability of geometrical parameters of kinematical model and presenting the non-redundant-parameter model in this paper, a simple approach for the probe parameters calibration of AACMM is proposed, to improve its portability and ensure the accuracy of AACMM. In addition a very simple accessory was designed to hold the spherical probe as a data capture device. Gauss-Newton method was adopted as an optimization method to figure out the probe parameters. A program was developed to carry out the calibration process. Experimental results prove that the calibration approach proposed in the paper was effective.

This paper based on the analysis and research of radio altimeter and its basic principles, it introduces a design for I/Q modulator's radio altimeter testing system. Further, data got from the test had been analyzed. Combined with the testing data of the altimeter, a construction of the I/Q modulator's radio altimeter testing system is built.

This paper presents the results of the effort to develop a transfer alignment algorithm designed to align a low-cost Fiber Optic Gyroscope Inertial Measurement Unit(FOG-IMU) with the Position and Azimuth Determining System(PADS) of Guided Multiple Launch Rocket System(GMLRS) in a short time with high accuracy. The Ring Laser Gyroscope IMU(RLG-IMU) of the PADS is defined as the Master Inertial Navigation System(MINS) and the FOG-IMU as the Slave Inertial Navigation System(SINS). The accurate attitude initializing of SINS based on the attitude information of both INSs can be accomplished by providing the normal launch motion(pitch and yaw). The relevant state equations and measurement equations of transfer alignment Kalman Filter(KF) are presented. A particular calibrating scheme is designed to determinate the parameters of the MINS and SINS just in the same time. The algorithm is verified by laboratory testing of both INSs under the compound manoeuvre of a three-axis turntable modeling the launch procedure of GMLRS.

During double flank rolling composite detection, the radial composite deviations of master gears has been existed and transferred to the measured gear by the primary harmonic curve. In order to improve measurement accuracy, a measuring instrument is developed for radial composite deviations of high-precision master gear in the paper. This instrument uses the structure of spring-suspend swing span to overcome the shortcomings of large rotation errors, low sensitivity, low resolution and large measuring force appearing in the traditional combination-type gear inspection instrument. Artificial intelligence technology is used to improve the efficiency and accuracy of this instrument. The result is that the measuring apparatus is able to meet the requirement and improve efficiency through the measuring experiments on master gears of precision grade 2 with modulus 2 mm and 3 mm, respectively.

The determination of the center of rotation for projection is a very important step for the establishment of a X-ray two-dimensional computed tomography imaging system. The error of the center of rotation may lead to artifact in computed tomography image. In this work, the current popular measurement methods for the center of rotation are described and their advantages and disadvantages are reviewed, and a new method is thus put forward through analysis. The proposed algorithm is based on the laws: 'A particle is scanned a circle by computed tomography scanner, then the integral of the particle's projection address under each projection view equals to zero' and 'The sum of the coordinates of crossing points of projection sine curves of two random particles equals to zero'. The center of rotation for projection is determined by calculating the mean of projection address of the X-ray beam penetrating object. Compared with the current methods, the proposed algorithm needs no phantom and geometry parameter. The algorithm is real-time and has high measurement precision. The feasibility of the method is validated using the experiment results.

Bias of magnetometers and target total value is obtained precisely via calibration equipment. Then, real time calibration weight matrix is obtained using LMS adaptive algorithm. It is proved through experiment that bias is obtained with good stability and accuracy compared with parameter estimation; after calibration, diversionary error is reduced from 33nT to 4nT. Furthermore, diversionary error is calibrated well using a proton magnetometer without rotating the magnetometer over one circle. Experiment results show that it not only reduces diversionary error fluctuation but also eliminates system error compared with other methods.

By analyzing the dynamic error of CMM, a model is established using BP neural network for CMM .The most important 5 input parameters which affect the dynamic error of CMM are approximate rate, length of rod, diameter of probe, coordinate values of X and coordinate values of Y. But the training of BP neural network can be easily trapped in local minimums and its training speed is slow. In order to overcome these disadvantages, genetic algorithm (GA) is introduced for optimization. So the model of GA-BP network is built up. In order to verify the model, experiments are done on the CMM of type 9158. Experimental results indicate that the entire optimizing capability of genetic algorithm is perfect. Compared with traditional BP network, the GA-BP network has better accuracy and adaptability and the training time is halved using GA-BP network. The average dynamic error can be reduced from 3.5μm to 0.7μm. So the precision is improved by 76%.

According to the definitions of the diameters in the new generation Geometrical Product Specifications(GPS), the evaluation models of least square diameter, minimum circumscribed diameter, maximum inscribed diameter, area diameter, circumference diameter and volume diameter are built on the cylindrical coordinate system for the section measuring path, the element measuring path and the bird-cage measuring path in this paper. A cylindrical coordinate measuring machine for the measurement of the diameters above is introduced. Based on the external standard cylinder with super high precision, a relative calibration method for the measurement of the radial size is promoted. The influence of several special cases of the installation of the cylinder on the calibrating results is analyzed, and the calibrating equation related to the special cases is given.

This paper presents a radiometric calibration method based on visibility function and uniform source system. The uniform system is mainly comprised of an integrating sphere and a monitoring silicon detector. The current of the silicon detector with a visibility function filter corresponds to the luminance at the exit port of integrating sphere through standard luminance meter transfer. The radiance at the camera entrance pupil is calculated for different solar zenith angles and Earth surface albedos by the MODTRAN atmospheric code. To simplify the calibration process, the radiance at its entrance pupil is integrated by visibility function. The shift smear of the frame transfer CCD is removed by the radiometric calibration and the amending ratio factor is introduced in the retrieving methods. The imaging experiment verifies the reliability of the calibration method and retrieves good quality image.

In order to provide the beneficial expression of lens distortion for star trackers, the numerical results of the grid distortions of four typical star tracker lens systems have been investigated, and then data fitting is done with combined multinomial of different number of terms and powers of radial radius. The results indicate that the expression of relative distortion including terms of the one, two, three and four powers of the radial distortion is beneficial in terms of accuracy, and the fitting function with high-order is not quite helpful in providing a more accurate expansion. In order to further validate this distortion model, a star tracker camera calibration approach has been simulated with the data obtained by ray tracing via the Non-Sequential Components of ZEMAX, with imperfect alignment and assembly taken into account. Simulation results also indicate that the four-order of the radial distortion is beneficial.

On-line calibration is widely used no matter in science research or industrial production. In this paper, an on-line calibration approach for industrial displacement transducers has been developed. We used laser displacement sensor as standard and improved its accuracy to meet the requirements in different applications. In order to achieve the objective, laser sensor must be calibrated by automatic interference comparator. Laser sensor and automatic interference comparator measured the same displacement simultaneously and obtained the laser displacement sensor's calibration curve by analyzing the measurement data. Then the on-line calibration system including mechanical device and calibration platform was developed with the calibrated laser sensor. Numerous factors, such as verticality, colors, reflector material and vibration, contribute to errors in the compact laser displacement sensor measurements under field conditions. Analyzing the data obtained from the device's application of air spring system in automatic interference comparator, the presented paper outlines the error compensation methods and mathematical model. Experimental results show that laser sensor on-line calibration system can solve factory calibrating problems with accuracy requirement over 0.3%.

Truck scale is widely applied to many fields such as storage, trade, transport, communication, industry and mine. Conventional method of error compensation for truck scales is fussy and the accuracy of weighing result is low. An error compensation method based on complex BP neural networks (CBPNNs) is proposed in this paper. Considering the character of error in scale's different weighing zones, the sub-BPNNs are constructed, and each one is used to compensate the weighing error of a weighing zone. The adaptive choice network is founded to automatically choose suitable sub-BPNN, and then the chosen sub-BPNN optimally compensates the error of different weighing ranges. Emulational experiments show that the weighing error of the truck scale with this proposed method is less than that of using a single RBFNN to compensate the error of total weighing range, and all results of field verification show that the maximum eccentric error is -4kg and the maximum repeatability error is +6kg, which is far less than that of the 3th class scales defined by International Recommendation OIML R76 "Nonautomatic Weighing Instruments".

Double Parallel Joints coordinate measuring machine (CMM) is a new type coordinate measuring device with 9 structural parameters with accuracy difficult to be ensured just by processing and assembly. Calibration is needed to identify the structural parameters of the measuring machine. This article describes the calibration process of such a Double Parallel Joints CMM, and simulation was employed to analyze how the number of samples and angle measurement accuracy influence the measurement precision and calibration result during calibrating process. The conclusions are very instructive to precision design or error allocation and calibration process of the Double Parallel Joints CMM.

Precision through-lines, coaxial airlines, are the most accurate microwave impedance standards. They are widely applied in the TRL calibration method. The air-lines are also important standards which are used to test network analyzer systems. In addition, the scattering parameter and uncertainty of coaxial air-line are important for improving the accuracy of VNA. However, the conventional microwave measurement systems have limitations in observing and obtaining accurate information of the performance of coaxial air-lines. In this paper, a new approach is proposed that determines microwave scattering parameter by physical components and assumed models. Experimental results demonstrate the efficacy of the proposed algorithm in comparison to the experimental results obtained from microwave measurement. In addition, the estimated uncertainty is also presented.

The quasi-static method with application of half-sine pressure pulse is presented to calibrate the piezoelectric sensor, which is used for the dynamic pressure measurement of weapons. A pressure generator based on the drop hammer hydraulic system is manufactured to get the half-sine pressure pulse. The oil cylinder of the generator is reconstructed to install four standard pressure sensors and two calibrated sensors simultaneously. With pressure taken from four standard sensors as calibrating excitation, and response data obtained from calibrated sensors, the working sensitivities of sensors are worked out through regression analysis. The experimental results obtained with sensor 6215 at the national shooting range shows that it is effective to calibrate piezoelectric sensors using half-sine pressure pulse. The residual standard deviation of the equation fitting is less than 0.7%; the linearity is less than 0.21%; and the relative uncertainty of the four standard sensors is less than 0.7%, under the precision target of the calibration system acceptance.

The analytical equation for the thermal field of a helical gear under normal working condition in a stable thermal field is established using mathematical physics, and the thermal deformation of the gear can be computed using this equation. The variations of gear geometric parameters, such as radial dimension, tooth depth, spiral angle, pressure angle, flank clearance and etc., are investigated with respect to the temperature change. According to the analytical and computational results obtained using the equation, the thermal deformation of the gear is strongly dependent on the choice of parameters, which is also confirmed using simulation software (COMSOL Multiphysic software). This is significant for the improvement of the rotation precision and working efficiency of screw gears.

To meet the requirement of Nano-scale dimensional metrology, length standards with features below 100 nanometers are indispensible instruments. Our group has successfully fabricated length standards with periodic length of 213±0.1nm using the laser focused atomic deposition method, which is related to the atomic transition frequency and thus retraceable to a constant measured with high accuracy. For further improvement of the quality of these standards, we propose the use of Zeeman slower, which consists of an array of symmetrically positioned small discrete NdFeB magnets. Ideal magnetic field distribution is obtained employing Zeeman-tuned Doppler cooling theory. A simple and effective point-like magnetic dipoles model (MD) is used to represent the magnets during simulation. Two kinds of different oriented MDs are compared and only one is selected. By introducing local field contribution approximation, periodic array assumption and a new relative field deviation parameter, MDs array's configuration are calculated and optimized. The overall RMS of the difference between the ideal and calculated field in the whole length is reduced to 3.08E-3 T, and an optimal MDs array configuration is found and presented.

Many modern MEMS devices incorporate multi-layered structures. However, the metrology of such structures is struggling to keep pace with their manufacture. In this paper the measurement of the internal geometry of MEMS devices using optical coherence tomography and infra-red confocal microscopy is discussed. Both measurement techniques provide non-contact, non-invasive measurements of internal geometry. However, both techniques use relatively new technologies for measuring internal geometry and the understanding of their capabilities is limited. The study reported in this paper has mainly focused on the thickness measurement of layers. The performance of both instruments has been investigated by measuring a 50 μm thick plate artefact that had been calibrated using a traceable stylus instrument. The standard uncertainties associated with the measurements of the artefact are 0.391 μm for optical coherence tomography and 1.085 μm for infra-red confocal microscopy. Finally, the capabilities of the two instruments have been highlighted by measuring a pressure sensor containing multi-layered structures. These measurements demonstrated that both instruments have the ability to measure the thickness of layers and to image internal geometrical structures.

For the single silicon cantilevers with low kinetic Reynolds numbers from 0.06 to 0.17, a modification of the existing approximate model for air damping analysis is presented. The mass added at the end is found to improve the quality factor of a cantilever in atmosphere. Silica gel is added at the end of the cantilever, as the loading mass. For a mass-loaded cantilever of 465x10x0.8 μm³, the quality factor is improved from 7.25 to 19.07, according to the loading mass of 21.79 ng. However, the frequency of the cantilever declines from 5.54 kHz to 1.68 kHz, resulting in a worse force detection resolution at the end.

The lens constructed with slits perforated on the thin metallic film is designed by simulated annealing algorithm. And two demonstrates are carried out to validate the directional design algorithm. First, the lens with one focal spot is considered. After the width of each slit is obtained, the finite-difference time-domain method is used to check the performance of the designed lens. It is found that the focal length is 800nm and the full-width at half-maximum of the focal spot is 252nm, which corresponds to the preset objective well. Then, the lens with three focal spots is also designed by this algorithm and the performance of the designed lens is quite close to the objective. This is the first work to introduce directional algorithm into design SPP lens. It may pave the way for the design sub-wavelength optic devices.

SU-8 is not only an epoxy-based negative-tone photoresist but also a potential building structural material which can be directly used as movable parts in micro structures for its unique UV curing characters and high-aspect ratio. It is particularly suitable for the fabrication of a wide range of low-temperature processes objects, such as micro valves, micro gear wheels and micro grippers. A standard mechanical property parameter database of SU-8 in microscale has not been established while its characters can vary significantly depending on the process conditions. The Young's modulus is one of the important parameters to evaluate the mechanical properties of this novel structural material, especially for the optimum design, performance realization and reliability analysis of micro devices. This paper presents the design of free-standing SU-8 thin film specimens with different sizes. The fabrication processing is demonstrated and the Young's modulus is achieved through tensile testing. The experiments are operated on a micro-tensile testing system. The force is measured by a load cell with accuracy of 0.25 mN and elongation of specimen is obtained from a displacement sensor with accuracy of 0.1 um. The measured Young's modulus of 60um wide SU-8 specimens from force-displacement curves is about 2.2±0.1 GPa. The behavior of plastic deformation is also detected before elastic deformation during the experimental process.

Extreme water repellency is greatly desired for microfluidics and self-cleaning applications. Post-like aligned carbon nanotube (CNTs) films were grown on the Ni-coated Si substrates by a plasma enhanced chemical vapor deposition (PECVD) technique. The surface of morphologies of the pretreated Ni thin films were investigated using a non-contact mode of atomic force microscope (AFM) and the structural properties of as-grown CNTs films were characterized using scanning electron micrograph (SEM) and X-ray diffraction (XRD). The contact angles and the rolling angles on such films were measured through an optical contact angle meter. Wettability studies revealed the films exhibited a superhydrophobic behaviour with a higher contact angle (161.7°±1.5°) and lower rolling angle (less than 4°)-a water droplet moved easily on the surface. The post-like aligned CNTs showed discrete pillar composed of carbon nanatubes, these pillar formed nanostructure in the films, which made it easy for small water droplets to be suspended on a surface approaching that of a perfect air-water interface and strongly affected the contact angle and the rolling angle.

Fast Mobility Particle Sizer (FMPS) is an electrical mobility instrument used to measure the nanoparticle number concentration and size distribution in an office environment. Actual measurements indicate the distributions of ultrafine particle number and size in office air are inhomogeneous in space. The nonaparticle size is bimodal and log-normally distribution in an office environment when only people activities are considered. The traffic pollutant in the outdoor including the automobile tail gas and the dust will change the particles size distribution and enhance the particle number concentration those of indoor air. It can also be seen from the results that the laser printer releases a large number of nanoparticles, especially around 80nm in diameter in the printing process. The laser printer may be the mainly ultrafine particle source in the office air.

A quantum mechanical Monte Carlo simulation is carried out for one-dimensional laser cooling of Chromium atoms. Chromium atom beam collimation via transverse laser cooling is essential for the fabrication of periodic nanometer scale structures by laser-focused atomic deposition. Such structures can be used as precision pitch standards for nanometer scale measurement and engineering. We explore the roles played by several factors, such as laser intensity and detuning, in the cooling process. Calculation results show different dependencies for cooling rate and ultimate temperature to be reached with given sets of parameters. Also, for atoms with different initial velocities in the transverse direction, the conditions under which optimal collimation effect is achieved can differ. Consequently, the current experimental setup, which utilizes LIF spots from marginal beams to monitor the laser collimation, can produce cooling effects which are not optimal for the end product.

In order to study the dynamic characteristics of silicon micro-cantilever in high temperature environment, the relationship between the first-order resonance frequency of micro-cantilever and the environment temperature was theoretically analyzed. The dynamic measurement equipment was developed for the MEMS microstructure in the high temperature environment. Both the base excitation with PZT and the electrical discharge excitation method were adopted to excite the micro-cantilever under test. The impulse response signal of the microstructure can be obtained using the Laser Doppler Vibrometer. The temperature-frequency characteristics of silicon micro-cantilever has been experimentally studied. Test results show that the resonance frequency of silicon micro-cantilever slightly decreases with the increasing temperature, and it is almost a linear dependence between the change in temperature and the change in resonance frequency, which is consistent with the result of theoretical analysis.

The stochastic diffusive motions of sub-micrometer tracer particles have important effects on the velocity measurement accuracy of microfluidic particle image velocimetry (Micro-PIV). In this paper, we investigate the diffusions of 520nm particles in a square channel under the temperatures from 291K to 343K by micro-PIV/PTV technique. The displacements of particles in a couple of fames images within 30ms time intervals were evaluated by the PIV/PTV hybrid algorithm. Based on this, the logarithm distributions of square displacements and the spatial mean square displacements (SMSDs) were calculated. The results show that the distributions of particles displacements are fundamentally same under the same temperature at different moments. The logarithm of square displacements has the distributions ranging from -17 to -11, showing quasi-normal distribution characters. The value of spatial mean square displacements linearly increases with the increase of temperature, which indicates that the diffusion capabilities of particles have the increasing trend.

Ceramics are increasingly used in the fields of aerospace, communication, mechanical and modern biomedical engineering. With high hardness, strength and abrasive resistance, the machined ceramic components are most likely to contain surface/subsurface damages, influencing strongly the performance and reliability of ceramic components. Nanoindentation test is an advanced technology in measuring the elastic modulus and hardness of the materials in micro-nano scale based on Oliver-Phar's equation. Nanoindentation has been employed extensively to characterize the mechanical properties of a wide range of materials including ceramics. To characterize the surface/subsurface damage in ceramics, a degraded elastic modulus based damage variable is defined to describe the damage induced property degradation of the materials based on the traditional Kachanov continuum damage mechanics (CDM) framework. A simple characterization method for surface/subsurface damage is realized based on nanoindentation test. The alumina bulk samples are chosen to study the surface/subsurface indentation induced damage by nanoindentaiton. The elastic modulus under various indenting loads is measured with Conical and Berkovich tip. The variation of the elastic modulus and indentation induced damage with load and displacement are analyzed in detail. Experimental results show that the proposed method is feasible and satisfactory.

Twice hot-embossing, a new technology of hot-embossing proposed, can effectively reduce the error of hot forming caused by hot equipment. The depth / width ratio of micro-channel on the metal concave-mother-template is an influence parameter of twice hot-embossing; Optimization of the parameters, the PMMA convex-template has been produced in 120°C, ± 6MPa by twice hot-embossing.

In this paper, the through-focus scanning technique using a conventional bright-field optical microscope is introduced for nanoscale dimensional analysis with nanometer sensitivity. This technique uses a set of through-focus image maps (TFIMs) obtained at different focus positions instead of one 'best-focus' image and considers the through-focus image as a unique 'signal' that represents the target. The boundary element method (BEM) and the rigorous coupled-wave analysis (RCWA) method were applied to simulate the optical responses and to obtain the TFIMs of finite aperiodic and infinite periodic structures, respectively. The sensitivity of the through-focus technique for the nanoscale dimensional changes of targets was analyzed by using the differential through-focus image maps (DTFIMs). The simulation results validate the use of this technique for nanoscale metrology.

Position tolerance is used in geometric dimensioning and tolerancing to specify tolerances for the location of holes. The tolerance zone for holes is usually cylindrical and the allowable position tolerance is the diameter of the tolerance zone. If holes are used in flat parts, as e. g. sheet metals, it is sufficient to use circular tolerance zones. In order to assure the quality and to reduce the risk to accept products which do not fulfil the design requirements, statistical process control is used in industry. In this paper it is shown, how process capability indices and the associated risk can be calculated for circular position tolerance zones.

Methods of data processing in stereoscopic system for the control of spatial objects displacements are considered. Possibility of using perturbation theory for estimation of systematic and accidental errors in stereoscopic measuring system is based.

The time-of-flight method was used to calibrate an optical fiber length standard and its uncertainty of measurement was evaluated theoretically and experimentally according to the Evaluation of measurement data - Guide to the expression of uncertainty in measurement (GUM), JCGM 100:2008. The major uncertainty components in the measurement of transit time difference were identified and analyzed. The uncertainty due to temperature instability was investigated experimentally in the temperature range from 20 °C to 25 °C using a temperature chamber with precise temperature control. The temperature coefficient of the fiber length standard was derived by linear regression of the measurement data. The experimental results showed that the temperature control is critical for the calibration of optical fiber length standard. When the temperature instability was improved from ± 2 °C to ± 0.1 °C, the expanded measurement uncertainties for the optical fiber length standard (optical length : ~11780 m) were significantly reduced from 0.16 m to 0.014 m at wavelength of 1310 nm and from 0.19 m to 0.015 m at wavelength of 1550 nm.

This study aims at inventing a low-price but high-precision 3D touch trigger probe (or a CMM probe). The tip ball of the stylus, with a diameter smaller than 100 μm, is made by a micro electro discharge machine and wire electro discharge grinding. The stylus is mounted at the centre of a stiff cross-form frame, which in turn is suspended on four micro beams. As proven by several experiments, this structure restricts the degrees of freedom on three directions. The displacement sensor and 2D angle sensor is performed using modified commercial DVD pickup heads to measure the three degrees of motional freedom on the suspension structure. As for application, since the tip ball is difficult to identify by naked eye, we use modified commercial webcam and microscope to create a micro imaging system. This imaging system has been tested to have 2.8mmx2.1mm field of view, and 1.5mm depth of field.

The dual-observation adjustment model is proposed, which has advantages of meeting the necessary abundant observations for posterior estimation and improving precision and reliability of network adjustment. This model is characterized by more condition equations and easier to meet the estimable condition of posteriori estimation. A example is calculated by the model. The result show that differences, between true values and adjusted values used typical method of three gyroscopic sides, are -7", -62", -54" respectively, but the differences of Helmert method are -10",-12",-15".The studies we have performed indicate that the proposed model dramatically improves the precision and reliability of control network adjustment for underground by Helmert variance component estimation. Consequently, the model is particularly suitable for precision data processing of underground control network, and also provides theoretical basis for designing the surveying scheme of precision control network.

Existed simulation works always emphasize on procedural verification, which put too much focus on the simulation models instead of simulation itself. As a result, researches on improving simulation accuracy are always limited in individual aspects. As accuracy is the key in simulation credibility assessment and fidelity study, it is important to give an all-round discussion of the accuracy of distributed simulation systems themselves. First, the major elements of distributed simulation systems are summarized, which can be used as the specific basis of definition, classification and description of accuracy of distributed simulation systems. In Part 2, the framework of accuracy of distributed simulation systems is presented in a comprehensive way, which makes it more sensible to analyze and assess the uncertainty of distributed simulation systems. The concept of accuracy of distributed simulation systems is divided into 4 other factors and analyzed respectively further more in Part 3. In Part 4, based on the formalized description of framework of accuracy analysis in distributed simulation systems, the practical approach are put forward, which can be applied to study unexpected or inaccurate simulation results. Following this, a real distributed simulation system based on HLA is taken as an example to verify the usefulness of the approach proposed. The results show that the method works well and is applicable in accuracy analysis of distributed simulation systems.

LEDs are temperature sensitive devices. Many other characteristics of LEDs strongly depend on their thermal characteristics. So accurate measurement for the junction temperature and thermal resistance of LEDs is important. The uncertainty analysis in these measurements, which is important for accurate measurements, is given in this paper. The standard evaluation method for measurement uncertainty in GUM is used. The junction temperature of an LED is measured by indirect measurement for its forward voltage under constant current. The uncertainty components are from the measurement for the initial junction temperature, the steady forward voltage, the initial forward voltage and the calibration of the voltage-temperature coefficient. The thermal resistance is calculated with the measured junction temperature and the thermal power. The uncertainty components are from the measurement for the junction temperature, input current and forward voltage. Analysis results show that the uncertainty of the junction temperature is the most dominant uncertainty contribution in the measurement for the thermal resistance. In the junction temperature measurement, the uncertainty in the calibration of the voltage-temperature coefficient contributes significantly. Thermal equilibrium and good thermal conducting condition should be obtained. These results give a better understanding and practice guide to an accurate measurement for the junction temperature and thermal resistance of LEDs.

The theories and techniques for improving machining accuracy via position control of diamond tool's tip and raising resolution of cutting depth on precise CNC lathes have been extremely focused on. A new piezo-driven ultra-precision machine tool servo system is designed and tested to improve manufacturing accuracy of workpiece. The mathematical model of machine tool servo system is established and the finite element analysis is carried out on parallel plate flexure hinges. The output position of diamond tool's tip driven by the machine tool servo system is tested via a contact capacitive displacement sensor. Proportional, integral, derivative (PID) feedback is also implemented to accommodate and compensate dynamical change owing cutting forces as well as the inherent non-linearity factors of the piezoelectric stack during cutting process. By closed loop feedback controlling strategy, the tracking error is limited to 0.8 μm. Experimental results have shown the proposed machine tool servo system could provide a tool positioning resolution of 12 nm, which is much accurate than the inherent CNC resolution magnitude. The stepped shaft of aluminum specimen with a step increment of cutting depth of 1 μm is tested, and the obtained contour illustrates the displacement command output from controller is accurately and real-time reflected on the machined part.

This paper presents a novel intelligent power quality analyzer, which can be used to analyze the collected dynamic data using the modern uncertainty principle. The analyzer consists of components used for data acquisition, communication, display, storage and so on, and has some advantages including strong computing ability, good on-line performance, large storage capacity, high precision, and user friendly interface, etc. In addition, the reliability of measurement results is evaluated according to the international standards; while the uncertainty principle of the international survey is adopted for the evaluation of an electrical energy quality analyzer for the first time, it offer a perfect GB code in addition to the evidence to a perfect GB code.

An state feedback control is presented for systems with ellipsoidal parametric uncertainty,the stable analysis is based on linear matrix inequality and lyapunov method,then the robust control gain can be easily derived by solving linear matrix inequality.In addtion, ellipsoid optimization algorithm is proposed to generate a sequence of ellipsoids with decreasing volume to identify the ellipsoidal parameter in the systems considering input-output measurement datas and the constrain conditions. Finally robust control and parameter optimization are combined to get a state feedback controller for systems considering ellipsoidal uncertainy parameter. The efficiency of this method is illustrated with a simulation example.

In all accuracy indexes of gears, measurement of involute tooth profile's error is a difficult technical problem. A doubledisc instrument for measuring involute is introduced, which can be used to measure reference involute. The main errors sources of the instrument are analyzed, and all measurement errors are simulated by Mont-Carlo method. After analyzing error sequence, the double disc instrument's measurement uncertainty is 0.45μm when measuring gear (m=4, z=30, α=20°), which is less than the value evaluated by GUM method, and more reliable and accurate.

A high precision 2-D laser measuring instrument is designed to meet the needs of high precision measurement. Through the error analysis of the measuring system, the geometrical errors show certain stability in the results. Geometrical correction methods are intensively researched. The angle between two axes of the measured plate and axes of the instrument produces deviations of coordinates X and Y of the points on the plate. Different coordinate systems are not roughly aligned. An inclined correction model is proposed to compensate the deviations and transform the coordinate systems. Then the perpendicular compensation model is proposed using the least square approximation method and the relationship between the coordinates X and Y. To reduce the effect of random error and other geometrical errors, a multi-position correction algorithm is presented through two different measuring positions. The measurement results verify that these methods and models are accurate and feasible.

This paper presents a mobile 3D coordinate measuring system for large scale metrology. This system is composed of a network of rotating laser automatic theodolites (N-RLATs) and a portable touch probe. In the N-RLAT system, each RLAT consists of two laser fans which rotate about its own Z axis at a constant speed and scan the whole metrology space. The optical sensors mounted on the portable touch probe receive the sweeping laser fans and generate the corresponding pulse signals, which establish a relationship between rotating angle of laser fan and time, and then the space angle measurement is converted into the corresponding peak time precision measurement of pulse signal. The rotating laser fans are modeled mathematically as a time varying parametrical vector in its local framework. A two steps on-site calibration method for solving the parameters of each RLAT and coordinate transformation among the N-RLATs. The portable probe is composed of optical sensors array with specified geometrical features and a touch point, on which the coordinates of optical sensors is determined by the N-RLATs and the touch point is estimated by solving a non-linear system. A prototype mobile 3D coordinate measuring system is developed and experiment results show its validity.

When measuring the control error of CNC systems, the errors brought by machine tools will affect the veracity of CNC test. A new test approach based on simulation model of machine tool is proposed in order to well solve the problem. The structure and principle of the test approach is demonstrated. The simulation model of virtual machine tool and servo feed system are completed based on Simulink. The effect of nonlinear factors such as backlash and friction, are considered sufficiently in the modeling process of virtual machine tool. The validity of machine tool model is verified by simulation. Experimental setup is built to test the motion control ability in the process of circular interpolation, using the proposed test approach. The results of the experiment prove the validity of the test method. The machine tool model set up in this paper can comparatively accurately exhibits the kinematics characters of the real machine tool, and the proposed test method provides a new way for the comprehensive and reliable test of the motion control ability of the CNC system.

Error analysis of target location for Mast Mounted Electro-Optical Stabilized Platform based on multi-body kinematics theory is presented in this paper. Firstly, a typical structure of OMS, which is mounted on the reconnaissance vehicle, is introduced briefly and Multi-body kinematics theory is used to illustrate the topology structure and coordinates relations. Accordingly, target location equations between target and OMS are derived. Secondly, the characteristics and compensation methods are discussed in detail for the error analysis, which influence the system target location accuracy, such as imaging sensors errors, stabilized platform errors and equipments errors. Finally, simulation results based on Monte Carlo and experiment results are presented, showing that axis zero bit, consistency, verticality errors and equipments alignment errors are the primary factors, which influence system target location accuracy. After the compensation, the accuracy has been improved 2 orders and reached 5m/0.06⁰.

Geometrical Product Specifications is an international standard system regarding standardization of dimensional, tolerancing, surface texture and related metrological principles and practices in the charge of ISO/TC213. Integrated information system is necessary to encapsulate the knowledge in GPS to extend its application in digital manufacturing. Establishing a suitable data structure for GPS data is one of the main works in building the integrated information system. This paper is focused on cylindricity and the main points are as follows: proposes the complete verification operator and the complete drawing indication for cylindricity consistent with GPS standard system; models the inter/intra relationships between the elements of operations involved in cylindricity and integrates them by category theory; solves the storage format and closure of query for the categorical data model by the pull-back structure and functor transform in category theory respectively.

Immune algorithm is applied in pattern synthesizing of thinned array. Against the structural characteristic of rectangular plane thinned array, pattern function with form of Kronecker product is used in order to reduce the amount of the computation and improve the speed of operation. Immune algorithm is improved through the use of adaptive clone and Gauss Variation in order to overcome blind search of the algorithm. As a result searching efficiency is advanced. Immune algorithm and genetic algorithm are respectively used in side-lobe optimizing of rectangular thinned array. The result which using immune algorithm is obviously superior than which using genetic algorithm immune algorithm can reduce the side-lobe of rectangular thinned array, which show the flexibility and effectiveness of the immune algorithm and Immune algorithm has a better global convergence than genetic algorithm.

The loss theory of all the factors impacting on the output signal of the EFPI fiber-optic sensor is comprehensively analyzed. The results indicate that the fringe visibility and the output light intensity reduce after being affected by these factors, but the influence of other factors except for the F-P cavity length is very small and can therefore be neglected, and that the larger mode field diameter of the single mode optical fiber has a shorter cavity length room for design/fabrication.

A new design is made for Differential Plane Mirror Interferometer, which has simpler construction, but broader applications for nano-measurement. Due to its symmetrical optical configurations, the high measurement accuracy of geometrical parameters can be achieved with sub-nanometer. With this special arrangement and the use of some additional optical components, several specification measurements have become easily to implement and have higher exactness, such as for linear displacement, small rotation, straightness, perpendicularity, parallelism and etc. In addition, because of its simpler optical configuration with few optical components, it is easier for manufacturing and thus decreases the cost. This will make it possible to create new measurement instruments and broaden the market for laser interferometer. The stability and resolution of both Michelson interferometer and our new type of Differential Plane Mirror Interferometer were tested. The experiment results proved its outstanding capabilities.

2D motion platform plays an essential role in an automatic optical inspection (AOI) system, whose speed and positioning accuracy directly determine the inspection accuracy, efficiency and stability of the system. Conventional PID control is not able to meet the demands of high precision, high performance requirements and so on. This paper proposes whole closed-loop algorithm, which is a new control algorithm to achieve quick dynamic response and small tracking error simultaneously. According to an actual 2D motion platform model in Matlab/Simulink simulation, a series of experiments have been conducted, and the results show that the whole closed-loop PID controller is better than the conventional PID control with satisfactory accuracy and robustness, and enhances dynamic and static performance. The simulation results were compared with the theoretical research to verify the validity of the algorithm described in this paper. The new algorithm is useful in targeting the best control for motion platforms.

A tracking measurement method is introduced using pan-tilt-zoom cameras based on machine vision theory. The modeling of a pan-tilt-zoom camera system is described. The model formula given represents the relationship between the coordinates of a spatial point and its corresponding image coordinates when the system focus, zoom, aperture and illumination are adjusted to track the measured object. The modeling technique has excellent applicability and facilitates the assembly and alignment of the camera. The only requirement for alignment is to align the image sensor plane parallel to the tilt rotation axis.

SrBi₂Ta₂O₉ (SBT) thin films have been prepared on fused quartz substrates by using metalorgnic decomposition (MOD) method. X-ray diffraction (XRD) patterns show that films are polycrystalline in nature at annealing temperature of 750°C. The original optical energy band gap E_g obtained is about 4.57 eV. The changes of the E_g values of SBT films in H₂-contained ambient (forming gas, 5%H₂ + 95%N₂) at different annealing temperature are investigated by measurement of optical transmittance. The reductive atmosphere and temperature exhibit strong effects on the E_g values and the roughness of SBT films. Some significant changes of E_g values for the films are observed at 450°C and 500°C in the forming gas ambient. The E_g values increase from 4.57eV to 4.81eV and 4.92eV, respectively. These results could be attributed to degradation of polarization of SBT films, which being induced by Bi deficiency. Forming gas ambient has played an important role in the reductive reaction.

This study presents a "cold-stored liquid-vapor heat exchanger" to improve the performance of dual-temperature refrigerator system, for the installation of "cold-stored liquid-vapor heat exchanger" to measure the improving the performance of system. The study designs four different experimental models for making analytical discussion, and these models include: Model-A, dual-temperature refrigerator system (control group); Model-B, electronic expansion valve, which replaces mechanical evaporating pressure regulating valve; Model-C, dual-temperature refrigerator system equipped with a "traditional liquid heat exchanger"; and Model-D, dual-temperature refrigerator system equipped with an "cold-stored liquid-vapor heat exchanger" developed by the study. As known from analysis of the experimental data, under the operation of Model-B, the overheating situation at the return conduit of medium-temperature evaporator can be effectively controlled. Furthermore, the model can enhance the refrigeration speed, and improve the problems of accumulation of refrigerator oil as well as the shutdown and instability of pump appeared in traditional evaporating pressure regulating valve. After making analysis and comparison under the operation of Model-C, the COP of dual-temperature refrigerator is found improved by around 21.7%. When experimental analysis and comparison are made under the operation of Model-D, it is found that air-cooled liquid-gas heat exchanger can effectively provide better overcooling degree, and this device can improve the exhaust of compressor and excessively high temperature of machine shell. Eventually, the overall COP can be effectively improved by around 29.5%.

To wire-bond automatically, the IC lead positions on the CAD drawing and the corresponding ones on the extracted substrate image should be pre-verified. This paper proposed an AOI approach for IC lead index auto-verification which conquered the lead shape distortion, golden exposed, shifting, rotation, and scaling difficulties of extracted substrate image. Experimentations revealed that the proposed AOI approach can accurately verify the corresponding leads between a CAD drawing and the extracted substrate image with high repeatability.

A method based on measurement of critical refraction angle is proposed for measurement of optical glass refractive index independent of environment temperature. The critical refraction angle difference between the test sample and a standard refractive index block is measured first, and then the refractive index difference is obtained by a linear regression algorithm and the refractive index of the sample can be calculated from it. The requirement for environmental temperature is 25±5 °C , which can be easily satisfied on the production line. Compared with the non-linear algorithm used for direct measurement, this method is simpler, more efficient, and can directly get the refractive index value at standard temperature. Experimental result shows that the measurement repeatability is 1×10^-5. The method can be used for fast and accurate measurement of the refractive index for the same glass material in mass production (e.g. X-cube made of K9 optical glass).

As improper installation for aspherical component will inevitably bring the tilt errors to the measured data, the reliability of measured data reduces. Considering that the characteristics of a general elliptic equation include information about direction and location, this paper presents a method based on ellipse fitting to remove tilt errors, which are included in the sampled data of meridian of aspherical component. The experimental results verify the reasonable and correctness of this method. Consequently, this method can effectively isolate the tilt errors from the measured data, simplify the detection method and improve the processing efficiency.

The perturbation induced by signal frequency is one of the main problems for tracking differentiator design, and classical linear differentiators are usually sensitive to signal frequency. An improved second-order sliding mode nonlinear tracking differentiator is proposed in this paper using Lyapunov stability theory, considering the robustness of sliding mode control theory. This tracking differentiator can track and differentiate any signal. At the same time it has a simple form and is easy to be applied. A numerical simulation is presented for the linear tracking differentiator and the nonlinear tracking differentiator with different input signals, and results verified the effectiveness of the second order sliding mode tracking differentiator. A method to eliminate perturbation caused by noise is presented at the end of this paper.

Modified gamma distribution was used to describe the distribution of particles in clouds. The polydisperse particle system may be converted into a monodisperse particle system. 1) The averaged radius of nonspherical particles associated with a given size distribution, 2) the averaged scattering parameters of water droplets in cumulus, stratus and stratocumulus and that of ice crystals in cirrus, and 3) infrared emissivity of a cirrus layer from the mixing ratios and effective sizes of cloud drop and ice crystal were separately calculated. Simulation results indicate that all scattering parameters of water droplets in cumulus, stratus and stratocumulus are similar. Cross sections increase with the increasing equivalent radius. While efficiency factors vibrate with the increase of equivalent radius. The averaged albedo reaches its peak between 2 and 3 micron, and then decrease with the increasing equivalent radius. The averaged asymmetry factor also vibrates with the increase of equivalent radius. But the scattering parameters of ice crystals in cirrus change differently, and they vary linearly with equivalent radius.

The row coordinates array of a circle center is computed with upper and lower edge arrays of the circle. Using it as a statistic, find the row coordinate values most frequently appeared. This value is expanded into a row coordinate range, according to the row coordinates range, elements are selected from the upper and lower edge arrays, two row coordinates arrays are obtained from the upper and lower edge arrays, circle-center row coordinates are computed with two row coordinates arrays. The same method is applied to dispose the column coordinates arrays of left and right edges. Compute circle-center column coordinates. A final radius is got with circle center coordinates and those elements selected from edges array. The total computation of the algorithm is estimated, the processing time of an image is tens of milliseconds. Experiments demonstrate that the algorithm has good accuracy of radius measurement and the capacity of noise suppression.

Conventional sonic testing method has such limitations as monotony of signal characteristic quantity, regular shape requirement of measured workpiece, limited ability to identify only one type of defect, etc. This paper establishes the mathematical model of modal vector of free vibration object of arbitrary order, analyzes the effects of vibration modes on the various types of crack default with magnetic tiles commonly used in industry as study object, then gives the relationship between the frequencies of high-order vibration mode and the location, length, depth of the same type crack defects and that between the frequencies of high-order vibration mode and 4 kinds of defects common in magnetic tiles including axial short crack through the top of the arc, tangential short crack through the bottom of the arc, tangential crack in the intrados and axial crack in the intrados, and finally 3 types of magnetic tiles were tested to verify its effectiveness. The results are very helpful in automatic detection of internal defects in workpieces.