One-shot surface profile measurement using polarized phase-shifting
Author(s):
Yuan-Fang Chen;
Yi-liang Du
Show Abstract
An instantaneous polarized phase-shifting interferometer (IPSI) with an optical image combiner is designed to form a
one-shot surface profile measurement system. The interference images are captured simultaneously by using one CCD
camera. Digital image correlation (DIC) method is applied effectively to correct the position mismatch among the
images. Test of the measurement system on flat mirror, tilted mirror and wafer are given. An average error between
0.07μm~0.09μm can be achieved, and the maximum error is about 0.2μm.
One-shot 3D shape and color measurement using composite RGB fringe projection and optimum three-frequency selection
Author(s):
Zonghua Zhang;
Sixiang Zhang
Show Abstract
A composite RGB fringe projection and processing method is presented to simultaneously obtain 3D shape and color
information of objects from one-shot acquisition. Three fringe sets with optimum fringe numbers are coded into the red,
green and blue channels of a digital light projector to generate one composite RGB fringe pattern. The deformed fringes
on an object surface are recorded by a three-chip color CCD camera from a different viewpoint. Fourier transform
analysis is applied to the obtained fringe patterns in each color channel to retrieve the wrapped phase maps. Absolute
phase across the full-field is calculated from the three obtained wrapped phase maps on a pixel-by-pixel basis using the
optimum three-frequency method. Color data are also extracted from the same composite RGB fringe pattern image, so
there is an exact one-to-one correspondence between the absolute phase and color data. Only one RGB fringe image is
required to calculate the shape and color information, thus the proposed method can measure dynamic objects.
Experimental results on static and moving objects having discontinuities and/or isolated surfaces show the validity of the
proposed method for measuring the shape and color information.
Influence of partially coherent illumination on aerial-image-based aberration measurement of projection optics in lithographic tools
Author(s):
Tingting Zhou;
Shiyuan Liu;
Wei Liu;
Lijuan Wang
Show Abstract
In this paper, the aberration measurement technique using aerial image sensor (AIS) is further derived, and the influence
of partially coherent illumination on the performance of this technique is analyzed comprehensively in practice. The AIS
based technique detects the intensity of the aerial image to obtain the wavefront aberration on each sampling point of the
exit pupil using a set of 36 binary gratings with different pitches and orientations. The simulation work conducted by the
lithographic simulator PROLITH has demonstrated that the aberration measurement errors grow with the partial coherent
factor increasing. Two effects of the partially coherent illumination are proposed to interpret such influence that causes
the measurement errors.
Microstructure testing with digital holography
Author(s):
Qieni Lü;
Baozhen Ge;
Yiliang Chen;
Jin Zou
Show Abstract
An optical system of digital holography based on 4f system for microstructure measurement is studied. Fresnel off-axis
hologram generated by a magnified image of microstructure is recorded with a CCD, and the magnified reconstructed
image can be obtained by the angular spectrum method. The quantitative phase information of the microstructure under
test is obtained. A theoretical analysis is performed in detail and the experiment done, and the experimental results are
also given. The research shows that the method presented in this paper can be applied to micro-object imaging and its
quantitative measurement.
Optimization of pupil sampling scheme for aerial-image-based aberration measurement of projection optics in lithographic tools
Author(s):
Lijuan Wang;
Shiyuan Liu;
Wei Liu;
Tingting Zhou
Show Abstract
In this paper, the aberration measurement technique using aerial image sensor (AIS) is further discussed, and an
approach to optimize the pupil sampling scheme for this technique is proposed. The accuracy of this technique heavily
relies on the pupil sampling scheme as it has a significant impact on the random error propagation of the Zernike
coefficients. We formulate the optimization problem using a continuous function and using the gradient information to
search the solution space. We also employ the regularization framework using penalty functions to restrain the
complexity of the sampling scheme. The simulation work has demonstrated that the pupil sampling scheme obtained by
the proposed optimization approach are more suitable than those by the trial and error method.
Determination of magneto-optical characteristics of hexaferrites from 200 GHz to 1THz using time domain spectroscopy
Author(s):
Ranxi Zhang;
Bin Yang;
Yan Zhang;
Robert S. Donnan
Show Abstract
Gyrotropic, magnetically-hard hexaferrite materials, are very promising candidates to operate as quasi-optical nonreciprocal
devices at high frequencies (> 90GHz), with the consequent advantage of obviating the need for requiring
extra biasing magnets and avoiding low temperature demagnetization. In this paper, a THz TDS system is used to make
measurements on a thin (2.02 mm thickness) hexaferrite plate for both parallel and perpendicular polarisation of the
pump beam. From these data, the intrinsic circular-polarisation transmittances of both senses of polarisation are
computed and these are analysed to determine the magneto-optical constants of the hexaferrite plate over the range of
200 GHz to 1THz.
The research on promoting the measuring accuracy of UV radiometers
Author(s):
Bo Huang;
Caihong Dai;
Jailin Yu
Show Abstract
The aim of this paper is to promote the accuracy of the quantity for spectral irradiance of standard lamps at transferring,
optimize the calibration uncertainty of ultraviolet irradiance, analyze and solve the problem which will effect the
measuring course of ultraviolet irradiance, and provide reliable calibration standard for application areas. The main
contents include: 1. Put forward a new three segment fitting function of spectral irradiance of standard lamp and an
optimizing method for non-linear parameter. Compare relative errors of different curve fitting methods by a new
successive error analysis method. The relative deviation of the new curve fitting function is: 0.27% between 250nm and
2500nm which is acceptable comparing to the uncertainty of national primary standard of spectral irradiance lamp. 2.
Through a new designed measurement system for cosine response property of UV radiometers, we do some measuring
experiments to 21 kinds of UV radiometers and calculate the relative deviation of each UV meters. By measuring
experiments we can understand the cosine response property of UV radiometers exactly and do cosine compensation
accordingly. 3. Design and fulfill an experimental system to reflect the measuring errors of UV radiometers when
measuring sources and calibrated sources are mismatched. Calculate the spectral mismatch correction factor and spectral
matching characteristic factor to modify the measuring data.
Correlation between linear and angular kinematic errors in prismatic joint of machine tools
Author(s):
Abdul Wahid Khan;
Wuyi Chen
Show Abstract
In this particular research authors have made an effort to investigate the relationships between linear and angular
elemental errors through a pragmatic way and analyzing them. Correlation between the errors was considered by the case
study of the coupling mechanism between the joint kinematic angular and straightness errors of a prismatic joint of a
machine tool, and was validated through measurement. The laser interferometer was employed in conjunction with its
optics under controlled environmental conditions for validation purposes. Prismatic joint of a 5-axis grinding machine
was used for error characterization and its quantification by establishing the relevance between linear (straightness) and
angular (pitch and yaw) errors. Results exhibited a quite agreement to the relationship while compensation factor added
with the methodology. It was investigated whether the methodology is beneficial for reducing the elements of parametric
calibration which provides an efficient characterization and error evaluation, or is just better for an estimation and quick
check of a machine tool error.
The effects of water quality on the measurement results of nanoparticles' effective diameter and polydispersity by Photon Correlation Spectroscopy
Author(s):
Jun Xiang;
Peng Han
Show Abstract
The impurities in solution affect the measurement results of effective diameter and polydispersity of nanoparticles by
Photon Correlation Spectroscopy. The purification of solution should be taken adequate concern to reflect the real
characteristics of measured nanoparticles. The impurities in ultrapure water of three manufacturers were observed by
differential interference microscope, Nikon Eclipse ME600. Based on the micrographs results, one of the equipments
was chosen to manufacture water, and the water was purified into three different purification stages. The micrographs
and background scattering light intensity of the three kinds of water were analyzed, and then the three kinds of water
were used to measure standard particle nominated 90nm, and the measurement angle was from 50° to 130°. The
measurement results indicate that water with high quality being used to measure nanoparticles can get stronger scattering
intensity and lower value of polydispersity, and it is suitable for measurement with high precision. Impurities in water
would weaken the light intensity scattered by measured nanoparticles and affect the measurement results of effective
diameter and polydispersity. When laser power was relative lower, the effective diameter increased as angle. So the
impurities in solution and the laser power should be paid special attention. Suggestions about choosing different stages of
water purification for measurement with different precision are also given, when the equipment of water purification is
determined. The effects of floc in ultrapure water on the measurement of nanoparticles still need study in future.
Measurement of thin film shape with a sinusoidal wavelength scanning interferometer using a white light source
Author(s):
Osami Sasaki;
Hiroshi Ueno;
Takamasa Suzuki
Show Abstract
A halogen lamp and an acousto-optic tunable filter are used to construct a sinusoidal wavelength-scanning
interferometer with the scanning width of 210 nm. A linear wavelength-scanning with the scanning width of 220
nm is utilized to determine amplitudes of three different interference signals produced from multiple-reflection
lights by front and rear surfaces of a thin film. Amplitudes of time-varying phases produced by a sinusoidal
wavelength-scanning and constant phases in the interference signals are estimated by minimizing a difference
between detected signals and theoretical ones. From the estimated values, the positions of the front and rear
surface of the thin film with a thickness of about 460 nm are measured with an error less than 4 nm.
Vibration measurements based on demodulating the phase of a fiber 3dB-coupler Michelson interferometer
Author(s):
Min Li;
Fang Xie;
Junyu Ren
Show Abstract
A fiber interferometric vibration measurement system which is based on demodulating the phase of a fiber Michelson
interferometer which is made with a fiber 3dB-coupler is presented. In the work, the system employed the characteristics
of fiber Brag gratings (FBGs) to interleave two fiber Michelson interferometers which share almost the same part of the
main optical path. One of the fiber interferometers is used to stabilize the system, employing an electronic feedback loop
to drive a piezoelectric actuator to tune the optical path of the reference beam in order to keep the interferometer in
quadrature state. By this way, the low frequency drifts in the phase of the interferometric signals which are resulted from
environmental disturbances are compensated for. The other one is used to perform the measurement task. By employing
the characteristics of 3dB-coupler, the interferometric signals from the two outputs of the 3dB-couper are 180º out of
phase. The two interferometric signals are input into an electronic processor and convert into currents, which are linear to
the power of the optical interferometric light. The signals are collected by NI USB-5132 acquisition card and processed
by a program in a personal computer. The measurement system is configured with fiber and fiber components which are
integrated together. As the cutoff frequency of the feedback loop is 1.5Hz, the measurement system is capable of
measuring vibration with frequencies bigger than 1.5Hz and the amplitude of the measured vibration is not limited.
The dynamic interferometry technology of 4.5-meter concave aspherical mirror and relativity precision analysis
Author(s):
Zhao Wang;
Wei Zhang;
Zhi-bin Ren
Show Abstract
The dynamic interferometry is used to overcome the problem of the vibration and the air turbulence present in the testing
process of concave aspherical mirror, whose aperture is extra large, and optical path is extra long. Aiming to 4.5m
aperture concave mirror, two schemes have been designed: offner refractive and reflective compensators. The analytical
model of the theoretical error analysis under the dynamic interferometry condition has been built. According to the result
we can come to a conclusion that using the method of dynamic interferometry, the accuracy of measuring can be reached
within λ/80. The optical testing path of mirror with multiple segments has been designed in the end. Results of this paper
could provide references for the design, processing, assembling and testing technologies of large or extra large optical
system.
Research on chromatic dispersion measurement of PCF based on Michelson white-light interferometry
Author(s):
Dagong Jia;
Yong Zhu;
Xuemin Zhang;
Hongxia Zhang
Show Abstract
Photonic crystal fibers (PCFs) as a special type of optical fibers have a wide range of applications
including fiber lasers, amplifiers, telecom components, fiber-optic sensors of various kinds and
quantum optics. Chromatic dispersion (CD), which is one of the PCFs' most important parameters,
plays key roles in its performance and the device which is made of it. Due to the diversity of PCFs'
structure and study of its relevant devices, the precision measurement of PCFs' CD is particularly
important. Based on the analysis of CD measurement method, a set of experimental system for
measuring PCFs' CD value was developed by using white-light Michelson interferometry. The
maximum CD is 1000ps/nm using this system. The algorithms of extracting the CD from the
interference spectra were studied. Experiments were carried out to measure the PCFs' CD value based
on the CD measurement system. The experimental results show that: the CD value of PCF is
-25.8634 ps/(nm • km) at 1300nm wavelength.
Development of oral cavity inspecting system
Author(s):
Hongxia Zhang;
Di Wu;
Dagong Jia;
Yimo Zhang
Show Abstract
An oral cavity inspecting system is designed and developed to inspect the detail of teeth. The inspecting system is
composed of microscopic imaging part, illuminating part, image capture and processing, display part. The two groups of
cemented lenses were optimized to minimize the optical aberration and the collimated beam light is gotten between the
two lenses. A relay lens is adopted to allow the probe to access the oral cavity depth. The illumination optic fiber is used
and the brightness and color temperature can be adjustable. The illumination fiber end surface is oblique cut and the
optimum angle is 37°. The image of teeth is imaged on CMOS and captured into computer. The illumination intensity
and uniformity were tested and the proper parameter is set. Foucault chart was observed and the system resolution is
higher than 100lp/mm. The oral inspecting system is used to test standard tooth model and patho-teeth model. The tooth
image is clear and the details can be observed. The experimental results show that the system could meet dental medical
application requirements.
Content measurement of textile mixture by Fourier transform near infrared spectroscopy
Author(s):
Li Liu;
Li Yan;
Yaocheng Xie;
Songzhang Li;
Ge Xia;
Libin Zhou
Show Abstract
A new method for accurate measurement of content of textile mixture based on Fourier transform near infrared
spectroscopy is put forward. The near infrared spectra of 56 samples with different cotton and polyester contents were
obtained, in which 41 samples, 10 samples and 5 samples were used for the calibration set, validation set and prediction
set respectively. The wavelet transform (WT) was utilized for the spectra data compression. From the linear and
nonlinear perspective, multivariable linear regression (MLR) model based on the Lambert - Beer's law and back
propagation (BP) neural network model based on WT were developed. It indicates that the prediction accuracy of
WT-ca3-BP network model is 2% for calibration sample and 4% for validation sample, which is much higher than the
MLR model and is suitable for the prediction of unknown samples. On the basis of not changing the structure of the
WT-ca3-BP network model, calibration and validation samples were utilized fully to be re-set to new calibration samples,
which upgraded this model. The upgraded WT-ca3-BP network model was applied to predict unknown samples.
Experimental results show that this approach based on Fourier transform Near Infrared Spectroscopy can be used to
quantitative analysis for textile fiber.
Vibration errors in phase-shifting interferometer
Author(s):
Hao-ming Wei;
Ting-wen Xing
Show Abstract
Unexpected mechanical vibrations can significantly degrade the otherwise high accuracy of phase-shifting interferometer
(PSI). Because the data acquisition takes place over time, sensitivity to vibration is as a function of the frequency, the
phase, the amplitude of vibrations, the smoothness of test surface and the slope coefficient of reference plane. A complete,
nonlinear, continuing mathematical model of PSI with well defined longitudinal and transverse vibrations is presented.
The approach to quantifying vibration is using the discrete sum formula instead of the continuing integral model.
Computer simulations are performed over a range of vibration frequencies and amplitudes for 4,7,11 and 15 frames
phase-shift algorithms. Numerical simulation results demonstrate the methods to increase the accuracy of PSI is to
choose more phase steps and higher speed CCD camera and PSI with small slope coefficient of reference surface and
good smooth test surface has low sensitivity to transverse vibration. Finally programs basing on the phase-shifting
interference theory are given to imitate the process of obtaining interferogram with vibrations. After intensity signal is
processed through PSI algorithm and phase unwrapping algorithm, the sensitivity of PSI to vibration is achieved and
described by the difference of the computer phase and test phase. The results of numerical simulation are supported by
several examples on dummy experimental platform.
Research of full-field deformation measurement system
Author(s):
Kaiduan Yue;
Mei Yuan;
Yaxing Yi;
Zhongke Li;
Fei Zhang;
Longfei Jian
Show Abstract
It is very important to measure the vibration amplitude and the dynamic deformation of the object
so Electrical Speckle Pattern Interferometry technique has developed rapidly in recent years because of
its Non Destructive Testing (NDT) methodology. A dynamic Electrical Speckle Pattern Interferometry
technique was described in the paper. The Spatial Phase-shift System was implemented through four
CCD cameras. The object light interferes with the given phase shifting value of reference light at the
baget of each CCD camera. The vibration amplitude and the dynamic deformation can be measured by
the phase detecting method. The error of the influence of the disturbance of the air, the influence of the
changing temperature, and the influence of the vibration of the environment can be eliminated. The
image matching and image emendation technology were used for the images of four CCDs to optimize
the result of the measurement. The Space Phase-shift System was promoted by the transient vibration
and dynamic deformation system.
On-line measurement of profile parameters of rectangular holographic photoresist gratings during development
Author(s):
Shiming Wei;
Lifeng Li
Show Abstract
This paper presents a method for on-line measuring photoresist grating profiles during the development process by detecting the diffraction efficiencies of surface-relief photoresist gratings on transparent substrates. A He-Ne laser of 594.1 nm wavelength is employed as the monitoring light source. Firstly, the groove depth of a grating is determined from the minimum value of the monitoring curve of the 0th-order transmission intensity. Then, with the groove depth known, the duty cycle of the grating is measured from the -1st-order transmission intensity. The feasibility of our method has been demonstrated through fabrication of many rectangular photoresist gratings of 1200, 2200, and 3000 lines/mm on glass substrates. Good agreement between the on-line, real-time measured results and the scanning electron microscopy results is obtained.
Machine tools error characterization and compensation by on-line measurement of artifact
Author(s):
Abdul Wahid Khan;
Wuyi Chen;
Lili Wu
Show Abstract
Most manufacturing machine tools are utilized for mass production or batch production with high accuracy at a
deterministic manufacturing principle. Volumetric accuracy of machine tools depends on the positional accuracy of the
cutting tool, probe or end effector related to the workpiece in the workspace volume. In this research paper, a
methodology is presented for volumetric calibration of machine tools by on-line measurement of an artifact or an object
of a similar type. The machine tool geometric error characterization was carried out through a standard or an artifact,
having similar geometry to the mass production or batch production product. The artifact was measured at an arbitrary
position in the volumetric workspace with a calibrated Renishaw touch trigger probe system. Positional errors were
stored into a computer for compensation purpose, to further run the manufacturing batch through compensated codes.
This methodology was found quite effective to manufacture high precision components with more dimensional accuracy
and reliability. Calibration by on-line measurement gives the advantage to improve the manufacturing process by use of
deterministic manufacturing principle and found efficient and economical but limited to the workspace or envelop
surface of the measured artifact's geometry or the profile.
An inversion of plume gas concentration distribution based on multivariate regression analysis
Author(s):
Qing Ye;
Xiaoquan Sun;
Li Shao;
Yafu Wang
Show Abstract
In light of the difficulties to directly measure plume gas concentration by existing methods, the paper proposed an
inversion algorithm based on multivariate regression analysis. We first of all built up a multivariate regression model of
plume gas concentration by dividing the plume into several homogeneous layers along the observation direction. Then a
group of discrete spectral data was sampled out from plume infrared radiation curve at the intervals of certain wave
numbers. Thus the spectroscopic data without atmospheric attenuation could be obtained when the discrete spectral data
was divided by the atmospheric transmittances at corresponding wave numbers. After that, we worked on the
temperature profile of the plume, figuring out the average temperature of each layer of plume through integration
according to the outcomes of plume layering. At the same time, supported by the High Resolution Temperature Gas
Spectral Database (HITEMP), we also computed out the average absorption coefficient of each layer of plume. Thereby,
the triplicity of the spectroscopic data without atmospheric attenuation, the average temperature of each layer of plume
and the average absorption coefficient of each layer of plume, as the input parameters for the multivariate regression
model of plume gas concentration, could finally enable us to work out the concentration distribution of the plume gas
along the observation direction by least squares method which, however, only took into consideration the effect of vapor
and carbon dioxide. The comparison with the concentration distribution acquired through numerical computation of
plume flow field proves the feasibility of the inversion algorithm.
A polarization-modulated multichannel Mueller-matrix scatterometer for smoke particle characterization
Author(s):
Qixing Zhang;
Lifeng Qiao;
Jinjun Wang;
Jun Fang;
Yongming Zhang
Show Abstract
The polarization properties of scattered light are being exploited to determine the optical and physical information of
small particles. In this paper, a scatterometer is developed for simultaneously measuring the Mueller scattering matrix
elements as functions of the scattering angle. The scatterometer uses an electro-optic modulator to modulate the
polarization state of the incident light, and uses two photomultipliers provided with different polarization optics to
consist multichannel polarization-state detector. The instrument takes advantage of combination of the polarizationmodulation
technique and division-of -amplitude photopolarimeter, which make for a compact design and substantial
increase in measurement throughput and speed. The methods of calibration and alignment using the polarizationmodulated
light are established, with which the instrument is calibrated precisely. The methods of data processing and
error analysis of the measured Mueller matrix elements are developed. A hybrid experimental/theoretical approach to
study the light scattering properties of smoke particles is also presented.
Depth measurement using infrared thermography
Author(s):
Yan Huo;
Yue-jin Zhao;
Cun-lin Zhang;
Yan-hong Li;
Zhi Zeng
Show Abstract
Infrared Thermography is a Nondestructive Testing and Evaluating (NDT&E) technique. it is an effective technique
for quantitative prediction of defect depth and defect area, an analysis of depth measurement based on theoretical
one-dimensional solution of pulsed thermography is used, assuring the depth of defects by calculating break time that the
Logarithmic time evolution of the health area begins to deviate from that of the defective area. Several back-drilled
flat-bottom holes which located at three different depths in the aluminum plate are used as simulated defects. Meanwhile,
other two coating samples buried with nine defects are also detected. The experimental results of the infrared
thermography can demonstrate the capability to predict the depth of defects. The advantages and disadvantages of this
method are also outlined.
A tunable external cavity laser diode with no mechanical movement
Author(s):
Takamasa Suzuki;
Ryuichi Nagai;
Osami Sasaki
Show Abstract
An external-cavity laser diode that performs static wavelength scanning is proposed. It eliminates problems such as
repeatability and tuning rate that arise due to mechanical movements induced in the external cavity of conventional
systems because it requires no mechanical elements. Experiments have revealed that the scanning range and tuning rate
are 1.3 nm and 1 kHz, respectively.
Light scattering modeling of bacteria using spheroids and cylinders
Author(s):
Chunxia Feng;
Lihua Huang;
Jie Han;
Guangchao Zhou;
Aijun Zeng;
Yongkai Zhao;
Huijie Huang
Show Abstract
Numerical simulations of light scattering by irregularly shaped bacteria are carried out using the T-matrix method. A
previously developed T-matrix code for the study of light scattering by randomly oriented non-spherical particles is used
for the current purpose and it is validated against Mie-theory using coccus. Simplified particle shapes of spheroids and
cylinders for simulating scattering by irregularly shaped bacteria are studied. The results for the angular distributions of
the scattering matrix elements of B.Subtilis at wavelength 0.6328μm are presented. Their dependence on shape and
model are discussed. Analysis suggests that spheroids perform better than cylinders for B.Subtilis. Calculations of the
scatter matrix elements to determine bacteria sizes as well as shapes may be an accurate method and may be used to
determine what the bacteria are.
Optical measurement of atmospheric refractive index structure constants
Author(s):
Xiwen Qiang;
Jingru Liu;
Fei Zong;
Junwei Zhao;
Yan Li
Show Abstract
Atmospheric turbulence increases bit error rate and degrades beams quality for wireless laser communication links as
laser light propagation in the turbulent atmosphere, and atmospheric refractive index structure constant is an important
parameter for statistics of atmospheric turbulence. Characteristics of atmospheric turbulence in the atmosphere varies
randomly and the experiments in the real atmosphere are expensive, so it is an important way to simulate atmospheric
turbulence in laboratory for investigation on laser beams propagation in through the atmosphere. The structure parameter
of the atmospheric turbulence in laboratory was measured based on measurement of angle-of-arrival (AOA) fluctuations
of centroids as laser beam through the simulated-turbulence. The results shows a good agreement with the previous result
measured by thermal method, the strength of simulated-turbulence was 1000 times stronger than that in the real
atmosphere. The characteristics of turbulence varies temporally with air temperature and wind velocity, and statistics of
atmospheric turbulence was presented for various air temperature and wind velocity along the propagation path.
A single channel spatial polarization encoding and decoding method based on photoelastic modulator
Author(s):
Jie Han;
Aijun Zeng;
Chunxia Feng;
Guangchao Zhou;
Huijie Huang;
Hongbing Qian
Show Abstract
A method to encode and decode the spatial position using polarization is proposed. Birefringent wedge and photoelastic
modulator (PEM) are used to encode and modulate the laser with a polarizer and an analyzer. The state of polarization
(SOP) of laser beam changes gradually along the gradient direction of birefringent wedge. The spatial polarization
encoding beam is transmitted by a beam expander to form a spatial encoding field. A part of laser carrying the
information of spatial position in the field is received by detector. With signal processing, the harmonic terms of detected
intensity are obtained to realize the single channel decoding. With the single channel spatial polarization encoding and
decoding method, the problem of incorporating automatic gain control (AGC) between separate channel signals can be
overcome and the precision of decoding is improved by its rotation-invariant feature, and the results of decoding vary
linearly with retardation in the range of ±180°. In experiments, the relationship between decoding spatial position and the
true value of position is linear. Usefulness of the method is verified.
Color identification and fuzzy reasoning based monitoring and controlling of fermentation process of branched chain amino acid
Author(s):
Lei Ma;
Yizhong Wang;
Qingyang Xu;
Huafang Huang;
Ning Chen
Show Abstract
The main production method of branched chain amino acid (BCAA) is microbial fermentation. In this paper, to monitor
and to control the fermentation process of BCAA, especially its logarithmic phase, parameters such as the color of
fermentation broth, culture temperature, pH, revolution, dissolved oxygen, airflow rate, pressure, optical density, and
residual glucose, are measured and/or controlled and/or adjusted. The color of fermentation broth is measured using the
HIS color model and a BP neural network. The network's input is the histograms of hue H and saturation S, and output is
the color description. Fermentation process parameters are adjusted using fuzzy reasoning, which is performed by
inference rules. According to the practical situation of BCAA fermentation process, all parameters are divided into four
grades, and different fuzzy rules are established.
Measurement and evaluation on advanced adaptive optoelectronic sensor system
Author(s):
Quanxin Ding;
Hua Liu
Show Abstract
To answer the new challenge in project R & D on multiple subjects engineering optics, system design and essential
methods applied to structure effective system. Base on system engineering theory, traditional optical design optimization
is developed. General global optimization, which based on central optics system integrated with up-to-date
comprehensive modules and methods in created way, is presented and supported by abundant results of research and
development. Advantages such as system intellect, response ability, research periods and compatibility for renew
situations demonstrate validity and potential.
Method for decrease of the centroid error of star image caused by stellar spectrum
Author(s):
Hai-bo Liu;
Ji-chun Tan;
Shui-hua Huang;
Xiu-jian Li;
Li Liu;
Wei Tan
Show Abstract
Due to the residual chromatic aberration of lens in star tracker, the position accuracy of the star image decrease with the
increase of the field of view (FOV). The spectral distribution characteristics of guide star catalog including about 4600
stars are analyzed statistically, and the function model of stellar spectrums is established in this paper. The centroid
position for each of the guide star images is a function of its color type and the radial distance to the center of the FOV.
The principle of calibration of the centroid error is to make the weighted polynomial, and use a least square fitting
approach to obtain the best values of the position errors compensatory parameters for star image considered in a wide
field of view (FOV) and with different color temperature. As an example, at the 2.5 DEGREES (FOV) star position
errors for Spectral types F, G and K are 10.80μm, 6.5174μm and 4.3479μm respectively. The star position RMS error is
reduced from 1.06 pixels to 0.13 pixels, after implementing the spectral compensation scheme for the lens system of a
star tracker.
Used digital speckle correlation method to measure vibration
Author(s):
Haitao Yan;
Zhiqiang Zhen;
Zhengxin Tang
Show Abstract
Used digital speckle correlation method (DSCM) to measure is researched. The experiment is
designed and the laser irradiates a PZT which is driven by some signal to obtain the dynamic speckle
patterns. The dynamic speckle patterns are shot by CCD, then the DSCM is used to process the sequential
images and also the experiment is simulated. The movement of reflection target is controlled by PZT which
is driven by the different model signal. When the reflection target is moving, the dynamic speckle patterns
are shot by CCD, the sequential images are stored in computer through an image board. Then the digital
speckle correlation method is used to process the sequential images. There are three output parameters after
the images correlation calculation: (xi ,yi) and α that represent for position and moving direction of the
object, Initial (xi ,yi) is (0,0). (▵xi , ▵yi) represents pixel difference in coordinates of two adjacent images. α is the angle specifying the direction of the object's motion relative to the x-axis: αε[00,900]. Varying the
speed of the aluminum plate, variant values of (▵xi ,▵i) are obtained and varying the direction of
numeric control caterpillar track, variant values of α were obtained. From the obtained displacement and
the collected frequency, the vibration frequency was obtained. The experimental results show the DSCM
can confirm the frequency and displacement of vibration, and have a good agreement with the simulation
results, and the results show the digital speckle correlation method can be used to measure vibation.
The self-reacting machining process of optical accessories and the precision testing
Author(s):
Zhao Wang;
Zhong-hui Hu;
Wei Zhang
Show Abstract
Along with modern science and technology development, Optical precise instrument, especially in space applied optical
precise instrument, all set the very high request in the surface quality and the processing precision aspect, and have
already achieved a nanometer precision to the surface roughness Ra request. Therefore this paper puts forward to use
self-reacting machining method, process for floating polish, as well as measure and analyze the shape, appearance,
roughness of work-piece surface. Through comparing proof with the work-piece surface condition that the grinding
processing method of tradition gets: in from meet processing condition take off , the plasticity region processing that can
be stabilized and realize brittleness optical material gets very good processing surface quality. Under the experiment
condition of this paper, can get Ra 2-3nm processes mirror surface in shorter time.
Modal analysis of low-level-light aiming sight-glass based on vibration testing conditions
Author(s):
Youtang Gao;
Si Tian;
Jianliang Qiao;
Jun Niu;
Benkang Chang
Show Abstract
Low-level-light (LLL) sight-glass measurement technologies based on multiple environmental testing conditions are
always concerned by military equipments manufacturers. The article puts forward the concrete steps and method of
vibration environmental testing measurement according to military optical equipments environments testing standards.
Using vibration theory and mathematical modeling analysis, vibration modal of LLL aiming sight-glass based on
vibration testing conditions is constructed and analyzed. In order to study dynamic characteristic of vibration system,
coordinates of the physical model are converted to modal coordinates. By means of equating system modal, vibration
modal is impacted by damping coefficient. Emulating the system under the damping coefficientξ from 0.1 to 1 and
natural frequency n
ωn is 89, the results indicate that damped systems is influenced by coordinates conversion of transfer
function. The structure with less damping usually can be regarded as the proportional damping system otherwise can be
considered as the general damping system.
Small roll angle measurement based on auto-collimation and moiré fringe
Author(s):
Xu-guang Bai;
Sheng Cai;
Ming Dai
Show Abstract
A novel method for small roll angle measurement based on auto-collimation and moiré fringe is presented. A right-angle
prism is used as an indicator of small roll angle around the optical axis, and a CCD is used to collect moiré fringes that
are generated by scale grating image which is reflected by prism and index grating. Any small roll angle of the prism will
change the include angle of the grating pair and meanwhile induce a change in the moiré fringe period. The relationship
between roll angle and period of moiré fringes is established. The period data is obtained by image processing. The
experimental result certifies that the principle of small angle measurement method based on auto-collimation and moiré
fringe is correct and feasible. The measuring error is smaller than 0.2" within 7' range compared with 0.2" autocollimator.
Design of an MCU-controlled laser liquid turbidimeter based on OPT101
Author(s):
Yang Liu;
Huiying Xu
Show Abstract
With the rapid development of industry, accurate detection of liquid turbidity has attracted more and more attention, and
been widely applied to many industries. According to the Mie scattering and the Rayleigh scattering law, this paper
presents a novel design of laser liquid turbidimeter which uses the method of determining the turbidity by means of
detecting the 90° scattered light. The entire detection system mainly consists of a 650nm red laser source, a light receiver
(OPT101) and photoelectric conversion devices, an A/D converter, a data processing and controlling unit, a screen
display device (LCD) and a power supply module. This turbidimeter is proved to be an intelligent instrument, which
makes the process of measuring greatly simplified by displaying the result of turbidity in a digital form directly. It
operates normally at a temperature range from 0 oC to 50 oC . From 0 NTU to 1000 NTU, the measuring ranges can
be adjusted in accordance with the situation of samples automatically, and a single measurement takes about 1.608 ms. A
high precision of 0.001 NTU is realized in our experiments. After repeated measurements, an average error of ±2.2% is
obtained, and the repeatability is less than 1%. Moreover, two measuring modes are provided, one can store and view the
measuring records repeatedly, while the other can be used for batch testing with an additional alarm device. This
turbidimeter possesses a good practicality either in laboratory measurement or in industrial and environmental
inspection.
Experimental studies of PCS system for measuring of nanometer particles
Author(s):
Shao-yong Deng;
Qi Zhang
Show Abstract
A series of dynamic light scattering (DLS) experimental systems basing on photon correlation spectroscopy (PCS) are
brought forth for measuring the size of nanometer particles and the corresponding measuring results are shown. The
results obtained through these experimental systems are all compared with the results obtained by instrument of
Brookhaven. Mono-disperse and double disperse nanometer particle solutions systems are both studied. The light source
is the diode laser with the single transverse mode and its wavelength is 532 nm. It is the avalanche photon diode (APD)
instead of the traditional photomultiplier tube (PMT) is selected as the detector for its high quantum efficiency. The
scattering light transmits in a closed channel. The experimental systems are designed in two different kinds. The first
kind of experimental system is a system without fiber. The second kind of experimental system introduces one fiber for
transmission of scattering light. In these two kinds of experimental system, the influences of the polarization state of the
incident laser are investigated. The photon counting board is a product of self designed and the dynamic software
correlation system is introduced instead of the traditional hardware digital correlator for lower costs. The size of the
nanometer particles is computed by the famous CONTIN and NNLS programs.
Measurement of the laser beam quality using knife-edge method
Author(s):
Ji-hua Wen;
Li-ping Jia;
Yue-hong Zhu
Show Abstract
The parameter of laser beam is to evaluate the characteristics of the laser beam from quality. Laser
beam analysis apparatus in this paper is use knife-edge method to get the laser beam quality. This
machine move knife-edge line with laser beam cross section, which on the mechanical platform.
Light detector measure the transmission power of laser beam. The sensor's analog signal input the
A /D converter, then change digital corresponding signals. The instrument's measure system can
calculated the parameter of the laser beam though the power and the position of the power that be
measured.
The knife-edge in the measure system must be sure has good quality, thinning enough, and
must be perpendicular to the direction of the axis laser beam, or it will impact on measurement
accuracy. During the measure process, in order to decrease the measurement error we must
carefully rotating micrometer screw device. It mainly because the response speeds of light detector
and A/D converter is not fast enough.
In waist position, laser power density is relatively high, so the situation should be based on
the actual choice of laser power to prevent the knife-edge will not burn.
At last using the MATLAB to carry out the simulation analysis, the method is proved that it
can accurately recover the complicated energy distribution, and the system is proved that it can
improve the measurement accuracy effectively and can get parameter of laser beam goodly.
Key words: knife-edge method, laser beam quality, MATLAB, energy distribution, laser beam
analysis apparatus, natural density filter
Processing technology of interferogram for thin film thickness measurement
Author(s):
Jun-hong Su;
Jin-man Ge
Show Abstract
Measuring the thin film thickness by modern interferometry has advantages of the whole test, high precision and
non-contact measurement, the kernel of which is to obtain necessary surface shape and parameter by processing
interferogram with reasonable algorithms. The pre-treatment of the interferogram is the most crucial and a basal part,
which includes the edge identification of based on Mathematical Morphology, regional extension based on the 2-D FFT
and unwrapped and wrapped phase based on the non-weighted least squares algorithm for DCT. At the result, surface
distribution can be obtained, which lays the groundwork for getting the thin films thickness correctly. In this paper, the
image collection of the SiO2 film and the pretreatment of interferogram is performed. The result indicates that it is
basically consistent to the result tested by Zygo interferometer.
Single-image based dimensions inspection technology for planar industrial parts
Author(s):
Ji-hua Chen;
Yan-yun Jiang
Show Abstract
The industrial parts' dimensions are the important characteristics for their eligibility evaluation; typically, the multiple
cameras system is the preferred technology that fitting the inspection, especially for on-line testing, but the cameras
calibration, images matching, etc. are necessary when put in practice, also, multiple cameras system is either too costly
or impractical sometimes. A novel dimensions inspection technology based on single-image for planar industrial parts is
presented. The technology described here uses single-image taken by a camera in arbitrary pose, and requires four
scale-bars with known distances sticking on the planar industrial part, the four known distances are used to correct the
single-image to normal, and the part's dimensions are obtained by triangulation comparability from the normal image.
The utilities of this method are its low-cost, simplicity, ease of implementation and camera calibration needless. The
technology is being used in the real-time inspection of precision machining for the evaporator tubes plate of nuclear
boiler, applications show that the method is effective, and the typical dimensions accuracy is 0.05 mms if the testing
range is about 0.5ms by 0.5ms per-time.
Optoelectronic measurement in deformation of blast shock with Doppler effect
Author(s):
Lei Shao;
Hongli Liu;
Chengzhi Jiang
Show Abstract
This paper attempts to explore the feasibility of a system based on laser Doppler technique which has been established to
realize remote dynamic measurement of high velocity deformation parameters of explosion vessel. It aims at developing
a stable and reliable non-contact instrument with high precision for the measuring of explosion on site. Doppler signal's
SNR is very low in remote measurement of explosion vessel, a moving solid object with high velocity. To enhance
signal intensity, restrain noise and extract weak Doppler signal is the key to realizing remote measurement with high
precision. Both optical structure optimizing and digital signal processing used to solve the arduous problem above will
be discussed in this paper. The test results prove that the relative error of the instrument is less than 1% in measuring
displacement.
A novel method measuring optical fiber nonlinear coefficient based on XPM
Author(s):
Shuangxi Zhang;
Xuqiang Wu;
Fei Ai;
Chengmei Zhang;
Bo Zhang;
Benli Yu
Show Abstract
In optic communication systems, the nonlinear effect of the optical fiber is of great importance. There are several
methods measuring optical fiber nonlinear coefficient. A novel method measuring optical fiber nonlinear coefficient is
proposed, which is based on a Mach-Zehnder interferometer fabricated with 3×3 coupler, polarization controller and so
on. According to cross phase modulation (XPM), when two optical waves are injected into the same optical fiber, the
phase of one optical wave will be changed because of the other one. So a sinusoidal phase signal will be generated
through coupling a sinusoidal modulated high-power laser into one arm of the interferometer, and then the three outputs
of the interferometer will contain the sinusoidal phase signal. According to the characteristic of the 3×3 coupler, the
phase difference between the three outputs is 2π / 3 . Through mathematics disposition of the three outputs of the
interferometer, a couple of orthogonal signals can be yielded. Then the amplitude of the sinusoidal phase signal can be
demodulated accurately by arctan method. The length of the optical fiber and the power of the laser can be measured
easily, according to expression about the nonlinear phase shift induced by XPM, the optical fiber nonlinear coefficient of
certain wavelength will be calculated. The optical fiber nonlinear effect is simulated by the software optisystem, and the
process measuring the optical fiber nonlinear coefficient is analyzed in detail based on the schematic design.
Dynamic deformation inspection of a human arm by using a line-scan imaging system
Author(s):
Eryi Hu
Show Abstract
A line-scan imaging system is used in the dynamic deformation measurement of a human arm when the muscle is
contracting and relaxing. The measurement principle is based on the projection grating profilometry, and the measuring
system is consisted of a line-scan CCD camera, a projector, optical lens and a personal computer. The detected human
arm is put upon a reference plane, and a sinusoidal grating is projected onto the object surface and reference plane at an
incidence angle, respectively. The deformed fringe pattern in the same line of the dynamic detected arm is captured by
the line-scan CCD camera with free trigger model, and the deformed fringe pattern is recorded in the personal computer
for processing. A fast Fourier transform combining with a filtering and spectrum shifting method is used to extract the
phase information caused by the profile of the detected object. Thus, the object surface profile can be obtained following
the geometric relationship between the fringe deformation and the object surface height. Furthermore, the deformation
procedure can be obtained line by line. Some experimental results are presented to prove the feasibility of the inspection
system.
Design and tolerance analysis of compensator for high order aspheric surface testing
Author(s):
Xu Chen;
Weiqi Liu
Show Abstract
High accuracy is required in surface testing of 90nm nodal point lithography projecting lens. By comparing various
aspheric surface testing methods, we adopt Offner null compensator to test the aspheric surface in the point diffraction
interferometer at last. In this paper, an Offner compensator is presented on the base of the third order aberration theory to
test concave aspheric surface, the optical construction parameters of which is determined by introducing equal-quantities
spherical aberration to compensate all orders of aspheric coefficients. The field of view of the system is 0.02º; the
structure layout of the compensator is a meniscus positive lens combined with a Plano-convex positive lens. The design
results indicate that: primary and high order aberrations are balanced well, MTF exceeds diffraction limit,
root-mean-square (RMS) of wave front error <λ/167. The F-number of the system can achieve F/1.64. By the analysis of
the process of aspheric surface testing with the designed system, a loosen distribution of the tolerance was presented
based on the accuracy of measuring apparatus.
Experimental study on absolute spectral responsivity value transfer with cryogenic radiometer
Author(s):
Xueshun Shi;
Kunfeng Chen;
Hongyuan Liu;
Hengfei Wang;
Quanshe Sun
Show Abstract
The spectral responsivity measurement theoretical outline was demonstrated. Absolute spectral responsivity of the
Silicon trap detector is calibrated with laser intensity stabilizer, closed loop refrigeration cryogenic radiometer. Seven
wavelength laser beams of 476.1nm, 488nm, 514.7nm, 568nm, 632.8nm, 647.1nm and 1064nm, are chosen for the
calibration experiments. Relative spectral responsivity of the cavity pyroelectric detector is calibrated in the band from
600nm to 15μm. Absolute spectral responsivity of the pyroelectric detector is transferred at 1064nm. The absolute and
relative measurement uncertainty is evaluated. Results demonstrated that the absolute spectral responsivity of the Silicon
trap detector and the cavity pyroelectric detector is 0.3954A/W, whose uncertainty is better than 0.04%, and 5.4E-7A/W,
whose uncertainty is better than0.4%, respectively, at 1064nm. The pyroelectric detector absolute spectral responsivity
uncertainty is better than 5% in other wavelength.
On-orbit visual principle point monitoring system of three-line array camera
Author(s):
Yong Lv;
Qibo Feng;
Lishuang Liu;
Qingshan Chen
Show Abstract
Visual principle point is a key photogrammetry parameter while the position change of it can only indirectly be estimated
by the inverse calculation of the ground control point presently. To get the exact position change of the visual principle
point an on-orbit monitoring system of three-line array camera is proposed. The system is composed of light source part
and photoelectric detecting part that move along with the lens and the line array CCD respectively. The position change
of the visual principle point can be derived by the position change of the two light spots. This system will not change the
structure of the camera and influence the function of it. Experimental system is built up and ground test results prove the
feasibility of the monitoring system and show the accuracy of it is better than 1μm.
Simulation of ultraviolet laser-induced fluorescence LIDAR for detecting bioaerosol
Author(s):
Peng Liu;
Yinchao Zhang;
Siying Chen;
Tian Lan;
Yuzhao Wang;
Zongjia Qiu;
Weiguo Kong;
Guoqiang Ni
Show Abstract
The biological warfare agent (BWA) is a kind of terrible threat during the war or raid from the terrorist. Last decade, the
interest in utilizing ultraviolet laser-induced fluorescence (UV-LIF) LIDAR to detect the bioaerosol cloud has risen in
order to measure the distribution of the bioaerosol particle. The UV-LIF LIDAR system can remotely detect and classify
the bioaerosol agents and it is an active detecting system. As the infrared absorbing in the atmosphere is less, the range
of infrared remote sensing is very far. The infrared laser at 1064 nm wavelength firstly begins to work in the UV-LIF
LIDAR system and the aerosol cloud can be detected at very long range through the elastic backscattering signal from
aerosol irradiated by infrared laser. But the category of aerosol can't be identified yet. If the infrared elastic
backscattering level exceeds a threshold, UV laser at 355 nm wavelength will be triggered and induce the fluorescence.
The excitated spectra of fluorescence can be used for discrimination of different aerosol species and particle
concentration. This paper put forward for a UV-LIF LIDAR system model and the principle of the model is described
summarily. Then the system parameters are presented and the simulation and analysis of the infrared elastic
backscattering and laser-induced fluorescence are made, which is based on these parameters. Raman backscattering
signal of Nitrogen gas in the atmosphere generally is taken to reduce measuring error, so the article also simulates this
Raman backscatter signal at 387 nm wavelength. The studies above may provide some valuable instructions to the design
of a real UV-LIF LIDAR system.
Analysis for angle anisoplanatic effect of the steady thermal blooming
Author(s):
Yunqiang Sun;
Fengjie Xi;
Xiaojun Xu;
Qisheng Lu;
Wuming Wu;
Hongbin Chen
Show Abstract
The effect of beacon Anisoplanatism needs to be considered in analyzing the error of the adaptive optical system.
Therefore, thermal blooming anisoplanatic effect of the Gaussian beam is analyzed numerically and theoretically. Wavefront
distortion of the Gaussian beam caused by thermal blooming anisoplanatic effect is expanded by the Zernike
polynomials. The Zernike coefficient and the fitting error are obtained by numerical calculations. The comparisons
between the Zernike coefficients indicate that the defocus item is the most important to the angular anisoplanatic error.
Based on the Wave-front distortion caused by the thermal blooming angular anisoplanatic effect, the defocus coefficient
of the Zernike polynomials is obtained theoretically. The result of the angular anisoplanatic error calculated by
theoretical formula is consistent with the outcome of the numerical calculation, and the result also indicates that the
angular anisoplanatic error is the function of the caliber size and varies as the square of the anisoplanatic angle. The
square relation of angle anisoplanatism is consistent with the result obtained by the turbulence angular anisoplanatic
effect.
Ellipsometric data inversion of absorbing films by simulated annealing - simplex hybrid algorithm
Author(s):
Zuohuah Huang;
Lijuan Wang;
Zhenjiang He
Show Abstract
A simulated annealing-simplex downhill hybrid algorithm is presented to solve the problems of ellipsometric data
inversion. Basing on Monte Carlo technique of simulated annealing algorithm, the hybrid algorithm uses simplex
downhill algorithm to get the local optimization and avoids the local optimization to get the global optimization by
Metropolis accepting principle, then the global optimum ellipsometric data are obtained quickly. A typical model with
single-layer absorbing film was dealt with by the hybrid algorithm and the simulated annealing algorithm respectively in
numerical simulation experiments. The results show that the hybrid algorithm is feasible, credible and ascendant in
ellipsometric data inversion. Furthermore, with the same testing conditions and inversion precision, the hybrid algorithm
can save time with two quantity degrees, so it will be found more applications in practice.
Infrared object detection: the influence of flying altitude and velocity
Author(s):
Yaxing Yi;
Kaiduan Yue;
Mei Yuan
Show Abstract
Based on the analyze of the infrared object detection mechanism, a new physical quantifier --detectability, which is
used to describe how difficult it is to detect an object, has been defined. The change of flying velocity influence the
radiation characteristic; the change of flying altitude also influence the radiation characteristic of the object ,the radiation
characteristic of atmosphere background, the most effect view of detector for the object, atmospheric transmittance of the
path and so on. Based on the large number of calculation, the article analyses the rule of the influence and change, the
influence that the flying altitude and velocity to infrared band detectability. The analyzing result show that when the
flying velocity of target enhances 0.5 Mach, the work range will enhance 5 kilometers for the same infrared detector. The
detectability of an object will increase as the flying altitude increasing until reach the 8 kilometers; at the altitude of 8 to
10 kilometers the detectability reaches the max, when the altitude overrun 10km the detectability of an object will reduce
as the altitude increase.
Online image acquisition system of magnet chip surface quality based on asynchronous reset
Author(s):
Kaihua Wu;
Zhengjie Li;
Shaopeng Hu
Show Abstract
Magnet chip is a kind of industrial work piece widely used in electronic equipment. Manual examination is still the main
method for its surface quality test and cannot meet the demand of high efficiency and accuracy. A universal online image
acquisition method was proposed based on asynchronous reset of CCD. The fast trigger, precision placement, movement
blur and image definition were resolved. (1)A focused optical fiber was used in optoelectronic sensor to generate trigger
signal timely when work piece moved through the little optical spot. (2)Precision hardware time-delay and asynchronous
reset pulse generation circuits were designed. The image was acquired only when work piece moved into the designed
position. (3) The image acquisition was fulfilled by hardware interrupt mode. The maximal processing time could be
designed to ensure the normal acquiring flow. (4) Quantitative relation between position accuracy and speed, time-delay
error, CCD resolution and imaging region was deuced. Relation between moving blur and speed, exposure time was also
decided. (5)The entire time sequence of asynchronous reset was designed. (6) Testing system was designed. The position
accuracy achieved 0.1mm when moving speed reached 100mm/s. Moving blur was limited in less one pixel size.
Experiments showed the system can meet the demand of real and online measurement of magnet chip surface quality.
Measurement of surface bidirectional reflectance distribution based on parabolic mirror
Author(s):
Ju Ren;
Jian-lin Zhao
Show Abstract
A novel approach and system based on parabolic mirror is proposed for measuring a surface's bidirectional reflectance
distribution function (BRDF) rapidly and accurately. In virtue of a truncated paraboloid with reflecting film on the
interior surface, the angular distribution of surface optical reflectance in tri-dimensional space is transformed into a twodimensional
planar image, which is collected by a CCD camera and goes though a followed angular mapping and data
processing correspondingly, a fast measurement of in plane and out of plane reflectance distribution is realized within a
few minutes. Furthermore, the laser beam is reflected by parabolic mirror to irradiate the sample surface in various
incidence angles. Primary measurements and analysis of surface reflectance of varied substance along with various
machining process are carried out with this system. Results indicates that this novel measurement system, compare with
conventional ones, can avoid the measuring errors generated by the fluctuation of laser's power and the sensitivity of the
detector, as well as dramatically shorten the acquisition time. In addition, a compact and portable configuration eases the
measurement procedure consumedly.
A new method for obtaining aerosol backscattering ratio with partial pure rotational Raman spectrum
Author(s):
Yuzhao Wang;
Yinchao Zhang;
Siying Chen;
Tian Lan;
Zongjia Qiu;
Weiguo Kong;
Peng Liu;
Guoqiang Ni
Show Abstract
The error of retrieving the aerosol backscattering ratio with partial Raman spectrum is calculated in present paper. A
new method is presented for reducing the error. One low-level and one high-level spectrum line are chose to make up a
new pseudo-line independent on the temperature. Finally, aerosol backscattering coefficient ratio profiles of the
atmosphere were obtained from the signals of a rotational Raman Lidar in our lab. The results show that Tropospheric
aerosol backscattering coefficient ratio can be retrieved by using the new rotational Raman pseudo-line without
considering the relation between aerosol extinction and backscattering.
Partial coherence theory relating to dispersive medium involved interference
Author(s):
Qingshan Chen;
Yueqiang Li;
Yong Lu;
Feng Jiang
Show Abstract
Interferometry is one of the effective approaches for characterizing dispersive optical components. The foundation is
partial coherence theory. A derivation of partial coherence theory relating to the characterization of dispersive medium is
presented here by combining with the measurement of CFBG (Chirped Fiber Bragg Grating), a dispersive fiber optic
component with wide application in the compensation of the dispersion in optical telecommunication system. In the
derivation the dispersion property, generally neglected in conventional partial coherence theory, is taken into account. It
will make sense for instructing the measurement, research and investigation employing interferometric system in which
dispersive medium is involved.
The application of new simulated annealing genetic algorithm in film characters measurement
Author(s):
Dong Chu;
Xing-zhi Gong;
Liang Cheng;
Fei-hong Yu
Show Abstract
A new global optimization method for thin film thickness calculation is presented in this paper. A new
adaptive simulated annealing (ASA) combining with genetic algorithm is brought out. Adding
traditional genetic algorithm to simulated annealing process avoids the premature convergence problem
and improves the ability of global searching effectively. Firstly it generates a new group of local
optimums through genetic and mutation operation; then the solutions are accepted at a certain
probability, and will be calculated respectively in ASA process as the initial solutions. At last conjugate
gradient algorithm is utilized to search accurately and quickly. This new ASGA can effectively
enhance the robustness of the algorithm and reduce the limitation of the searching area. The
experimental results show that the proposed algorithm can calculate the thickness of single layer and
2-layer thin film within the range of 10nm to 1μ m and less than 4% calculation error.
Design of wide field and high resolution video lens
Author(s):
Ze-xin Xiao;
Binzhou Zhan;
Haimei Han
Show Abstract
Online detecting is increasingly used in industrial process for the requirement of product quality improving. It is a trend
that the "machine detecting" with "machine version + computer intelligence" as new method replaces traditional manual
"eye observation". The essential of "machine detecting" is that image of object being collected with high resolution
video lens on sensor panel of photoelectric (CCD ,CMOS) and detecting result being automatically gained by computer
after the image saved and processed. "Machine detecting" is developing rapidly with the universal reception by
enterprises because of its fine accurateness, high efficiency and the real time. Video lens is one of the important
components of machine version system. Requirements of wide field and high resolution enlarged the complexity of
video lens design. In this paper a design case used in visible light with field diameter Φ32mm, β=-0.25× and NA'=0.15.
We give design parameters of the video lens which obtained with theoretically calculating and Oslo software
optimization: MTF>0.3 in full field and 215lp/mm, distortion <0.05%.This lens has an excellent optic performance to
match with 1.3 million pixels 1/2"CCD, and a high performance price ratio for being consist of only 7 single lens in the
way of 5 units.
Adaptive optics techniques without a wave-front sensor based on guide laser in atmospheric laser communications
Author(s):
Xiaolin Wang;
Xiaojun Xu;
Pu Zhou;
Haotong Ma;
Zejin Liu
Show Abstract
In order to improve the performance of the intensity modulation with direct detection atmospheric laser communication
system, adaptive optics technique without a wave-front sensor based on guide laser is proposed. Performance metric
detector replaces the wave-front sensor in the adaptive optics, so that the invalidation of wave-front measurement and
compensation in strong scintillation is avoided. The induced guide laser eliminates the misjudgment of attribute the
intensity change caused by intensity modulation to the phase distortion. Numerical simulation based on SPGD algorithm
shows that when the performance metric of the guide laser is increased from 0.09 to 0.67, the far-field Stehl ratio of
carrier wave laser can be increased from 0.0028 to 0.6138, almost 220 times improvement, which indicates the adaptive
optics system can reduce the bit-error and improve the performance of atmospheric laser communication greatly.
Monitor system of cable tension with fiber Bragg grating
Author(s):
Zhaoxia Wu;
Aijuan Song;
Tiegen Liu;
Zhiquan Li
Show Abstract
Measuring cable-stayed bridge's cable tension in real time is very worthiness in construction control, cable replacing and
bridge's health monitoring. A novel distributed cable tension fiber Bragg grating vibrate measuring system is designed in
this paper. Utilizing the relationship between tension and frequency to measure the cable tension indirectly based on
theory of string vibration. Double fiber Bragg grating micro accelerometer is designed to improve measuring sensitivity
and resolution. Using continues wave tunable frequency technique to demodulate the distributed grating vibrating
measuring system and applying the system in tensional stress control when build the bridge. The experiment results and
theory indicate that the monitoring system has a simple structure with good stability, linear response capacity, and wide
measurable range of the cable tension. It is can satisfy the needs for long term monitoring of cable-stayed bridge, as well
as provide continuous and accurate information.
Research of the temperature measurement of high-energy laser energy meter and energy loss compensation technique
Author(s):
Xun Yu;
Hui Wang;
Ji'an Wu;
Fang Wang;
Qian Li
Show Abstract
The energy measurement of high energy laser is converts incident laser energy into heat energy, calculates energy
utilizing absorber temperature rise, thus the energy value can be gained. Temperature measurement of high-energy laser
energy meter and energy loss compensation during the course of the measurement were studied here. Firstly,
temperature-resistance characteristics of resistance wire was analyzed, which was winded on exterior surface of the
absorbing cavity of high-energy laser energy meter and used in temperature measurement. Least square method was used
to process experiment data and a compensation model was established to calibrate the relationship of temperature vs.
resistance. Experiment proved that, error between resistance wire and Pt100 is less than 0.01Ω and temperature error is
less than 0.02°C. This greatly improves accuracy of the high energy meter measurement result. Secondly, aimed to the
compensation of laser energy loss caused by absorbing cavity's heat exchange, the heat energy loss of absorbing cavity,
resulted from thermal radiation, heat convection and heat conduction was analyzed based on heat transfer theory. Its
mathematics model was established. Least square method was used to fit a curve of experiment data in order to
compensate energy loss. Repetitiveness of measurement is 0.7%, which is highly improved.
Research of the standard wave-front reconstruction
Author(s):
Jun Han;
Jin Zhang;
Ji'an Wu;
Fang Wang;
Chi Zhang
Show Abstract
In optical interference measurement, the standard wave provided by the standard optical flat owing to the influence of
manufacturing processes, affects seriously on the improvement of the accuracy of the test. To solve this problem, a
method brings forward based on the computer-generated hologram to achieve the reconstruction of the standard
wave-front; Secondly, on the basis of the mathematical model of standard wave-front reconstruction, the required
wave-front is reconstructed in use of the different coding to encode wave-front hologram and MATLAB; Finally, the
different coding techniques for standard wave-front have been compared. The results show that the theory based on the
standard computer-generated hologram wave-front reconstruction algorithm can achieve the standard wave-front
reconstruction.
Methods to measure wave front of light beam
Author(s):
Q. W. Wang;
T. Sun;
C. S. Han;
S. Dong;
A. Yu. Rodionov;
A. S. Shirin;
V. N. Skekhtman
Show Abstract
The light beam wave front form is often base to complete accurate parameter calculations of such objects under test as
optical systems and components, transparent and reflecting materials, man-made radiation souses and so on. The
adequacy of measured data to reconstruct wave front form and technical practicability of various optical measuring
systems are analyzed to determine applicability of such methods and devices as Hartmann Method, Wavefront Sensing
by Pseudo Phase-Conjugate Interferometry, Talbot Method, Phase Modulation Method, Linnik Interferometer and
Shearing Interferometry. Information losses of wave front spatial frequency spectrum are determined on mention
methods and optical systems. Experimental data and end-use measurements are submitted.
Identification of oil spills by near-infrared spectroscopy (NIR) and support vector machine (SVM)
Author(s):
Weihong Bi;
Ailing Tan;
Yong Zhao;
Meijing Gao
Show Abstract
The identification of the spilled oil is an essential and important part in the investigation and handling of oil spill
accidents. The combination of near-infrared spectroscopy (NIR) and chemometrics is ideal for such a situation. NIR
spectroscopy is a powerful and effective technique and qualitative information can be obtained with classification models.
Support vector machines (SVM) have been introduced recently in chemometrics and have proven to be powerful in NIR
spectra classification tasks, such as material identification and food discrimination. In this work, the SVM is utilized to
classify near infrared spectroscopy of simulated spilled oils of gasoline, diesel fuel and kerosene on the marine. A good
classification performance is obtained :the identification rate were 100%, 96% and 98% on the test sets respectively.
Accuracy assessment of novel two-axes rotating and single-axis translating calibration equipment
Author(s):
Bo Liu;
Dong Ye;
Rensheng Che
Show Abstract
There is a new method that the rocket nozzle 3D motion is measured by a motion tracking system based on the passive
optical markers. However, an important issue is required to resolve-how to assess the accuracy of rocket nozzle motion
test. Therefore, calibration equipment is designed and manufactured for generating the truth of nozzle model motion such
as translation, angle, velocity, angular velocity, etc. It consists of a base, a lifting platform, a rotary table and a rocket
nozzle model with precise geometry size. The nozzle model associated with the markers is installed on the rotary table,
which can translate or rotate at the known velocity. The general accuracy of rocket nozzle motion test is evaluated by
comparing the truth value with the static and dynamic test data. This paper puts emphasis on accuracy assessment of
novel two-axes rotating and single-axis translating calibration equipment. By substituting measured value of the error
source into error model, the pointing error reaches less than 0.005deg, rotation center position error reaches 0.08mm, and
the rate stability is less than 10-3. The calibration equipment accuracy is much higher than the accuracy of nozzle motion
test system, thus the former can be used to assess and calibrate the later.
Measuring the wavefront distortion of a phased-array laser radar by using a real-time optoelectronic measurement system
Author(s):
Chunyan Zheng;
Jian Wu
Show Abstract
A real-time optoelectronic measurement system is proposed to measure the wavefront distortions of scanning beams of a
phased-array laser radar. This measurement system includes electric control rotating and translating platforms and a
cyclic radial shearing interferometer(CRSI). CRSI is an effective interferometry to mesure the laser wavefront. A
inversion algorithm is used to precisely reconstruct wavefront phase distribution from interferograms generated by the
CRSI. An actual experiment of laser wavefront distortion measurement is implemented successfully. The experimental
results show that this optoelectromic measurement system can measure laser wavefront distortion of a phased-array laser
radar in accuracy and in real time.
Research on distortion measurement and calibration technology for TV-seeker
Author(s):
Xun Yu;
Qian Li;
Xu Jiang;
Fang Wang;
Hui Wang
Show Abstract
In order to satisfy the detective distance requirements of TV-seeker, dual-CCD scheme is used in its optical imaging
system. But the distortion of CCD camera has seriously affected on the image quality, which can not get high-precision
image of registration and mosaic. Therefore its quantitative measurement and calibration is the key to the attack accuracy
of the precision guided weapon. Aiming at the problem as distortion of TV-seeker, firstly Tsai two-stage method based on
radial constraint is used to calibrate the CCD camera whose interior parameter and exterior parameter have been
determined. The high performance electronic target is established whose advantages are high contrast, high brightness,
excellent uniformity and so on by use of TFT-LCD spatial light modulator and visible image display technology. On
basis of this, the distortion measurement system is formed to measure the CCD camera. Then polynomial model is
established by applying the inversion algorithm and the measured distortion is calibrated by the least squares fit. The
calibrated result shows that the measurement precision using this algorithm is higher than that using the positive one
obviously and the average distortion after calibration is better than 0.15%.
A soft x-ray streak tube designed for ICF
Author(s):
Li Gu;
Qinlao Yang
Show Abstract
Electron optical analysis and simulation of the streak tube is completed, which is a core component of the camera system
for ICF investigation. Principles and methods of the streak tube are applied to design the tube. The tube structure and
voltage parameters are obtained according to electron optical theory. Multiple important evaluation parameters are also
obtained through computer simulation and numerical analysis of the model. Results reveal that the designed image tube
has a time resolution better than 11ps, sweep time distortion better than 43ps and space distortion smaller than 4%.
Moreover, it also has a good spatial resolution. The steak tube is fabricated, static performance is tested and experimental
data is analyzed. The experimental results show that the tube has a good static performance and meet the design
requirements.
Noise filtering of rotational Raman lidar using threshold amendment for atmospheric temperature measurement
Author(s):
Weiguo Kong;
Siying Chen;
Yinchao Zhang;
Tian Lan;
Zongjia Qiu;
Yuzhao Wang;
Peng Liu;
Guoqiang Ni
Show Abstract
Pure Rotational Raman Lidar is a new technique for detecting vertical troposphere temperature profile. Since the
backscattering Raman signals are so weak that the photon-counting method is applied by using a multiscaler. By setting
the threshold of the multiscaler, most noises mixed with the signals can be filtered. However, difference exists between
the set threshold and the actual threshold of the two count channels, and also exists between the set thresholds of the two
count channels. This will affect quick-setting of the appropriate thresholds. In this paper, a rule is put forward and the
measuring system is established to confirm the set threshold value corresponding to an actual one, making use of the
amplitude fluctuation of square wave. By this system, pairs of set threshold and actual threshold are obtained, and the
curve of the set threshold against the actual threshold of a single count channel, as well as the curve of thresholds of the
two count channels, is fitted. The theoretical analysis is well agreed with the experimental results, and it indicates that
the appropriate threshold can be set more quickly by using the curve.
The application of uniaxial crystal reflectivity in NO[sub]2[/sub]-DIAL optical path
Author(s):
Kai Yang;
Ben Xu;
ShaoTao Zhi
Show Abstract
Differential Absorption Lidar for detecting atmospheric NO2 (NO2-DIAL) is used extensively for its high precision and
spatial resolution, and the measurement can be done real-time with a wide range. The uniaxial crystal reflectivity must
be considered in optical path adjustment. From the point of view of energy, based on optical electromagnetic theory and
Jones matrix, the relationship between intermediary reflectance and polarization state of incident light is discussed, and
the normal relational expression of them is gained. An experiment example is given, and the measured value of the
example is in conformity with the computer simulation curve. The result shows that the regulation of crystal reflectivity
has useful significance for adjusting the optical path of NO2-DIAL.
Photocatalytic degradation of SO[sub]2[/sub] by diffuser of light pipe coated with Nanometer TiO[sub]2[/sub] thin films
Author(s):
Yanpeng Wu;
Chongfang Ma
Show Abstract
Diffusers are important parts of a light pipe which can diffuse light evenly to the place need to illuminate. The lamphouses
used in the experiment were two ultraviolet radiation lamps with the power of each lamp 8W and main
wavelengh was 365nm. The ultraviolet intensity on the surface of the catalyst was about 120μW/cm2. The experiments
also showed that diffusers without photocatalysis could reduce the fraction volume of SO2 in a little box of 0.1 m3
volume made up of stainless steel from 1.0 × 10-6 to 0.36 × 10-6. Diffuser coated with photocatalysis within 1h SO2
fraction volume decomposed from 1.0 × 10-6 down to 0.25 × 10-6 with faster and more complete degradation of SO2. The
experimental results showed that the performance of photocatalysis combined with diffusers of light pipe had better
effect in a small space.
Analysis of survey of exterior surface color of buildings in Beijing
Author(s):
Yanpeng Wu;
Fan Zhang;
Deying Li
Show Abstract
The survey mainly concerns the use of the external surface color of buildings in Beijing. The color parameter values of
the external surface of buildings color are accessed through contrasting with the Chinese Standard Color Chip on-site.
Hue, lightness and chroma are analyzed to research the color of the external surface of buildings. The data provide a
basis for the advanced research of the energy consumption of buildings. Using the color reduced the energy consumption
of buildings; especially in summer air-conditioning energy consumption is of great significance.
Novel packaging method for optical fiber collimator based on image processing
Author(s):
Jianxin Qiu;
Pin Zhong
Show Abstract
In the processing of fiber collimator packaging, the main factor that impacts the packaging quality is the optical coupling
loss which aroused by the phase offset of optical fiber base pin inclined surface and grin lens inclined surface. Based on
"detectable" and DFT, a new fiber collimator packaging method has been put forward. Using machine vision and digital
image processing technology to make sure tips at correct phase, then the tips was inserted into the stainless steel sleeve
and keep a feed motion to regulate the gap between the tips and grin lens. This way helps find the best packaging phase
and makes sure the biggest output power. The system is composed of CCD camera, image acquisition card and VC++
image processing software. Experiments proved the effectiveness and practicality, the phase tolerance can be controlled
in ± 3° and meet the fiber collimator packaging precision requirement. This packaging process have been used in
practical production and it improved efficiency and qualified rate, it also has applied for the invent patent.
A measured-data processing method based on MATLAB wavelet for distributed optical fiber sensing system
Author(s):
A. H. Chen;
H. Y. Zeng;
G. L. Jiang;
P. Y. Zhu
Show Abstract
The development of the hidden hazard in earth and rockfill dams is a long-term process, but the symptom of its
occurrence can be extracted from monitoring measured-data. However, severe disaster may happen since the cryptic
proof in these measured-data was ignored. A method of data processing to identify the seepage degree is proposed.
Distributed optical fiber sensing system is employed to monitor the change of the temperature caused by the seepage
flow inside the dam. Due to tiny difference between two temperatures of the earth and stable seepage water, measureddata
need to be processed further to identify unconspicuous seepage flow. MATLAB wavelet method is used to analyze
these tiny changes hidden in measured-data, which is effective to tell the location and degree of the seepage.
A novel method for measuring the 2D information of burst strong flashing object in space
Author(s):
P. Zhong;
Ye Jin
Show Abstract
The burst strongly flashing event taking place in space such as strong explosion in low air is very random in time and
position, and its duration time is very short. In this paper, a photoelectric measuring device, namely, 2D angle localizer
for measuring 2D angle of a burst strongly flashing object appearing in place randomly has been presented. It mainly
includes detecting head with narrow slot, cylinder silicon photoelectric receiver, absolute photoelectric encoder and
computer. It can complete the measurement of 2D information, namely, the azimuth angle and pitching angle of the
center position of a spatial flashing object. The principle of measuring angle and basic structure of measuring angle
device are introduced. The critical parts of the device are briefly described. A contrast experiment of measuring the sun's
2D angle by 2D angle localizer and theodolite was made. The measuring results and accuracy analysis have been given.
Due to being equipped with variable gain amplifiers and three silicon photoelectric accepters with cylinder surface, the
2D angle localizer has the characteristics of Wide dynamic measurement range and omnidirectional angle measurement.
The measuring accuracy of 2D angle localizer is more than 2mil and the act of measuring can be finished in 0.5s.
SNR analysis according to the practical factors for Mie-scattering lidar
Author(s):
Zongjia Qiu;
Siying Chen;
Yinchao Zhang;
Tian Lan;
Yuzhao Wang;
Weiguo Kong;
Peng Liu;
Guoqiang Ni
Show Abstract
The effectiveness of the lidar scattering signal can be intuitively reflected by SNR. Thus the effective detection range can
be objectively evaluated. Usually by theoretical analyzing the devices of lidar signal detection system, an ideal SNR
model of scattering signal can be built. Under these circumstances the theoretical SNR might be an inflated value. For
instance, when the detection distance is 20Km the SNR can be up to 20dB. However, in the practical experiment the
10Km's SNR is merely 3dB. From the results, it can be deduced that the effective distance range is far less than the
simulation value. Consequently, other practical factors must be considered in SNR analysis for Mie-scattering lidar. In
the paper the results of Mie scattering lidar experiment are shown firstly. Then the SNR is calculated through deducting
the background noise. The background radiation specific gravity is also presented in this paper. The photomultiplier
tubes dark-current is detected. And the effect of all noise components to the SNR is estimated. Meanwhile, some improve
measurements to reduce the interference noise are mentioned.
Hardware circuit implementation of computer-generated holographic algorithm
Author(s):
Xianzhong Jian;
Lihui Guo;
Huaisheng Wang
Show Abstract
This paper presents a novel computer-generated hologram algorithm fit to be implemented on hardware circuit,
called recurrence formula method. In order to improve the speed of the hologram computation, the computation units
based on this algorithm in FPGA chip were implemented by programming the chip with the Very-hight-speed
Integrated Circuit Hardware Description Language. The number of the units is determined by the resources of the
FPGA chip. Much more computation units can also be implemented by paralleling more FPGA chips to work
together. This article will promote the implementation of the computer-generated holographic display technology.
Calibration based on computer vision in measurement of the density of bullet fall
Author(s):
Husile Mergid;
Zhanhua Huang
Show Abstract
For solving the shortages such as difficult and complicate initial calibration, especially aimed at the difficulty in
measurement of incidence, a measure model based on linear partition method of computer vision was presented. According
to the principle of intersection measurement, a mathematic model of measurement system was established and calibration
model was deduced. The measuring position was about 0.5%.
Research on full-field measurement of optical film thickness by processing double interferometric fringes based on digital wavefront interferometry
Author(s):
Long-jiang Chen;
Yi-yong Liang;
Jian-bo Luo;
Chun-hui Zhang;
Guo-guang Yang
Show Abstract
In this paper, a novel optical-film thickness measurement method by the concurrent phase-unwrapping technology
of double interferometric fringes based on digital wavefront interferometry (DWI) is presented. By using this
method, some experiments were implemented on some substrates covered with a kind of optical film such as
mono-layer transparent photoresist. The experimental values of photoresist-layer thickness were acquired by the
computer-aid digital processing of two groups of interferometric fringes synchronously. These results match well
with accurate data measured by spectroscopic ellipsometer. Compared with common techniques of optical-film
thickness measurement, the proposed method has a few advantages as following: non-contact, undamaged, realtime,
adaptive capacity to environment and high accuracy, etc. Theoretical simulation and experimental studies
show that the method has favorable measuring robustness. In addition, the method can be applied to guide, control
and improve optical fabrication based optical film techniques. Furthermore, it is also applicable to the thickness
measurement of curved-surface monofilm or planar multi-layer film, which is important for the optical film-coating
of conventional optical systems based on curved-surface lens.
Influence and correction of temperature on optical measurement for fat and protein contents in a complex food model system
Author(s):
Xuedian Zhang;
Min Chang;
Kexin Xu
Show Abstract
Near infrared spectroscopy has been proposed as an effective way for measuring complex component compositions noninvasively.
However temperature-induced spectral variation can cause accuracy problems if not taken care of in a proper
manner. The influence of temperature on optical measurements has been studied for determining fat and protein contents
in complex food systems. A model system consisting of mixtures of fat, protein, water and emulsion was developed to
create an imitation of complex food systems. The changes in optical properties, including the absorbance coefficients and
reduced scattering coefficients, of the system from 25°C to 40°C were measured in the wavelength from 1100 to 1670
nm. Complex changes in the absorbance coefficient and decreasing changes in the reduced scattering coefficients with
the increasing temperature were founded. The mechanisms of the influences were analyzed. In order to correct the effect,
a statistical method was needed. Then, a method called global robust temperature calibration model is proposed.
Accordingly, the validating experiments using the samples made up of 54 complex food systems were executed. The
experimental results indicated that the method can significantly reduce the temperature effect on optical measurement.