Proceedings Volume 7506

2009 International Conference on Optical Instruments and Technology: Optical Systems and Modern Optoelectronic Instruments

Yongtian Wang, Yunlong Sheng, Kimio Tatsuno
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Proceedings Volume 7506

2009 International Conference on Optical Instruments and Technology: Optical Systems and Modern Optoelectronic Instruments

Yongtian Wang, Yunlong Sheng, Kimio Tatsuno
View the digital version of this volume at SPIE Digital Libarary.

Volume Details

Date Published: 20 November 2009
Contents: 15 Sessions, 97 Papers, 0 Presentations
Conference: International Conference on Optical Instrumentation and Technology 2009
Volume Number: 7506

Table of Contents

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Table of Contents

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  • Front Matter: Volume 7506
  • Micro- and Nano-optics
  • Optical Measurement and Instrument
  • OCT and Spectrometry
  • Optical System Design
  • Display Systems
  • Novel Optical Elements and Optical Communication
  • Optical Testing
  • Other Design Issues
  • Poster Session: Spectrometry, Micro, and Physical Optics
  • Poster Session: Photoelectronics and Laser Optics
  • Poster Session: Optical and Illumination Design
  • Poster Session: Optical Measurement
  • Poster Session: Optical Grating and Optical Film
  • Poster Session: Other Design Issues
Front Matter: Volume 7506
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Front Matter: Volume 7506
This PDF file contains the front matter associated with SPIE Proceedings Volume 7506, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference and Symposium Committees listings.
Micro- and Nano-optics
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Diffractive optics with plasmonics and metamaterials
Il-Min Lee, Hwi Kim, Junghyun Park, et al.
In this study, investigations on the diffractive optics with plasmonics and metamaterials are presented. The object and the scope of this presentation are mainly on introducing the state-of-arts in field of diffractive optics with plasmonics and metamaterials. Including recent studies made by our group, several numerical and experimental results will be presented.
Brightness field and luminance distribution of light guiding plate using micro molding
Chiung-Fang Huang, Jeou-Long Lee, Yung-Kang Shen, et al.
This research points out the brightness field and luminance distribution of the microstructure of a light guiding plate by micro injection molding (MIM) and micro injection-compression molding (MICM). The process of a light guiding plate includes photo-etching, micro molding techniques (MIM and MICM), and optical field measurement. The results show that the luminance of microstructure of light guiding plate made by MICM is better than those made by MIM. The results also indicate the most important processing parameter is the mold temperature for the luminance distribution of light guiding plate whether made by MIM or MICM. The maximum luminance of the light guiding plate is the 80 Nit (cd/m2) on micro molding. The brightness field distribution of light guiding plate made by MICM is more uniform than those made by MIM for the same processing parameters. The micro injection-compression molding is a more suitable process than micro injection molding for the fabrication of light guiding plate on a backlighting unit.
Optical Measurement and Instrument
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Activity at Instrument Technology Research Center (ITRC)
Shu Wen Li, Fong Zhi Chen, Don Yau Chiang, et al.
This talk aims to introduce the general missions, organization, human resources, and research fields of Instrument Technology Research Center in Taiwan. The four main research fields ranged from electro-optics and remote sensing, nanotechnology and bio-medical, vacuum and thin-film technology, and instrumentation and auto-system engineering are introduced, trying to impress you the center activities and to seek for the research collaboration opportunities with better mutual understanding.
Analog mean delay method (AMD) for real-time fluorescence lifetime microscopy (FLIM)
Sucbei Moon, Youngjae Won, Dug Young Kim
We present a new high-speed lifetime measurement scheme of analog mean-delay (AMD) method which is suitable for studying dynamical time-resolved spectroscopy and high-speed fluorescence lifetime imaging microscopy (FLIM). In our lifetime measurement method, the time-domain intensity of a decaying fluorescence light source is acquired as an analog waveform, and the lifetime information of the source is extracted from the calculated mean temporal delay of the waveform.
Zooming effect of three-dimensional shape measurement system using projection method
Saburo Uchida, Hao Zhu, An Kang Yang, et al.
An automatic three-dimensional shape measurement system using an optical spatial modulator and robot arm has been proposed. The system is composed of an optical spatial modulator from which grating patterns are projected on the surface of the object, a digital camera controlled by a robot arm, and a computer. The patterns on the surface of the object were taken into the computer by the digital camera, and the 3D coordinate of the surface of the object was calculated by modified 3D coordinate conversion equations. The three dimensional shape was measured without any contact in short time in the system. The system was improved using mechanical and optical method and data analysis by modified program. Using zoom lens in the camera, the measurement accuracy and range were improved by using correct proofreading factor per camera pixel and reasonable threshold setting. In this modified system, proofreading factor per camera pixel are measured as a zooming factor, therefore this system don't need to use camera factor and is convenient system.
Study on the effects of noises on the measurement results of nanoparticles' effective diameter and polydispersity using PCS
Guoguang Wu, Jun Xiang, Guanling Yang
Photon Correlation Spectroscopy (PCS) is one of the important methods for the measurement of nanoparticles' effective diameter and polydispersity. Noise has a significant impact on the measurement accuracy. To reduce the effects of noises on the measurement results of nanoparticles' effective diameter and polydispersity is an important means to improve the measurement accuracy. The theory of PCS is presented. The effects of noises on autocorrelation function (ACF) and inversion results of nanoparticles' effective diameter and polydispersity are introduced. The limitation of baseline selection method in weak noise situation is pointed out. Original photon scattering signal was acquired using high-speed acquisition method and the characteristic of photon signal were analyzed. The effects of noises with different strength levels on ACF and inversion results were simulated. Based on the baseline difference, more accurate results were achieved using the method of eliminating the distorted ACF caused by strong noises. The effectiveness of this method to improve the measurement accuracy was proved with example.
Principle and application of portable NIR tea drinks analyzer
Liyi Jiang, Huacai Chen, Fuli Liu
Tea polyphenols (Tp) and free amino acids (Aa) are the most important quality materials in tea drinks. Due to the high number of samples to be analyzed, new analytical techniques providing fast and reliable data about the quality are essential. Therefore, a portable near-infrared spectroscopy (NIR) analyzer was developed for real-time, continuous and quantitative determination of Tp and Aa in tea drinks. The portable NIR tea drinks analyzer is composed of a lamphouse, a temperature-controlled sample chamber, an optical fiber and an InGaAs array mini grating spectrometer. The analyzer is compact, lightweight and robust with no movable elements. The software with the functions of spectrum acquisition, model establishment, method selection and real-time analysis was also developed for the analyzer. Using partial least squares (PLS) regression, the calibration models for the quantification of Tp and Aa were established with reference to the GB methods (the national standard methods). The values of root mean square error of cross validation (RMSECV) of the models for Tp and Aa calibration were 0.059 mg/mL, 0.005 mg/mL, the values of the correlation coefficients (R2) were 0.99 and 0.98 respectively. The relative standard deviation (RSD) of ten repetitive testing were 3.17% and 4.15%. It suggested that the portable NIR tea drinks analyzer could be a fast and reliable alternative for tea drinks quality testing.
OCT and Spectrometry
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Progress of OCT and its applications
Masato Ohmi, Masamitsu Haruna
Optical coherence tomography (OCT) is the cross-sectional imaging of biological tissue based on the low-coherence interferometry, where the image resolution is around 10 ìm with the imaging depth of 1 to 2 mm. Since its first demonstration, OCT has been developed intensively for clinical diagnoses of ophthalmology and arteriosclerosis. Beside the clinical applications, OCT is used for analysis of physiological functions underneath the human skin surface. Recently, we proposed and demonstrated the dynamic OCT for in vivo observation of physiological functions of small organs underneath the skin surface. In the dynamic OCT, tomographic images are obtained time-sequentially for tracking of the dynamics of eccrin sweat glands and peripheral vessels. In the last three years, the dynamic skin physiology has been analyzed using both time-domain (TD) OCT and swept source (SS) OCT. In this paper, we present progress of OCT as well as the dynamic analysis of mental sweating and pulsation of a small artery in synchronization with the heartbeat using SS-OCT.
Time-frequency distributions in spectroscopic Fourier-domain optical coherence tomography
Ling Wang, Minghao Guan, Yong Yang, et al.
Current analysis for spectroscopic optical coherence tomography (SOCT) signals is limited by an uncertainty relationship between time (depth) and frequency (wavelength). Various joint time-frequency distributions (TFDs) can meliorate the limits to obtain the best information. Synthesized signals which correspond to three typical SOCT signals in the Fourier-domain under different SOCT imaging schemes, were generated and validate several different TFDs, including short time Fourier transform (STFT), continuous wavelet transform (CWT), Wigner-Villy distribution (WVD), and smoothed pseudo WVD (SPWVD). We found that different SOCT imaging scheme requires different optimal TFDs. STFT offers the most reliable and fast time-frequency (TF) analysis, which is appreciate for retrieving the absorption spectra from a homogeneously absorbing media; WT offers the best spatial resolution or the best spectral resolution locally; WVD generate the most compact TF analysis, but suffers from the artifacts due to the cross terms. SPWVD is applied to yields high spectral and spatial resolution and be free from the artifacts and limitations commonly observed with WVD.
Design of a continual zoom system with high speed for hyperspectral imagers
Qiang Lu, Yiqun Ji, Weimin Shen
A continual zoom system with high speed and visible wavelength range is designed. The lens has the advantages of high etendue and telecentricity in image space. It can be used properly as the fore objective of imaging spectrometers with high resolution since its image size doesn't change with the defocus of detector plane and its illumination in the plane is rather uniform. According to the characteristics and performance of the optical system of our hyperspectral imager, the structural selection and the initial parameter calculation are introduced in detail. The designed optical system with mechanical compensation is presented. The zoom ratio of the lens is 4 and the relative aperture 1:2. Its effective focal length is 55mm at short focus end and 220mm at long focus end. Its field angle is from 2 degrees to 8 degrees. Its distortion is lower than 0.6 per cent. The MTF value at the spatial frequency of 35lp/mm is higher than 0.77. The evaluation of its image quality shows that the designed zoom system can meet the requirements of our hyperspectral imager as its fore objective.
Optical System Design
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Information technologies in CAD system for lens design
I. L. Livshits, V. N. Vasiliev
Research Project of Optical Information Technology is presented, where, so called, CAD system for lens design and analysis was established for the purpose of acceleration on the development of optical devices. These devices will be implemented into new types of optical information systems such as multi-pixel objectives, etc.
An optical design of partitioning the lens surface area
Norihisa Sakagami, Kouei Hatade
In this research we suggest partitioning the lens surface area of an optical design to decrease the field curvature and astigmatism while satisfying the miniaturization demand of a camera module carried by a cellular phone. We compensate for the field curvature corrected by the imaging lens and / or the astigmatism of an optics element, and we partition the lens surface to establish a difference in shape between the center domain of the lens and the surrounding domain of the lens. The center domain and the surrounding domain of the lens is each decided by shape to compensate for the field curvature and astigmatism individually. Based on the above-mentioned procedure, this presentation suggests means to raise the optical performance while satisfying the miniaturization of a camera module carried by a cellular phone.
Design of visual optical system for eye and vision examination
Xuemin Cheng, Jianshe Ma, Hanzhong Liao
The design of a visual optical system for eye and vision examination using video-based chart is investigated in this paper. It produced a virtual image larger than the original display and much farther away from the tester eye. The diagonal length of a virtual image is enlarged as the optical system is designed to match the resolution of human eye. The optical system provides a wide observing area. The optical system also has a large field of view. It has a comfortable long eye relief. The design results and image analysis are also discussed in this paper.
Design of optical system for autonomous APS star sensors
Feng Wu, Weimin Shen
The modern spacecrafts harassed by the "lost-in-space" problem frequently desire for retrieving their orientations autonomously while performing missions especially in deep space. Star sensor becomes a preferred assistant which determines the attitudes with very high accuracy. Autonomous APS star sensors have been the development trends in virtue of their lighter weight, smaller size, less power, and the ability to acquire attitude knowledge autonomously. By analyzing the principle of attitude measurement applying star identification algorithm, the requirements for the aberration correction and imaging quality of their optical systems are discussed. The statistics of star numbers in different orientations is analyzed making use of guide star catalogs established with various limiting star magnitudes and fields of view (FOV). The method to determine parameters of the optical system including aperture size, FOV, focal length and spectrum range is introduced. These parameters meeting the demand of the Pyramid identification algorithm utilized in this paper to realize the autonomous attitude reorganization in any orientations are calculated. Accordingly, a star camera is designed with STAR 1000 APS as its detector. Its focal length, aperture diameter and circular field of view are 43.56mm, 27.3mm and 20 degrees, respectively. Structure selection and aberration correction schemes are presented. Aberrations including coma, astigmatism, and distortion and lateral color are corrected, and spherical aberration and longitudinal color are controlled. This camera is telecentric in the image field which assures that the star identification is still valid even though the image plane suffers from a deviation as a result of the environmental alteration and manufacture errors.
Impact of the temperature gradient on optical system parameters: modeling and analysis
Hong Chang, Zhi-gang Fan, Shou-qian Chen, et al.
A simplified mathematical model was proposed to describe the relationship between image quality and temperature gradient. It can be used to determine the maximal allowable temperature gradient in which optical system was applicable, as well as the applicability of optical system in given temperature gradient condition. Firstly, under some assumption conditions, the thermal deformation of optical surface and refractive index distribution caused by temperature gradient distribution were analyzed, and a simplified mathematical model was built to describe the impact of radial temperature gradient on optical parameters. Secondly, the model was validated by using finite element analysis software analyze an infrared lens. Finally, an application example was given. The image quality of a refractive infrared optical system in thermal environment with radial temperature gradient was analyzed by using the mathematical model proposed above and optical design software.
Display Systems
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Integral floating system: new approach of autostereoscopic display
Integral floating system is recent development of autostereoscopic display. It consists of the integral imaging system and the floating device as depicted in the name. The integrated image forms a floating 3D image in the vicinity of the observer through the floating device which can be either a convex lens or a concave mirror. The integral floating system can provide dynamic 3D images with great feel of depth. This paper reviews the main concepts and the special characteristics of the integral floating system. Moreover, some improvements and analysis will be presented with some basic experimental results.
Real-time correction and fusion for optical distortions in head-mounted displays
Dongdong Weng, Yue Liu, Yongtian Wang
Free-form-surface prism (FFSP) based HMDs have widespread application value and prospect in the fields of virtual reality and augmented reality. A key problem of the FFSP-based HMDs is the correction for optical distortions. The distortion correction can be performed with an additional optical system, but the additional system will add the expense and complexity of the HMDs. This paper presents a software-based method to correct optical distortions in FFSP-based HMDs, in which a distortion map with predistortion information is constructed to correct the distortion and a pixelfusion process is performed to improve the quality of the predistortion image. The correction process and the fusion process are accomplished by GPU in real-time. The performance of the proposed method is analyzed and validated via an inspection system, in which a high-performance CCD camera is used to evaluate the result of the correction and fusion.
Novel speckle suppression in LCoS based laser projection
Mingjie Sun, Zukang Lu
When coherent light scattered from a rough surface, speckle is detected by an intensity detector. In laser projection, speckle severely affects the image quality and therefore must be suppressed. It is mostly achieved by vibrating or rotating a diffuser or a diffractive optical element (DOE) in illumination system. These methods can effectively reduce the speckle, but also cause energy loss of the illumination light due to source extension. A novel way of speckle suppression, which is in principle by varying incident light angle continuously within a light pipe, is proposed. Both theoretical and experimental systems are built. Experimental results show that the new method brings the speckle contrast down to 3.45% and preserves more than 90% energy.
Novel Optical Elements and Optical Communication
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Holographic optical elements and devices based on polyfunctional photo-thermo-refractive glass
Nikolay Nikonorov, Vladimir Aseev
A new polyfunctional photo-thermo-refractive (PTR) glass doped with erbium and ytterbium has been developed for the first time. The glass combines itself three opportunities: fabrication of lasers or amplifiers, recording of volume Bragg gratings (VBG) or holographic optical elements (HOE), fabrication of planar waveguides or fiber. The glass can be classified as optical polyfunctional material. The polyfunctional PTR glass exhibits good spectral, luminescent, and lasing characteristics, as well as photorefractive and ion exchangeable properties. Different HOE and devices on the base of the polyfunctional PTR glass have been demonstrated for photonic applications.
Optical properties of liquid prism and its application
Jing Wan, ZhongCheng Liang
Liquid prism is a sort of prism composed of liquid as the body. It can singly work or be integrated on the optofluidic chip, which takes advantage of the unique properties of liquids to create adaptive systems. The optical properties of the prism can be flexibly changed by filling liquid or not as well as by adjusting the concentration of liquid. Taking advantage of this point, the liquid prism can be applied in optical communication, dye lasers, liquid analysis in biochemistry and medicine fields, optical imaging system, optical measurements and optical experiments, etc.. The liquid prism can serve as both the refraction prism and reflection prism in application. Here an optical switch based on the liquid prism and two approaches to analyze liquid by the liquid prism are presented and the optical properties of corresponding liquid prisms are discussed. Here the liquid prism is used to change light path in the optical switch or to analyze the refractive index, density, concentration and dispersion of liquid.
An integrated optical control and communication system for free-space environments
Xian Jin, Jason E. Barg, Jonathan F. Holzman
A corner-cube-based integrated retroreflective structure is introduced as a novel instrument for free-space optical (FSO) communications. The structure is composed of three independent and mutually-orthogonal silicon photodiodes (PDs) and is shown to have capabilities for real-time optimization and control by way of differential photocurrent sampling between adjacent PDs. A balanced system with minimal differential signal levels is ultimately indicative of perfect optical alignment and differential triangulation is used to obtain this optimized alignment. Such a scenario is ideallysuited to bi-directional FSO communication links with the fundamental requirements for optical retroreflection, detection, and modulation. Both active downlink and passive uplink FSO communications are demonstrated.
The design of scanning fiber optical system
Yangbo Bai, Peng Zu
A novel scanning fiber optical system for multi-channel optical switch has been demonstrated. This scanning fiber system consists of motor, photoelectric encoder, EPOS position controller, Field Programmable Gate Array (FPGA), fiber laser, transmitting energy fiber bundle, reflector, five-dimensional optical adjustable mounts, etc. In this device, the control system is composed of EPOS position controller and FPGA. Furthermore, the photoelectric encoder is directly connected to the central shaft of the motor to read its position information. The reflector is slantways fixed on the other end of the motor central shaft. Also, the fiber bundle is fixed by optical adjustable mounts to achieve slight position adjustment, which is used as launching system of this configuration. In the operation process, the motor in uniform rotation state drives the photoelectric encoder and the reflector at the same angle velocity. The photoelectric encoder reads the incremental signal and absolute position signal of motor, and then sends them to EPOS position controller and FPGA respectively. FPGA sends square wave signal to the fiber laser under the control of EPOS position controller and FPGA. Triggered by the square wave signal, the fiber laser emits a laser pulse to the center point of the reflector. At the same time, the reflector makes the laser pulse transmitting into a certain transmitting energy fiber according to the angle of the reflector at that moment. Therefore, with the motor rotates at uniform speed, the laser pulse is sent to different fibers, by which multi-channel optical switch is completed.
An investigation on multiwavelength laser using a semiconductor optical amplifier
Yangbo Bai, Wanghua Xiang, Xiaoyan Xu, et al.
The paper demonstrates a novel multi-wavelength ring laser for light source in dense wavelength division multiplexing (DWDM) system, which consists of semiconductor optical amplifier (SOA), high-birefringence fiber loop mirror (Hi-Bi FLM), polarization controller, etc. Among these devices, SOA is used as optical gain medium; Hi-Bi FLM serves as wavelength selecting comb filter. When SOA is driven with higher injection current, the number of output multi-wavelength, and the single channel power and total power all increase gradually due to the inhomogeneous broadening in SOA gain medium. When SOA is driven with a 280-mA dc current at room temperature, it tends to gain saturation state, and simultaneous stable oscillation of 18 lines with the equal line spacing of 0.8 nm (100 GHz) is obtained in the range of 1571.3 nm ~ 1587.1 nm. The power fluctuation among the lasing lines is less than 6 dB and each line-width is less than 0.118 nm. Furthermore, the signal to noise ratio is greater than 25 dB. By adjusting the polarization controller in Hi-Bi FLM, the frequency tuning range of the overall output multi-wavelength is up to 50 GHz.
Design of laser beam divergence angle program control system
Chuang-xin Zhang, Yang Jiao, Shi-guang Yang, et al.
In order to meet some fields' need for the laser beam of variable divergence angle, a divergence angle program control system was designed in this paper. The system realized the automatic control, based on "computer + stepping motor+ the collimation system". It consisted of a collimation system, a control software unit, a hardware unit and the detection unit. In the collimation system, the relationship between the output beam divergence angle and the distance between the two lenses was found by theoretical analysis. Then the output beam divergence angle could be controlled precisely when the distance was altered precisely by stepping motor. Experiment was carried out to validate feasibility of the design. The result showed that the design was effective and it was easy and fast to alter control beam divergence angle, based on the design.
Optical Testing
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Optimization of the computer-generated hologram in null test of sculptured surface
Ping Su, Guoguo Kang, Qiaofeng Tan, et al.
Sculptured surfaces are increasingly used in design of modern compact optical systems. Null test with computergenerated hologram (CGH) using commercial interferometer is generally adopted to test sculptured surfaces. To quickly estimate the maximum line density of the null CGH and determine whether the sculptured surfaced can be null tested or not, the best fitting sphere of the sculptured surface under test is firstly calculated and the deviation between the sculptured surface and the best fitting sphere is calculated along the normal direction of the best fitting sphere. The direction of optical axis and the optical arrangement are optimized to obtain a null CGH with minimum line density. And now the deviation between the sculptured surface and the best fitting sphere is calculated along the normal direction of the sculptured sphere, which is in accordance with the practical design of the null CGH. Simulated results show the validity of the method of the best fitting sphere, the estimated and designed maximum line density of the null CGH is accordant. Finally CGHs for null test of two sculptured surfaces are designed.
Lens decenter and tilt measurement by interferogram
Min-Wei Hung, Wen-Hong Wu, Kuo-Cheng Huang
For the recent years, the vigorous development of the electro-optic industry, particularly the digital camera and the cellular phone camera, has placed a larger and larger demand for the optical devices. Among the optical lens, the aspherical optical lens plays the key component because the aspherical lens may provide better imaging quality then the spherical lens does. For the manufacturing reason, the aspherical lens is prone to a decenter or tilt issue with respect to the optical axes of its two surfaces. To measure decenter and tile error specifically would help to obviate the deficient lens, but most of the present measuring method can't provide this function. This paper proposed a new method to specifically measure the decenter and tile of lens by observing the interferogram of each surface. And the corresponding measuring instrument, which contains interferometer and motion stages, was introduced as well.
Stray light analysis and baffle design of remote sensing camera for microsatellite
Rongbao Shi, Jiankang Zhou, Weimin Shen
A two-mirror catadioptric system with corrective lens groups is adopted in the remote sensing camera of microsatellite. Compared with the refractive system, it has the advantage that its performance is hardly influenced by thermal environment. Stray light results in image blur and the contrast reduction of the camera. It is necessary to analyze and control it. In traditional way, stray light can be effectively suppressed with a long baffle, which is not suitable for microsatellites with limited space. And a compact one with high performance is designed. First of all, model of the camera is set up and its stray light is analyzed with Lighttools. The main and the primary baffles are designed and optimized. Then the point source transmittance is calculated to evaluate and verify the designs. Its veiling glare index is also simulated and calculated based on black-patch measurement.
Laser beam collimation testing with defocus grating
Haotong Ma, Fengjie Xi, Pu Zhou, et al.
A novel method for testing the collimation of laser beam with defocus grating is presented. Defocus grating combined with lens of short focus length allows simultaneous imaging of two defocused spots in the ±1 diffraction order spot. When the well collimated beam passes through the defocus grating, the diameter of the ±1 diffraction order spot is equal to each other. The relationship between the collimation of the incident beam and diameters of the ±1 diffraction order spots are analyzed in detail. The position of the pinhole and pointing errors of the collimation system can be detected by the defocus grating. The feasibility of this method is verified experimentally on the collimation of the He-Ne laser. The method which has a simple data processing algorithm does not require any referencing or fringe analysis and can be implemented full-optically.
Other Design Issues
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On maximum field components in the focal point of a lens
H. P. Urbach, S. F. Pereira, D. J. Broer
We determine field distributions in the pupil of a high NA lens, that give, for a given power incident on the lens, the maximum electric field amplitude in focus in a specific direction. We consider in particular the cases of maximum longitudinal and maximum transverse components. The distribution of the maximum longitudinal component in the focal plane is narrower than that of the focused Airy spot and hence can give higher resolution in imaging.
Study about AFS swerve mode
Hong Liu, Lanfang Jiang, Qin Zhao, et al.
A swerving mathematical model was established after stating the shortage of the present AFS swerving algorithm. The conception of 'expected lighting distance' was extended to 'expected lighting bound' and approximate treatment of geometry of light beam falling to ground of headlamp was processed. The expected lighting bound was ascertained and the lighting range of turning angle of headlamp was calculated. The calculation formula of turning angle of headlamp was worked out. It was indicated that the turning angle of inside and outside of headlamp calculated by revised algorithm was reasonable by comparing calculation. Finally the control strategy about the turning angle of inside and outside headlamp when turning was worked out. It is of practical significance in promoting the active safety, reducing the traffic accidents caused by insufficient angle and range of irradiation of headlamp.
The optimized calculation of driving points distribution in large segmented mirrors
Mei Hui, Yu-di Zou
The cophase calibration system is applied for adaptive optical phasing with a large segmented telescope mirror, which commonly uses 3-DOF micro-position device with three micro-displacement actuators to drive segments in parallel, making the entire segmented mirror in phase at one time and obtaining the desired sensor readings accordingly. In order to run the active control system to make the segments cophase, it is necessary to calculate the coordinates of the three driving points correctly for segmented mirrors specially limited in geometric parameters, especially for the stability and sensitivity of the micro-positioning device. The mirrors will be supported on a massively parallel system of electrostatically controlled, interconnected microactuators that can be coordinated to achieve precise actuation Adjusting posture of each segment independently so as to obtain the co-phasing errors and to control them at a nanometer level. Several generations of individual actuators as well as parallel arrays of actuators with segmented mirrors have been designed. A mechanical model of the system has been constructed and simulated numerically to obtain the actual position of three actuators using the RPY angle describing means. A three-channel parallel control scheme has been developed and implemented on a segmented mirror array. A universal evaluating method for optimization is prompted and will be a good guide to the design optimization of micro-positioning device for each segmented mirror when the mirrors are groundbased horizontally.
Study on the wavefront coding characteristics by ray tracing method
Huaiyu Cai, Tao Lei, Liqiang Fan, et al.
It is quite important to study the wavefront coding characteristics further for deeper understanding the theory of wavefront coding, and improving the quality of final image restoration and the coding performance of the system. First of all, a model to study the coding relationship between the incident ray and the emerging ray in different parts of aperture was established by ray tracing method based on a finished design of the handy wavefront coding system for measuring the crack width in concrete. Second, the rotation relation between the phase mask and its corresponding PSF was discussed. Finally, the analysis and evaluation of the shape, size and the intensity distribution of PSF along with different fields were completed. The results show that the PSF azimuths of the coded system vary with the different placement of phase mask and the PSF expands seriously in the meridian direction (expanding rate 59.9%) while nearly remains the same in the sagittal direction when the object field increasing. It will help us to divide isoplanatic regions and modify the PSF for the final image restoration.
Design of H-PDLC grating array chopper applied in frequency division multiplexed integrated confocal microscopy
Ken Wen, Jihong Zheng, Guoqiang Sun, et al.
A new type of electrically controlled optical chopper based on Holographic Polymer Dispersed Liquid Crystal (HPDLC) grating array is demonstrated in this paper. H-PDLC grating can be erased and become transparent to the incident beam when applied the external voltage. H-PDLC grating recovers and diffracts incident light in the original way after removal the driving voltage. Thus the intensity and the frequency modulation to the incident beam can be achieved through adjusting the voltage applied on the H-PDLC cell. Compared with a conventional chopper, the H-PDLC gratings exhibit more advantage like much faster response time, the grating array is much more integrated and easier to be fabricated etc. Moreover, electro-optical properties including response time and diffraction efficiency of H-PDLC gratings are investigated. By optimizing some parameters, H-PDLC chopper cell with a microsecond response time and high diffraction efficiency is obtained. The driving voltage of H-PDLC can be reduced through controlling the droplet size in H-PDLC and the thickness of the grating. As the application example, the chopper is applied in the new born frequency division multiplexed multichannel fluorescence confocal microscopy so that it can improve the temporal and spatial resolution ability of the microscopy system.
Poster Session: Spectrometry, Micro, and Physical Optics
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Study on infrared imaging spectrometer with large aperture static interferometer
Lin Ma, Weijian Zheng, Junhong Su
The imaging spectrometer for remote sensing of hazardous clouds is required for high performances, and expected to satisfy the performances simultaneously, such as spectral and spatial resolution, optical throughput, real-time capability and stability. Recent developments in long-wave infrared focal plane array combined with the mastering of Fourier transform spectrometer technology allow the realization of two kinds of infrared imaging spectrometer with large aperture static interferometer for detection, monitoring and localization of hazardous clouds from long distance. In this paper, the basic structures and operating principles are introduced at first. Then the performance parameters are analyzed and the restricting equations of the parameters are deduced. At last, the feasibility for remote sensing of hazardous clouds is demonstrated.
The development of monitoring system on water polluters by UV/VIS spectroscopy
Min Chang, Xuedian Zhang, Liuji Xing
UV/VIS spectroscopy has been proved to be an effective way for monitoring water quality non-invasively. However, the present method can only provide the synthesized information of the water pollution by using the sum parameters like TOC, DOC or TSS. The changes in the composition of the water cannot be detected. For monitoring water polluters, a UV/VIS spectrometer for in-situ and on-line measurements has been developed. It utilizes the UV/VIS range (200-750 nm) for the pollutant component measurement. A Xenon lamp is used as a light source. Fiber sensor is used as a probe and the diffuse reflectance spectra of the water are measured for the in-situ application. In order to measure the different polluters, a diffuse reflectance board, the position of which can be adjusted to the optical length of the measured polluters, is installed the front of the fiber. The spectra of the water can be measured in 5s. Then the method of the differential optical absorbance spectroscopy (DOAS) is employed to decrease the interference from the common mode noise. Finally, the polluter's concentrations can be derived by calibration between the UV/VIS spectra and the reference concentrations of the calibrate sample set by using Partial-Least-Square (PLS) regression.
Near-infrared spectroscopy and pattern recognition techniques applied to the identification of Jinhua ham
Honglian Li, Zhilei Zhao, Yanping Pang, et al.
Near-infrared (NIR) diffuse reflectance spectroscopy and pattern recognition techniques are applied to develop a fast identification method of Jinhua ham. The samples are collected from different manufactures and they are nineteen Jinhua ham samples and four Xuanwei ham samples. NIR spectra are pretreated with second derivative calculation and vector normalization. The pattern recognition techniques which are cluster analysis, conformity test and principal component analysis (PCA) are separately used to qualify Jinhua ham. The three methods can all distinguish Jinhua ham successfully. The result indicated that a 100 % recognition ration is achieved by the methods and the PCA method is the best one. Overall, NIR reflectance spectroscopy using pattern recognition is shown to have significant potential as a rapid and accurate method for identification of ham.
Surface plasmon resonance optical sensing for simultaneous multi-channel biological monitoring
Wei Peng, Soame Banerji, Yoon-Chang Kim, et al.
This paper presents a multi-angle optical analysis device based on surface plasmon resonance (SPR) for simultaneous biological sample detection. Most applications of optical SPR devices were designed to measure refractive index (RI) of liquid or gas sample by measuring the signal wavelength or angle, the sensitivity and stability of which is easily affected by the fluctuation of various interior or exterior test conditions. In this study, we have proposed a multi-channel optical SPR device which can monitor SPR changes at different wavelengths and angles. The preliminary experimental results demonstrate the characteristic responses of SPR signals from different angles changes independently correspond to the refraction index changes of the liquid samples with which they are in contact. The experimental results confirmed that a practicable high-sensitivity multi-channel SPR biological measurement instrument could be completed with further developments.
Rigorous vector analysis of diffractive microlens by using the finite-difference time-domain method
Yuling Liu, Hua Liu
We use finite difference time domain (FDFD) method as rigorous vector analysis model to simulate the focusing process of diffractive microlens (DML). Differing with most analysis model which the near field distributions are calculated by FDTD and then far field are obtained by using of propagation method, we obtain the fields in whole computational space by using of FDTD only. The advantages are that all the results are vector based and the computational time is saved greatly. In this paper, we present two methods to obtain wave amplitude, one is comparison method, and the other is integral method. Depending on wave amplitude in the whole computational space, one can conveniently obtain distributions of electric field intensity and calculate the time-average Poynting vector. We also present the formulation for calculating diffractive efficiency of DML based on time-average Poynting vector which denotes energy flow. As demonstration, a DML is analyzed by using of these algorithms. The time depended graphic results of FDTD show the process of wave propagation. The distribution of electric field intensity illustrates the focusing of the normal incident light. The focus pattern in the focal plane is also show. The diffractive efficiency of the DML is calculated by using of the energy flow method in this paper. The results show the high accuracy and efficiency of the model.
Realization of Fourier transform imaging spectrometer based on all-reflective optics
Ningfang Liao, Wenmin Wu, Deqi Cui, et al.
We present our latest research development of the all-reflective Fourier transform imaging spectrometer based on the principle of wavefront-splitting interference. The optical configuration of this system includes a set of Fresnel's double mirrors and a number of other reflective telescopes or mirrors. The major advantages of this system includs higher optical throughput, larger spectral bandwidth, and less chromatic aberration as compared with conventinal chromatic-despersion imaging spectrometer . In this paper ,the optical principle and the prototype device of our system are introduced, and the latest experimental results from our prototype device are presented.
Poster Session: Photoelectronics and Laser Optics
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Design of a highly stable LD power supply and a highly reliable protection circuit
Min Zhou, Aiwen Zhang, Zhiping Cai, et al.
We have contrived some new technologies to design new-style LD power supply in order to pursue the high stability of output current and the reliable working condition. High-performance constant current drive source on the basis of dual operational amplifier with high sensitive feedback loop and voltage regulator module greatly reduces the current ripple and improves the stability of output current. Through precise testing, we obtain the results that the output current ripple is below 0.09% and the output current stable degree is less than 0.03%, which are much lower than those of other existing ordinary LD power supplies. We have also designed a high-efficiency dual slow-start surge-absorbing loop, accompanied by a filter network, which has reduced the impact of the surge current effectively. We obtain that the peak value of surge current is no more than 0.938%, which is advanced in the field of LD power drive designing. Besides, the protection circuit could make circuit loop stay at a certain unchanged status when it is in over-current condition or not, which greatly improve the security and reliability of the whole system.
Impact of lamp instability on rotating compensator based ellipsometry
Chunguang Hu, Lidong Sun
The influence of statistical noise such as lamp instability, photon shot noise, and detection noise on the signal quality in rotating compensator based ellipsometry (RCE) is investigated by means of mathematical modeling and simulations. The results uncover the transfer route from noise to measurement error under different experimental conditions, and thus provide a basis for noise diagnosis and control in RCE systems.
Beam profile of laser pointer (VFL-350) after launching in telecommunication fiber optic
Mir Saeed Sarollahi
VFL-350 (Visual Fault Locator) Light Source is used to check single-mode and multimode optical fiber cables and components for faults or to locate individual fibers in a bundle. Loss as intrinsic loss (absorbsion and scattering), mechanical loss (splices and connections) are important to estimate the amount of errors in data transmission process (both in single as well as multimode fibers). That is one of the most important parameter of change intensity profile of laser beam. Standard light source that used in this project is an optical pen that have semi guassian beam with out put power 1 mw(class 1) & λ=635 nm that make follow result: Beam propagated from this light source have semi guassian shape and result of some transverse mode. Beam intensity profile of this light source after launching in multimode fiber optics (length=2m & connector: have 20% loss compared by beam intensity profile of optical pen.(connector loss). Situating a filter in path of multi mode fiber optic, don't any change in beam intensity profile of multi mode fiber optics.
High-power blue LED light source system
Ping Liang, Yibo Zheng, Qiang Liu
A new high-power blue LED light source system for portable OSL instrument is presented. High-power blue LED light source system with optical components are arrange in order to realize high radiation intensity of the stimulate light source, high-power blue LED luminous intensity are controlled by multi-channel controllable constant source. The experiment results show that the system is simple, small, blue uniform stability and high strength, as the stimulate light source for the portable OSL instruments.
A new polarization multiplexing method for the micro LCOS projector optical system
Qin-xiao Liu, Wen-zi Zhang, Hui-fang Gao, et al.
In this paper we present a new polarization multiplexing method for the micro LCOS projector optical system. We use calcite to separate the P and S light with respect to the PBS used in the traditional way. The specific method is described as follow: the special lens group or TIR is used to collimate emission ray from the light source. The ray from the lens is changed into approximate parallel light. A convergent component is used to get the convergence light on the exit facet of the calcite. Because of the structure characteristic of the calcite, the angel between optical axis of crystal and cleavage surface is 45 degree. Then we can get two separate convergence light spot on the exit facet of the calcite which stands for the P and S light respectively. The linear half wave plate is used to convert the state of the polarization. Then light pipe and relay imaging lens are used to meet the requirements of the uniformity and incident angle on the micro LCOS chip.
The design of data acquisition system of the NIRS instrument based on USB
Xiaolong Guo, Dong Chu, Peng Liu, et al.
The near infrared spectroscopy (NIRS) is the main apparatus for near-infrared spectrum analysis, which has been widely used in agriculture, biology, petrifaction, foodstuff, medicament, spinning and other fields. In this paper, we successfully designed a high-sensitivity, high-resolution, high-speed, real-time and USB2.0-based near infrared spectroscopy data acquisition system, and discussed the design ideas of multi-functional NIR spectrometer on hardware and software. On the basis of deeply analysis of the construction and principle of near infrared spectrometer and principle of optics, we set up the near infrared spectroscopy system, developed the software system of data acquisition and data processing, did some preliminary experiments and made analysis on the results. The results of the experiments demonstrate the instrument can reflect the spectral characteristics of YAG laser and meets the design requirements.
Study and experiment of ship movement simulation for free space laser communication
Tingyu Wang, Songlin Zhuang
Free space laser communication (FSOC), which features high anti-EM interference capability, good security, is the important method of the communication between ships. According to the ship motion equations, this paper mainly discusses the motion law of the ship in the wind waves by using linear system theory. We use a four-degree-of-freedom platform with a horizontal, a vertical and two rotating motions to simulate the laser movement caused by ship movement in the wind waves, and give, as an example, a realization of laser movement caused by ship roll movement in the wind waves. This platform can be used in the lab for the ship-borne free space optical communication (FSOC) system conveniently and accurately.
Demonstration of 80Gbit/s all-optical SOA-based wavelength conversion
Nan Jia, Kangping Zhong, Tangjun Li
All-optical SOA-based non-inverted wavelength conversion of 80Gbit/s by using a structure which consists of a SOA and a followed optical filter is demonstrated. Result illustrates that SOA-based wavelength converter has a weak nonlinear performance if the optical pulse with a wide spectrum. Moreover, a non-inverted 40Gbit/s and non-inverted 80Gbit/s All-optical wavelength conversion using this simple structure with a narrow spectrum are also demonstrated. Result shows shat the wavelength conversion at 40Gbit/s can be easily achieved, the wavelength converted eye diagram is clear. However, the eye diagram is not very clear at 80Gbit/s due to the performance of filter.
Laser diode end-pumped efficient coupling system based on microlens arrays
Feng Huang, Wenwu Jia, Yuefeng Wang, et al.
Efficient pumped coupling is one of the important technologies of diode pumped solid state laser system applying end-pumped structure. This work present a novel pumped coupling optical system based on microlens arrays. In the coupling system, the light of laser diode stack is incident on an imaging microlens array, that cuts the beam into a number of beamlets. Subsequently these beamlets are overlapped in the pumped surface of laser media through an aspheric focusing lens. Then a high homogeneity pump field is realized. Furthermore, for different aspect ratios of the homogenized spot two microlens arrays with crossed cylindrical lenses are used to match different pump field size. Such coupling system was designed by ray tracing method using ZEMAXTM Non-Sequential Components analysis tools. The non-sequential raytracing simulation shows that a 5 × 5 mm2 Top-Hat intensity pump profile was got at a working distance of 40 mm and the homogeneity of the intensity distribution is better than 90%. In comparison with the traditional coupling optical system homogenization by means of microlens arrays is more flexible and requires a reduced number of optical components.
A kind of detection method for laser warning annunciators based on tunable laser source in hemisphere space
Hongbin Shen, Gang Li
Now the detection method of performance data of laser warning annunciators is the conventional target board law of diffuse reflection, this method operation is complex, has poor efficiency, therefore, the study of high efficiency and fast detection method and testing system has important meaning. A method based on tunable simulating laser pulse in hemisphere space has been proposed. In order to simulate a laser subject practically to realize the test for annunciators, the position of a laser source on a hemisphere is controlled, and the output power, wavelength and modulating frequency of the laser source can be adjusted. The locating mechanical structure of the hemisphere surface applying to stepper motor drive has been designed, the software system and the circuit has been developed based on the technique, using AVR microcontroller ATmega16 to fulfill the function of laser power controlling, wavelength adjustment, frequency modulation and position controlling of hemisphere surface. The method and technique are more efficient compared with the former method for it can be realized by the mechanical & electrical conjunction. The mechanical and electrical structures are given and discussed in this paper.
Temperature distribution of laser crystal in end-pumped DPSSL
Yibo Zheng, Liping Jia, Lei Zhang, et al.
The temperature distribution in different cooling system was studied. A thermal distribution model of laser crystal was established. Based on the calculation, the temperature distribution and deformation of ND:YVO4 crystal in different cooling system were obtained. When the pumping power is 2 W and the radius of pumping beams is 320μm, the temperature distribution and end face distortion of the laser crystal are lowest by using side directly hydrocooling method. The study shows that, the side directly hydrocooling method is a more efficient method to control the crystal temperature distribution and reduce the thermal effect.
Laser-diode double-end pumped Tm3+:GdVO4 laser using three-mirror folded cavity
Jiali Lin, Chaohong Huang, Guoxiong Cai
Using excellent host of Gadolinium Vanadate (GdVO4), Tm3+:GdVO4 laser has many advantages, such as high heat conductivity, little thermal effect, large stimulated emission cross-section, and low laser oscillation threshold. And due to its stronger and broader absorption spectrum in the 800 nm region, highly-efficient AlGaAs laser-diode (LD) can be adopted as pump source. In this paper, the properties of various kinds of Tm3+-doped laser crystals are compared in the first place. Then by describing the energy transmission process of Tm3+-doped system at the 2 μm band and establishing the quasi-three-level rate equation, we obtain the expression of threshold pump power and slope efficiency. Moreover, considering thermal lens effect of GdVO4, the three-mirror folded resonator is analysed using the method of transmission matrix and optimized numerically. A low-threshold, high-power, and good-stability LD double-end pumping Tm3+:GdVO4 solid-state laser is designed by the guidance of the optimized resonator parameters. We obtained a fundamental mode 1920 nm laser output.
Far field description of laser diode arrays
Qiang Xu, Yiping Han
A new model is applied to describe the field distribution at the output of the LDAs. Formalism describing of the far-field radiation patterns of a laser arrays is presented, base on rigorous solutions of the Helmholtz equations. The beam-divergence angles normal and parallel to the junction plane are concluded. Theoretical results presented are in close agreement with the experiments. and the final result is expressed in a form convenient for diffraction analysis of LDAs beams.
High diffraction efficiency for ultra-short laser pulse by superposed reflection volume phase gratings
Guangwei Zheng, Jichun Tan
An innovative configuration - two pieces of reflection volume phase gratings superposed is put forward, in order to highly diffract the ultra-short laser pulse. Based on Kogelnik's coupled wave theory, and discrete Fourier transform, the diffraction efficiency of the configuration for ultra-short laser pulse is formulated. And the diffraction efficiency for laser pulse with a Gaussian shape in temporal domain is simulated. The results show that when the two gratings' vectors are parallel to each other, and their parameters are selected appropriately, the diffraction spectrum of the configuration is approximately composed of those of the two gratings. The diffraction efficiency of 70fs Gaussian laser pulse can be improved to 0.96, which is 0.20 larger than that by only one piece of the grating. It is very useful for the application of ultra-short laser pulse, such as beam deflector with high diffraction efficiency, spectral beam combination, and so on.
Simulation and analysis of laser coherent combining system based on adaptive fiber optic collimator array
Chao Geng, Xinyang Li
This paper reports a new method for piston and tilt control in the laser coherent combining system. Adaptive fiber optics collimators have been developed to correct beam-tilt. The SPGD algorithm is employed to correct a given wavefront. The relative parameters which directly influence the algorithm's convergence are studied. The adaptive fiber optics collimator's working principle is confirmed.
The research and design of novel free-space optical communication
Jia Wang, Xin Yu, Yang Li
A novel free-space optical (FSO) communication system is proposed in this paper. The beam divergence of transmit antenna is designed smaller and the receiving antenna is made by large aperture nonimaging optical system. A transmission mode of "small beam divergence and large receiving aperture" is designed, which can optimize the detection equation and improve the bandwidth, link distance and reliability of FSO system. The surface accuracy requirement of nonimaging optical system and the equipments are low. The pulse stretch caused by surface error has little effect to the bandwidth of FSO system, and satisfies the requirement of most communication.
Poster Session: Optical and Illumination Design
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Optical design of a long range dual field of view thermal imaging camera in 3-5μm waveband
Ramin Khoei
In this work, the design study of a switchable dual field of view thermal optical system for 3-5 μm is presented. A mechanical holder switches in and out lenses to the whole optical system to change the focal length from 60. A cooled 320×256 focal plane array with 30 μm pixel pitch is imaging the rays gathered by thermal optics. To avoid vignetting which is caused by the presence of the detector cold shield, a relay lens is used to image the entrance pupil of optics on the cold shield.
The optical modeling tool and a simulation method for air turbulence in large opto-mechanical systems
Jian-liang Shi, Ge Ren
The paper presents a new optical modeling tool developed for solving the optical sensitivities with respect to air perturbation. The tool is a Matlab based software package allowing the user to configure the model, select analysis options and process the results. When assessing the impact of disturbances on high-performance systems, it is critical that the disturbance models can be fairly representative of the actual disturbances. Partitioning the clam air by many planes, we can view the air as an array of lens of different index of refraction and the air perturbation as the planes jitter. The overall model architecture is presented in detail. The overall framework is applied to an integrated model of telescope to demonstrate its practical use. The simulation results show the air turbulence near two mirrors affect the performance of system mostly, with the air turbulence near primary mirror being dominant.
Design and simulation of the surface shape control system for membrane mirror
Gengsheng Zhang, Minxue Tang
The surface shape control is one of the key technologies for the manufacture of membrane mirror. This paper presents a design of membrane mirror's surface shape control system on the basis of fuzzy logic control. The system contains such function modules as surface shape design, surface shape control, surface shape analysis, and etc. The system functions are realized by using hybrid programming technology of Visual C# and MATLAB. The finite element method is adopted to simulate the surface shape control of membrane mirror. The finite element analysis model is established through ANSYS Parametric Design Language (APDL). ANSYS software kernel is called by the system in background running mode when doing the simulation. The controller is designed by means of controlling the sag of the mirror's central crosssection. The surface shape of the membrane mirror and its optical aberration are obtained by applying Zernike polynomial fitting. The analysis of surface shape control and the simulation of disturbance response are performed for a membrane mirror with 300mm aperture and F/2.7. The result of the simulation shows that by using the designed control system, the RMS wavefront error of the mirror can reach to 142λ (λ=632.8nm), which is consistent to the surface accuracy of the membrane mirror obtained by the large deformation theory of membrane under the same condition.
Research and application on imaging technology of line structure light based on confocal microscopy
Wenfeng Han, Zexin Xiao, Xiaofen Wang
In 2005, the theory of line structure light confocal microscopy was put forward firstly in China by Xingyu Gao and Zexin Xiao in the Institute of Opt-mechatronics of Guilin University of Electronic Technology. Though the lateral resolution of line confocal microscopy can only reach or approach the level of the traditional dot confocal microscopy. But compared with traditional dot confocal microscopy, it has two advantages: first, by substituting line scanning for dot scanning, plane imaging only performs one-dimensional scanning, with imaging velocity greatly improved and scanning mechanism simplified, second, transfer quantity of light is greatly improved by substituting detection hairline for detection pinhole, and low illumination CCD is used directly to collect images instead of photoelectric intensifier. In order to apply the line confocal microscopy to practical system, based on the further research on the theory of the line confocal microscopy, imaging technology of line structure light is put forward on condition of implementation of confocal microscopy. Its validity and reliability are also verified by experiments.
Dome design and coupled thermal-mechanical analysis of supersonic missile
Xing-qiao Ai, Qun Wei, Hong-guang Jia
A review of high-speed flow pressure and aerodynamic heating effect on Supersonic missile's dome is given. The dome should have excellent properties in optical, mechanical and chemical characteristics. A design of dome on supersonic mode is described according to tactical guide line of a missile. The dome made of quartz which is about 8mm thick and 141mm in window diameter. To check up the reliability of the dome, a reasonable finite element model (FEM) of dome is established, and a thermal-mechanical Analysis to the dome by finite element software NASTRAN has carried on, through these can obtained the distribution of temperature field and stress field when the speed is 2.3Ma. The results indicated that the stress was concentrated in the joint of the dome end and the Missile Section, and the maximum stress was 16.4Mpa. The stress of other nodes was smaller than the allowable stress of quartz glass. Reference to the results of the analysis, a lightweight revision to the dome structural dimension and a new method of dome fixing have put forward, which can reduce the stress concentration.
Design of signal reception and processing system of embedded ultrasonic endoscope
Ming Li, Xiaodong Chen
Embedded Ultrasonic Endoscope, based on embedded microprocessor and embedded real-time operating system, sends a micro ultrasonic probe into coelom through the biopsy channel of the Electronic Endoscope to get the fault histology features of digestive organs by rotary scanning, and acquires the pictures of the alimentary canal mucosal surface. At the same time, ultrasonic signals are processed by signal reception and processing system, forming images of the full histology of the digestive organs. Signal Reception and Processing System is an important component of Embedded Ultrasonic Endoscope. However, the traditional design, using multi-level amplifiers and special digital processing circuits to implement signal reception and processing, is no longer satisfying the standards of high-performance, miniaturization and low power requirements that embedded system requires, and as a result of the high noise that multi-level amplifier brought, the extraction of small signal becomes hard. Therefore, this paper presents a method of signal reception and processing based on double variable gain amplifier and FPGA, increasing the flexibility and dynamic range of the Signal Reception and Processing System, improving system noise level, and reducing power consumption. Finally, we set up the embedded experiment system, using a transducer with the center frequency of 8MHz to scan membrane samples, and display the image of ultrasonic echo reflected by each layer of membrane, with a frame rate of 5Hz, verifying the correctness of the system.
Baffle design for a Cassegrain telescope
Cheng-Fang Ho, Shenq-Tsong Chang
The baffle design and analysis of a panchromatic push-broom camera were investigated for a Cassegrain telescope in this paper. A specially designed flower-look baffle is surrounded by the hole of the primary mirror and secondary mirror. With this design, the flower-look baffle can block the direct-hit stray light and reduce the off-axis field of view (FOV) vignetting. The modulation transfer function (MTF) of this design is increased 10 % as compared to the performance of the traditional baffles. This camera is equipped with a large field of view (FOV) which can get a wide swath and can provide high-resolution image for observation and monitoring of environmental pollution and disaster. The optical system assembly (OSA) of the camera is a kind of Cassegrain telescope which contains two reflection mirrors and five corrected lenses. Compared with other off-axis telescopes, this traditional optical configuration can be manufactured and aligned much easily. In a large FOV Cassegrain design, the central hole of the primary mirror is larger than that in a traditional Cassegrain design. The rays out from FOV pass though the central hole easily and reach the focal plan assembly (FPA) directly. This kind of stray light carries strong energy flux which significantly reduces the image performance. A baffle subsystem is needed in order to avoid the direct stray light exposure. The performance evaluation of the baffle system and the MTF comparison results from two kinds of baffle shapes are included in this study. It indicates that the flower-look shape is more efficient in keeping the relative illumination and MTF than traditional tube shape. The maximum benefit of the flower-look baffle is found for increasing off-axis tangential MTF.
The design and application of laser triangulation ranging system based on virtual instruments
Tuo Wang, Qianqian Wang
Laser triangulation ranging is a method of distance measure using laser as the light source and based on the triangulation ranging principle. It has many advantageous characteristics such as non-contacted measurement, high accuracy, and a large degree of strength against disruption. As a result, it is widely used in the industrial production. An integrated real-time laser triangulation ranging system based on virtual instruments is introduced in this paper. The measuring principle, the hardware components and the real-time virtual instrument program are introduced. As well as, the results of the measurement are presented and analyzed.
Research and hardware implementation of image enhancement algorithm in OLED system
Meihua Xu, Ke Li, Yule Fan
During the process of generation and transmission, images will be influenced by the performance of imaging system, quantization noise or some other actors. The image will appear some phenomenons like clarity decrease and low contrast. For the sake of improving the picture quality in OLED system, time sequence control logic and hardware of the whole OLED system were implemented based on the detailed analysis of OLED panel electrical characteristics and various gray scale scanning principles. Sub-field scanning working mode is adopted in the design. Gray scale is 64 and vertical sweep frequency is 60Hz~100Hz.FPGA is the core control device in the whole system, the DVI decoded signal is processed. The design realizes the real-time video display on OLED. The utilization of parameters regulated homomorphic filtering technology is studied to improve the quality of color image. At first, the high and low frequency parts are departed with the help of illumination reflectance model.Then the digital image is processed with approximate high-pass filter, the simplified filtering algorithm made a compromise solution between the complex of hardware implementation and image quality. In the end, by the frequency domain inverse transformation, images got enhanced. The experiment results show that the particular information extrudes and the whole visual effect is improved after the process.
Analysis and optimization of the stereo system with a biprism adapter
Xiaoyan Li, Rong Wang
More and more applications need stereoscopic imaging to analyze the characteristic of things, so three-dimensional information is needed to visualize and analyze. The stereoscopic imaging can be obtained by single camera or two cameras. There are several approaches for creating stereo images with a single camera. One of the simplest and most frequently used has been to place an optical adapter in front of the existing lens, and two images are formed by two beams through one camera lens. Biprism can be used as stereo adapter. As light go through the biprism, an angle change occurs due to the prism, the light refracted at the two surfaces, angle of the prism α with also reflection index n determine the angle change δ of the light. And δ is the maximum field of view. Bigger angle of biprism can obtain bigger range of stereoscopic imaging, however, the larger of the angle of biprism, the larger of lateral color aberration the biprism caused, which can affect the resolution of the stereoscopic imaging. This paper also analyzes the nonlinear magnification and color aberration of the biprism stereo adapter.
Fly-eyes illumination analysis
Wenzi Zhang, Qinxiao Liu, Huifang Gao, et al.
The Fly-eyes element has been widely applied to acquire uniform illumination in microscope, printing, projection, and so on. With large number of fly-eyes pieces and specified aperture shape, illumination of high efficiency, high uniformity, and specified area shape can be acquired. In this paper, mathematical expressions for fly-eyes illumination are derived for free form incoming light distribution. With these expressions, the reason why uniform illumination can be acquired with fly-eyes is given, and the defects of fly-eyes illumination is also discovered. According to traditional design experience, the illumination uniformity acquired by fly-eyes illumination will be increased with the increment of fly-eyes number. But with the derived expressions, it can be found that there are some limitations for this experience. For some odd symmetrical illumination cases, uniform illumination can not be acquired even with large number of fly-eyes pieces. This feature of fly-eyes illumination should be pay good attentions when dealing with non-symmetrical illumination cases. Another feature of fly-eyes illumination is that discrete angular distribution instead of continuous angular distribution of output light is acquired, and this discrete angular pattern varies with numerical aperture of the incoming light. This may be a bad feature for microscope with fly-eyes illumination, but this is a good feature for projection. With these derived mathematical expressions, guidelines for the application of fly-eyes illumination can be found and a deep view into the fly-eyes illumination can be acquired.
Monitoring of a small top lighting solar light pipe system
Yanpeng Wu, Zhiyou Yue, Rendong Jin
Solar light pipes are effective method to induce sunlight into the room need to be illuminated to improve vision quality. This paper presents the results of monitoring a small solar light pipe located inside a windowless test box of about 0.22m3.The light pipe is 720mm long with the diameter 180mm.The average reflectivity of the internal surface is 0.82.The system has been monitored with luminometers to evaluate the distribution of the luminance on a working-plane under sunny conditions, cloudy conditions and overcast conditions. All the luminometers are automatic digital equipments, according with CIE photopic standard. The solar light pipe used in the experiment achieved minimum illuminance of 140lx overcast sky and achieved maximum of 1657lx under sunny condition. At the corner, the illuminance value decrease rapidly.The experimental results showed that uniformity ratio of illuminance of the light pipe variable with the sky conditions. Uniformity ratio of illuminance was 0.48 under overcast conditions, 0.44 at cloudy conditions, and 0.83 at sunny conditions in the middle in the test box. Compare the experimental results of sunny conditions with the values of overcast conditions, the difference is the intensity of the illuminance under sunny conditions was stronger and evenly than under the cloudy conditions.
Compact LED based LCOS optical engine for mobile projection
Wenzi Zhang, Xiaoyan Li, Qinxiao Liu, et al.
With the development of high power LED (light emitting diode) technology and color filter LCOS (liquid crystal on silicon) technology, the research on LED based micro optical engine for mobile projection has been a hot topic recently. In this paper one compact LED powered LCOS optical engine design is presented, which is intended to be embedded in cell phone, digital camera, and so on. Compared to DLP (digital light processor) and traditional color sequential LCOS technology, the color filter based LCOS panel is chosen for the compact optical engine, this is because only white LED is needed. To further decrease the size of the optical engine, only one specifically designed plastic free form lens is applied in the illumination part of the optical engine. This free form lens is designed so that it plays the roles of both condenser and integrator, by which the output light of LED is condensed and redistributed, and light illumination of high efficiency, high uniformity and small incident angle on LCOS is acquired. Besides PBS (polarization beam splitter), LCOS, and projection lens, the compact optical engine contains only this piece of free form plastic lens, which can be produced by plastic injection molding. Finally a white LED powered LCOS optical engine with a compact size of less than 6.6 cc can be acquired. With the ray tracing simulation result, the light efficiency analysis shows that the output flux is over 8.5 ANSI lumens and the ANSI uniformity of over 80%.
Optical design of optical transfer function instrument
Liangjun Zhang, Xinhua Chen, Yuheng Chen, et al.
The optical design of Optical transfer function (OTF) instrument, which is based on the image Fourier analysis method, is presented. To perform infinite conjugate testing of an optical system, the designed system is mainly composed of the object generator, lens under test, and image analyzer. The object generator offers an object at infinite distance with known spectral and spatial content. It includes the illumination system and the collimating system. The illumination system is analyzed and optimized with CODEV and LightTools software. Performance evaluation indicates that its illumination uniformity in the required area is above 95% .The collimation system based on an off-axis parabolic mirror is of the focal length of 2000mm and the entrance pupil diameter 200mm. Through optimization, the image quality of the collimator is excellent and its on-axis modulation transfer function (MTF) approaches diffraction limit. Collimated beam of the target is imaged by the lens under test. The image is magnified and acquired by image analyzer, which is made up of four parts: an infinite conjugate microscope objective, a tube lens, an eyepiece and a CCD camera. Image Results show that this designed scheme meets the requirements of this OTF instrument.
Poster Session: Optical Measurement
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Determination of zero incident angle by optical feedback effect and its applications in the measurement of refractive indices
Xiao-Kang Zhang, Run-Hua Li
Prisms are involved in many instruments of measurements of refractive indices. The optical feedback effect in a semiconductor laser introduced by the reflection of a prism was applied to the determination of zero incident angle. Without any additional optical components or calibration setups the angular resolution reached 0.00074°. This approach was used in refractometers and prism coupling system. Prisms, water, wintergreen oil and a quartz plate were measured by total internal reflection technique and the optical feedback effect. In the measurement of prism, we proposed that the base angle of a detected prism should be appropriately prepared so as that the refractive index of an isosceles prism made of any material can be precisely measured. The results for a SrTiO3 prism with a base angle 30.0169 degree was 2.3780 at 659 nm. The measurements of water and wintergreen oil were performed by a reference prism made of SrTiO3. We found that the result for a quartz plate wouldn't be influenced by the index matching liquid between the plate and a reference prism, which was intentionally introduced, only if the index of the liquid was larger than that of the quartz. The refractive index of a polymer film was measured accurately and the maximum of deviation from mean was ±0.0001.
Distortion measurement of push-broom imaging spectrometer
Yuheng Chen, Yiqun Ji, Jiankang Zhou, et al.
The requirement for low distortion in either spatial or spectral direction of a push-broom imaging spectrometer has been recently recognized. Though distortion scale of as much as 1 or 2 pixels have been accepted in previous spectrometer designs, it is suggested to be limited to the order of hundredth of a pixel to preserve the validity and integrity of the spectral imaging data. The developed push-broom imaging spectrometer adopts a reflective Offner relay structure and provides good optical correction and compact size. The spectral and spatial distortion measurement is of significance for instrument performance evaluation and alignment guidance. In this paper, two easy-to-implement and effective measurement methods for both spatial and spectral distortion are presented. By using a standard Hg-Cd lamp as both the illuminating source and the object, the spectroscopic image of the slit focusing onto the CCD focal plane is collected. In certain rows of the image, the center positions of every spectral line are recorded. Through the comparison of recorded positions of different rows, the spectral line bending of the calibrated imaging spectrometer is worked out. In the continuous spectrum illumination condition and by using a self-made mask as the object, the entrance slit image is cut into tens of tiny rows that correspond to different image heights. The center positions of 5 typical rows are calculated and five chromatic distortion curves are worked out with certain interpolation method.
Measurement accuracy analysis and error correction of CCD light-projection diameter measurement system
Qing Song, Chunsong Zhang, Jiayong Huang, et al.
The error source of the external diameter measurement system based on the double optical path parallel light projection method are the non-parallelism of the double optical path, aberration distortion of the projection lens, the edge of the projection profile of the cylinder which is affected by aperture size of the illuminating beam, light intensity variation and the counting error in the circuit. The screw pair drive is applied to achieve the up-and-down movement in the system. The precision of up-and-down movement mainly lies on the Abbe Error which is caused by the offset between the centerline and the mobile line of the capacitive-gate ruler, the heeling error of the guide mechanism, and the error which is caused by the dilatometric change of parts resulted from the temperature change. Rotary mechanism is achieved by stepper motor and gear drive. The precision of the rotary mechanism is determined by the stepping angle error of the stepper motor, the gear transmission error, and the heeling error of the piston relative to the rotation axis. The method of error modification is putting a component in the optical path to get the error curve, which is then used in the point-by-point modification by software compensation.
The measurement of refractive index homogeneity of the large diameter Ge plate using interferometry
Jun He, Lei Chen
The method is presented to measure the homogeneity of the refractive index of infrared optical material, germanium (Ge) plate, using infrared interferometer working at 10.6μm. In order to measure the refractive index homogeneity of large diameter infrared material, the infrared standard lens is used in the test arm of infrared interferometer. The Ge plate is placed in the infrared spherical wave brought by infrared standard lens. The difference is measured between the wavefront with Ge plate and the one without Ge plate by the infrared interferometer working at 10.6μm. The addition aberration caused by Ge plate needs to be eliminated with Zernike polynomials fit from the results. As the Ge plate is too soft to process, its surface form may not meet the requirement for the measurement. In order to improve the measuring accuracy of the refractive index homogeneity, the surface deformations of two boundaries of the Ge plate are measured by phase-shifting digital interferometer working at 0.6328μm. The surface deformations are removed from the result of the refractive index homogeneity measurement. In this way, the measuring accuracy of the refractive index homogeneity is up to 10-5. A piece of Ge plate is tested. The peak-valley (PV) value of its refractive index deviation is 3.65×10-5, and the root mean square (RMS) value is 4.11×10-6.
Modeling and simulation of an optical system for surface roughness measurement
Xiaomei Xu, Shoubin Liu, Hong Hu
A novel model of an optical system for surface roughness measurement is proposed, which is based on the study of the scattering characteristic of rough surfaces and theories for intensity-modulated fiber optic sensors. The effect of the rough surfaces and the fiber optic sensor head to the measurement model are analyzed respectively. In order to guide the surface roughness measurement experiment, some simulation of the optical system has been done on a computer. Though the modeling and simulation of the surface roughness measurement system are under certain assumptions and conditions, the research results are valuable to experiment applications yet.
Laser scanning system for large diameter measurement
Liang Chen, Shuqin Zhang, Shangzhong Ji, et al.
In this paper, it is described the work principle and total structure and design of the laser-scanned measuring systerm for the large diameter. Signal characteristics of scanning system is described,the circuit and method for boundaries detection and drift errors. The feasibility of the system is tested by practice, the accuracy of boundary distinguishing is up to ±1μm,and continuous working errors up to ±5μm,measurement range up to 0~400mm. This system shows a better method for measuring large diameters.
Co-phase error correction of the optical sparse aperture system
Dayong Wang, Juan Zhao
Optical sparse-aperture system can be designed to obtain high resolution in astronomical object imaging with several independent small-aperture telescopes. However, the images from separated telescopes are not only overlapped but also have same phase. Ordinarily, the phase of each sub-aperture can be obtained by wave-front sensing technology, such as phase retrieval algorithms, but this method requires more than one CCD and interfere the wave front. In this work, we use the differences between PSFs from each sub-array to get the type and size of the co-phase error. Finally, submit the results to mechanical system as a feedback for phase retrieval. We used Golay-3 system as an example to verify the above conclusions. The output is consistent with the pre-set value within the allowable error. The results show that this method is feasible and reasonable.
Poster Session: Optical Grating and Optical Film
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Near-field diffraction of a hexagonal array at fractional Talbot planes
Wei Wang, Hong Zhu
Hexagonal array structure is not only a nature-preferred basic structure widely exists in nature, but also is an important pattern that has been widely used in optoelectronics field. Talbot effect and fractional Talbot effect is one of the most basic optical phenomena that has received extensive investigations both because it is a fundamental Fresnel diffraction effect and also because of its wide applications. As one of the most application of the Talbot effect, Talbot array illuminators have been extensively studied since Lohmann and Thomas put forward for the first time. One-dimensional and two-dimensional orthogonal Talbot array illuminators are in-depth investigated and can be designed and manufactured based on the theory of the fractional Talbot effect. A hexagonal array is a periodic nonorthogonal array that cannot be represented by orthogonal array. Thus, it is difficult to analyze the diffraction field of hexagonal arrays at fractional Talbot planes. Previous studies have shown that light distribution at Talbot distance can be considered multiple copies of the original aperture by shifting and superimposing. In this paper, qualitative analysis of a hexagonal array is carried out at fractional Talbot planes based on the fractional Talbot theory. Theory and experiment analysis show that diffraction patterns at 1/6 and 1/3 Talbot distance are consist of nine equally spaced copies of the original aperture, and each copy is shifted by 2a and a (a represent the side length of the hexagon) from another copy, respectively. Experimental results are in good agreement with the theoretical analysis.
Study on image acquisition in 3-D sensor system of arc welding pool surface shape using grating projection
Xiaopu Ai, Nansheng Liu, Yiqing Wei, et al.
Detecting 3-D information on welding pool surface shape is difficult due to the arc light interference, high temperature radiation and pool surface specular reflection. The characteristics of mirror like reflection on pool of liquid surface are studied. Besides the way to obtain clear information-rich image of the pool area is discussed under the strong arc light. Because of the strong arc light above the pool will affect the imaging of the relatively weaker laser stripes seriously, we need to choose a suitable shooting angle and shooting distance to achieve well image. According to all these factors, the optimal combination of the sensing structure parameters in theory is deduced. Based on this work, a vision detecting of arc welding pool surface topography system was putted up in our laboratory, also actual measurement was carried out to obtain more clear images of deformation laser stripes in welding pool. This will provide the three-dimensional reconstruction a strong support.
Research on projection grating pitch in GTAW surface sensing based on Fourier transform profilometry
Xian Hu, Nansheng Liu, Xiaopu Ai, et al.
Selecting an appropriate pitch is one of the most important aspects to ensure the system measurement range and precision in grating projection principle of 3D profile measurement while the Fourier transform frequency spectrum is separated completely. According to the concept of the equivalent wavelength, the basic requirement for measurement system and the selection of projection grating pitch are discussed in this paper to avoid shadows and frequency spectrum alias in a crossed-optical-axes system in Fourier Transform Profilometry (FTP). The influence of CCD sampling to the FTP is also discussed to obtain CCD sampling condition. When the CCD sampling frequency is unchanged, it is necessary to reduce the grating frequency which means to increase the grating pitch to satisfy the sampling condition. Finally, the range of the grating pitch is determined, and the optimal grating pitch is obtained after the experiments.
Spatial filtering for high power laser beam by volume Bragg grating
Haobin Zheng, Yanlan He, Jichun Tan
Nowadays, the most widespread used space filters are pinhole filters, consisted of a lens with a pinhole in the focal plane, requiring for matching spatially a focused laser beam to a small hole. Experimentally, the initial alignment of spatial filters is difficult, if the pinhole position changes, a laser can damage the pinhole when the power is increased or even permanent damage due to heating. In contrast, non-spatial filtering, a holographic filter element, which made of volume Bragg grating, is inserted in the laser beam path to selectively diffract light propagating at a particular angle, without a lens or a pinhole. A volume Bragg grating is operated directly on the laser beam propagation angle without focus, made use of the grating's angular selectivity, which alignment is easier than pinhole filter, and endures a high-power laser. In this thesis, a volume Bragg grating was fabricated in a 40μm-thick photopolymer, with period of 911.3nm, preparing for a low-pass non-spatial filtering. It achieves an angular selectivity of 35mrad; diffraction efficiency about 95%. Nevertheless, the results of the experiment can be verified with the theory, but not suitable for high-power application. In that case, the photopolymer's grating should be replaced with a photo-thermo-refractive glass.
Analysis of film thickness for magnetron sputtering system with more than one workbench
Tao Wang, He Yu, Zhiming Wu, et al.
In this article, the thickness uniformity of thin films deposited by magnetron sputtering system involved in both planetary circumrotate model and traditional model by rectangle target were investigated respectively. It was shown that the thickness uniformity of films by magnetron sputtering system with rotation and revolution at the optimum ratio value of Wz/Wg 0.5 is superiority to traditional system which with 0.3 of thickness relative deviation at coordinative condition. Moreover, the relative deviation was dropped as the addition of distance from substrate to target. The results were in accord with that obtained experimentally.
Genetic algorithm used in interference filter's design
Jinsong Li, Xiumin Gao
An approach for designing of interference filter is presented by using genetic algorithm (here after refer to as GA) here. We use GA to design band stop filter and narrow-band filter. Interference filter designed here can calculate the optimal reflectivity or transmission rate. Evaluation function used in our genetic algorithm is different from the others before. Using characteristic matrix to calculate the photonic band gap of one-dimensional photonic crystal is similar to electronic structure of doped. If the evaluation is sensitive to the deviation of photonic crystal structure, the approach by genetic algorithm is effective. A summary and explains towards some uncompleted issues are given at the end of this paper.
Study on the optical property of P-C doped a-Si:H thin films
Haihong Cai, Wei Li, Yadong Jiang, et al.
Hydrogenated amorphous silicon (a-Si:H) thin films doped with Phosphorus (P) and Carbon (C) were deposited by plasma enhanced chemical vapor deposition (PECVD). The influence of carbon on the optical property and the content of hydrogen and carbon in the P-doped a-Si:H films were investigated by means of X-ray photoelectron spectroscopy, spectroscopic ellipsometry and Fourier-transform infrared spectroscopy, respectively. The results show that the C-Si bonds in the P-C doped a-Si:H thin films can be observed clearly, and the content of hydrogen and carbon as well as the optical band gap increases with increasing CH4 gas flow rate, but the refractive index decreases with increasing CH4 gas flow rate in the CVD chamber.
Poster Session: Other Design Issues
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Surface defects detection based on anisotropy of local fractal dimensions
Yan Zeng
In order to detect the defects in a random surface, the local fractal dimension(LFD) of the random surface image and its anisotropy are studied in this paper. An algorithm to estimate the anisotropy of local fractal dimensions based on moments of the increments is obtained, and the ratio of horizontal and vertical differential of LFD which can characterize the anisotropy of local fractal dimension is proposed. The parameter overcomes the local textual irregularities by representing the region stationary of a non-stationary rough surface. Images of variant random surfaces and defects are investigated. The results of experiments show that the method and parameter proposed are robust, which extract local morphologic features of roughness anisotropy in random surfaces distinctly. By measuring the rupture joint of the ratio, the defects in random surfaces can be detected and located sensitively.
Application comparison of horizontal photoelectric system with x-y double-axis gimbal photoelectric system fixed on soft-rope hanged platform
Wei Yu, Xing-fa Liu, Jia-guang Ma
Two common structures were often adopted to construct the photoelectric system that fixed on soft-rope hanged platform. Both of the horizontal photoelectric system and X-Y Double-Axis Gimbal photoelectric system have blind regions, so they have different application. This article regarded the photoelectric system fixed on soft-rope hanged platform as multi-rigid-body system. Lagrange equation and augmented body theory were employed to establish the balloon borne photoelectric system's dynamic model as torques that imposed on the photoelectric system were considered. Channel matrix and matrix of constraint force element and some other matrixes were used to describe the photoelectric system's dynamics. Numerical simulations have been performed to compare the two kinds of balloonborne photoelectric system's performance. According to simulation result, different application situation were given for the two structure photoelectric systems fixed on rope hanged platform. The x-y double-axis photoelectric system is adequate for tracking high-elevation object, and has better stabilization ability against pendulum disturbance. The horizontal photoelectric system was good at tracking low-elevation object and has better ability to eliminate twist torque.
Efficient regularization parameter estimation based incomplete orthogonalization method
The regularization parameter plays a crucial role in the quality of a restored super-resolution image. In this paper, we propose a method for parametric regularization based on the incomplete orthogonalization method. The method truncates the Arnoldi recurrence. Specifically, an integer k is selected so that it is necessary to keep only the k previous orthogonal vectors for Arnoldi process. The others are not needed in the process and may be discarded. The method can be inexpensively computed by the incomplete orthogonal process. Thus a convenient way for choosing the regularization parameter is presented.
Design of autotrack detecting instrument for solar UV radiation
Jiangtao Xia, Xiaoli Mao, Jing Zhao
In order to autotrack the object and detect the solar UV index, a reliable real-time high-precise instrument is proposed in this paper. This instrument involves two subsystems: the autotrack and detecting modules. The autotrack module consists of four-quadrant photo detector, multi-channel signal processing circuit and precise stepping system. The detecting module designed for dada measurement and acquisition is made up of the ultraviolet sensor UV460 and high precision A/D converter MAX1162. The key component of the entire instrument is ultralow-power microprocessor MSP430 which is used for entire system controlling and data processing. The lower system of autotracking and measurement is communicated with upper PC computer by RS232 module. In the experiment, the tracking precision of two-dimensional motion revolving stage is calibrated to be less than 0.05°. Experimental results indicate that the system designed could realize the precise autotracking and detecting function well, and the measure precision of system has reached the desirable target.
Variable-step-size LMS adaptive filter for digital chromatic dispersion compensation in PDM-QPSK coherent transmission system
Tianhua Xu, Gunnar Jacobsen, Sergei Popov, et al.
High bit rates optical communication systems pose the challenge of their tolerance to linear and nonlinear fiber impairments. Digital filters in coherent optical receivers can be used to mitigate the chromatic dispersion entirely in the optical transmission system. In this paper, the least mean square adaptive filter has been developed for chromatic equalization in a 112-Gbit/s polarization division multiplexed quadrature phase shift keying coherent optical transmission system established on the VPIphotonics simulation platform. It is found that the chromatic dispersion equalization shows a better performance when a smaller step size is used. However, the smaller step size in least mean square filter will lead to a slower iterative operation to achieve the guaranteed convergence. In order to solve this contradiction, an adaptive filter employing variable-step-size least mean square algorithm is proposed to compensate the chromatic dispersion in the 112-Gbit/s coherent communication system. The variable-step-size least mean square filter could make a compromise and optimization between the chromatic dispersion equalization performance and the algorithm converging speed. Meanwhile, the required tap number and the converged tap weights distribution of the variable-step-size least mean square filter for a certain fiber chromatic dispersion are analyzed and discussed in the investigation of the filter feature.
CCD based digital optical transfer function testing instrument
Xinhua Chen, Yuheng Chen, Liangjun Zhang, et al.
As the development of image processing and area array detectors, CCD has been used widely in optical transfer function (OTF) measurement for it can realize fast measurement and avoid scanning operation. An OTF testing instrument using CCD camera is introduced in this paper. This instrument works in visible wavelength with 200mm entrance pupil diameter. The highest spatial frequency this instrument can measure is up to 200lp/mm. This instrument is composed of four parts, that is, object generator, image analyzer, control system and software. A 50mm plano-convex lens is used to calibrate this OTF testing instrument. According to the calibration results, measurement error of this testing instrument is less than 0.04, while its repeatability is less than 0.03.
Software for analysis of existing lens to discover starting point
Matvei A. Pashkovskiy, Irina L. Livshits, Sergey C. Stafeev, et al.
This article describes algorithm for patent analysis. The main goal of the algorithm is to discover structural scheme of optical system: sequence of elements and its purposes. Examples are given. This software could be used both for research and educational purposes.
Analysis of optical field distribution of the super-Gaussian beam passing through continuous phase plate
Hao Yan, Chunlin Yang, Shenglin Wen, et al.
The design and manufacure of Continuous Phase Plate(CPP) with a large aperture is very significant and useful to the Inertial Confinement Fusion(ICF) and some physical experiment related due to its several advantages such as high energy availability ratio and easily controllable focal spot's profile. Various processing errors will be inevitably introduced for the limitation of the fabrication technique and hence produce aberrated laser wavefront, which is very influential for the process of beam's propagation and focusing. In this paper we numerically simulate and compare the optical filed distributions of phase-aberrated super-Gaussian beam passing through both designed and manufactured CPP with a large aperture and deep phase. The simulation results prove the CPP's beam smoothing performance and high tolerance of the super-Gaussian beam's far-field focal plane intensity distributions,which has been added by the random phase screen, furthermore, the modulation influence of intermediate frequency phase error to the near-field light intensity distribution has also been simulated and proved, from which we can improve the fabrication technique and optimize the design method.
Design and laboratory calibration of the compact pushbroom hyperspectral imaging system
Jiankang Zhou, Yiqun Ji, Yuheng Chen, et al.
The designed hyperspectral imaging system is composed of three main parts, that is, optical subsystem, electronic subsystem and capturing subsystem. And a three-dimensional "image cube" can be obtained through push-broom. The fore-optics is commercial-off-the-shelf with high speed and three continuous zoom ratios. Since the dispersive imaging part is based on Offner relay configuration with an aberration-corrected convex grating, high power of light collection and variable view field are obtained. The holographic recording parameters of the convex grating are optimized, and the aberration of the Offner configuration dispersive system is balanced. The electronic system adopts module design, which can minimize size, mass, and power consumption. Frame transfer area-array CCD is chosen as the image sensor and the spectral line can be binned to achieve better SNR and sensitivity without any deterioration in spatial resolution. The capturing system based on the computer can set the capturing parameters, calibrate the spectrometer, process and display spectral imaging data. Laboratory calibrations are prerequisite for using precise spectral data. The spatial and spectral calibration minimize smile and keystone distortion caused by optical system, assembly and so on and fix positions of spatial and spectral line on the frame area-array CCD. Gases excitation lamp is used in smile calibration and the keystone calculation is carried out by different viewing field point source created by a series of narrow slit. The laboratory and field imaging results show that this pushbroom hyperspectral imaging system can acquire high quality spectral images.
Feature points detection and tracking based on SIFT combining with KLT method
Hongbing Wang, Zhenming Peng, Jie Liu, et al.
For feature point detection with variable scale, rotation, variable illumination and variable 3D view port, a feature point detection and tracking method combining scale invariant feature transform (SIFT) and KLT (Kanade-Lucas-Tomasi) is proposed in this paper. SIFT feature point detection method is improved and it is used to detect feature points of image, and then KLT method is used to track the feature points continuously. In order to verify the feasibility of the proposed method, simulation experiments are carried out in real scene image sequences with different complexity using this method, better results of detection and tracking are obtained and the obtained feature point is more stable than conventional method.
Double-threshold image segmentation method based on gray gradient
Zhihua Fan, Chunhong Wang, Xiaoyu Ma
For the segmentation of the dim point target and the extended target under sky background which has low resolution, an automatic thresholding method based on spatial gradient information is presented. It can separate the point target and the extended target from the background even under the strong noise condition, providing good segmentation results for the point target as well as the accurate information of the shape for the extended target. This method first marks the pixels as the background or the target using the image gray gradient roughly, then fit the grayvalue of pixels in the background area to obtain two thresholds, with which the image can be segmented according to the pixel position, and finally the morphological filter is adopted to remove the noise in the segmented image. The experiment shows that, when compared to Otsu in low resolution images with even background, our method can work more accurately and robustly.
An optical scan-calibration system in scanning near-field optical microscopy
Yunliang Wu, Hao Zhang, Keyi Wang
Scanning Probe Microscopes(SPM) use piezoelectric actuators to generate the scans. But the nonlinearities inherent in the piezoelectric actuators limit the usefulness of the instruments in precision metrology. This paper describes a simple optical beam displacement sensor that is used to accurately measure the (x,y) position of a piezoelectric tube scanner used in Scanning Near-field Optical Microscope(SNOM). As the nonlinearities is too complex to make up a simple math model, this paper use the Artificial neural network to Calibrate the nonlinearities.
Exponential increased partitions method for three-dimensional active imaging
Xiuda Zhang, Huimin Yan, Jinliang Yao, et al.
Three-Dimensional(3D) Active imaging are usually employed for target detection and recognition[1~3]. In recent years, many methods have been presented for high-speed 3D active imaging[4~5]. However, for those methods employ one group of images only maintains one more gated partition, the depth resolution increases linearly with the number of images. This character limits the performance of 3D active imaging systems. In this paper, we demostrate how to overcome this limitation. In our method, we introduce an exponential code method to ploting out partitions which makes the depth resolution increased exponential with the number of images. Furthemore, oure poltiong is robust and realible for it is based on binary principle.