Journals >Opto-Electronic Engineering
Contents
2009
Volume: 36 Issue 1
28 Article(s)
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Research Article
Review and Prospect of Image Restoration with Space-variant Point Spread Function
FENG Hua-jun, TAO Xiao-ping, ZHAO Ju-feng, LI Qi, and XU Zhi-hai
Compared with the image with Space-invariant Point Spread Function (SVPSF), the restoration of the image with SVPSF ,whose degradation function in the object domain is different from point to point, is more difficult because of the extraction, storage and calculation of massive PSFs. Fortunately, three methods have beeCompared with the image with Space-invariant Point Spread Function (SVPSF), the restoration of the image with SVPSF ,whose degradation function in the object domain is different from point to point, is more difficult because of the extraction, storage and calculation of massive PSFs. Fortunately, three methods have been proposed to solve the problems: coordinate transformation approaches, sectioned restoration methods and direct algorithms, which are aimed to reduce the data storage, decrease the computational complexity, and improve convergence rate. The paper summarizes the research on the reconstruction of the image with SVPSF in the history, and then points out the crucial problems of the development of the issue in the future. Moreover, a total variation majorization-minimization sectioned restoration algorithm based on gradient ringing metric image quality assessment is exhibited..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 1 (2009)
Fast Sobel Edge Detection Algorithm Based on GPU
ZUO Hao-rui, ZHANG Qi-heng, XU Yong, and ZHAO Ru-jin
The traditional Soble edge detection algorithms for optimization and implementation which were designed for common processor such as CPU, DSP and FPGA, could not be effectively applied on Graphics Processor Unit (GPU). A fast Sobel edge detection algorithm is presented based on NVIDA’s GPU which support Compute UnifiedThe traditional Soble edge detection algorithms for optimization and implementation which were designed for common processor such as CPU, DSP and FPGA, could not be effectively applied on Graphics Processor Unit (GPU). A fast Sobel edge detection algorithm is presented based on NVIDA’s GPU which support Compute Unified Device Architecture (CUDA). On the basis of the parallel architecture and hardware characteristic of GPU, the fast algorithm introduces three methods to improve the implementation performance: Texture Storage technology optimizes the data storage structure, multiple point access technology improves the data access efficiency, and symmetry computation technology reduces the computation complex. The experiment result shows that GPU can effectively implement the fast algorithm and processing speed of 8-bit 4 096×4 096 pictures can be up to 190 fps, which is 122 times faster than CPU-based implementation..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 8 (2009)
DCT Domain Embedded Image Compression Based on Morphological Dilation and Difference Reduction
ZHANG Ming, BI Du-yan, and LIU Zhi
A novel DCT domain image coder is proposed according to both intra-block clustering of significant coefficients and inter-block similarity. The algorithm utilizes morphological dilation to extract and encode the clustered significant coefficients, and elaborately adaptive arithmetic models are designed for significanceA novel DCT domain image coder is proposed according to both intra-block clustering of significant coefficients and inter-block similarity. The algorithm utilizes morphological dilation to extract and encode the clustered significant coefficients, and elaborately adaptive arithmetic models are designed for significance encoding and signencoding, which can eliminate intra-block and inter-block correlation of the DCT coefficients effectively. The difference reduction is used to encode the position of the start pixel in each cluster and scattered coefficients, which can improve the coding efficiency of the insignificant coefficients. Furthermore, the algorithm employs pre-filtering and post-filtering to optimize coding performance and restrain blocking artifacts. As a kind of embedded coder, the algorithm is also rate scalable. Experimental results show that the performance of the new coder is superior to conventional coders. For example, for the Lena and Barbara image at 0.25 bpp, the proposed method outperforms JPEG2000 by 0.4 dB and 1.7dB in peak signal-to-noise ratio, respectively..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 13 (2009)
Improved Unwrapping Processing Method for Panoramic Vision Images Based on Forward Mapping
ZHANG Fan, ZHU Qi-dan, XU Guang, and ZHANG Zhi
The main aim of unwrapping processing is to transform omni-directional images into undistorted ones. An improved unwrapping processing method is brought forward based on forward mapping and the imaging feature of hyperboloidal catadioptric panoramic vision system. Firstly, the pixels of the omni-directional images are The main aim of unwrapping processing is to transform omni-directional images into undistorted ones. An improved unwrapping processing method is brought forward based on forward mapping and the imaging feature of hyperboloidal catadioptric panoramic vision system. Firstly, the pixels of the omni-directional images are mapped to the virtual observation plane, and then unwrapped image is restored by using the modified Shepard scattered data interpolation method, which avoids distortion induced when interpolation is applied in the omni-directional image directly. The experimental results indicate that the improved method is an effective cure for the nonlinear distortion of omni-directional images as well as effective promoter for the smoothness of gray surface and precision of interpolation, bringing more natural result..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 20 (2009)
Total Variation Denoising Algorithm of Speckle Pattern Interferometry Fringe
ZHANG Fang, LIU Wen-yao, DAI Lei, and XIA Lin
Denoising is the key problem in electronic speckle pattern interferometry. The total variation image denoising algorithm for Electronic Speckle Pattern Interferometry Fringe (ESPI) is proposed and the fidelity coefficient is improved. First, the energy function of the image is defined by total variation model, and thenDenoising is the key problem in electronic speckle pattern interferometry. The total variation image denoising algorithm for Electronic Speckle Pattern Interferometry Fringe (ESPI) is proposed and the fidelity coefficient is improved. First, the energy function of the image is defined by total variation model, and then the optimal solution of this energy function is obtained by variation method. The method transforms the image denoising processing into solving a partial differential equation. The proposed method was tested on computer-simulated and experimental speckle fringe patterns, respectively. Both qualitative and quantitative results show that this technique is capable of not only significantly filtering but also preserving fringe contrast..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 26 (2009)
Non-calibration Points Algorithm for the Image Correction
QI Zhan-hui, and ZHANG Suo-ping
Some calibration points need to be placed in the shooting region by the traditional image correction, and then the image is corrected based on the knowledge of the computer vision. A novel algorithm without a calibration point is proposed for image correction. Four virtual calibration points are constructed with the heSome calibration points need to be placed in the shooting region by the traditional image correction, and then the image is corrected based on the knowledge of the computer vision. A novel algorithm without a calibration point is proposed for image correction. Four virtual calibration points are constructed with the help of some information on camera's internal physical structure and the Direct Linear Transformation (DLT) algorithm, and the correction coefficient is calculated by means of these virtual calibration points. According to the correction coefficient, the true shape of an object is obtained. The new algorithm is tested by correcting six images. Furthermore, the reasons for a micro-error are analyzed. Meanwhile, some methods for decreasing error are presented..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 31 (2009)
Fast Identification and Location for Series Image of Airborne Electro-optical Tracking System
WANG Guo-fu, OU-YANG Shan, LIU Qing-hua, and DING Yong
To meet the special demands of airborne electro-optical tracking system for rapid recognition and accurate positioning, a fast identification and location algorithm is required. Through the in-depth characteristics analysis of continuous images sequence and airborne electro-optical tracking system and integrated with vTo meet the special demands of airborne electro-optical tracking system for rapid recognition and accurate positioning, a fast identification and location algorithm is required. Through the in-depth characteristics analysis of continuous images sequence and airborne electro-optical tracking system and integrated with variation and movement information of precision turntable, an image processing algorithms is put forward based on the information corner. On the basis of the corner variation information of precision turntable, we obtain the margin target residual map through difference computing among a row of multi-frame image sequence. Combing with the median filtering and adaptive gate tracking algorithm, we multiply the residual map to remove most random noise. The method can greatly reduce the computing capacity and achieve the objectives of fast tracking of moving targets. Result of target image sequence test shows that the algorithm is fast and stable and thus can meet the requirements of the airborne electro-optical tracking system for tracking real-time image..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 36 (2009)
Passive Location Method Based on Characteristic Lines
YU Yong, and GUO Lei
A novel passive location method is presented by using IR seeker image. As the seeker Field of View (FOV) is small and target distance is much bigger than target size, a monocular algorithm using characteristic lines to estimate target distance is developed based on the fact that the camera model can be described as weaA novel passive location method is presented by using IR seeker image. As the seeker Field of View (FOV) is small and target distance is much bigger than target size, a monocular algorithm using characteristic lines to estimate target distance is developed based on the fact that the camera model can be described as weak perspective projection. Compared with traditional passive location method, the proposed algorithm utilizes the size and angle of characteristic lines in image to represent the variation of object attitude and the method improves the location precision and makes the location process independent on attitude estimation. Experimental results manifest that the proposed algorithm can locate the target accurately in low SNR, and the algorithm can adapt to the change of attitude..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 41 (2009)
Multi-target Segmentation in Multi-sensor Images in Complex Scenes
MA Chao-jie, YANG Hua, LI Xiao-xia, LING Yong-shun, WU Dan, and WANG Jing-wen
The multi-target segmentation in complex background could be solved effectively by synthetically utilizing multi-sensor images’ gray level distribution, fractal dimension and active contour evolution technology. Firstly, according to image inherent attribution, the images were enhanced using the histogram specificationThe multi-target segmentation in complex background could be solved effectively by synthetically utilizing multi-sensor images’ gray level distribution, fractal dimension and active contour evolution technology. Firstly, according to image inherent attribution, the images were enhanced using the histogram specification. Then the regions of interest were selected in multi-sensor images by using fractal dimension features for visible images, maximum entropy method for infrared images and the local threshold for Lidar images. The regions-of-interest obtained in multi-sensor images were across verified, so background clutter could be further eliminated. Finally, the target contour estimation could be used as the initial growth curve for active contour evolution processing, and the better target contours were obtained on the true target boundaries. A large number of segmentation tests on multi-sensor images in complex scenes prove the validity and reliability of the scheme..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 47 (2009)
Dynamic Target Tracking with Kalman Filter as Predictor
YU Dan, WEI Wei, and ZHANG Yuan-hui
Aimed at target tracking in the video image sequences, the tracking algorithm which combines the Mean shift algorithm and Kalman filtering has been proposed, but the offset in the image plane caused by the motion of the robot can not be ignored when implementing the real-time moving object following with a mobile robotAimed at target tracking in the video image sequences, the tracking algorithm which combines the Mean shift algorithm and Kalman filtering has been proposed, but the offset in the image plane caused by the motion of the robot can not be ignored when implementing the real-time moving object following with a mobile robot. Based on the description of the relationship between the offset and the motion, the target dynamics with the motion of robot as the external control is depicted, and the algorithm that combines the Mean shift and Kalman filter in a novel way is proposed. With the state estimation of Kalman filter as the starting position of the Mean shift and with the converge location of the Mean shift as tracking results of current frame, the state estimation is replaced with the converge location of the Mean shift. Two algorithms work alternately and interact with each other. Experiment results indicate that the proposed algorithm is real-time and robust on dynamic target tracking under complex outdoor environment..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 52 (2009)
Movement Monitoring System Design for Embankment Dams Using Fully Distributed Sensing Along Optical Fiber
ZHU Ping-yu, LENG Yuan-bao, WANG Shao-li, and JIANG Gui-lin
Aim at solving online hidden deformation monitoring problems for the embankment dams with long distance and large area, a monitoring system using distributed stimulated Brillouin scattering optical fiber sensing is proposed. Data acquisition principle of the distributed optical fiber sensing instrument is briefly introAim at solving online hidden deformation monitoring problems for the embankment dams with long distance and large area, a monitoring system using distributed stimulated Brillouin scattering optical fiber sensing is proposed. Data acquisition principle of the distributed optical fiber sensing instrument is briefly introduced and Data Flow Diagrams (DFDs) is analyzed. Take the Yellow River embankment dam as an example of being monitored. The monitoring system based on DiTeSt-STA202, which is a distributed optical fiber sensing instrument made by Omnisens, is constructed. The database of monitoring system consists of four parts, original data from sensors, database, user output, and user operations, which can process and manage these data including real-time monitoring and previous posted data. It also provides important information and guide for the expert decision-making system of embankment dam safety monitoring and maintenance..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 57 (2009)
Theory Analysis and Experiment of the Double-square Wave Modulation in FOG
XU Wen-yuan, ZHANG Chun-xi, ZHANG Xi, and LI Lin
The bias stability is an important parameter of Fiber Optic Gyro (FOG). The Y waveguide 2π voltage and the crosstalk, to some extent, decide the performance of the bias stability. Based on square wave modulation, a double-square wave modulation method is proposed, which can perform the function of rapid adjustment of YThe bias stability is an important parameter of Fiber Optic Gyro (FOG). The Y waveguide 2π voltage and the crosstalk, to some extent, decide the performance of the bias stability. Based on square wave modulation, a double-square wave modulation method is proposed, which can perform the function of rapid adjustment of Y waveguide 2π voltage through four-state modulation and demodulation. The adjusting time around zero rotation speed is reduced from 300s to 1s. Meanwhile, the coherent detection theory is applied to make a study of the crosstalk of the square wave modulation and the double-square wave modulation, which draws a conclusion that the double-square wave modulation can suppress crosstalk. Experimental results show that the crosstalk can be reduced from 0.22o/h to 0.04o/h, and the FOG’s bias stability can be improved..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 63 (2009)
Multi-spot Measuring Gas Array Detection System and Spectral Analysis
LIAO Hai-yang, Lü Jian-bo, HOU Chang-jun, ZHANG Hong-ying, and ZHU Bin
In allusion to the requirement of single-component gases identification and trace concentration measure, a gas array inspect system is put forward based on absorption spectrum measure and multi-spot measure technology, and a novel array gas-sensitive sensor is developed which takes metallic porphyrin as sensitive materIn allusion to the requirement of single-component gases identification and trace concentration measure, a gas array inspect system is put forward based on absorption spectrum measure and multi-spot measure technology, and a novel array gas-sensitive sensor is developed which takes metallic porphyrin as sensitive material. In addition, the principle of the system and the spectral response pattern for two kinds of gaseous simulacrums are mainly researched, and partial least square combined with BP neural networks recognition model for response pattern and calculative algorithm for trace concentration measure are provided. At last, the experimental results show that the prediction correct rate for 50 unknown samples of gaseous Dimethyl Methyl Phosphonate (DMMP), Dimethyl Benzene (DMB), Sarin, Soman and Phosgene is 98%, and the maximum relative measuring errors of gaseous DMMP and gaseous DMB are 3%..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 68 (2009)
Novel Measurement System and Analytical Method for White LED Phosphors
LI Li, and MOU Tong-sheng
In order to achieve high-efficiency white LEDs and get the optimal matching between phosphors and LED chips, a novel measurement system and an analytical method for white LED phosphors were proposed. According to the measurement principles of phosphor, monochromatic light was adopted to excite the phosphor, and phosphoIn order to achieve high-efficiency white LEDs and get the optimal matching between phosphors and LED chips, a novel measurement system and an analytical method for white LED phosphors were proposed. According to the measurement principles of phosphor, monochromatic light was adopted to excite the phosphor, and phosphors’ excitation characteristics were obtained. With each single excitation spectrums, three-dimensional spectral power distribution for a phosphor was achieved, and the spectrum of white LED was acquired by combination with the spectrum of blue LED chip. Luminous efficiencies of the phosphor under different excitation conditions were analyzed. The experimental results show that the measurement system and analytical method are feasible for choosing optimal matching between phosphors and LED chips, and can establish a good foundation for achieving high-efficiency white LED..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 73 (2009)
Extraction of Moiré Fringe Signal for Photoelectric Encoder Based on Grating Self-imaging
WANG Yu-zhi, AI Hua, and HAN Xu-dong
High quality moiré fringe signal with a large gap between gratings can be obtained by employing grating Fresnel self-imaging for the construction of photoelectric rotary encoder, and the high contrast of moiré fringe remain unchanged, which permits the construction of optical encoder with fine gratings. A theHigh quality moiré fringe signal with a large gap between gratings can be obtained by employing grating Fresnel self-imaging for the construction of photoelectric rotary encoder, and the high contrast of moiré fringe remain unchanged, which permits the construction of optical encoder with fine gratings. A theoretical analysis of the Fresnel field observed behind one or two binary amplitude gratings, which was illuminated by a monochromatic plane wave, was presented based on the principle of Fourier optics. A mathematical model of the intensity distribution of Fresnel images and moiré fringe was developed. The theoretical formula was programmed in the MATLAB for convenient graphic calculation results, which analyzed the impact of some parameters such as the gap between gratings on moiré fringe signal. The theoretical analysis is corroborated by experiment..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 78 (2009)
Rock Detection in the Landing of Lunar Probe Based on Passive Image
DING Meng, CAO Yun-fenga, and WU Qing-xian
For autonomous landing of lunar probe, to develop autonomous landing and hazard avoidance technology is very necessary and the key of this technology is hazard detection. The focus of this paper was to present an algorithm for autonomous rock (one kind of hazard on moon surface) detection based on passive images. The pFor autonomous landing of lunar probe, to develop autonomous landing and hazard avoidance technology is very necessary and the key of this technology is hazard detection. The focus of this paper was to present an algorithm for autonomous rock (one kind of hazard on moon surface) detection based on passive images. The paper could be divided into three parts. Firstly, Maximum 2D Entropy Thresholding was employed for detection of rock shadow. Secondly, the result of shadow detection was combined with rock contour extraction for more precise center point of ellipse which describes rock area. Finally, the parameters of this ellipse were computed and rock areas were confirmed. Experimental studies demonstrate that the algorithm of rock detection can describe scope of rock area more successfully than only shadow-based method..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 82 (2009)
Numerical Analysis of Aero-optic Effects Induced by the Turbulence Flow Field Surrounding Super/Hypersonic
YANG Wen-xia, CAI Chao, DING Ming-yue, and ZHOU Cheng-ping
Numerical simulation and analysis of aero-optic effects caused by the hyper-speed turbulence fields under different flight conditions were carried out. The aero-optic effects were characterized with the associated optical transfer functions. First, the analysis and computation of the aero-optic effect under different fNumerical simulation and analysis of aero-optic effects caused by the hyper-speed turbulence fields under different flight conditions were carried out. The aero-optic effects were characterized with the associated optical transfer functions. First, the analysis and computation of the aero-optic effect under different flight conditions were addressed, where the parameters characterizing the hyper-speed turbulence field were obtained by solving its N-S equations via CFD methods. The infrared ray trajectories passing through a flow field of non-homogeneous refraction indices were acquired with the gradient index ray-tracing method, and the transfer function to represent the aero-optic effects was derived using the principles of Fourier optics. The simulation results showed that the aero-optic transfer function is characterized as a low-pass filter, which results in the blurring and shifting of the objects in the acquired images..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 88 (2009)
Design of Spherical Surface Imaging Projection Lithography Lens
ZHAO Li-xin, ZHANG Yu-dong, WANG Jian, DAI Yun, GAO Hong-tao, DONG Xiao-chun, and RAO Xue-jun
Referring to the fabrication characteristics of three-dimensional continuous microstructure on the intraocular lens or contact lens, the method for designing spherical surface imaging projection lithography lens was introduced based on the spatial optical modulator such as Digital Mirror Device (DMD). According to charReferring to the fabrication characteristics of three-dimensional continuous microstructure on the intraocular lens or contact lens, the method for designing spherical surface imaging projection lithography lens was introduced based on the spatial optical modulator such as Digital Mirror Device (DMD). According to characteristics of the projection lens, the image-surface was spherical, and the field curvature was corrected by the negative lens. According to the diffraction theory, the numerical aperture was optimized in order to eliminate the DMD structure effect. Integrated with the grid of DMD imaging, projection lens were simulated, designed and optimized by using ZEMAX optical design software, and the optimized results were analyzed .For the designed example, its working wavelength is g-line (436 nm), radical curvature of imaging surface is 22.5 mm, imaging area is Ф6 mm, numerical aperture NA=0.1, MTF＞0.8 at the resolution of 7.8 μm(64 lp/mm), and its distortion ＜±0.05%..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 93 (2009)
Design of Refractive/Diffractive Plastic Optical System in Glasses Virtual Displays
WU Hai-qing, SUN Qiang, WANG Jian, SONG Gui-cai, and DONG Ke-yan
The properties of plastic lens applied in 3D virtual displays are studied and a Polymethyl Methacrylate (PMMA) optical system for glasses-type virtual displays is presented. By using a reflector, the beam path of the system is folded, which leads to a compact structure. A binary optical element is introduced into the sThe properties of plastic lens applied in 3D virtual displays are studied and a Polymethyl Methacrylate (PMMA) optical system for glasses-type virtual displays is presented. By using a reflector, the beam path of the system is folded, which leads to a compact structure. A binary optical element is introduced into the system to effectively correct the chromatic aberration and wavefront aberration. The imaging quality is improved, at the same time, system size and weight is greatly reduced. The total weigh of the optical system is just 9.8 g, the astigmatic and lateral color which need to be correct in visual system are 0.31 mm and 8.8 μm respectively, and the distortion is less than 7%. The full field of view is 32° and the angu1ar reso1ution is 0.8 mrad..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 98 (2009)
Design and Analysis on the Flexible Structure of the Optical Reflector Based on the Computer Aided Engineering
SUN Bao-yu
Referring to the optical rounded reflector of spherical surface used in a space remote sensor, a kind of flexible structure was designed for regulating thermal deformation. Theoretical analysis was done to its dynamic model and parameter of structure, and simulating analysis was also done to reflector module with technReferring to the optical rounded reflector of spherical surface used in a space remote sensor, a kind of flexible structure was designed for regulating thermal deformation. Theoretical analysis was done to its dynamic model and parameter of structure, and simulating analysis was also done to reflector module with technology of the Computer Aided Engineering (CAE) in order to solve the status of high rigidity of structure and poor thermal stability of thermal dimension. With the regulation of flexible structure, the optical reflector should keep not only the high rigidity of structure under the environment of statics and dynamics, but also fine stability of thermal dimension under thermal environment. Analysis result indicates that the surface accuracy of reflector meets the needs of the imaging quality under mechanics and thermal load, and the value of PV is less than 63.2 nm, which shows that the flexible regulating structure is reasonable to actual structure of the space remote sensor..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 103 (2009)
Optimization and Analysis for the Support of the Large Aperture Telescope Primary Mirror
WANG Yang, and ZHANG Jing-xu
The surface figure precision of the primary mirror in a large aperture telescope is a key factor influencing the imaging quality. In the opto-electronic system, the axis support point’s position of the primary mirror is important for the mirror surface figure error. Whether the axis supports points position is appropriThe surface figure precision of the primary mirror in a large aperture telescope is a key factor influencing the imaging quality. In the opto-electronic system, the axis support point’s position of the primary mirror is important for the mirror surface figure error. Whether the axis supports points position is appropriate will affect image quality in some degree. We research the axis support and radius support techniques of a large-aperture telescope primary mirror in detail. With finite element method software ANSYS, the primary mirror parameter model is built. We introduce how to decide the number of the different aperture mirror axis support points. The position of the different aperture mirror axis support points is optimized and the best position of support point is provided. The optimized analysis results indicate that the mirror surface figure error is satisfied. The surface figure is mostly influenced by the axial support system..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 107 (2009)
Magnetorheological Finishing Dwell Time Algorithm
SUN Xi-wei, HAN Qiang, YU Da-yong, and LIU Sheng
Magnetorheological Finishing (MRF) was an advanced optical machining method. The removal material was related with the dwell time when the work-piece was machined with MRF. On the base of analyzing the effect of machining parameter and the principle of surface control, the MRF dwell time algorithm based on matrix was pMagnetorheological Finishing (MRF) was an advanced optical machining method. The removal material was related with the dwell time when the work-piece was machined with MRF. On the base of analyzing the effect of machining parameter and the principle of surface control, the MRF dwell time algorithm based on matrix was presented according to Preston equation. The symmetry axis curve surface, such as aspheric surface, which was fit for optics general equation, was machined with MRF machine by using this interpolated algorithm. Simulation experiment results show that the spherical surface error can be constricted less than 20 nm by using the dwell time algorithm. The planar and spheric K9 optics glass was machined with MRF by using the dwell time algorithm, and the spherical surface, whose Ra is 0.636 nm and PV is 52.14 nm, is acquired..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 114 (2009)
Surface Coating Technique of Reaction Bonded SiC Mirrors
XU Ling-di, ZHANG Xue-jun, and WANG Xu
Recently, Reaction Bonded–SiC (RB-SiC) has become the most promising space mirror material due to its superior mechanical, thermal and physical properties. But surface roughness of polished RB-SiC is limited by the Si/SiC two phase structure of the material. To solve this problem, a kind of surface coating technique waRecently, Reaction Bonded–SiC (RB-SiC) has become the most promising space mirror material due to its superior mechanical, thermal and physical properties. But surface roughness of polished RB-SiC is limited by the Si/SiC two phase structure of the material. To solve this problem, a kind of surface coating technique was introduced to obtain ultra-smooth optical surface. Firstly, according to the application environment of space mirrors, proper coating materials were analyzed generally. Secondly, SiC deposited by new Ion Assisted Depositing (IAD) technique was chosen to be the coating material and properties of IAD-SiC film were tested. Finally, a series of polishing experiments on 6±0.5μm thick IAD-SiC layers were accomplished. Results show that surface roughness of the finished coating achieves less than 0.5nm RMS and the final surface figure is 0.033λ RMS (λ=632.8nm). The technique shows an access to process ultra-smooth and low scatter RB-SiC mirrors..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 120 (2009)
Fabrication of Volume Bragg Gratings for Spatial Filtering
ZHENG Hao-bin, HE Yan-lan, TAN Ji-chun, DING Dao-yi, HUANG Shui-hua, and ZHENG Guang-wei
A new approach of spatial filter was performed and the feasibility of volume Bragg gratings to be spatial filter was analyzed. Based on Kogelnik’s theory of one dimensional coupled waves, the main factors that affect diffraction efficiency and angular selectivity of volume Bragg gratings were discussed. With holographiA new approach of spatial filter was performed and the feasibility of volume Bragg gratings to be spatial filter was analyzed. Based on Kogelnik’s theory of one dimensional coupled waves, the main factors that affect diffraction efficiency and angular selectivity of volume Bragg gratings were discussed. With holographic method, volume Bragg grating was recorded into a photopolymer, and then the experiment on spatial two dimensional low-pass filter of laser beam was fulfilled. The experimental results show that: extending exposure time, in the media’s saturation range, may improve diffraction efficiency, and increasing the incident angle may enhance angular selectivity, whereas because of absorption, diffraction efficiency would be decreased. Therefore, when fabricated volume Bragg gratings are used for a spatial filter, the diffraction efficiency and angular selectivity should be simultaneously considered..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 125 (2009)
QVGA Liquid Crystal on Silicon Microdisplay
HUANG Ran, WANG Wen-bo, WANG Xiao-hui, DU Huan, OU Yi, HAN Zheng-sheng, FENG Ya-yun, and LING Zhi-hua
QVGA liquid crystal on silicon microdisplay chip is designed by using D/A converter constructed with comparators and counters, which reduce power consumption and design difficulty of the chip. A QVGA microdisplay video driver system is designed, and a video driver board is built using a CPLD as the central control unitQVGA liquid crystal on silicon microdisplay chip is designed by using D/A converter constructed with comparators and counters, which reduce power consumption and design difficulty of the chip. A QVGA microdisplay video driver system is designed, and a video driver board is built using a CPLD as the central control unit. Video system receives VGA signal output by computer and processes the signal by the control unit to implement the row and column transform and drive LCoS microdisplay chip to display video signal. Test result indicates that gray scales response of the pixel is correct and voltage level meets the requirement of liquid crystal material. The microdisplay chip can display 60Hz 320×240 dynamic video, the display response is fast, and design requirement of display function is satisfied..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 131 (2009)
Test System of Response for Infrared Detector Based on Modulated Laser
ZHAO Hu
In order to meet the requirements of response uniformity and rate of finished products in infrared detector manufacturing, studying and testing, a new test system of response for infrared detector is designed based on semiconductor modulated laser, which replaces blackbody radiation source. This system controls two-dimIn order to meet the requirements of response uniformity and rate of finished products in infrared detector manufacturing, studying and testing, a new test system of response for infrared detector is designed based on semiconductor modulated laser, which replaces blackbody radiation source. This system controls two-dimension scan workbench through computer, which accomplishes the data acquisition of detector. And the system uses the technology of VB call MATLAB realizing graphic model output, which reflects the response of detector clearly. The test process is completed automatically and the test precision reaches 0.001 2 V. The system provides an advanced method and test platform for studying and testing infrared detector automatically..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 135 (2009)
Pose Invariant Face Recognition Based on 3D Model
YANG Jun, LIU Zhi-fang, ZHANG Xiu-qiong, GAO Zhi-sheng, and YUAN Hong-zhao
An estimating pose angle method based on fuzzy math and a layered face recognition method by matching 2D probe image to 3D model were proposed in this paper. After classifying multi-pose images to different pose space, Primary Component Analysis (PCA) was used to get eigenfaces in the given pose space. While a probe imAn estimating pose angle method based on fuzzy math and a layered face recognition method by matching 2D probe image to 3D model were proposed in this paper. After classifying multi-pose images to different pose space, Primary Component Analysis (PCA) was used to get eigenfaces in the given pose space. While a probe image was recognized, its pose and fuzzy angle were estimated firstly and then they were matched in the estimated pose space by PCA method. Some candidates were gotten by upwards step and their 3D model were employed to generate dynamically virtual 2D images with view angles nearby fuzzy angle. Image correlation was employed as a classifier to match the probe image to the virtual images. The experiment result shows that the proposed method is robust to pose variant..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 140 (2009)
Face and Expression Recognition Based on Supervised Isomap
ZHU Ming-han, LUO Da-yong, and WANG Yi-jun
A face and facial expression recognition method based on supervised isomap is proposed. The method can recognize the facial identity and facial expression simultaneously. Firstly, facial expression images were projected in low dimension manifold space. The points projected in the manifold space were separated accordingA face and facial expression recognition method based on supervised isomap is proposed. The method can recognize the facial identity and facial expression simultaneously. Firstly, facial expression images were projected in low dimension manifold space. The points projected in the manifold space were separated according to their identity. At the same time, these images with the same identity were clustered in light of their expression class. Then, test images were embedded in the manifold space by using nonlinear mapping method. Finally, the identity and expression of test images were recognized by applying weighed k-nearest neighbor method. The experimental results in Cohn-Kanade and JAFFE face database show that the method can attain better recognition effect of face and facial expression..
Opto-Electronic Engineering
- Publication Date: Oct. 08, 2021
- Vol. 36, Issue 1, 146 (2009)
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