Journals >Opto-Electronic Engineering
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2011
Volume: 38 Issue 9
28 Article(s)
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Research Article
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[in Chinese]
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 1 (2011)
Focal Plane Assembly and Calibrating of CMOS Star Sensor
ZHONG Xing, JIN Guang, WANG Dong, and XING Fei
Focal plane’s misalignment is analyzed theoretically to match the requirement of high precision CMOS star sensor. System for assembly and calibrating measurement of CMOS star sensor is established. Defocusing distance and tilt of detector plane are acquired by on-axis and off-axis star sensor imaging test through colliFocal plane’s misalignment is analyzed theoretically to match the requirement of high precision CMOS star sensor. System for assembly and calibrating measurement of CMOS star sensor is established. Defocusing distance and tilt of detector plane are acquired by on-axis and off-axis star sensor imaging test through collimator’s image plane moving. Some CMOS star sensor with 50 mm focal length, F/1.25, and 20° field of view is successfully assembled under direction of testing data. Defocusing distance is less than 0.01 mm, and tilt is less than 2′. Principal distance test and distortion calibration are done with measuring system. Principal distance is calculated to be 49.77 mm, and the error is 0.007 2 mm. Distortion of star sensor system is calibrated by third order polynomial fitting data, and the residual error caused by distortion can be reduced to 6.6″ when measuring single star..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 1 (2011)
Reflection Characteristics of On-orbit Satellite Based on Bidirectional Reflectance Distribution Function
WANG Fu-gang, ZHANG Wei, and WANG Hong-yuan
Visible reflection characteristics of an on-orbit satellite were studied based on background radiation, surface material properties, orbit parameters, and the relative motion between satellite body and solar array. The Bidirectional Reflectance Distribution Functions (BRDF) of three common surface materials of satellitVisible reflection characteristics of an on-orbit satellite were studied based on background radiation, surface material properties, orbit parameters, and the relative motion between satellite body and solar array. The Bidirectional Reflectance Distribution Functions (BRDF) of three common surface materials of satellite at typical angles were measured. An improved Sun BRDF model of three materials was established. The method for calculating the incident vector in the coordinate system of solar array with a single degree of freedom rotation was proposed. The satellite reflection characteristics were simulated by its given physical dimension and surface physical parameters. The peak radiant intensities reflected by the satellite bodies which were coated by yellow thermal control coating or silver thermal control coating and the solar array were 6.91×104 W/sr, 6.42×104 W/sr and 9 707 W/sr, respectively. These peaks were in different space positions. The result shows that the reflection characteristics of satellite are affected by surface materials, physical dimension, attitude, orbital parameters and so on, as well as the solar array cannot be neglected when the satellite characteristics are analyzed..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 6 (2011)
Sampling Technology on Video Signal of Spaceborne High Speed TDICCD Camera
SHI Jun-xia, GUO Yong-fei, SI Guo-liang, and ZHU Hong-yin
In order to improve the image quality of a high speed airborne Time Delay and Integration Charge Coupled Device (TDICCD) camera, a method to precisely adjust the Correlated Double Sample (CDS) signals is proposed. Moreover, a method to compensate the temperature excursion of the driver is proposed. First, the principleIn order to improve the image quality of a high speed airborne Time Delay and Integration Charge Coupled Device (TDICCD) camera, a method to precisely adjust the Correlated Double Sample (CDS) signals is proposed. Moreover, a method to compensate the temperature excursion of the driver is proposed. First, the principle of CDS is introduced, and the influence of sample position on a TDICCD camera is analyzed. Then, a method is proposed to adjust the sample signals precisely, which is based on the MUXCY in FPGA. At the same time, the effect of temperature excursion of the driver on TDICCD signal is analyzed, and an adaptive method is proposed to compensate the temperature excursion, which could satisfy the sample timing relationship. Experiments were made from two aspects, which were based on the TDICCD imaging system in our project. One is aimed to the effect of the precision of sample position on imaging quality, and the other is aimed to temperature. Experiment results show that the methods proposed can adjust the sample position precisely, which can improve the dynamic range of an image, and adapt the temperature excursion of the driver. Before compensation, the signal and noise ratio of the image acquired at -36℃ is 37.4 dB. After compensation, the signal and noise ratio of the image acquired at -36℃ is 51 dB..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 13 (2011)
High-speed Multi-spectral TDICCD Image Data Transmission System
ZHU Hong-yin, GUO Yong-fei, SHI Jun-xia, and SI Guo-liang
For multi-channel high-speed Charge Couple Device (CCD) image data transmission, a new high-speed multi-spectral Time Delay Integrated CCD (TDICCD) image data transmission system was designed and applied successfully. Overall system design principle and realization in FPGA were introduced. Especially, the key technologFor multi-channel high-speed Charge Couple Device (CCD) image data transmission, a new high-speed multi-spectral Time Delay Integrated CCD (TDICCD) image data transmission system was designed and applied successfully. Overall system design principle and realization in FPGA were introduced. Especially, the key technology such as Field Programmable Gate Array (FPGA) function division, time-division multiplexing storage and Low Voltage Differential Signaling (LVDS) interface were described in detail. Finally, 60 channels’ parallel image data of 5 TDICCD were converted into 7 channels serial image data. Experiments show that the system’s single channel output data rate is up to 1.38 Gbit/s, and total effective data output rate is up to 8.66 Gbit/s. The system works stably with high effective and transplantable property..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 19 (2011)
A Method of Automatic Extraction of Image Control Points for UAV Image Based on POS Data
LU Heng, LI Yong-shu, and JIANG Yu
The Unmanned Aerial Vehicle (UAV) images have the characteristics of high overlapping degree and heavy image processing workload. In order to improve the efficiency of UAV photogrammetry and take the advantages of fast mapping by the UAV technology, a method of extraction of image control points by correcting POS data The Unmanned Aerial Vehicle (UAV) images have the characteristics of high overlapping degree and heavy image processing workload. In order to improve the efficiency of UAV photogrammetry and take the advantages of fast mapping by the UAV technology, a method of extraction of image control points by correcting POS data was put forward. According to the principle of correct UAV POS data, POS data correction model was established and POS data error correction parameter were acquired by layout a small amount of the control points in regional network, and the corrected POS data were used in extraction of UAV images control points. The study results show that the method for UAV image rapid processing has good practical value..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 25 (2011)
Projectile's Attack Angle Measurement with CCD Vertical Target
WANG Miao, and XU Wei
Based on the measurement principle of CCD vertical target, a new measurement method of the attack angle is given, which can calculate the attack angle by measuring the positions of the head and the tail-end of the projectile on the target. The system can measure the attack angle of the projectile while measuring the poBased on the measurement principle of CCD vertical target, a new measurement method of the attack angle is given, which can calculate the attack angle by measuring the positions of the head and the tail-end of the projectile on the target. The system can measure the attack angle of the projectile while measuring the position information. Analyze the measurement precision of the position of the system, and deduce relevant formula about attack angle measurement. Through practical tests, analyze the measurement precision of attack angle and discuss the feasibility of this method. The results turn out that the new method for measuring the attack angle is feasible and the CCD vertical target can be used to measure the attack angle in the shooting range, expanding the ability of the CCD vertical target..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 30 (2011)
Improved Row Action Iterative Super-resolution Restoration for Thermal Microscope Imaging System
GAO Mei-jing, LU Xin, and SHI Xiao-li
In order to improve the spatial resolution of the designed optical plate rotating micro-scanning thermal microscope imaging system, a method of optical micro-scanning super-resolution reconstruction for the thermal microscope imaging system was presented based on the improved frequency-domain image registration techniqIn order to improve the spatial resolution of the designed optical plate rotating micro-scanning thermal microscope imaging system, a method of optical micro-scanning super-resolution reconstruction for the thermal microscope imaging system was presented based on the improved frequency-domain image registration techniques and the new row action iterative method. The working principle and the method were analyzed. Different reconstruction methods were applied to reconstruct the visible image and the infrared image. Moreover, the evaluation parameters were given. Results of simulation and real thermal microscope images processing showed the availability of the method. The image spatial resolution and quality were improved with more detail. The system can be applied into many systems which need high spatial resolution minute thermal analysis. The algorithm can also be applied into the uncontrolled optical micro-scanning imaging systems and has wide application prospect..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 35 (2011)
Software Compensation Techniques for Accuracy Improvement in Alignment System Based on Digital Image
WANG Quan-dai, XIAO Ji-ming, and LI Peng-yang
The software compensation techniques are investigated to improve the alignment accuracy in the alignment system for layered manufacturing process. The filtering algorithm with little degradation on image, which combines the SUSAN with multi-frame averaging, is introduced to alleviate the mark image distortion due to thThe software compensation techniques are investigated to improve the alignment accuracy in the alignment system for layered manufacturing process. The filtering algorithm with little degradation on image, which combines the SUSAN with multi-frame averaging, is introduced to alleviate the mark image distortion due to the filtering processing. The focus measure function based on Power Spectrum in Frequency Domain (PSFD) is adopted as the auto-focus function of the system and then the positioning error due to defocus is reduced or eliminated. Concerning the calibration residual error and its repeatability of various models, the cubic polynomial model is used to describe and calibrate the geometric distortion of mark image and the alignment error due to image geometric distortion is less than 0.25 μm after calibration. The alignment error due to mechanical instability of the alignment setup is reduced to less than 1.3 μm through mechanical swing trace fitting and error compensation. Finally, adopting the hybrid programming method with Delphi and Matlab, the software functions mentioned above are implemented and integrated..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 40 (2011)
Analysis of Effect of Lateral Fabrication Errors on Binary Optical Elements
YIN Ke-wei, HUANG Zhi-qiang, LIN Wu-mei, and XING Ting-wen
Misalignment and line width errors are main fabrication errors in Binary Optical Elements (BOE). It is important to analyze the influence of fabrication errors on binary optical element designers. We provided a layer by layer MATLAB analysis method based on scalar diffraction theory to study relationship between diffraMisalignment and line width errors are main fabrication errors in Binary Optical Elements (BOE). It is important to analyze the influence of fabrication errors on binary optical element designers. We provided a layer by layer MATLAB analysis method based on scalar diffraction theory to study relationship between diffractive efficiency and lateral fabrication errors about 4 step and 8 step binary optical elements. Our main findings are that diffraction efficiency can be controlled by dominating misalignment errors for 8 step binary optical elements, and it also can be compensated by adjusting line width and alignment. This method is convenient and precise to analyze fabrication errors of binary optical elements..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 46 (2011)
Sliding Mode Control of Macro-micro System for Wafer Stage of Lithography
WU Zhi-peng, CHEN Xing-lin, and LIU Chuan
To improve the tracking precision and respond speed, a macro-micro control structure is chosen and the actuators are the linear motor and voice motor. The micro stage accomplishes the short-stroke movement and ensures the high tracking precision, and the macro stage makes large-stroke movement to keep that the voice moTo improve the tracking precision and respond speed, a macro-micro control structure is chosen and the actuators are the linear motor and voice motor. The micro stage accomplishes the short-stroke movement and ensures the high tracking precision, and the macro stage makes large-stroke movement to keep that the voice motor is not closed to saturation. The control system is designed based on sliding mode control theory to ensure the robust of the control system. In order to achieve low-pass effect, an optimal integral sliding surface is designed based on frequency-shaped method. A variable gain switch control law is introduced to reduce chattering. Simulation results show that the maximum position tracking error and standard deviation is 8.7 nm and 2.2 nm during the scanning exposure process. Scanning speed is smooth and high frequency components of position error signal have been reduced effectively..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 50 (2011)
Depolarization Technologies of EDFS for FOG
LI Xu-you, ZHANG Xin, HAO Jin-hui, and HONG Wei
Depolarization pump structure of Erbium Doped Fiber Source(EDFS) is designed to solve the problem that polarization state of pump influences high precision EDFS average wavelength stability for Fiber Optic Gyroscope (FOG). This structure is adopted to Lyot depolarizer to depolarize pump light, and the Lyot depolarizer Depolarization pump structure of Erbium Doped Fiber Source(EDFS) is designed to solve the problem that polarization state of pump influences high precision EDFS average wavelength stability for Fiber Optic Gyroscope (FOG). This structure is adopted to Lyot depolarizer to depolarize pump light, and the Lyot depolarizer parameters selection is analyzed theoretically in the design construction. Experimental results prove that the polarization property of Wavelength Division Multiplex (WDM) affects the EDFS average wavelength stability, and the design structure can effectively reduce polarization property of WDM. When EDFS parameters have been optimized, considering that the pump of polarization state influence EDFS average wavelength stability, measure EDFS in the temperature cabinet. Experimental results show that without control polarization state, EDFS average wavelength stability is 77 ppm, while, adopting the structure of pump light complete depolarization, EDFS average wavelength stability is enhanced to 4 ppm..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 55 (2011)
Modular Interference of Polarization Maintaining Photonic Crystal Fiber
LU Xin, BI Wei-hong, MA Shuo, and LIU Feng
To improve the modular interference sensitivity and temperature stability, a Polarization Maintaining Photonic Crystal Fiber (PM-PCF) was used to design the modular interference sensors. The modular interference in a PM-PCF was investigated, and the relationship between phase difference of LP01 and LP11 even mode and iTo improve the modular interference sensitivity and temperature stability, a Polarization Maintaining Photonic Crystal Fiber (PM-PCF) was used to design the modular interference sensors. The modular interference in a PM-PCF was investigated, and the relationship between phase difference of LP01 and LP11 even mode and interference output intensity distribution was given. The relationship plot of relative effective refractive index and wavelength was got. An experiment was set up to demonstrate the intensity distribution of far field interference output from the PM-PCF. The experiment results show that the modular interference output lodes’ intensity of PM-PCF will exchange with each other when strain is applied on the PM-PCF. This phenomenon can be adapted for designing novel optic-fiber strain sensors..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 60 (2011)
Study of Laser Beam Coherent Combination
CHEN Jing, XUE Hai-zhong, LIU Xue-wen, SHEN Yan, MAO Deng-sen, and ZHANG Wen-ping
The arrangement of laser beams influences the efficiency of coherence. The article analyses how filling factor influences the efficiency of coherence based on theories calculation and simulation. In the meantime, the article analyses how the orientation error caused by each beam’s installation error influences the effiThe arrangement of laser beams influences the efficiency of coherence. The article analyses how filling factor influences the efficiency of coherence based on theories calculation and simulation. In the meantime, the article analyses how the orientation error caused by each beam’s installation error influences the efficiency of coherence, and these installation errors are hard to be avoided whatever in experiments or ultimate engineering practice. According to the result of analysis, a project tentatively named off-axis focusing arrangement is proposed, theoretical model is built up, and the inside contact of focal distance, beam waist and the peak power are got. Ultimately, the article contrasts the simulation result between off-axis focusing arrangement and parallel arrangement, discusses the merits and shortcomings of each other, and provides a convincing theory support to the following experiments..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 65 (2011)
Wind Loading Distortion Analysis of an Active Primary Mirror
YAO Ping, ZHANG Xue-jun, and ZHANG Yu-dong
One of the critical considerations for large telescopes is primary mirror distortions caused by wind load. In thin-mirror active optic systems such as Subaru Telescope, the fixed-point Force Feedback (FFB) algorithm is used to suppress wind load. The concept of pressure mode is brought up and the majority information oOne of the critical considerations for large telescopes is primary mirror distortions caused by wind load. In thin-mirror active optic systems such as Subaru Telescope, the fixed-point Force Feedback (FFB) algorithm is used to suppress wind load. The concept of pressure mode is brought up and the majority information of distortions caused by wind is extracted. The FFB algorithm based on pressure mode is studied and the following conclusions are drawn: aberrations caused by wind consist mainly of piston, tilt, astigmatism and defocus; with equal coefficients pressure modes of piston and tilts produce larger aberrations and push more forces on fixed points; the FFB algorithm based on pressure mode can suppress mirror deformations introduced by wind..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 71 (2011)
Analysis of Active Lap’s Surface Shape in Fabricating Large Off-axis Aspheric Mirror
LIU Hai-tao, ZENG Zhi-ge, and ZHANG Wei
The Computer Controlled Active Lap (CCAL)’s real-time surface shape in fabricating large off-axis aspheric mirror is analyzed by using coordinates transform theory, and a universal method for calculating the lap’s real-time profile is also presented. The physical parameters of off-axis aspheric mirror in New Solar TeleThe Computer Controlled Active Lap (CCAL)’s real-time surface shape in fabricating large off-axis aspheric mirror is analyzed by using coordinates transform theory, and a universal method for calculating the lap’s real-time profile is also presented. The physical parameters of off-axis aspheric mirror in New Solar Telescope (NST) is used to be simulated as an example, and the active lap’s surface shape in grinding and polishing process is got. The application in two aspheric reflected mirrors (Φ1 030 F/1.6 ellipsoid and Φ1 250 F/1.5 paraboloid)’ grinding shows that this method can be used to describe the lap’s surface shape exactly in fabrication. The results from analysis and calculation can be used in next off-axis aspheric mirror fabricating..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 77 (2011)
Supporting Effect Study on Primary Mirror of Ground-based Telescope
ZHOU Chao, WANG Zhi, ZHAO Yong-zhi, WANG Zhi-chen, and WANG Huai
The primary mirror surface figure precision is a key factor for the large ground-based telescope. In order to study the surface figure error caused by gravity deformations of primary mirror cell, and axial and lateral supporting system, the mirror cell and mirror supporting structures for a telescope were introduced. AThe primary mirror surface figure precision is a key factor for the large ground-based telescope. In order to study the surface figure error caused by gravity deformations of primary mirror cell, and axial and lateral supporting system, the mirror cell and mirror supporting structures for a telescope were introduced. A precise finite element model of the primary mirror, mirror cell and mirror supporting structure was established by using the finite element method. Deformation of the primary mirror surface under supporting was calculated and the surface figure was tested by ZYGO interferometer. By contrast with the calculated results and tested results, it shows the mirror surface figure error caused by the supporting structures, and verifies the correctness of the finite element model..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 84 (2011)
Rapid Analyzer of Glaucoma Filter Based on Fiber Conduction
YANG Ji-chun, LIU Tie-gen, and LI Yin-xin
Glaucoma screening should follow the simple, fast and effective principles. A rapid high-precision screening analyzer is developed to meet the needs of large-scale screening. Intensity uniformity about each stimulus point of the analyzer is good. By using fiber conduction technology, intensity difference between the stGlaucoma screening should follow the simple, fast and effective principles. A rapid high-precision screening analyzer is developed to meet the needs of large-scale screening. Intensity uniformity about each stimulus point of the analyzer is good. By using fiber conduction technology, intensity difference between the stimulus points of screen is less than 5%. Moreover, the stimulation point intensity has high precision. By using single chip pulse width modulation, the intensity accuracy reaches 0.001 Nit. Combined with four-point theory for rapid screening, the early diagnosis of glaucoma has been completed..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 88 (2011)
LED-based Illumination System for Solid-state Volumetric True 3D Display
FENG Qi-bin, NIU Hong-lin, HUA Yi-kui, and Lü Guo-qiang
A solid-state volumetric true 3D display developed by Hefei University of Technology consists of a single DMD, an UHP lamp, a color wheel of RGBRGB and 240 Hz, a hollow light tunnel, 20 LC shutters, projection lens, folder mirrors, and control circuits etc., which have the disadvantages of low refresh rate and small coA solid-state volumetric true 3D display developed by Hefei University of Technology consists of a single DMD, an UHP lamp, a color wheel of RGBRGB and 240 Hz, a hollow light tunnel, 20 LC shutters, projection lens, folder mirrors, and control circuits etc., which have the disadvantages of low refresh rate and small color gamut. A LED-based illumination system is presented, comprising RGB LED modules, collimation lens, X-cube, and focusing lens to replace the UHP and the color wheel. The RGB LED modules emit RGB lights in sequence. The uniform RGB rectangular spots are produced at the end of the light tunnel. Without color wheel, the refresh rate could reach 60 Hz. The simulation and practical results show that the LED-based illumination system can completely satisfy the requirements of true 3D display..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 93 (2011)
The Illumination System Design of One Chip DLP Optical Engine Based on LED Light Source
LIU Yi, LIN Zu-lun, QI Kang-cheng, WANG Xiao-ju, RUI Da-wei, and SHEN Ni
Achieving good illumination performance in a compact illumination system is the main development direction of micro-projector. A compact illumination system of one chip Digital Light Processor (DLP) projector making use of LED light source is introduced based on the analysis of the DLP micro-projection display system. Achieving good illumination performance in a compact illumination system is the main development direction of micro-projector. A compact illumination system of one chip Digital Light Processor (DLP) projector making use of LED light source is introduced based on the analysis of the DLP micro-projection display system. The length of the relay system is shortened to about 50 percent while the light spot is big enough for illuminating the 0.3 inch Digital Micromirror Devices (DMD). Meanwhile, two models of illumination system respectively based on an ideal point source and an extended surface source are simulated by ZEMAX software. The 500,000 threads tracing simulation results show that, our design can achieve uniform light spot in a relative small system size. The utility rate of luminous energy of this illumination system is about 33 percent..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 99 (2011)
Stereo Visual Localization Algorithm Based on 2D-3D Binocular Motion Estimation
XU Yun-xi, JIANG Yun-liang, and CHEN Fang
Motion estimation algorithm of stereo vision is one of the important factors which affect the accuracy of stereo visual localization. The traditional 3D-3D motion estimation is greatly affected by noise, so the accuracy of algorithm is not high. We propose a new stereo visual localization algorithm based on 2D-3D binocMotion estimation algorithm of stereo vision is one of the important factors which affect the accuracy of stereo visual localization. The traditional 3D-3D motion estimation is greatly affected by noise, so the accuracy of algorithm is not high. We propose a new stereo visual localization algorithm based on 2D-3D binocular motion estimation. In our method, 2D image projection coordinates is directly used instead of 3D coordinates of feature after motion. Firstly, EPnP motion estimation is applied to determine matching inliers and initial motion parameters. We propose 2×2D-3D motion parameters optimization method based on Levenberg-Marquardt algorithm and geometric constraints between the 2D projection of binocular cameras. Optimal 2D-3D motion estimation is achieved by minimizing the error between the observed 2×2D image points and the re-projected 2×2D image points of stereo cameras from the reconstructed 3D features. Simulated experiment and outdoor real experiment show that our method performs well in accuracy and robustness, and are better than traditional 3D-3D methods..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 104 (2011)
Freeform Ophthalmic Lenses Power Map Measurement Using Ronchi Test Techniques
WANG Yuan-yuan, CAI Jian-qi, and Lü Fan
With the development of freeform ophthalmic lenses, especially the appearance of ophthalmic lenses, the traditional optical power meter can’t satisfy the optical power measurement requirements. In this paper, the principle and optical structure of freeform Lens power map measurement based on Ronchi test techniques is iWith the development of freeform ophthalmic lenses, especially the appearance of ophthalmic lenses, the traditional optical power meter can’t satisfy the optical power measurement requirements. In this paper, the principle and optical structure of freeform Lens power map measurement based on Ronchi test techniques is introduced. The simulation is made by using ray trace to analyze the measure accuracy change with Ronchi grating pitch..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 111 (2011)
Thermal Characteristics Test Based on the Structural Function Theory
ZHAO Xue-li, JIN Shang-zhong, WANG Le, LIANG Pei, CEN Song-yuan, CAO Yu-jie, LI Xuan, and LI Liang
To measure the thermal characteristics of LED, one method based on the structural function theory was studied. Thermal test equipment was used to measure the transient temperature curve of LED samples by changing the power input of LED. Then, the parameters such as thermal resistance and thermal capacitance can be analTo measure the thermal characteristics of LED, one method based on the structural function theory was studied. Thermal test equipment was used to measure the transient temperature curve of LED samples by changing the power input of LED. Then, the parameters such as thermal resistance and thermal capacitance can be analyzed through structure function extracted from the temperature curve. Compared with conventional methods, the method has the nondestructive advantages. Furthermore; it can measure more accurately the distribution of each part of the LED with good visual effect. So it is one of the effective means to evaluate the thermal characteristics of high power LED..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 115 (2011)
Block-based Adaptive Super Resolution Algorithm
XIAN Hai-ying, FU Zhi-zhong, WAN Qun, and XU Jin
This paper addressed the multi-frame super-resolution reconstruction. A novel block-based adaptive super resolution algorithm was proposed, and the size of matrixes was reduced greatly. The size of matrixes was related to the size of block, and independent of the size of sequence. Consequently, it could reduce the memoThis paper addressed the multi-frame super-resolution reconstruction. A novel block-based adaptive super resolution algorithm was proposed, and the size of matrixes was reduced greatly. The size of matrixes was related to the size of block, and independent of the size of sequence. Consequently, it could reduce the memory capacity, and improve the processing efficiency. Experiments showed that this algorithm did not have high requirement on the estimation precision of motion parameter. If estimation precision was low, the performance of the algorithm was better than traditional multi-frame SR algorithm. Therefore, the proposed algorithm was more appropriate for practical application..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 119 (2011)
Slender Object Extraction for Image Segmentation Based on Centerline Snake Model
LIU Hong-jiang, WANG Ren-huang, HE Zui-hong, and LI Xue-cong
To extract slender object from image with strong interference, a method based on Snake is proposed by using centerline and width’s curve. Making use of the centerline symmetry of slender object, the contour is described by using two one-dimensional functions about centerline and width instead of two-dimensional expressTo extract slender object from image with strong interference, a method based on Snake is proposed by using centerline and width’s curve. Making use of the centerline symmetry of slender object, the contour is described by using two one-dimensional functions about centerline and width instead of two-dimensional expression. By evolving this two functions to meet the minimization energy of snake model, the object is accurately extracted. The symmetry of edge gradient is used, and a weighting function is mentioned to increase the image force. By this way, the interference can be avoided and iterations can be reduced. The improved algorithm reduces the number of control points and the size of calculation, and the results can be obtained automatically and fast. Experiments show that the improved algorithm is effective..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 124 (2011)
Registration of Infrared and Visible Images Based on Improved SIFT Feature
ZHAO Ming, and LIN Chang-qing
Referring to the problem of the less correlative intensity image registration, an improved approach based on Scale Invariant Features Transform (SIFT) is proposed. First, according to the performance of SIFT in three instances: affine transform, adding Gaussian noise and different intensities, SIFT vector values which Referring to the problem of the less correlative intensity image registration, an improved approach based on Scale Invariant Features Transform (SIFT) is proposed. First, according to the performance of SIFT in three instances: affine transform, adding Gaussian noise and different intensities, SIFT vector values which was easily affected by different intensities were constrained through given threshold when extracting SIFT feature points. Then, the false matching points were deleted by similar quadrangle in the precise math process. Finally, least squares method was employed to find optimal solutions to affine transform equations. Experimental results show that the proposed approach has a better performance than original SIFT algorithm, and can achieve a high accuracy and moderate complexity level..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 130 (2011)
A Novel Rapid Detection Method of Multi-circle
LUO Xue-gang, and Lü Jun-rui
Aiming at the detection of Multi-Circle, a novel method based on a combination of circular symmetry and rotation transformation is proposed. According to the circle geometrical properties, taking the straight line as axis of symmetry through the center of circle and paralleling to abscissa, symmetric points named pointAiming at the detection of Multi-Circle, a novel method based on a combination of circular symmetry and rotation transformation is proposed. According to the circle geometrical properties, taking the straight line as axis of symmetry through the center of circle and paralleling to abscissa, symmetric points named point set P1 are searched from the points on the edge of the image. After the image rotated, symmetric points are searched from it, with reverse rotation transformation, and named point set P2. Making use of circle rotational symmetry, the point set that is the intersection of P1 and P2 is on a circle, which will realize the detection of circle. Compared with Randomized Hough Transform (RHT) and Randomized Circle Detection (RCD) which are most widely applied, the experimental results show that the algorithm has the advantages of rapid detection and simple implementation..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 137 (2011)
Bayesian Framework for Visual Attention Model Based on Transition-sliding Window
HU Zheng-ping, and PANG Jing-chao
According to the thought that the salient object in an image is often conspicuous, compact and complete, a Bayesian salient object extraction model based on space distribution and local complexity of the transition window is proposed. First of all, the bright saliency value map is obtained by computing the contrast of According to the thought that the salient object in an image is often conspicuous, compact and complete, a Bayesian salient object extraction model based on space distribution and local complexity of the transition window is proposed. First of all, the bright saliency value map is obtained by computing the contrast of local area and its multiple scales neighborhood, and then the color saliency value map is computed by using conspicuous, space distribution and locally uniform of color information. Meanwhile, the orientation saliency value map is obtained by multi-scale analysis responses of Gabor filters. The above saliency values are inputted into the single-scale Bayesian framework model based on transition-sliding window. Then the probability of that a pixel’s salient is computed by comparing the saliency values inside the window and outside the transition window. Finally, the saliency map of the input image is obtained by taking the maximum value, so the salient object is located and extracted according to the saliency map. The proposed method is applied to all kinds of images, and the better test results show that the algorithm is feasible and valuable..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 38, Issue 9, 142 (2011)
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