Journals >Opto-Electronic Engineering
Contents
2012
Volume: 39 Issue 9
24 Article(s)
Export citation format
Research Article
Research Progress of Active Shape Control of Spacial Membrane Mirror
GUAN Ying-zi
Spacial membrane mirror is widely used in the space optical system since it has characteristics such as very low areal density, excellent volumetric packaging efficiency and low manufacturing cost. The key technology of membrane mirror is active shape control which is classified according to the position of actuator inSpacial membrane mirror is widely used in the space optical system since it has characteristics such as very low areal density, excellent volumetric packaging efficiency and low manufacturing cost. The key technology of membrane mirror is active shape control which is classified according to the position of actuator in this work. Subsequently, the features of the actuator are detailed. The researches of the shape control reported both on computer modeling and testing have been overviewed by the author, in which the modeling methods, mount and their demonstrated contents have been focused on. Finally, the developing perspective has been emphasized in this work..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 1 (2012)
Improved Bitrate Control for Satellite Images
CHEN Xiao, and XU Xiao-qing
JPEG2000 is an ideal satellite image compression scheme. However, most computation is redundant and memory resources are large in JPEG2000, which is difficult to adapt to the transmission of the high real-time requirements and the limited resource satellite images. Therefore, a novel rate control algorithm based on theJPEG2000 is an ideal satellite image compression scheme. However, most computation is redundant and memory resources are large in JPEG2000, which is difficult to adapt to the transmission of the high real-time requirements and the limited resource satellite images. Therefore, a novel rate control algorithm based on the rate distortion slope of satellite images is proposed. According to the downward trend roughly of the number of bit planes required for the code block and the three properties of the rate-distortion slope, a simple formula is provided to achieve the rate-distortion slope as the threshold of tile 1 encoding, and the code passes that less than this threshold are skipped, so it does not need to code all code passes. Experimental result indicates that the storage of the algorithm accounts for PCRD about 33%, while PSNR remains unchanged at the bit rate of 0.125 bpp. Therefore, this method can effectively improve the coding efficiency of satellite images..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 7 (2012)
Semi-physics Simulation of Small Satellite Attitude Control in Stereo Imaging
XU Kai, JIN Guang, ZHANG Liu, and SUN Zhi-yuan
Along with the constantly promoting demand of the function of small satellite, stereo imaging of small satellite is one of hot subjects in aerospace field study recently. The study aimed at attitude control during stereo imaging in the same orbit of small satellites with single linear CCD camera. Through analysis and iAlong with the constantly promoting demand of the function of small satellite, stereo imaging of small satellite is one of hot subjects in aerospace field study recently. The study aimed at attitude control during stereo imaging in the same orbit of small satellites with single linear CCD camera. Through analysis and investigation, the operational rule of stereo imaging in the same orbit of small satellite was found out. Meanwhile, the algorithm of stereo imaging in the same orbit attitude control and semi-physical simulation system has been designed by using the similar principles and attitude operation rule of small satellite. Based on single-axis air-bearing platform and satellite components, semi-physical simulation platform of small satellite attitude control has been built. Finally, semi-physical simulation of small satellite attitude control system has been conducted at the stereo imaging. The results of the simulation indicate that small satellite pitch axis was maneuvered 52° within 75 s and three-axis reached a steady state. The pointing accuracy was 0.05° and attitude stability was 0.005°/s. It is demonstrated that the attitude control strategy can accomplish stereo imaging in the same orbit of single linear CCD optical load small satellite..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 12 (2012)
Remote Sensing Image Fusion Using Edge Information
LU Ya-ning, GUO Lei, and LI Hui-hui
Curvelet transform, as a method of Multiscale Geometric Analysis (MGA), is more suitable for image processing than wavelet and more appropriate for analyzing the image edge characteristics of curve and line, and it has better approximation precision and sparsity description. In addition, the representation contains morCurvelet transform, as a method of Multiscale Geometric Analysis (MGA), is more suitable for image processing than wavelet and more appropriate for analyzing the image edge characteristics of curve and line, and it has better approximation precision and sparsity description. In addition, the representation contains more directional information, and contains more directional information. The methods of integrating PAN image and MS image are proposed based on curvelet transform. PAN image and I image, which is given by a linear HSI transform are given by curvelet transform to obtain coarse coefficients and detail coefficients. The new coarse coefficients are obtained by using edge information and features of PAN image. The detail coefficients are dealt with a function for enhancing faint edges. Then, the inverse curvelet transform get the new intensity I image (Inew). Finally, Degree of Distortion (DoD) and Space Frequency (SF).etc are used to evaluate the result. The results of experiment indicate that the method excels those of based on HSI or curvelet transform in preserving spectral information and enhancing resolution..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 18 (2012)
Systematic Error Correction for High Trajectory Optical Measurement Based on Fixed Star
LI Guo-you, FU Cheng-yu, HE Pei-long, and ZHANG Ya-hui
Due to the measuring equipment and the influence of environment, there are some systematic errors in the data of high trajectory optical measurement. However, the systematic error correction is the key for high precision positional parameters. Aiming at this problem, the systematic error sources were analyzed when the Due to the measuring equipment and the influence of environment, there are some systematic errors in the data of high trajectory optical measurement. However, the systematic error correction is the key for high precision positional parameters. Aiming at this problem, the systematic error sources were analyzed when the target was above 80 km, the corresponding error model was set up, and the correction method was put forward according to the fixed star observation, based on the correction method of fixed star that the air refraction error and the axis errors of device were corrected together. To verify the effectiveness of the method, it was applied to the actual high trajectory optical measurement. The experimentation results show that the correction effect is obvious and the precision of correction can be improved to 2"..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 24 (2012)
The Optical Precision Alignment of the Earth Simulator for Double Conical Scanning Infrared Horizon Sensor
Lü Yin-huan, LIU Shi-shen, CUI Wei-xin, and LEI Cun-dong
The optical precision calibration constrains the ground testing performance of the double conical infrared horizontal scanning sensor. A real-time three-dimensional coordinate measurement system is established by using two electronic theodolites, and optical precision alignment of the double conical infrared horizontalThe optical precision calibration constrains the ground testing performance of the double conical infrared horizontal scanning sensor. A real-time three-dimensional coordinate measurement system is established by using two electronic theodolites, and optical precision alignment of the double conical infrared horizontal scanning Earth Simulator is achieved based on above-mentioned system. Actual measured data are compared with the reference theoretical design value, and measuring loft and comparison are carried out repeatedly. Furthermore, the hot and cold boundaries of the Earth simulator are adjusted. These steps can constrain the accuracy of boundary feature point coordinates of the Earth Simulator within error of 0.2 mm. High-precision position control ensures the noise-equivalent-angle precision testing performance of the double conical infrared horizontal scanning sensor, and controls the noise-equivalent-angle (3σ) within 0.07 degree..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 29 (2012)
An Active Disturbance Rejection and Sliding Mode Control of an Opto-electronic Platform Servo System
ZHOU Tao
An active disturbance rejection and sliding mode controller based on a reference model is studied. It comprises an active disturbance rejection controller and a global sliding mode controller. The active disturbance rejection controller with a tracking differentiator is designed according to the reference model, which An active disturbance rejection and sliding mode controller based on a reference model is studied. It comprises an active disturbance rejection controller and a global sliding mode controller. The active disturbance rejection controller with a tracking differentiator is designed according to the reference model, which regulates the reference model output to track the command input signals accurately. The global sliding mode controller regulates the controlled plant output of a servo system to track the reference model output in high precision. Experiments results of the opto-electronic platform servo system demonstrate that the new controller could compensate the parameters’ uncertainty and the nonlinear disturbance and increase the tracking precision of the servo system. The system is globally robust..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 35 (2012)
A Moving Object Detection Algorithm Based on Learning Vector Quantization
WANG Shi-dong, ZHOU De-chuang, and WANG Jan
A moving object detection algorithm based on Learning Vector Quantization (LVQ) is presented. By training samples, the threshold vector of extracting the moving objects has the self-adaptive ability. The input vector includes components of YCbCr color space and direction feature of Gray Level Co-occurrence Matrix (GLCMA moving object detection algorithm based on Learning Vector Quantization (LVQ) is presented. By training samples, the threshold vector of extracting the moving objects has the self-adaptive ability. The input vector includes components of YCbCr color space and direction feature of Gray Level Co-occurrence Matrix (GLCM). These two features are integrated to the algorithm, which has the efficiency of inhibiting the disturbance of background brightness variation. Experiment results indicate that the moving objects can be extracted correctly by using the algorithm, even if the complex background has an acute brightness variation..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 42 (2012)
Real-time Visual Simulation System for Photoelectric Theodolite
XIONG Shuai, FU Cheng-yu, TANG Tao, and LIU Xing-fa
Real-time visual simulation system for photoelectric theodolite can be used for operator training and theodolite testing. The function structure of the theodolite simulation system was established. It mainly performs theodolite scene simulation and tracking state solving. The virtual CCD camera imaging simulation, the Real-time visual simulation system for photoelectric theodolite can be used for operator training and theodolite testing. The function structure of the theodolite simulation system was established. It mainly performs theodolite scene simulation and tracking state solving. The virtual CCD camera imaging simulation, the target track simulation, the target miss-distance calculation, the background cloud simulation and the real-time graphics effects addition in the theodolite scene simulation were discussed. Simulink model of the theodolite tracking control system was established, and its code was generated with Real-time Workshop (RTW). The model code was overwritten to build the tracking state solving module. VC++, Vega, OpenGL and OpenGL Shading Language (GLSL) were adopted to develop the simulation system, and the demand of real-time was satisfied. Real theodolite system is not needed in this simulation system that the cost of training and testing decreases. Moreover, the simulation system is useful for the analysis and design of real theodolite system..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 49 (2012)
Multi-objects Tracking with Dual-level Particle Filter Embedded Semi-supervised Hough Forests
LIN Yi-ning, WEI Wei, and DAI Yuan-ming
This paper focuses on multi-objects tracking problems in monocular camera and mutative background complex scenes. We achieve multi-objects tracking in dynamical scenes under a semi-supervised learning framework, which combines tracking-by-detection method and particle filter together, integrates unreliable information This paper focuses on multi-objects tracking problems in monocular camera and mutative background complex scenes. We achieve multi-objects tracking in dynamical scenes under a semi-supervised learning framework, which combines tracking-by-detection method and particle filter together, integrates unreliable information sources and extracts a high-confidence observation model from it. Then an objects maintenance scheme is carried out to cope with occlusion, background changing, entry/exit and so on. The results on standard datasets demonstrate advantages of the proposed algorithm in complex environment, particularly on scenes with occlusion and obstruction..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 56 (2012)
People Re-identification Based on Online Multiple Kernel Learning in Video Surveillance
CHEN Fang, and XU Yun-xi
In the non-overlapping multi-camera or single camera video surveillance, re-identification of tracked target is very important. Due to weakness of traditional support vector machine in feature fusion, a new people re-identification method is proposed based on online multiple kernel learning. We extract complementary viIn the non-overlapping multi-camera or single camera video surveillance, re-identification of tracked target is very important. Due to weakness of traditional support vector machine in feature fusion, a new people re-identification method is proposed based on online multiple kernel learning. We extract complementary visual word tree histogram and global color histogram from tracked people foreground image sequence in video, and then multiple kernel learning method is used for online train people visual appearance. Finally, we obtain multiple kernel feature fusion model of people appearance. Experimental results show that our method can train people appearance model rapidly, meet the real-time requirement of video surveillance, and attain higher recognition performance than single feature appearance model and single kernel support vector machine method..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 65 (2012)
Single Observer Passive Target Tracking Based on Adaptive Gene H∞Filter
ZHOU Hang, FENG Xin-xi, and CHEN Mao
Single observer passive target tracking based on adaptive gene H∞ filter is proposed for the highly non-linear passive location and tracking system, which means that tracking filters often failed to catch and keep tracking of the emitter. On the basis of sigma point transformation technique and H∞ filtering method, theSingle observer passive target tracking based on adaptive gene H∞ filter is proposed for the highly non-linear passive location and tracking system, which means that tracking filters often failed to catch and keep tracking of the emitter. On the basis of sigma point transformation technique and H∞ filtering method, the proposed algorithm can decrease linearization error of high nonlinear system and solve the noise uncertainty problem. The algorithm has a control abnormal innovations, which can efficiently restrain the unfavorable influence out of outliers, and apply the scaled factor and a fading factor to adjust the distance of sampling-point to center-point and the covariance matrix of estate predict error. And then the problem of non-local effects of sampling can be resolved and single observer passive target tracking system is more robust to measurement error of time difference of arrival: Simulation results show that the proposed algorithm is similar to sigma point H∞ filtering method in computational complexity, and the algorithm outperforms the sigma point H∞ filtering method in tracking accuracy as stability. Therefore it is more suitable to the nonlinear state estimation..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 72 (2012)
IR Target Detection Based on Morphological Gradient
WU Ya-bei, WANG Wei-hua, WU Ju-hong, and CHEN Zeng-ping
We address the problem of detecting targets with different areas in air background, which will be very complex when containing part of ground. A target detection approach based on morphological gradient is proposed. Firstly, morphological gradient of the IR frame is computed. Then the air region is gotten based on the We address the problem of detecting targets with different areas in air background, which will be very complex when containing part of ground. A target detection approach based on morphological gradient is proposed. Firstly, morphological gradient of the IR frame is computed. Then the air region is gotten based on the morphological gradient. At last, targets in the air region are detected and labeled. Because morphological gradient is sensitive to the slow changing grayscale on IR targets’ boundaries, morphological gradient is used to strengthen targets’ boundaries and detect targets by detecting the boundaries. Our experiments show that the method yields good detecting performance and is suitable for detecting targets with different areas..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 81 (2012)
Target Segmentation for SAR Images Based on Nonsubsampled Contourlet Characteristic and PCNN
WU Jun-zheng, YAN Wei-dong, BIAN Hui, NI Wei-ping, and LU Ying
To solve the problem of automatic target segmentation for SAR images, a target segmentation algorithm for SAR images was proposed after the analysis of nonsubsampled contourlet transform and pulse coupled neural networks. Via researching the characteristics of low and high frequency, the conclusion was acquired that thTo solve the problem of automatic target segmentation for SAR images, a target segmentation algorithm for SAR images was proposed after the analysis of nonsubsampled contourlet transform and pulse coupled neural networks. Via researching the characteristics of low and high frequency, the conclusion was acquired that the first one contained probable region of target mainly. Correspondingly, the latter contained fine contour and background disturbance mainly. Fire image of low frequency was produced by Pulse Coupled Neural Networks (PCNN) acting on low frequency image, and the region which the target located was confirmed on the basis of segmentation for the fire image using OTSU method. A characteristic figure was constructed for the high frequency, and the fine configuration of the target was acquired on the basis of segmentation for characteristic figure’s fire image. Experiments with MSTAR images were processed and the proposed algorithm was compared with algorithms based on fuzzy C mean and Markov random fields. The results indicate that the proposed algorithm which has more accurate segmentation for SAR target and more strongly immune ability for speckle was effective..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 86 (2012)
Skills of Several Signal Synchronization Problems in Laser Interferometer System
WANG Xuan-ze, ZHOU Hao, ZHAI Zhong-sheng, YANG Lian-gen, and LIU Wen-chao
Several signal synchronization problems based on piezoelectric ceramics (PZT) of laser interference system have been described. Firstly, as for D/A of collection card to drive PZT and A/D high speed sampling, two methods are described respectively. One is using Visual C++ by improved software algorithm to implement synSeveral signal synchronization problems based on piezoelectric ceramics (PZT) of laser interference system have been described. Firstly, as for D/A of collection card to drive PZT and A/D high speed sampling, two methods are described respectively. One is using Visual C++ by improved software algorithm to implement synchronization and the other combines hardware and software to implement synchronization. And PZT linear characteristics curve is drawn to comprise pros and cons of two synchronization method. Secondly, for common collection card with several channels is asynchronous, and the lower sampling frequency is, the larger the errors is, by the way of increasing Analog Input (IA) channels, symmetric layout sampling channels are used to eliminate errors because of sampling interval, which can realize high precision adjacent quadrant phase difference. Meanwhile, it has some effect on filter. Lastly, moving average is analyzed by spectrum characteristic. Experimental results indicate that the way of synchronism will improve the system measurement precision of phase, and filtering algorithm can filter background noise caused by light intensity and optical electronic devices..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 93 (2012)
The Influence of Stress Effect of Output Mirror on the Control of Non-planar Resonators
YANG Hao-dong, LIANG Dong-ming, ZHANG Yan-xiu, and YUE Huan-yu
A mathematic model for calculating the ellipticity of the output beams in square planar ring resonators is given. By analyzing the mathematic model, the stress effect of the output mirror has the unsymmetrical influence on the clockwise and counterclockwise ellipticities of output beams. Moreover, the validity of the tA mathematic model for calculating the ellipticity of the output beams in square planar ring resonators is given. By analyzing the mathematic model, the stress effect of the output mirror has the unsymmetrical influence on the clockwise and counterclockwise ellipticities of output beams. Moreover, the validity of the theoretical analysis is verified by the experiment. Based on these novel results, the method for aligning the light path, which is aligned by measuring the clockwise and counterclockwise ellipticities of output beams, cannot control the distortion angle of square ring resonators effectively..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 101 (2012)
A Feedback Compensation Algorithm for RLG Dither Stripping
FAN Jin-chuan, FANG Zhong-chun, and Lü Hang-wei
The stripping for dither signal is an important subject in the field of Ring Laser Gyro (RLG), but there has hardly been a stripping scheme that does not cause time delay or has high accuracy, which limits the range of RLG application badly. According to the problem, a new algorithm based on high frequency sampling forThe stripping for dither signal is an important subject in the field of Ring Laser Gyro (RLG), but there has hardly been a stripping scheme that does not cause time delay or has high accuracy, which limits the range of RLG application badly. According to the problem, a new algorithm based on high frequency sampling for RLG dither stripping was studied, which provides real time output signal due to subtraction between signals from gyro and angle rate sensor, and decreases effect from environment by compensating angle rate signal within a feedback loop. Firstly, the theory of this new algorithm in dither stripping was analyzed, then material design was given, and it was compared with former schemes in simulated result lastly. According to the conclusion from simulation, the new algorithm reduces dither residue greatly in the static and dynamic state, and hardly cost time, which makes it possible that the strapdown inertial navigation system based on RLG is used in high dynamic aircraft..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 108 (2012)
Experiment of Visible CCD Damaged by Laser Operating in Different State
HAO Xiang-nan, LI Hua, NIE Jin-song, BIAN Jin-tian, and LEI Peng
The experiment that visible CCD was damaged by CW laser, 40 kHz laser and 5 kHz laser was carried out individually. Similar injury phenomenon was observed, which includes point damage, linear damage and complete damage. And the resistance between driving electrodes and substrate was measured corresponding to every injuThe experiment that visible CCD was damaged by CW laser, 40 kHz laser and 5 kHz laser was carried out individually. Similar injury phenomenon was observed, which includes point damage, linear damage and complete damage. And the resistance between driving electrodes and substrate was measured corresponding to every injury state. Stereoscan photographs of the three damaged CCD slug were obtained to analyze the micromorphology of damaged positions. Through analysis, the causes of three different injury phenomenon were extracted and the different mechanism of CW laser, 40 kHz laser, 5 kHz laser irradiating CCD was discussed. The conclusion is that superficial injury causes point damage; light leakage and cutting out of driving electrodes lead to linear damage; and the injury of insulating barrier results in complete damage. Furthermore, fusion is the main process of CW laser irradiation; carburation and ablation are major causes of 40 kHz laser injuring CCD; and the factors of 5 kHz laser injuring CCD consist of carburation, ablation, eroding and recoil strength..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 113 (2012)
Calibration of Radial Distortion and Intrinsic Parameters Using a Single Image
ZHU Yun-fang
A method of calibrating radial distortion and intrinsic parameters based on a single template image is proposed. The method based on the constraint that straight lines in the 3D world are imaging as circular arcs in the image plane under the single parameter division model. With the input temple image, the straight linA method of calibrating radial distortion and intrinsic parameters based on a single template image is proposed. The method based on the constraint that straight lines in the 3D world are imaging as circular arcs in the image plane under the single parameter division model. With the input temple image, the straight lines in the template and the corresponding circular arcs in the distorted image are first identified and estimated. Then the single distortion parameter and the center of distortion are estimated based on the parameters of circular arcs. After the image is undistorted, the homography matrix is calculated and the focal length is linearly estimated. These initial estimations are refined by minimizing the image reprojection error using Levenberg-Marquardt, and accurate results are finally acquired. Results of experiments with fish-eye camera and high-resolution digital camera show that the proposed method is simple, flexible and accurate..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 125 (2012)
Test of Transient Temperature for Spectrum Distribution of the Speckle Pattern Interferometry
WU Jin-hui, YANG Rui-feng, WANG Gao, and ZHAO Mao-tai
To improve the accuracy of the transient temperature detection system, Transient temperature inversion processing algorithms is proposed based on spectrum analysis of speckle pattern interferometry. The interference fringes are formed by speckle interferometry in the system. For transient temperature changes cause the To improve the accuracy of the transient temperature detection system, Transient temperature inversion processing algorithms is proposed based on spectrum analysis of speckle pattern interferometry. The interference fringes are formed by speckle interferometry in the system. For transient temperature changes cause the material strain, the speckle interference pattern changes. The interference fringes on the measured surface are obtained by the area array CCD collection before and after deformation. The corresponding spectrum density function will changes by the changes of transient temperature, and the amplitude changes of center wavelength is inverted by the speckle pattern interferometry. Through detecting and calculating the ratio of the amplitude of the center wavelength, the transient temperature can be obtained by spectrum analysis. In the analysis and calculation for the function of transient temperature and material strain, material strain and interference fringes, derived the amplitude and phase function of the transient temperature change and interference fringes, so as to provide the necessary conditions for detecting the use of spectral density function temperature. 660 nm laser diode, and SI6600 type area CCD detector is used to obtain the speckle pattern interference fringes, system extracts the amplitude ratio of the central wavelength from spectral distribution function, and by calculation and calibration the detection accuracyoftemperature can be achieved of 2. Compared to traditional ±℃methods of direct detection forinterference fringes changes, the newmethodsimprove the accuracy by nearly an order of magnitude. It is more accuratedetection, betteruniformity and betterstability..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 132 (2012)
Write Control Technology of NAND Flash Image Recording System
XU Yong-gang, REN Guo-qiang, WU Qin-zhang, and SUN Jian
To enhance the write bandwidth of NAND flash image recording system, the NAND flash on-chip write technologies of interleave, interleave two plane and two plane are researched and implemented respectively. Then, a new method based on NAND flash on-chip interleave write and off-chip 2 level pipelining is proposed, whichTo enhance the write bandwidth of NAND flash image recording system, the NAND flash on-chip write technologies of interleave, interleave two plane and two plane are researched and implemented respectively. Then, a new method based on NAND flash on-chip interleave write and off-chip 2 level pipelining is proposed, which utilizes the interleave load time of two NAND flash groups to fill the programming time. Finally, the controller with each write mode is realized in FPGA in the way of hardware. The experimental results show that on-chip two plane write speed and on-chip interleave two plane write speed are 1.489 03 times and 3.277 06 times of ordinary write speed respectively. However, the write speed of method proposed by this paper is 3.960 38 times of ordinary write speed, slightly higher than the 3.958 81 times of traditional off-chip 4 level pipelining. Moreover, proposed method can save 20% FPGA pin resources, and lower the cost and recording system realizing difficulty..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 138 (2012)
A Novel Approach to Region Quick Location of Serial Numbers in OCR of RMB Banknote
LI Chang-hai, YE Yu-tang, LIU Lin, LUO Ying, YE Han, and XU Wei
A novel approach to region location of serial numbers in Optical Character Recognition (OCR) of RMB is proposed. Firstly, a binary image was obtained by applying fixed threshold segmentation to the banknote image. Secondly, some of sample points of left and lower edges were selected by using sequential scanning. ThirdlA novel approach to region location of serial numbers in Optical Character Recognition (OCR) of RMB is proposed. Firstly, a binary image was obtained by applying fixed threshold segmentation to the banknote image. Secondly, some of sample points of left and lower edges were selected by using sequential scanning. Thirdly, due to the characteristic that the dot-product of vectors from two edge lines on non-damaged areas is zero, the sample points of edges on non-damaged areas were sifted by filtering sample points on damaged areas. So, a slope angle and a lower-left corner can be got by using least-square line regression on these points. Finally, the image was rotated and the lower-left corner after correction was gained by using rotation formula. Meanwhile, the number region was located by shifting fixed distance from anchor point, which makes the time consumption limited to few microseconds. The experimental results prove good robustness and high time efficiency, so the scheme has a broad application prospects in the system of optical character recognition of banknote..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 145 (2012)
Thermal Effects on Laser Beam Quality in the Inner Channel Propagation
Lü Ke, ZHENG Wei, and HUA Wei-hong
According to the relationship between the thermal effects and absorption coefficient of the inner channel gas, reaction length and intensity distribution of the laser beam, a model of thermal effects on laser beam quality in the inner channel propagation is established based on the steady-state heat-conduction equationAccording to the relationship between the thermal effects and absorption coefficient of the inner channel gas, reaction length and intensity distribution of the laser beam, a model of thermal effects on laser beam quality in the inner channel propagation is established based on the steady-state heat-conduction equation. The relationship among the temperature distribution, the optical path difference across the beam, RMS phase distortion, Strehl ratio in the far-field and the obscuration ratio, the axial flow velocity is calculated. The approximate calculation results of the temperature distribution are about the same as the theoretical results. The model provides a qualitative reference for the laser beam control system design and performance evaluation..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 9, 119 (2012)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20