Journals >Opto-Electronic Engineering
Contents
2012
Volume: 39 Issue 7
25 Article(s)
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Research Article
Multiple-beam Transmission Techniques for Wireless Laser Communication
KE Xi-zheng, CHEN Juan, and PEI Guo-qiang
In the atmosphere laser communication, scintillation caused by atmospheric turbulence could seriously affect the performance of communication system and increase bit error rate. Multi-beam transmission is an effective method to overcome this effect. We analyze the intensity probability distribution when transmitting wiIn the atmosphere laser communication, scintillation caused by atmospheric turbulence could seriously affect the performance of communication system and increase bit error rate. Multi-beam transmission is an effective method to overcome this effect. We analyze the intensity probability distribution when transmitting with different numbers of beams and analyze the intensity probability distribution with different aperture diameters when transmitting multi-beam. The results show that when the transmitting beam and the aperture diameter increase, intensity probability distribution more likely tend to normal distribution and the mean intensity probability density also increases. This article also analyzes the relationship between the normalized correlation coefficient of multi-beam transmission and the intensity variance. Besides, the bit error rate of multi-beam transmission in different turbulent environment is analyzed. Analysis results show that multi-beam transmission system can improve the intensity fluctuation on receiving surface well and reduce bit error rate.
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 1 (2012)
The Split Method of Test Signal in Optical Fiber Communication
CAO Jian-min, and CHEN Shi-bo
Different from the electrical signal, the optical signal has many problems in split method, such as too big insertion loss, the weak split test signal, and the test signal concerned in the split position. It is often not stable or can't meet the demand and fail in the actual optical communication engineering test pDifferent from the electrical signal, the optical signal has many problems in split method, such as too big insertion loss, the weak split test signal, and the test signal concerned in the split position. It is often not stable or can't meet the demand and fail in the actual optical communication engineering test process. A full optical design method of active splitter is presented to make full use of the optical amplifiers, which can be used to split test signal in optical fiber network. In addition to meeting the basic requirement of the test signal to have no effect on the original signal, it has a small insertion loss, draws out a strong signal, has a low cost and is unconcerned in test optical signal format etc. With the development of the technology of optical amplifiers, this full optical split method will get more attention..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 8 (2012)
Optical Network Fault Management Based on Dynamic
Fuzzy Association Rule Reasoning
WU Jian, and LI Xin-ming
Nowadays, optical network turns to be more complex. Once there occurs a failure, there will result in multi-alarm-events. On the other hand, an alarm might result from different faults. This paper describes the alarm correlation in optical networks based on data mining. We mine association rules for dynamic network resNowadays, optical network turns to be more complex. Once there occurs a failure, there will result in multi-alarm-events. On the other hand, an alarm might result from different faults. This paper describes the alarm correlation in optical networks based on data mining. We mine association rules for dynamic network resource and service by fully utilizing knowledge base formed before, which enables the framework can be easily updated and new discovery methods can be readily incorporated within it. Fuzzy logic is also used to convert numerical alarm attributes into linguistic terms. Once there are new unknown alarms occur in network, we use fuzzy reasoning based on fuzzy association rules (FARs) for fault diagnosis. It will shorten the recovery time and improve the performance of optical network fault management. Experiments are carried out to validate the accuracy &efficiency of our research..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 13 (2012)
Calibration Method of Large-arrange Small-angle Laser Triangulation Measuring System
HUANG Zhan-hua, LUO Zeng, LI Sha, YUAN Jue, CAI Huai-yu, and ZHU Meng
An improved calibration method were proposed to avoid the shortcoming that it has a huge nonlinear relationship between system input and output when using laser triangulation under large range small anger circumstance. Comparison among several typical calibration methods was firstly presented, by which the advantages aAn improved calibration method were proposed to avoid the shortcoming that it has a huge nonlinear relationship between system input and output when using laser triangulation under large range small anger circumstance. Comparison among several typical calibration methods was firstly presented, by which the advantages and disadvantages of each method were considered. A compound calibration method which has the potential of high precision and stability were then proposed. A displacement measuring system was completed based on this method, which was examined by experiments to have obvious superiority over those systems based on typical method when used in huge arrangement measuring..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 26 (2012)
Image Analysis and Accuracy Measuring for Location Detection of Micro Laser Target
YI Xin-hua, ZHANG Ya-nan, and ZHAO Dong-feng
In order to realize multi-laser beam pointing to the micro-target, the micro-target needs to be located accurately in the experiment of high power laser facility. According to the need of the detecting apparatus, a measuring simulationsystem based on vision system is set up to implement the accurate location and pointiIn order to realize multi-laser beam pointing to the micro-target, the micro-target needs to be located accurately in the experiment of high power laser facility. According to the need of the detecting apparatus, a measuring simulationsystem based on vision system is set up to implement the accurate location and pointing of target. This paper analyzes the effect about illumination light to the detection position of target based on the improved mean shift algorithm. A template matching method about correlation coefficient method is used to detect the center of target pinhole and the focus degree of image is employed to analyze the position accuracy of target hole when the image is out of focus. The experimental results demonstrate that the image detecting resolution is 0.4 μm and the position accuracy of measuring is 1.2 μm. When the defocusing amount is between -10 μm and 30 μm, the drift amount of center point is less than 1μm which can satisfy the measuring accuracy less than 8 μm..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 31 (2012)
Harris Corner Detection Algorithm Based on Two-dimensional EMD
ZHANG Jin-lin, CAO Peng, RUI Ting, ZHEN Shu-xin, and SUN Ren-wu
To solve the problem of the Harris corner detection algorithm which cannot detect corners in multi-scales, this paper applies the Empirical Mode Decomposition (EMD) to corner detection of two-dimensional images. First, the image is decomposed into some image detail layers (Intrinsic Mode Functions, IMF) by the EMD, theTo solve the problem of the Harris corner detection algorithm which cannot detect corners in multi-scales, this paper applies the Empirical Mode Decomposition (EMD) to corner detection of two-dimensional images. First, the image is decomposed into some image detail layers (Intrinsic Mode Functions, IMF) by the EMD, then use Harris corner detection operator on the details of the layer. Finally, filter the corner points layer by layer. The contrast experimental results show that, the new algorithm gets more corners, enhances the noise immunity and improves the image corner detection performance significantly..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 38 (2012)
Lane Departure Detection Based on the Slope of Lane Lines
YU Hou-yun, ZHANG Wei-gong2, and ZHAO Zhuan-ping
To resolve the lane departure detection on structural road, monocular vision is adopted as the perception. Respectively based on the verification of projective geometry and the position of the vanishing point of lane lines in the picture with pinhole camera model, the relationship between lane departure and the ratio oTo resolve the lane departure detection on structural road, monocular vision is adopted as the perception. Respectively based on the verification of projective geometry and the position of the vanishing point of lane lines in the picture with pinhole camera model, the relationship between lane departure and the ratio of lane line’s slope is concluded as a simple function which is unconcerned with the parameters of camera. Moreover, the experiment of measurement for the quantity of lane departure is performed with different camera orientation angles, and the result shows that the influence of small change of the orientation angles caused by the traffic direction can be neglected. Actual experiment result demonstrates that the precision of lane departure detection by this method is high, and the relative error is less than 5% compared with manual measurement. As stated above, the precision of lane departure detection by the method introduced is high and the complicated calibration of monocular camera can be avoided..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 43 (2012)
Observation of Relationship between Zenith
Luminance and Sun High Angle
LIU Wei-feng, XIE Yong-jie, CHEN Ruo-wang, and JING Chun-yuan
Zenith luminance is an important parameter of sky background radiation. In order to acquire the zenith luminance characteristic, the zenith luminance was measured with sky background measurement system at somewhere in Xinjiang. Experimental data was analyzed. The result indicated that there was a certain relationship bZenith luminance is an important parameter of sky background radiation. In order to acquire the zenith luminance characteristic, the zenith luminance was measured with sky background measurement system at somewhere in Xinjiang. Experimental data was analyzed. The result indicated that there was a certain relationship between the zenith luminance and sun high angle in sunshiny days. A relationship formula between the zenith luminance and sun elevation in sunshiny days was proposed. The validity of the formula was verified through the comparison of the calculation data with the experimental value. This relationship formula can be used to analyze the zenith luminance in real-time in sunshiny days. It is valuable to research sky background radiation luminance..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 49 (2012)
A Real-time Auto-focusing System for
Collimator with Large Aperture
LI Xiang, and ZHANG Xiao-hui
Large-aperture collimator was widely used in calibration and testing for various optical devices as a essential equipment for testing and calibration in laboratory. However, when collimator was defocused because of vibration, gradient change of temperature and airflow, divergence of beam which was emitted from collimatLarge-aperture collimator was widely used in calibration and testing for various optical devices as a essential equipment for testing and calibration in laboratory. However, when collimator was defocused because of vibration, gradient change of temperature and airflow, divergence of beam which was emitted from collimator was increased and result credibility of test was decreased. To solve the above problems, a new miniature auto-focusing system was presented which used pentaprism for a light feedback element. CCD was used as image receiving device, and software was applied to realize calculation of the system defocusing amount, which can monitor and test the focal plane of collimator on a high precision level for a long time. Computer simulation and test show that the system can reach 45μm auto-focusing resolution and fully meet the precision requirements for laboratory testing equipment..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 55 (2012)
The Measurement of Parallelism Based on Diffraction Grating
FU Hong, WU Qiong, LIN Bin, and CAO Xiang-qun
For parallelism measurement of large object, a parallelism measuring system which is composed of twodiffraction gratings is devised and established. The two gratings are placed orthogonal, and produce several parallel lines, which can be taken as baselines to measure the parallelism of the object. The picture taken by For parallelism measurement of large object, a parallelism measuring system which is composed of twodiffraction gratings is devised and established. The two gratings are placed orthogonal, and produce several parallel lines, which can be taken as baselines to measure the parallelism of the object. The picture taken by the camera is including the baselines and the object’s lines. Through this picture, it will get the coordinates of the baselines and the object’s lines. By the angle between the baselines, it can correct the angle between the object and the camera. By testing the angle of the large object in the new coordinate system, the parallelism of the object can be gotten. The result indicates that the method is simple with high accuracy..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 61 (2012)
Object Tracking Algorithm Based on Partial Feature Combination
XIA Yu, WU Xiao-jun, and WANG Hong-yuan
In order to avoid the poor robustness based on most of present observation models in small sample space, a particle filter algorithm for visual tracking based on partial feature combination is proposed. Partial features can represent the detail of target template effectively, and can alleviate the affection of object dIn order to avoid the poor robustness based on most of present observation models in small sample space, a particle filter algorithm for visual tracking based on partial feature combination is proposed. Partial features can represent the detail of target template effectively, and can alleviate the affection of object deformation, illumination change and partial occlusion in feature matching. The proposed method employs the idea of mixture of Gaussian and uses multiple modes to represent valid partial observation information. The strategy of fusion is more precise and reliable, thus can overcome the degeneracy problem by new measurement and improve the efficiency of object tracking. The small sample space can reduce quantity of particle and computational load in a certain extent. Experimental results indicate the proposed method is more effective than tracking algorithm with single feature or common multi-features fusion, and it has good performance in complex scene..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 67 (2012)
One Calculational Methods for the Target-missile LOS Angle
QIAO Peng-peng, LI Xiao-bing, and YANG Yu-zhe
In order to calculate the valid effective area of the target through the target-missile Line of Sight (LOS) angle, a calculational method for the target-missile LOS angle was put forward. Firstly, two target-missile LOS angles were defined and described about the mean of the two angles. Then, through analyzing the impaIn order to calculate the valid effective area of the target through the target-missile Line of Sight (LOS) angle, a calculational method for the target-missile LOS angle was put forward. Firstly, two target-missile LOS angles were defined and described about the mean of the two angles. Then, through analyzing the impact of multi-factors to the target-missile LOS angle, a calculational method of the target-missile LOS angle was discovered by using the theory of coordinate conversion. At last, the influence of the missile’s space location, the target’s space location and the target’s three pose angels on two LOS angle was simulated. Simulation results validated the validity of the method. At the same time, the method provides some reference value for the research on the valid effective area of the target and further achieving the target tracking..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 75 (2012)
Decoupling Research and Implementation of Compound-axis
Servo System Using a CCD Detector
WANG Shi-sen, TONG Shou-feng, and SONG Yan-song
The contradiction between large Field of View (FOV)and high frame frequency of detector and the input coupling problems between coarse tracking and fine tracking sub-unit were analyzed in compound-axis servo system using a CCD detector. Smart controller was developed to change the parameters of CCD detector online and The contradiction between large Field of View (FOV)and high frame frequency of detector and the input coupling problems between coarse tracking and fine tracking sub-unit were analyzed in compound-axis servo system using a CCD detector. Smart controller was developed to change the parameters of CCD detector online and the status of CCD detector were changed between large FOV during coarse tracking phase and high frame frequency during fine tracking phase. The output information of PZT driver and miss distance given by CCD detector and image processing unit were synthesized as the control input of the coarse axis sub-unit. What’s more， the control method was simulated，at the same time，a method was presented to estimate the system whether decoupled or not according to the tracking accuracy. The experiment data show that the control methods adopted eliminate the coupling problems of the system and get a good result..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 81 (2012)
Integrating Design of Millimeter Wave and Infrared
Dual-mode Imaging Seeker and Fuze
SU Zhi-mou, JIAN Jin-lei, REN Hong-bin, LONG Zhen-guo, and CHEN Hao
The coordinated efficiency of fuze and warhead can be improved by integrated design of fuze and seeker. On the basis of the merits of the millimeter wave and infrared dual-mode compound detection, one design of Guidance Integrated Fuzing (GIF) is proposed integrating with wave-control fuze. The algorithm flow of the GIThe coordinated efficiency of fuze and warhead can be improved by integrated design of fuze and seeker. On the basis of the merits of the millimeter wave and infrared dual-mode compound detection, one design of Guidance Integrated Fuzing (GIF) is proposed integrating with wave-control fuze. The algorithm flow of the GIF is stated together with the corresponding meeting model. The impact factors of the optimum detonating angle are analyzed together with expression of detonating time-lapse. Finally, the estimated optimum detonating angle and detonating time-lapse respectively based on α-β(GH) and α-β-γ(GHK) filter are contrasted. The simulation results validate the efficiency and applicability of the mentioned two filters. The GH filter suits the missile-target encounter model with low speed and big encounter angle, while GHK filter suits the model with high speed and small encounter angle. The filtered data are precise and are able to provide reliable data for the predicted algorithm of the GIF..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 90 (2012)
Optical Properties of Bi3.45Eu0.55Ti3O12 Ferroelectric Thin Films
RUAN Kai-bin, WU Guang-heng, ZHOU Hong, and WU Yi-bing
Bi3.45Eu0.55Ti3O12 (BEuT) thin films were prepared on quartz substrates by using chemical solution deposition technique, and the structural and optical properties of thin films were studied in this work. XRD results show that BEuT thin films exhibit a polycrystalline bismuth-layered perovskite structure, and the averagBi3.45Eu0.55Ti3O12 (BEuT) thin films were prepared on quartz substrates by using chemical solution deposition technique, and the structural and optical properties of thin films were studied in this work. XRD results show that BEuT thin films exhibit a polycrystalline bismuth-layered perovskite structure, and the average grain sizes increase with increasing annealing temperature. In the wavelength of above 500 nm, BEuT thin films show high optical transmittance, and the band gaps of all samples are nearly about 3.61 eV. The emission spectra of Eu3+ ions indicate that the photoluminescence of BEuT thin films is related to the annealing temperature of samples. The emission intensity firstly increases, reaches a maximum for the sample annealed at 700 ℃, and then decreases, which is related to thecrystallization of BEuT thin films..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 97 (2012)
Vision-based Adaptive Pedestrian Counting
YAO Jin-liang, QIAN Han-bo, and WANG Cheng
Pedestrian counting is recently focused by many researchers in intelligent visual surveillance domain because of its wide applications. A novel method for pedestrian counting is proposed based on the foreground pixels on virtual gate. The proposed method is composed of two processes which are adaptive learning and counPedestrian counting is recently focused by many researchers in intelligent visual surveillance domain because of its wide applications. A novel method for pedestrian counting is proposed based on the foreground pixels on virtual gate. The proposed method is composed of two processes which are adaptive learning and counting. In the learning stage, many pedestrian models in the current scene are firstly extracted using a pedestrian detection method based on HOG, and then these models are used to fit a line which can be used to determine the weight of every point. In the counting stage, we get the foreground pixels on virtual gate as well as their weights, motion vectors at each frame, and the amount of pedestrian passing the virtual gate can be obtained by accumulating all those moving pixels. The experimental results show that our method has real-time performance under the premise of counting precision..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 102 (2012)
[in Chinese]
[in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Since the feature extracted by the basic LBP operator are not complete and can not fully represent the local feature of face, a face recognition algorithm based on block completed local binary pattern is proposed. Firstly, the original face image is divided into small blocks from which the local difference value and ceSince the feature extracted by the basic LBP operator are not complete and can not fully represent the local feature of face, a face recognition algorithm based on block completed local binary pattern is proposed. Firstly, the original face image is divided into small blocks from which the local difference value and central pixel grayscale value are analyzed. Extracting the historgram statistical characteristics of each block by the Su2CLBP (8,2) 、 Mu2 CLBP (8,2) and C operator. Then, the CLBP histograms of all the blocks are linked to get the CLBP feature to be used as the CLBP(8,2) face descriptor. Finally, the classification is performed using a nearest neighbor classifier with Chi square as a dissimilarity measure. Experimental results on ORL、FERET face database show that the proposed algorithm can achieve high face recognition rate up to 99.5%、92% and 98.67%, which are 2.5%、8% and 2.67% higher than the block LBP algorithm. This work demonstrates that the completed LBP feature is complete and highly discriminable and has good performance in the ORL, FERET and YALE face database..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 109 (2012)
Meter Digital Identification on Weighted Hardness Feature Matching
CHEN Hong-yu, ZHOU Hai-feng, and SHAO Gui-fang
Meter digital identification is crucial for intelligent meter application. Current methods have lower recognition ratio at presence of tilt angle and half-digits. In order to solve this problem, the hardness feature parameters are introduced to measure anti-deformation ability on the direction of the projection target Meter digital identification is crucial for intelligent meter application. Current methods have lower recognition ratio at presence of tilt angle and half-digits. In order to solve this problem, the hardness feature parameters are introduced to measure anti-deformation ability on the direction of the projection target area. A number identification method based on the combination of digital structure feature and statistical feature is presented. By analysising different height and different angle of the figures acquired from Meter, the template library of digital top-down and bottom-up hardness characteristics is established. Weights are set according to the different importance of characteristics and the digital recognition is realized by using the method of weighted feature matching algorithm. Experiments prove that the algorithm is simple and efficient to words or words in half and has strong fault-tolerant with rotation and distortion..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 115 (2012)
A Robust Quantization-based Gray Watermarking
Algorithm in Discreet Wavelet Transform Domain
YE Tian-yu
A robust quantization-based gray watermarking algorithm based on discreet wavelet transform is proposed, which respectively inserts the original gray watermark image’s eight bit planes into the eight wavelet sub-bands of corresponding importance from the original cover image through odd-even quantization using proportiA robust quantization-based gray watermarking algorithm based on discreet wavelet transform is proposed, which respectively inserts the original gray watermark image’s eight bit planes into the eight wavelet sub-bands of corresponding importance from the original cover image through odd-even quantization using proportionally decreasing quantization steps. Experimental results show that it has strong robustness towards brightness-and-contrast adjustment, median filter, Gaussian low-pass filter, adding Gaussian noise, adding salt&pepper noise and JPEG compression..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 120 (2012)
Virtual Optical Image Encryption Based on Random Amplitude-phase Encoding
QIN Yi, WANG Hong-juan, WANG Li, YANG Xing-qiang, and LI Gen-quan
A new optical encryption approach, named Random Amplitude-phase Encoding (RAPE), is proposed by replacing one of the random phase plates by random amplitude plate in the Double Random phase Encoding (DRPE) system. First of all, we calculate the autocorrelation function of the encoded image, which indicates that the oriA new optical encryption approach, named Random Amplitude-phase Encoding (RAPE), is proposed by replacing one of the random phase plates by random amplitude plate in the Double Random phase Encoding (DRPE) system. First of all, we calculate the autocorrelation function of the encoded image, which indicates that the original image has been transformed to complex-amplitude stationary white noise. So this method leads to robustness against blind deconvolution. Then, computer simulations are carried out and the validity of the method is verified. At last, compared with the DRPE, some properties of this method are discussed. RAPE scheme has lower requirements for secret keys and behaves more robustly against partial key exposure attack. Nevertheless, we also point out that this system could only be realized by virtual optics..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 126 (2012)
A Dimming Method for LED Based on Two Channels’ PWM
WANG Ji-yong, and WANG Jian-ping
To realize dynamic lighting of LED, a dimming method based on two channels’ Pulse Width Modulation (PWM) and light-mixing technology was presented. According to the analysis on geometrical, photometric, colorimetric and electrodynamic constraints, the determinacy and limitation of two channels’ PWM dimming for realizinTo realize dynamic lighting of LED, a dimming method based on two channels’ Pulse Width Modulation (PWM) and light-mixing technology was presented. According to the analysis on geometrical, photometric, colorimetric and electrodynamic constraints, the determinacy and limitation of two channels’ PWM dimming for realizing Expected Photometric and Colorimetric Quantities (EPCQ) were demonstrated, and a quantitative model was established, which mapped the EPCQ into duty cycles. To examine the model, a light-mixing experiment with two kinds of white LED simulated variations of illuminance and correlation color temperature from dawn to midday. Mean deviations between theoretical values and measured values were obtained, which were 15 lx and 23 K respectively. Result shows that this method can effectively realize the light spectrum which has a specific requirement of EPCQ..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 132 (2012)
Design of Large Aperture Focal Plane Shutter
HU Jia-wen, MA Wen-li, and HUANG Jin-long
To satisfy the requirement of large telescope, a large aperture focal plane shutter with aperture size of φ200 mm was researched and designed, which could be started and stopped in a relative short time with precise position. Moreover, the blades could open and close at the same time at any orientation. Timing-belts anTo satisfy the requirement of large telescope, a large aperture focal plane shutter with aperture size of φ200 mm was researched and designed, which could be started and stopped in a relative short time with precise position. Moreover, the blades could open and close at the same time at any orientation. Timing-belts and stepper motors were adopted as the drive mechanism. Velocity and position of the stepper motors were controlled by the pulse generated by Digital Signal Processor (DSP). Exponential curve is applied to control the velocity of the stepper motors to make the shutter start and stop in a short time. The closing/open time of shutter is 0.2 s, which meets the performance requirements of large telescope properly..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 137 (2012)
A New Type of Large Dynamic Range of CCD Camera
Video Signal Processing Circuits
CHEN Zhi, QIU Yue-hong, WEN Yan, JIANG Bao-tan, and YAO Da-lei
Contemporary CCD especially the scientific grade CCD dynamic range is up to 100,000 electrons, and even capacity over 100,000 electrons. In order to take full advantage of these characteristics, it is necessary that the dynamic range of Analog-to-Digital Converter (ADC) must exceed the dynamic range of the CCD. The numContemporary CCD especially the scientific grade CCD dynamic range is up to 100,000 electrons, and even capacity over 100,000 electrons. In order to take full advantage of these characteristics, it is necessary that the dynamic range of Analog-to-Digital Converter (ADC) must exceed the dynamic range of the CCD. The number of bits provided bythe ADC must exceed 16 bits, while the high reliability and inexpensive 18～20 bit A/D converter is few. Firstly, we analyze CCD noise, and then the principle to extend the dynamic of the CCD in signal processing chain is presented using two low resolution ADC with different sensitivity. Then, we present a concrete example of improving the resolution of the ADC by two parallel low resolution ADCs. Finally, the laboratory imaging test results show that two low-resolution ADCs are used by combining raw quantization with fine quantization to achieve a high resolution, and improve the dynamic range of CCD camera..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 141 (2012)
Modeling Analysis and Verification of LSF for a Midwave Infrared Panoramic Imaging Sensor
ZHANG Jing, WANG Shu-rong, XUE Qing-sheng, and HUANG Yu
Panoramic imaging sensor operating in the Midwave Infrared (MWIR) band is an important new imaging sensor for maritime research and application. Line Spread Function (LSF) is one of the key parameters to quantitatively evaluate the image quality. The modeling analysis and testing of LSF are important for developing an Panoramic imaging sensor operating in the Midwave Infrared (MWIR) band is an important new imaging sensor for maritime research and application. Line Spread Function (LSF) is one of the key parameters to quantitatively evaluate the image quality. The modeling analysis and testing of LSF are important for developing an imaging sensor. In the present paper, the spectral radiation observed at the focal plane array of the panoramic imaging system is analyzed. The LSF of the panoramic imaging system is theoretically evaluated and tested through canted slit-method. The test results have proved the correctness of this theoretical model. The modulation transfer function is calculated by discrete Fourier transform for LSF. Results match the system theoretical MTF well, which indicates that LSF modeling analysis method is feasible..
Opto-Electronic Engineering
- Publication Date: Jan. 01, 1900
- Vol. 39, Issue 7, 146 (2012)
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