中国科学院机构知识库网格系统: 检索

Design of high speed and parallel compression system used in the big area CCD of high frame frequency (EI CONFERENCE) 会议论文 OAI收割
2011 International Conference on Precision Engineering and Non-Traditional Machining, PENTM 2011, December 9, 2011 - December 11, 2011, Xi'an, China
作者: Li G.-N.; Jin L.-X.; Zhang R.-F.; Wang W.-H.; Li G.-N.

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According to the area CCD camera of characteristics such as high resolution capacity and high frame frequency this paper puts forward a high speed and parallel image compression system of high integration degree. Firstly according to the work principle of the area CCD FPGA is adopted to realize the timing driving and multichannel and parallel analog signal handling to raise the export frame frequency of the area CCD. Secondly with an image compression scheme based on FPGA embedded processor MicroBlaze and ADV212 compression chip real time image compression and the high speed area CCD are realized. Finally by detecting the analog signal of the area CCD output the real time compression of the big area CCD image is carried out in different compression ratios and the compression performance is analyzed. Experiment result shows that this scheme can realize real time image compression with the biggest data rate of 520Mbps. When compression bit ratio is 0.15 the signal-to-noise ratio of peak value can reach 36 dB. Image collection and image compression are integrated which reduces the data transmission between them and improves systematic integration degree.

The research on statistical properties of TDI-CCD imaging noise (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Gu Y.-Y.; Shen X.-H.; He G.-X.

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TDI-CCD can improve the sensitivity of space camera without any degradation of spatial resolution which is widely used in aerospace imaging devices. The article describes the basic working principle and application characteristics of TDI-CCD devices analyses the composition of TDI-CCD imaging noise and propose a new method to analyze TDI-CCD imaging noise with statistical probability distribution. In order to estimate the distribution of gray values affect by noise we introduced the concept of skewness and kurtosis. We design an experiment using constant illumination light source take image with TDI-CCD working at different stage such as stage 16 stage 32 stage 48 stage 64 and stage 96 analyse the characteristics of image noise with the method we proposed experimental results show that the gray values approximately meet normal distribution in large sample cases. 2011 SPIE.

Study on spectrograph for ionosphere: A broadband imaging instrument prototype for far-ultraviolet (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Space Exploration Technologies and Applications, May 24, 2011 - May 26, 2011, Beijing, China
作者: Wang S.-R.; Lin G.-Y.; Yu L.

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Current research on space-based exploration for the ionosphere needs more advanced technologies. Because the spectral signals in the ionosphere distributing basically in the far-ultraviolet waveband are very weak. Usual spectrometer structures and detectors such as CCD can't receive enough information. Based on this principle of atmospheric sounding the imaging spectrometer prototype for ionosphere detection application was designed to solve the problem. This prototype consists of the telescope and the imaging spectrometer. The simple structure and small number of mirrors can help higher transmission efficiency be achieved and weak signals detection be implemented. The telescope is an off-axis parabolic mirror and the spectrometer is a modified Czerny-Turner spectral imaging system. Modified Czerny-Turner spectrometer contains a spherical mirror a fixed plane grating and a toroidal mirror. By adjusting the incident angle to the collimating mirror and using toroidal mirror coma and astigmatism were corrected well. We also optimize distances between the grating to the focusing mirror and the focusing mirror to the image plane to improve disadvantages of traditional Czerny-Turner structure. Designed results demonstrate that aberrations are substantially corrected and high image quality can be obtained in broad waveband. The photon counting Wedge-Strip-Anode detector with micro-channel planes as the receiving plane is accepted for the instrument prototype. The other photon counting 2-D detector responding well for weak light such as Cross-Delay line detector and MAMA detector can also be used for detection. The calibration and performances testing system is made of a vacuum system a deuterium lamp a monochrometer and the instrument prototype. Results obtained from the experiment show that the spectral resolution is 2.4 nm and the spatial resolution is 80 m. The other calibration experiments are running. The technology of the spectrometer prototype is important for the research and applications of ionosphere remote sensing. 2011 SPIE.

The imaging system design of three-line LMCCD mapping camera (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
作者: Zhao Y.; Yu D.; Yu D.; Zhao Y.; Zhao Y.

收藏 | 浏览/下载：17/0 | 提交时间：2013/03/25

In this paper the SNR tested in laboratory is better than 95 under typical working condition(the solar incidence degree is 30 the temperature of the focal plane module is controlled under 30 in a working period of 15 minutes. All of these results can satisfy the requirements about the synchronous photography the authors introduced the theory about LMCCD (line-matrix CCD) mapping camera firstly. On top of the introduction were consists of the imaging system of LMCCD mapping camera. Secondly the photography interval of line-matrix CCD of the nadir camera can satisfy the butter requirements of LMCCD focal plane module the reflectivity of the earth's surface is 0.3) of each CCD image the temperature control of focal plane module and SNR some pivotal designs which were Introduced about the imaging system Which give the guarantee of precision for satellite photogrammetry. 2011 SPIE. such as the design of focal plane module the video signal's procession the controller's design of the imaging system synchronous photography about forward and nadir and backward camera and the nadir camera of line-matrix CCD. At last the test results of LMCCD mapping camera imaging system were introduced. The results as following: the precision of synchronous photography about forward and nadir and backward camera is better than 4 ns and the nadir camera of line-matrix CCD is better than 4 ns too

Noise processing technology of a TDICCD sensor (EI CONFERENCE) 会议论文 OAI收割
2010 International Conference on Computer, Mechatronics, Control and Electronic Engineering, CMCE 2010, August 24, 2010 - August 26, 2010, Changchun, China
作者: Zhang L.-P.

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In the application of TDI-CCD the other is all kinds of interference noise produced in the working process of a TDI-CCD for reset noise because of its serious noise interference such as reset noise and 1 / f noise correlated double sampling is employed. The experimental results show that after noise processing the imaging quality is reduced etc. According to the features of noise the output S/N has been raised to about 50 dB. 2010 IEEE. so that it is necessary to study the noise characteristics of TDI-CCD. There are two categories of noise this paper has studied the corresponding noise-processing technology. For dark current noise one is the inherent noise refrigeration is taken including shot noise dark current noise fixed pattern noise and transfer noise etc.

Research on automatic multispectral images synthesis of space camera (EI CONFERENCE) 会议论文 OAI收割
Optoelectronic Imaging and Multimedia Technology, October 18, 2010 - October 20, 2010, Beijing, China
作者: Liu J.-G.; Wu X.-X.; Kong D.-Z.; Zhou H.-D.

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Multilinear CCD Sensor was often used on space cameras to obtain multispectral images with each line representing different band channels. However images of different band channels obtained at the same time didn't coincide as there were spaces between lines. Pixel numbers to be adjusted between images of different channels varied when the space camera worked by swaying forward and backward or adjusted row transfer period to compensate image movement. An automatic multispectral images synthesis algorithm of space camera was put forward on the basis of analysis of such phenomenon. In this algorithm a new evaluation function was used to determine pixel numbers to be adjusted and the image regions of each band channel to be clipped. In this way images of different band channels could be synthesized automatically to obtain an accurate colorful image. This algorithm can be used to dispose a large mount of images from space camera directly without any manual disposal so that efficiency could be improved remarkably. In validation experiments the automatic multispectral images synthesis algorithm was applied in synthesis of images obtained from outside scene experiment of a multispectral space camera. Result of validation experiments proved that the automatic multispectral images synthesis algorithm can realize accurate multispectral images synthesis of space camera and the efficiency can be improved markedly. 2010 SPIE.

Development and radiance calibration of three-waveband camera (EI CONFERENCE) 会议论文 OAI收割
International Symposium on Photonics and Optoelectronics, SOPO 2010, June 19, 2010 - June 21, 2010, Chengdu, China
作者: Wang J.; Liu Y.; Liu Y.; Sun Q.; Liu Y.

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An imaging system with three-waveband sharing one lens and an area CCD was developed. By rotating different filters into the beam path the required waveband was selected. The optical system which can image in ultraviolet visible and near infrared region was designed and the signal collecting system was integrated. The optical design and system integration have some advantages such as low cost small size and light in weight. To obtain a high imaging quality the radiation calibration is carried out in order to establish the relation between the average grey level of output image and the input radiance from the integrating sphere. According to the calibration data in experiments the radiation dynamic range and the best working point of the system are determined. The experiment result shows that the dynamic range of the image system is maximal when the exposure time is 8ms in ultraviolet 0.5ms in visible and 0.125ms in near infrared region. 2010 IEEE.

Driving techniques for high frame rate CCD camera (EI CONFERENCE) 会议论文 OAI收割
Electronic Imaging and Multimedia Technology V, November 12, 2007 - November 15, 2007, Beijing, China
Guo W.; Jin L.; Xiong J.

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This paper describes a high-frame rate CCD camera capable of operating at 100 frames/s. This camera utilizes Kodak KAI-0340 an interline transfer CCD with 640(vertical)480(horizontal) pixels. Two output ports are used to read out CCD data and pixel rates approaching 30 MHz. Because of its reduced effective opacity of vertical charge transfer registers interline transfer CCD can cause undesired image artifacts such as random white spots and smear generated in the registers. To increase frame rate a kind of speed-up structure has been incorporated inside KAI-0340 then it is vulnerable to a vertical stripe effect. The phenomena which mentioned above may severely impair the image quality. To solve these problems some electronic methods of eliminating these artifacts are adopted. Special clocking mode can dump the unwanted charge quickly then the fast readout of the images cleared of smear follows immediately. Amplifier is used to sense and correct delay mismatch between the dual phase vertical clock pulses the transition edges become close to coincident so vertical stripes disappear. Results obtained with the CCD camera are shown.

Application of CMOS APS star tracker with large FOV in attitude and angular velocity determination (EI CONFERENCE) 会议论文 OAI收割
Advanced Sensor Systems and Applications III, November 12, 2007 - November 14, 2007, Beijing, China
Lu D.; Guang J.; Shaoju W.; Tao C.

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The paper deals with the spacecraft attitude determination problem using a new kind of star tracker with large FOV based on CMOS APS. Star tracker has been developed since 1970s and proved to be the most accurate sensor ever used in the spacecraft attitude determination systems. But the traditional CCD star tracker also has some disadvantages such as small FOV high power consumption low sample rate and low working angular rate limit which prevent the use of CCD star tracker in attitude large angle maneuvering process. The new kind of star tracker based on CMOS APS has no such disadvantages and is more applicable on modern low-cost agile small satellites. Its higher sample rate and working angular rate limit over traditional CCD star tracker make it more adapt for spacecraft angular velocity determination. Because of the large FOV of the star tracker the mathematical model of traditional CCD star tracker with a small FOV is not appropriate. So a new mathematical model was quoted to fit the star tracker with a large FOV. An alternative adaptive algorithm was also introduced in the paper. It can help the EKF algorithm work lacking of accurate covariance of the observation noise. An optimal estimation algorithm was used to estimate the angular velocity directly from the star tracker measurements. Mathematic simulation results indicate the CMOS APS star tracker can give accurate attitude information and estimated angular rate. The method can be used as the chief attitude determination system design of low-cost satellite without gyros or be used as a backup strategy in the event of gyro failures to enhance the reliability of the attitude determination system.

Chip design of linear CCD drive pulse generator and control interface (EI CONFERENCE) 会议论文 OAI收割
2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies - Advanced Optical Manufacturing and Testing Technologies, November 2, 2005 - November 5, 2005, Xian, China
作者: Sun H.; Wang Y.; Wang Y.; Wang Y.; Wang Y.

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CCD noises and their causes are analyzed. Methods to control these noises such as Correlated Double Sampling (CDS) filtering cooling clamping and calibration are proposed. To improve CCD sensor's performances the IC called Analog Front End (AFE) integration of CDS clamping Programmable Gain Amplifier (PGA) offset and ADC which can fulfill the CDS and analog-to-digital conversion is employed to process the output signal of CCD. Based on the noise control approaches the idea of chip design of linear CCD drive pulse generator and control interface is introduced. The chip designed is playing the role of (1) drive pulse generator for both CCD and AFE and (2) interface helping to analysis and transfer control command and status information between MCU controller and drive pulse generator or between global control unit in the chip and CCD/AFE. There are 6 function blocks in the chip designed such as clock generator for CCD and AFE MCU interface AFE serial interface output interface CCD antiblooming parameter register and global control logic unit. These functions are implemented in a CPLD chip Xilinx XC2C256-6-VQ100 with 20MHz pixel frequency and 16-bit high resolution. This chip with the AFE can eliminate CCD noise largely and improve the SNR of CCD camera. At last the design result is presented.