中国开放科研知识云: 检索

Study on the calculation and application for asphericity of rectangle off-axis aspherics (EI CONFERENCE) 会议论文
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, November 19, 2008 - November 21, 2008, Chengdu, China
Li J.-F.; Xuan B.; Wang P.; Chen X.-P.; Zhang H.; Xie J.-J.; Song S.-M.

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Asphericity which affects the manufacturing process and the grinding quantity is an important parameter of optical aspherics. In this paper the approximation the least square fitting wavefront aberration sag methods are given for the calculation of optical asphericity. The effects of different definitions of optical asphericity are analysed to optimize the process of manufacture. A sag method is presented to solve the best-fit sphere and asphericity for an off-aixs aspheric mirror with a rectangle aperture of 180mm145mm and polishing quantity and distribution plots are given. The optical manufacturing and testing technology for different choices of best-fit spheres and asphericity are described and analyzed. Therefore proper definition of optical asphericity which is useful to manufacturing is very important for optical fabrication and test. 2009 SPIE.

Alignment of off-axis asphere and compensator with four poles (EI CONFERENCE) 会议论文
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, November 19, 2008 - November 21, 2008, Chengdu, China
Xuan B.; Chen X.; Wang P.; Li J.; Song S.; Chen Y.; Xie J.

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Aspheres are utilized widely thanks to the development of optical design manufacture and testing. Compensators are usually necessary when aspheres are under test. The alignment of aspheres and their compensators is a risk because it's tough to check whether the compensators work in right way. A new method of alignment with four poles is put forward in this paper. Optical interval error can be tight while it is quite important due to direct influence on central curvature conic constant and high order coefficients of aspherical surface. A modified on-axis Foucault apparatus is set up since it makes the optical axis visible and helps to control the error of off-axis amount. Some small holes are drilled in the metallic cell of the compensator so that the ends of poles can be stably relied on in order to increase operational repeatability. The method has been carried out practically and it matches the measurement result given by a set of theodolites. 2009 SPIE.

Micro-motion exposure method based on PZT piezoelectric ceramics (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2009: Material and Device Technology for Sensors, June 17, 2009 - June 19, 2009, Beijing, China
Sun W.-J.; Zhang M.-H.; Meng Z.

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There mainly is laser digital photofinishing technique and digital photofinishing technique based on LCD consisting of TFT and LCOS in the digital photofinishing field at the present time. The former have a good many merit such as wide color gamut high processing rate large output size and high brightness but his cost is very high his maintain technique being comparatively complex that result in difficult use for people. The utilization ratio of the latter is low because of lower resolution and lower aperture ratio for LCD but the digital photofinishing based on LCD have lower cost and higher utilization ration being suitable for people's current standard of living. Considering above mentioned problem a micro-motion exposure method based on PZT piezoelectric ceramics used in digital image photofinishing is presented. The two-dimension micro-motion exposure system consisting of PZT piezoelectric ceramics LCD panel polarizing film and spring strip is designed. By means of PZT piezoelectric ceramics the LCD panel is removed about the one half of the pixel size of the LCD panel for four times from the original place at the same time imaging system is exposed four times at the printing paper. The software is used to control the time synchronization the exposure time and motion range of the LCD panel. The system has advantages such as shorter response time than 0.1seconds lesser motion error than 0.01 microns high stability and repeatability. Experimental results show that the proposed micro-motion exposure method improve the picture brightness and enlarge output size at the meantime reducing the cost of the system. 2009 SPIE.

Real-time motive vehicle detection with adaptive background updating model and HSV colour space (EI CONFERENCE) 会议论文
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, November 19, 2008 - November 21, 2008, Chengdu, China
Rong-Hui Z.; Bai Y.; Hong-guang J.; Chen T.

收藏 | 浏览/下载：57/0 | 提交时间：2013/03/25

In the transportation monitor system we set up the area of interest (AOI) of the vehicle model and adjust the size of AOI dynamically in order to track vehicle accurately. The results of experiment show that motive vehicle detection by adopting digital image is one of key technologies. To detect motive vehicle accurately the arithmetic proposed in the paper can suppress shadow availably we establish an adaptive background updating model firstly. Noise is suppressed by using modality filter detect motive vehicle accurately and satisfy real-time motive vehicle tracking. 2009 SPIE. and we obtain binary image by using maximum entropy to choose dynamic adaptive threshold. Based on positive information of shadow and aspect feature of motive vehicle we adopt HSV colour space and double threshold to solve the problem of vehicle shadow. According to prediction result of Kalman filtering

Level 0 and level 1 data processing for a type of hyper-spectral imager (EI CONFERENCE) 会议论文
2009 International Conference on Optical Instruments and Technology, OIT 2009, October 19, 2009 - October 21, 2009, Shanghai, China
Li X.; Yan C.

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Hyper-spectral imaging (HSI) is a kind of optical remote sensor that can simultaneously obtain spatial and spectral information of ground targets. We are now designing a data processing system for a type of space-borne push-broom HSI then it performs radiometric and spectral calibration based on the ground calibration results and onboard calibration collection. The detailed algorithms for bad pixel replacement which has 128 spectral channels covering the spectral range from 400nm to 2500nm. With its large amount of spectral channels radiometric and spectral calibration were presented. After processing the HSI collects large volume of spectral imaging data need to be efficiently and accurately processed and calibrated. In this paper the digital numbers downlinked from the spacecraft can be converted into at-sensor absolute spectral radiance of ground targets the detailed Level 0 and Level 1 data processing steps for the HSI were presented. The Level 0 processing refers to a set of tasks performed on the data downlinked from the spacecraft thus providing accurate quantified spectral imaging data for various applications. 2009 SPIE. including decoding to extract science data separating the science data into files corresponding to different tasks (e.g. ground imaging dark imaging and onboard calibration) checking data integrity and instrument settings data format conversion and Level 0 files creation. The Level 1 processing performs several steps on Level 0 data. Firstly it corrects the image artifacts (mostly the SWIR smear effect) subtracts the dark background and performs the bad pixel replacement according to the prelaunch measurement

Multiresolution animated models generation based on deformation distance analysis (EI CONFERENCE) 会议论文
2009 International Conference on Computer Modeling and Simulation, ICCMS 2009, February 20, 2009 - February 22, 2009, Macau, China
Shixue Z.; Enhua W.

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In computer graphics animated models have been widely used to represent time-varying data. Reducing the models complexly is a common way to overcome the rendering limitations. In this paper 2009 IEEE. we propose an efficient method for generating multiresolution animated models based on deformation distance analysis. Our method obtains different LOD models by performing iterative edge contraction operations. We use deformation distance to analysis the deformation degree of the triangle planes during the whole animation and define a deformation weight to be added to the aggregated edge contraction cost. Thus features in areas with large deformation can be preserved well. Besides we propose a mesh optimization method for dynamic model sequence which can efficiently improve the temporal coherence and reduce visual artifacts between adjacent frames. The results show our approach is efficient easy to implement and good quality animated approximations with well-preserved fine details can be generated at any given frame. copy

Blind channel estimation of MIMO-OFDM based on FDPM (EI CONFERENCE) 会议论文
5th International Conference on Wireless Communications, Networking and Mobile Computing, WiCOM 2009, September 24, 2009 - September 26, 2009, Beijing, China
Gang W.; Ming Z.; Hua C.

收藏 | 浏览/下载：12/0 | 提交时间：2013/03/25

Subspace based methods have been widely discussed in multichannel estimation including MIMO-OFDM system. However direct subspace methods suffer from heavy computation complexity y of O(N3). In this paper a new subspace tracking technique called Fast Data Projection Method (FDPM) is proposed for adaptively tracking the noise subspace. The new algorithm has low complexity of O(NL) and is the only numerically stable low complexity algorithm for tracking subspaces corresponding to the smallest singular values. Simulation results show that the proposed scheme has similar performance to the original. 2009 IEEE.

Graph fitting test method for the interpolation error of Moire fringe (EI CONFERENCE) 会议论文
9th International Conference on Electronic Measurement and Instruments, ICEMI 2009, August 16, 2009 - August 19, 2009, Beijing, China
Wan Q.; Sun Y.; She R.; Liang L.; Lu X.; Du Y.

收藏 | 浏览/下载：22/0 | 提交时间：2013/03/25

Analysis of laser jamming to satellite-based detector (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2009: Laser Sensing and Imaging, June 17, 2009 - June 19, 2009, Beijing, China
Wang S.-W.; Guo L.-H.; Guo R.-H.

收藏 | 浏览/下载：16/0 | 提交时间：2013/03/25

The reconnaissance satellite communication satellite and navigation satellite used in the military applications have played more and more important role in the advanced technique wars and already become the significant support and aid system for military actions. With the development of all kinds of satellites anti-satellite laser weapons emerge as the times require. The experiments and analyses of laser disturbing CCD (charge coupled detector) in near ground have been studied by many research groups but their results are not suitable to the case that using laser disturbs the satellite-based detector. Because the distance between the satellite-based detector and the ground is very large it is difficult to damage it directly. However the optical receive system of satellite detector has large optical gain so laser disturbing satellite detector is possible. In order to determine its feasibility the theoretical analyses and experimental study are carried out in the paper. Firstly the influence factors of laser disturbing satellite detector are analyzed in detail which including laser power density on the surface of the detector after long distance transmission and laser power density threshold for disturbing etc. These factors are not only induced by the satellite orbit but dependence on the following parameters: laser average power in the ground laser beam quality tracing and aiming precision and atmospheric transmission. A calculation model is developed by considering all factors which then the power density entering into the detector can be calculated. Secondly the laser disturbing experiment is performed by using LD (laser diode) with the wavelength 808 nm disturbing CCD 5 kilometer away which the disturbing threshold value is obtained as 3.5510-4mW/cm2 that coincides with other researcher's results. Finally using the theoretical model the energy density of laser on the photosensitive surface of MSTI-3 satellite detector is estimated as about 100mW/cm2 which is largely exceed the disturbing threshold and therefore verify the feasibility of using this kind of laser disturbing the satellite-based detector. According to the results. using the similar laser power density absolutely saturate the requirements to laser disturbing satellite-based detector. If considering the peak power of pulsed laser even decrease laser average power it is also possible to damage the detector. This result will provide the reliable evidences to evaluate the effect of laser disturbing satellite-based detector. 2009 SPIE.

Study on the influence and disposal method of the micro-cracks of optical components (EI CONFERENCE) 会议论文
4th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Advanced Optical Manufacturing Technologies, November 19, 2008 - November 21, 2008, Chengdu, China
Chen X.-P.; Xuan B.; Wang P.; Li J.-F.; Song S.-M.; Zhang H.; Xie J.-J.

收藏 | 浏览/下载：21/0 | 提交时间：2013/03/25

Micro-crack is one of the most effective factor to the intensity and service life of optical components. Owing to the micro-crack on surface actual strength of optical components is reduced severely even less than ten-percent of its theoretical strength. According to fracture mechanics the mechanisms of the formation and propagation of micro-crack and the growth theory of sub-critical micro-crack are discussed in the paper firstly. Based on practice an on-line test method disposing etching holes-the molecule-infiltrating method and the principles of acid-etching method disposing micro-crack are described. Followed by the demolishing mechanism of abrasives and a more reasonable removal redundancy of fine-grinding and polishing during optical production is given by using abrasives in different-size orderly. 2009 SPIE.

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