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A servo control system of dynamic target simulation device for aerial camera (EI CONFERENCE) 会议论文
2nd International Conference on Advanced Design and Manufacturing Engineering, ADME 2012, August 16, 2012 - August 18, 2012, Taiyuan, China
Ji Q.
收藏  |  浏览/下载：22/0  |  提交时间：2013/03/25
The imaging system design of three-line LMCCD mapping camera (EI CONFERENCE) 会议论文
International Symposium on Photoelectronic Detection and Imaging 2011: Advances in Imaging Detectors and Applications, May 24, 2011 - May 26, 2011, Beijing, China
Zhou H.-D.; Liu J.-G.; Wu X.-X.; Lv S.-L.; Zhao Y.; Yu D.
收藏  |  浏览/下载：11/0  |  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  
Research on radiometric calibration of interline transfer CCD camera based on TDI working mode (EI CONFERENCE) 会议论文
5th International Symposium on Advanced Optical Manufacturing and Testing Technologies: Optical Test and Measurement Technology and Equipment, April 26, 2010 - April 29, 2010, Dalian, China
Wu X.-X.; Liu J.-G.
收藏  |  浏览/下载：18/0  |  提交时间：2013/03/25
Interline transfer CCD camera can be designed to work in time delay and integration mode similar to TDI CCD to obtain higher responsivity and spatial resolution under poor illumination condition. However it was found that outputs of some pixels were much lower than others' as interline transfer CCD camera work in TDI mode in laboratory radiometric calibration experiments. As a result photo response non-uniformity(PRNU) and signal noise ratio(SNR) of the system turned for the worse. This phenomenon's mechanism was analyzed and improved PRNU and SNR algorithms of interline transfer CCD camera were advanced to solve this problem. In this way TDI stage was used as a variant in PRNU and SNR algorithms and system performance was improved observably with few influences on use. In validation experiments the improved algorithms was applied in radiometric calibration of a camera with KAI-0340s as detector. Results of validation experiments proved that the improved algorithms could effectively improve SNR and lower PRNU of the system. At the same time characteristic of the system could be reflected better. As working in 16 TDI stages  PRUN was reduced from 2.25% to 0.82% and SNR was improved about 2%. 2010 Copyright SPIE - The International Society for Optical Engineering.  
Phase error estimation with broadband white light by Phase Diversity (EI CONFERENCE) 会议论文
6th International Symposium on Precision Engineering Measurements and Instrumentation, August 8, 2010 - August 11, 2010, Hangzhou, China
Wu Y.; Wang B.; Wang Z.; Cao J.; Zhang X.
收藏  |  浏览/下载：12/0  |  提交时间：2013/03/25
The technique of Phase Diversity (PD) is widely adopted to measure the wavefront error caused by atmosphere turbulence and system error. PD solves the Zernike coefficients of the wavefront by utilizing two images obtained with different defocus value. In this paper  we propose a method to restore the image and estimate the wavefront error of an imaging system. And we use present white noises to verify the robustness of the algorithm. We design an experiment system and implement it in our laboratory. The proposed algorithm is validated by computer simulations and experimental results. To use a broadband white object in experimental system a reasonable simplification for the system model is done. Our results show that the robustness against Gaussian white noises of the method is better then the case when the variance value is 0.03. The proposed method can be used as a wavefront sensor and restore the degradative images by photoelectric image system. 2010 SPIE.  
Research on the support structure of the primary mirror of large-aperture telescope (EI CONFERENCE) 会议论文
3rd International Symposium on Advanced Optical Manufacturing and Testing Technologies, AOMATT 2007: Large Mirrors and Telescopes, July 8, 2007 - July 12, 2007, Chengdu, China
Yang W.; Jingxu Z.
收藏  |  浏览/下载：22/0  |  提交时间：2013/03/25
Large-aperture telescope can be used in surveying battlefield  researching landform  searching object  real-time monitoring  imaging  detecting and identifying spatial targets and so on. A large-aperture telescope for achieving high resolution power is designed to monitor spatial target and image in real time. Real-time monitoring plays an important role in military conflicts. The orbit parameter of object  quantity  geometrical shape parameter and so on can be obtained by detect spatial target. With the development of optical technology  people require larger aperture in optics-electronic (OE) system. By increasing optical aperture  the ability of collecting light and resolution power in the system can be enhanced. But the support structure of the primary mirror of large-aperture telescope will be a very difficult problem. With the increase of primary mirror aperture  the weight of the primary mirror will become larger than before. The root mean square (rms) of the primary mirror is affected by many factors  such as deadweight  deformation of heat  environment and so on. Due to the primary mirror of telescope is an important component of telescope system. By reducing the weight of primary mirror  precision of the system is ensured. During the designing phase  one can consider the supporting project of the primary mirror synthetically and analyze it roundly according to technical requirement of optical system and the effect factors. The final structural design can be reasonable. In an astronomical telescope  the surface of reflector is an important part for collecting dark radiation of celestial bodies. Its surface shape will have an effect on collecting efficiency of telescope radiant energy directly. So the rms must be very high. Optical system of large aperture  small wavelength and small focus can receive maximal light intensity. For ground-based optical astronomical telescope  the design proposed in the paper can satisfy the requirement of the possible minimum atmosphere seeing at astronomical observatory site and exert the use efficiency of the telescope adequately. So the accuracy of the traditional surface of reflector can assure that 90% of all the light energy can be focused on within the angle diameter range of the minimum atmosphere seeing  then 100% of light energy should be focused on the angle diameter range of minimum atmosphere seeing. Because the rms of mirror is very high  precise surface machining and accurate the support of mirror are very important tasks during designing and manufacturing the telescope. In the paper  various support techniques of a large-aperture telescope primary mirror are discussed and a 3.5 meter telescope system at the Starfire Optical Range (SOR) overviewed simply  which was operated by the Directed Energy Directorate of the Air Force Research Laboratory  Kirtland AFB  NM  USA from the ground-based O-E system for the observations of spatial target. We also analyze Theoretical elastic deformation of the Steward Observatory 2.3 meter mirror is analyzed.  
Support technique of ultra thin mirror in space optics (EI CONFERENCE) 会议论文
2nd International Symposium on Advanced Optical Manufacturing and Testing Technologies: Large Mirrors and Telescopes, November 2, 2005 - November 5, 2005, Xian, China
Gao M.-H.; Ren J.-Y.
收藏  |  浏览/下载：28/0  |  提交时间：2013/03/25
With the development of space optical system  the technique of ultra thin mirror come forth and is paid more attention because of less difficulty in machining  low cost  lightweight  no disassembly during detecting and maintaining. The key technique takes advantage of deformation of ultra thin mirror as the influence of environment to adjust the surface figure. Its accuracy meets requirement. An analysis method is based on finite element analysis (FEA)  and many items  including the amount of support points  the way of arrangement  the optimum design of support component are studied. The finite element method was used to analyze the mirror and some different mirror support schemes. The principal aim of the mirror analysis is to get numbers of support points and the ways of the support. There are three schemes including 12-6-1  12-8-1 and 16-8-1 models. Deformation of deadweight is calculated under the three conditions. The way of 16-8-1 is more suitable than the designs of other two. The support subassembly is amended to meet with the mirror surface RMS in the range of 30m. Deformation of the mirror with support structure has been calculated. The result is 16.52nm  lower than a quarter of the wavelength  which indicates the feasibility of the support scheme applied to mirror. Theoretical result for the best way of support is presented. The result of analysis shows that requirement surface figure could be met through adjusting support points. It predicts feasibility of the support technique and provides theoretical value for active adjustment in the laboratory. At present  support and adjusting experiment of ultra thin mirror is being carried on.  
Intelligent MRTD testing for thermal imaging system using ANN (EI CONFERENCE) 会议论文
ICO20: Remote Sensing and Infrared Devices and Systems, August 21, 2005 - August 26, 2005, Changchun, China
Sun J.; Ma D.
收藏  |  浏览/下载：18/0  |  提交时间：2013/03/25
The Minimum Resolvable Temperature Difference (MRTD) is the most widely accepted figure for describing the performance of a thermal imaging system. Many models have been proposed to predict it. The MRTD testing is a psychophysical task  for which biases are unavoidable. It requires laboratory conditions such as normal air condition and a constant temperature. It also needs expensive measuring equipments and takes a considerable period of time. Especially when measuring imagers of the same type  the test is time consuming. So an automated and intelligent measurement method should be discussed. This paper adopts the concept of automated MRTD testing using boundary contour system and fuzzy ARTMAP  but uses different methods. It describes an Automated MRTD Testing procedure basing on Back-Propagation Network. Firstly  we use frame grabber to capture the 4-bar target image data. Then according to image gray scale  we segment the image to get 4-bar place and extract feature vector representing the image characteristic and human detection ability. These feature sets  along with known target visibility  are used to train the ANN (Artificial Neural Networks). Actually it is a nonlinear classification (of input dimensions) of the image series using ANN. Our task is to justify if image is resolvable or uncertainty. Then the trained ANN will emulate observer performance in determining MRTD. This method can reduce the uncertainties between observers and long time dependent factors by standardization. This paper will introduce the feature extraction algorithm  demonstrate the feasibility of the whole process and give the accuracy of MRTD measurement.  
Research on the radiometric calibration of TDI CCD remote camera (EI CONFERENCE) 会议论文
ICO20: Illumination, Radiation, and Color Technologies, August 21, 2005 - August 26, 2005, Changchun, China
Liu Y.-X.; Hao Z.-H.
收藏  |  浏览/下载：10/0  |  提交时间：2013/03/25
Phase characteristics of laser beam in fibers (EI CONFERENCE) 会议论文
5th International Workshop on Adaptive Optics for Industry and Medicine, August 29, 2005 - September 1, 2005, Beijing, China
Chai C.; Liu S.; Liu J.; Wang L.; Jia G.
收藏  |  浏览/下载：19/0  |  提交时间：2013/03/25
The phase changing rates1 of laser beam in single mode polarization maintaining fiber (PMF)  Yb-doped rectangular inner cladding dual-clad fiber (DCF) and Yb-doped large-mode-area dual-clad fiber (LMF) are investigated by means of interference under situations with different exterior disturbance  for situations that all the fibers are used as transmission medium only  as well as amplifying medium with the last two. In this paper  phase fluctuation characteristics of the beam transmitted through the fibers with no amplification are presented. The results show that the phase fluctuation frequencies of the laser beam transmitted through these three kinds of fibers are mainly in the range of 100-200Hz  100-300Hz and 80-400Hz respectively in normal laboratory environment. The phase fluctuation frequencies of the laser beam transmitted through the DCF  in cases of when the environment temperature is changing  a constant pressure is applied to the fiber and when vibration is applied  are mainly in the range of 100-600Hz  100Hz-300Hz and 100-500Hz respectively. In the same cases  for the LMF  the phase fluctuation frequencies are mainly in the range of 150-600Hz  100-400Hz and 100-1000Hz  respectively. It indicates that for realizing phase stabilization  the bandwidth of any potential phase control2 system has to be in the range of a few kilohertz.  
A new method of image reconstruction with high resolution in X-ray coded aperture imaging (EI CONFERENCE) 会议论文
Laser-Generated, Synchrotron, and Other Laboratory X-Ray and EUV Sources, Optics, and Applications II, August 2, 2005 - August 4, 2005, San Diego, CA, United states
Hu J.; Cheng L.; Wu X.; Sun Y.; Bai Y.
收藏  |  浏览/下载：19/0  |  提交时间：2013/03/25
In the processing diagnosis of the inertia confinement fusion (ICF)  the ring coded aperture imaging technique is applied in order to gain high space and time resolutions simultaneously. The key of acquiring high spatial resolution is how to obtain a point spread function of an imaging system. The common method is the firsthand projection method which is an approximate one. The x-ray diffraction effect is neglected in the method  so the resolution of reconstructed image is decreased. We have derived the point spread function (PSF) of the ring coded aperture from scalar diffraction theory. And the Wiener filter is fabricated on the basis of the PSF. In National Key Laboratory of Laser Fusion  at China Academy of Engineering Physics  the imaging experiment on the diagnosis of ICF is completed using the ring coded aperture plate with inner diameter d1 = 250m and outer diameter d2 = 260m . The obtained coded image is processed by the Wiener filter which diffractive effect is considered. The processed results have shown that resolution and modulation contrast of acquired image are evidently better than the results obtained by the firsthand projection method.  

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