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Record 109 of
Title:Polarization detection with polarization interference imaging spectrometer
Author(s):Jian, Xiaohua(1,2); Zhang, Chunmin(1,2); Zhao, Baochang(3)
Source: Optik Volume: 122 Issue: 8 DOI: 10.1016/j.ijleo.2010.05.004 Published: April 2011
Abstract:A new method of measuring the intensity and state of polarization of optical radiation by means of the high resolution polarization interference imaging spectrometer (PIIS) is introduced and theoretically investigated in this paper. The error accuracy analysis is proposed, and it is proved that the system is very stable and precise in theory. In this new way, the polarized characteristics of light could be taken good use to analyze and distinguish objects in passive remote sensing with the PIIS, which means that the polarization interference imaging spectrometer now can be used not only as cameras and interferometers but also as polaristrobometers. ? 2010 Elsevier B.V.
Accession Number: 20111013730927
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Record 110 of
Title:Response calculation for NOPD beam by an improved algorithm based on the endochronic theory and test verification
Author(s):Wang, Wei(1); Li, Yuyan(2)
Source: Applied Mechanics and Materials Volume: 80-81 Issue: DOI: 10.4028/www.scientific.net/AMM.80-81.845 Published: 2011
Abstract:Non-Obstructive Particle Damping (NOPD) is a new damping technique which is based on traditional particle damping and impact damping technique. NOPD Structure has a good effect on decreasing sound and vibration. A new improved algorithm based on the endochronic theory is researched in the paper. Response calculation by the algorithm and tests for NOPD beam have been done in conditions of one, two and three holes filled with tungsten particles. Results show it feasible to calculate the response of NOPD structure by the improved algorithm, which affords an effective analysis method for engineering application of NOPD technique. ? (2011) Trans Tech Publications.
Accession Number: 20113514279555
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Record 111 of
Title:Studies on crystal attitude error tolerance in double crystal monochromator
Author(s):Yang, Xiao-Xu(1); Jiang, Bo(1); Guo, Zhi-Li(1); Ma, Ming(1); Zhou, Si-Zhong(1); Zhao, Shi-Min(2)
Source: Procedia Engineering Volume: 15 Issue: DOI: 10.1016/j.proeng.2011.08.999 Published: 2011
Abstract:The crystal attitude is necessary to be adjusted with the Bragg angle adjustment process because these crystals are moved to keep a fixed exit beam position and other reasons. The adjustment accuracy of these crystals attitude has some influence for Bragg angle, and the energy accuracy of output beam is affected father. These relationships between Bragg angle accuracy and crystal attitude angle are given. The analyzing results show that yaw angle of the first crystal has no influence over Bragg angle. Roll angle and pitch angle of double crystals have different influence over Bragg angle. ? 2011 Published by Elsevier Ltd.
Accession Number: 20115214631709
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Record 112 of
Title:All-digital pulse generator for gradually modulated semiconductor laser
Author(s):Song, Zhiyuan(1); Feng, Li(1); Zhu, Shaolan(1); He, Haodong(1); Gao, Cunxiao(1); Niu, Linquan(1)
Source: Chinese Optics Letters Volume: 9 Issue: SUPPL. 1 DOI: 10.3788/COL201109.S10306 Published: June 2011
Abstract:An all-digital design method consisting of a laser drive circuit for gradually modulating the frequency, pulse width, and amplitude of the output of semiconductor laser is demonstrated. Field programmable gate arrays (FPGAs) and accurate delaying chip are used to generate the pulse. The repetition rate and pulse width of the laser pulse gradually adjust from 1 to 10 kHz and 700 ps to 3 ns, respectively. Furthermore, the time of the rising and falling edges for the laser pulse is less than 800 ps. ? 2011 Chinese Optics Letters.
Accession Number: 20113214224376
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Record 113 of
Title:Aircraft recognition based on multiple classifier fusion with multiple invariants
Author(s):Zhu, Xufeng(1,2); Ma, Caiwen(1)
Source: Yi Qi Yi Biao Xue Bao/Chinese Journal of Scientific Instrument Volume: 32 Issue: 7 DOI: Published: July 2011
Abstract:The difficulties of aircraft image automatic recognition method are analyzed, and the advantages of using multiple classifier fusion for aircraft recognition are pointed out. Then, four kinds of invariants, which include affine moment, Zernike moment, wavelet moment, gradient module of SIFT feature descriptor, are combined with support vector machine to produce four kinds of classifiers. An adaptive weighted voting method is adopted to carry out multiple classifier fusion for improving aircraft recognition rate. Simulation experiment results show that using the proposed adaptive weighted voting method of multiple classifiers, the aircraft recognition rate is superior to the recognition rates using the classifiers constructed with single invariants, and also superior to those using the multiple classifiers constructed with fixed weighted voting method and majority voting method.
Accession Number: 20113214224536
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Record 114 of
Title:Aircraft recognition scheme based on feature fusion and support vector machine
Author(s):Zhu, Xu-Feng(1,2); Ma, Cai-Wen(1); Liu, Bo(1)
Source: Guangdianzi Jiguang/Journal of Optoelectronics Laser Volume: 22 Issue: 11 DOI: Published: November 2011
Abstract:A new combination invariants method is proposed for aircraft recognition. For all kinds of aircraft types, Hu moments, affine moments and normalized Fourier descriptors are extracted and combined. As the above invariants are too dispersed, four kinds of normalized methods are studied and combined with support vector machine (SVM) to improve aircraft classification performance. Simulation results show that the classification performance is better by the combination invariants which are combined with support vector machine classifier or neuron network than that by any single kind of invariants which are combined with corresponding classifiers, and the classification performance is better by support vector machine classifier than that by traditional neuron network classifier. Moreover, when combination invariants are sent to intelligent classifiers, a special normalization method can improve the classification performance.
Accession Number: 20114914584354
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Record 115 of
Title:Development of control circuits for the CCD Stereo Camera of Chang'E-1 satellite based on FPGA
Author(s):Duan, Yong-Qiang(1,2); Wen, De-Sheng(1); Gao, Wei(1); Zheng, Pei-Yun(1); Zhao, Bao-Chang(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8196 Issue: DOI: 10.1117/12.900345 Published: 2011
Abstract:The CCD Stereo Camera is a principal science payload on board the Chang'E-1 (CE-1) satellite, developed and launched by China for the first Lunar Exploration Program. The principal task of the camera is to take image of the lunar surface in the visible band and obtains three-dimensional lunar terrain. The CCD Stereo Camera is designed based on threelinear array photogrammetric theories. The focal plane of the camera is comprised of a frame transfer CCD with size of 1024x1024 pixels. There are only three lines to be used to form a three-linear array, and the other lines are not used. The timing and control circuits of the camera are designed based on FPGA. An Actel's anti-fuse based FPGA, A1020B, is available, but the speed and logical resources of the device both are limited. This paper describes the design requirements, considerations and trade-off subject to the constraints. Especially, A novel logic circuit is introduced to generate the pulses with width of about 10ns～20ns with constraint of 8MHz external clock, which is used to design correlated double sampling (CDS) control signals and CCD reset signal. Finally, the result of flying verifications on-board of the timing and control circuits are also described. ? 2011 SPIE.
Accession Number: 20113614296313
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Record 116 of
Title:Compressed hyperspectral image sensing based on interband prediction
Author(s):Liu, Haiying(1); Li, Yunsong(1); Wu, Chengke(1); Lü, Pei(2)
Source: Xi'an Dianzi Keji Daxue Xuebao/Journal of Xidian University Volume: 38 Issue: 3 DOI: 10.3969/j.issn.1001-2400.2011.03.007 Published: June 2011
Abstract:A new compression algorithm for hyperspectral images based on compressed sensing is proposed which has the advantages of high reconstruction quality and low complexity by exploiting the strong spectral correlations. At the encoder, the prediction parameter between the neighboring bands is first estimated using the prediction algorithm and transmitted to the decoder. The random measurements of each band are then made, quantized and transmitted to the decoder independently. At the decoder, a new reconstruction algorithm with the proposed initialization and stopping criterion is applied to reconstruct the current band with the assistance of its prediction band, which is derived from the previous reconstructed neighboring band and the received prediction parameter using the prediction algorithm. Experimental results show that the proposed algorithm not only obtains a gain of about 1.2 dB but also greatly decreases decoding complexity. In addition, our algorithm has the characteristics of low-complexity encoding and easy hardware implementation.
Accession Number: 20112714115851
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Record 117 of
Title:Using an acousto-optic tunable filters for hyper spectro-polarimetric imaging
Author(s):Chang, Ling-Ying(1,2); Zhao, Bao-Chang(1); Wen, De-Sheng(1); Chen, Rong-Li(1); Qiu, Yue-Hong(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8196 Issue: DOI: 10.1117/12.901014 Published: 2011
Abstract:Of all the hyperspectral imaging system using the optical filtering elements available,. AOTF(Acousto-optic tunable filters) is best to choose a filtering optical element that has high-speed spectral selectivity with high resolution, it can greatly reduces the amount of data collection and processing. In this paper , First, the work principle of AOTF was introduced, then described the AOTF imaging system, it covers the spectral band from 400nm to 900nm with a spectral resolution of near 2nm at 400nm and 10nm at 900nm. The device can provide about 2.2° view field angle and 10mm aperture, which included TeO2 crystal, image optical system, a charged coupled device(CCD)camera, rf electronics and control and processing software. Finally the paper presented the results of laboratory image testing. ? 2011 SPIE.
Accession Number: 20113614296292
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Record 118 of
Title:Femtosecond laser machining characteristics in a single-crystal superalloy
Author(s):Zhang, Wei(1,2); Cheng, Guanghua(2); Feng, Qiang(1,3); Cao, Lamei(4)
Source: Rare Metals Volume: 30 Issue: SUPPL.1 DOI: 10.1007/s12598-011-0362-z Published: March 2011
Abstract:Femtosecond laser machining characteristics of a nickel-base single-crystal superalloy were investigated as a function of laser fluence and the number of laser pulses. The significant decrease of recast layer for femtosecond laser machining was observed compared with that for nanosecond laser machining. The ablation thresholds for 1, 10, and 100 femtosecond pulse exposure were measured. Two ablation regions of the ablated crater were observed. The change of the ablation diameter and depth depended on the laser fluence and the number of laser pulses. And higher laser fluence could enable a faster rate of laser-machining. ? The Nonferrous Metals Society of China and Springer-Verlag Berlin Heidelberg 2011.
Accession Number: 20120414719407
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Record 119 of
Title:Multilevel thresholding based on mean shift mode seeking
Author(s):Ma, Junyong(1,2); Wen, Desheng(1); Yang, Shaodong(1,2); Yao, Dalei(1,2)
Source: Journal of Computational Information Systems Volume: 7 Issue: 10 DOI: Published: October 2011
Abstract:A novel multilevel thresholding method based on mean shift procedure is proposed to resolve the problem that the optimal number of thresholds for multilevel thresholding can usually not be predetermined. The mean shift procedure is used to seek the minimal potential mode centroids, after which an iterative threshold selection method is employed to automatically determine every threshold between each pair of adjacent two mode centroids. Finally, multilevel thresholding with the multiple thresholds is utilized to segment the image. Excellent results have been obtained, testing the effectiveness of the algorithm. The proposed method can easily be used in bi-level segmentation, multilevel segmentation, lossy compression and so on. ? 2011 Binary Information Press.
Accession Number: 20114114415570
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Record 120 of
Title:Analysis to stray radiation of infrared detecting system
Author(s):Niu, Jin-Xing(1,2); Shi, Shuheng(1); Zhou, Ren-Kui(2)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8193 Issue: DOI: 10.1117/12.900014 Published: 2011
Abstract:In order to improve the detecting ability of dark target by infrared detecting system, stray radiation of the system should be studied before and suppression methods should be adopted. In the infrared detecting system, thermal emission of a room-temperature instrument may be several orders of magnitude larger than the flux of sources of target to be observed. When baffles and vanes are designed to suppress the stray radiation coming from sources outside of the field of view of the detecting system, their thermal radiation should be discussed together. In this article, the stray radiation of thermal emission of infrared detecting system is studied. How to design baffles, vanes and stops is introduced. Their structure models are established in TracePro. Their thermal emissions are simulated and analyzed by ray tracing program. The number of photons on a pixel which emitted from suppression structure which varies from 260K to 310K is given by simulation. From the simulation result, we can find that the stray radiation of thermal emission from inner baffle of primary mirror is the predominant source; The stray radiation of thermal emission of system with vanes on main tube is slightly bigger than that of the system with no vanes; the field stop placed at the first image plane can effectively decrease the number of photons of stray radiation. ? 2011 Copyright Society of Photo-Optical Instrumentation Engineers (SPIE).
Accession Number: 20114114420320
