2013
2013
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Record 181 of
Title:Athermalization design of catadioptric middle infrared dual field zoom system
Author(s):Jiang, Kai(1,2); Zhou, Sizhong(1); Li, Gang(1); Yang, Xiaoxu(1); Zhao, Rui(3); Zhang, Hengjin(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 42 Issue: 2 DOI: Published: February 2013Abstract:Hybrid refractive-diffractive design offers a new approach for athermalization design in wide temperature range. In this paper, working wavelength is in 3-5 μm. For cool 320 × 240 infrared detector, pixel size 30 μm × 30 μm, this system can realize 400 mm and 800 mm dual filed-of-view and the F-number of 2/4 respectively. Two systems both can obtain the cold shield efficiency of 100% though controlling machine structure. A diffractive surface was introduced in the shared part of two different focal length position. It achieve the athermal design using only one diffractive surface. The evolution of the system was given in the temperature range-40-60°C. The results show that at the spatial frequency of 18 lp/mm the MTF approach to the diffractive limitation.Accession Number: 20131616213956 -
Record 182 of
Title:Data uncertainty in face recognition
Author(s):Xu, Yong(1,2); Fang, Xiaozhao(1); Li, Xuelong(3); Yang, Jiang(4); You, Jane(5); Liu, Hong(6); Teng, Shaohua(7)Source: IEEE Transactions on Cybernetics Volume: 44 Issue: 10 DOI: 10.1109/TCYB.2014.2300175 Published: October 1, 2014Abstract:The image of a face varies with the illumination, pose, and facial expression, thus we say that a single face image is of high uncertainty for representing the face. In this sense, a face image is just an observation and it should not be considered as the absolutely accurate representation of the face. As more face images from the same person provide more observations of the face, more face images may be useful for reducing the uncertainty of the representation of the face and improving the accuracy of face recognition. However, in a real world face recognition system, a subject usually has only a limited number of available face images and thus there is high uncertainty. In this paper, we attempt to improve the face recognition accuracy by reducing the uncertainty. First, we reduce the uncertainty of the face representation by synthesizing the virtual training samples. Then, we select useful training samples that are similar to the test sample from the set of all the original and synthesized virtual training samples. Moreover, we state a theorem that determines the upper bound of the number of useful training samples. Finally, we devise a representation approach based on the selected useful training samples to perform face recognition. Experimental results on five widely used face databases demonstrate that our proposed approach can not only obtain a high face recognition accuracy, but also has a lower computational complexity than the other state-of-the-art approaches. ? 2013 IEEE.Accession Number: 20143900072743 -
Record 183 of
Title:Sparse coding from a bayesian perspective
Author(s):Lu, Xiaoqiang(1); Wang, Yulong(1,2); Yuan, Yuan(1)Source: IEEE Transactions on Neural Networks and Learning Systems Volume: 24 Issue: 6 DOI: 10.1109/TNNLS.2013.2245914 Published: 2013Abstract:Sparse coding is a promising theme in computer vision. Most of the existing sparse coding methods are based on either 0 or 1 penalty, which often leads to unstable solution or biased estimation. This is because of the nonconvexity and discontinuity of the 0 penalty and the over-penalization on the true large coefficients of the 1 penalty. In this paper, sparse coding is interpreted from a novel Bayesian perspective, which results in a new objective function through maximum a posteriori estimation. The obtained solution of the objective function can generate more stable results than the 0 penalty and smaller reconstruction errors than the 1 penalty. In addition, the convergence property of the proposed algorithm for sparse coding is also established. The experiments on applications in single image super-resolution and visual tracking demonstrate that the proposed method is more effective than other state-of-the-art methods. ? 2012 IEEE.Accession Number: 20131616216353 -
Record 184 of
Title:Engineering analysis of non-uniform internal heat source in the thermocouple under the second boundary condition
Author(s):Yang, Fanchao(1,2); Wang, Hongwei(3); Wang, Cailing(4); Hu, Binliang(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 42 Issue: SUPPL.1 DOI: Published: 2013Abstract:The domestic and foreign scholars have done a lot of work of research on the principle and the cooling performance of thermoelectric cooler, but most of them neglect the micro thermal conditions and regard the thermocouple internal heat source as uniform distribution. In order to make the analysis results more accurate and suitable for engineering application, Joule heat was used as non-uniform internal heat source of thermocouple in this paper and one kind of analysis model was set up: the model was based on linear ordinary differential equation and met the conditions of using principle of superposition. Therefore, this paper proposed an engineering method to calculate the temperature and distribution of heat flow in thermocouple based on the shunt and superposition principle. At last this paper got the temperature and distribution of heat flow of thermocouple under the second boundary condition. By checking the results, this paper proves the correctness of the formula and provides a theoretical guidance for the further research and application of thermoelectric refrigeration technology.Accession Number: 20134416940617 -
Record 185 of
Title:Image jigsaw puzzles with a self-correcting solver
Author(s):Zheng, Xiangtao(1,2); Lu, Xiaoqiang(1); Yuan, Yuan(1)Source: Proceedings - 2013 International Conference on Virtual Reality and Visualization, ICVRV 2013 Volume: Issue: DOI: 10.1109/ICVRV.2013.26 Published: 2013Abstract:Jigsaw puzzle is an intellectual game and serves as a platform for many scientific applications. Several computational methods have been proposed to deal with the jigsaw puzzle problem in recent years. However, there are still some drawbacks. First, these methods fail to consider the content consistency of the reconstructed images. Specially, the traditional measures only reflect similarity between adjoining pieces but neighboring pieces. Second, these methods cannot guarantee the overall reconstruction correctness, because the strategy of assembly merely tries to correct the measure of adjoining pieces at each step. To overcome these drawbacks, this paper proposes a new method which contributes the follows: 1) A new measure considers the transmission relationships of four neighboring pieces to make better use of content consistency. 2) A self-correcting mechanism avoids error accumulation of adjoining matrix and improves the overall accuracy of assembly, which is achieved through ordering the pairwise relations. Experimental results on 20 images demonstrate that the proposed method significantly improves the performance and outperforms the state-of-the-art methods. ? 2013 IEEE.Accession Number: 20140717300061 -
Record 186 of
Title:Image super-resolution via non-local steering kernel regression regularization
Author(s):Zhang, Kaibing(1); Gao, Xinbo(2); Tao, Dacheng(3); Li, Xuelong(4)Source: 2013 IEEE International Conference on Image Processing, ICIP 2013 - Proceedings Volume: Issue: DOI: 10.1109/ICIP.2013.6738195 Published: 2013Abstract:In this paper, we employ the non-local steering kernel regression to construct an effective regularization term for the single image super-resolution problem. The proposed method seamlessly integrates the properties of local structural regularity and non-local self-similarity existing in natural images, and solves a least squares minimization problem for obtaining the desired high-resolution image. Extensive experimental results on both simulated and real low-resolution images demonstrate that the proposed method can restore compelling results with sharp edges and fine textures. ? 2013 IEEE.Accession Number: 20141117461493 -
Record 187 of
Title:Calculation of effective nonlinear coefficient in BIBO for spontaneous parametric down conversion
Author(s):Huo, Guangwen(1,2); Zhang, Tongyi(1); Cheng, Guanghua(1); Zhao, Wei(1)Source: Journal of Nonlinear Optical Physics and Materials Volume: 22 Issue: 1 DOI: 10.1142/S0218863513500100 Published: March 2013Abstract:We theoretically investigate the effective nonlinear coefficient d eff of spontaneous parametric down-conversion (SPDC) process in biaxial nonlinear crystal BiB3O6 (BIBO). We solve the Fresnel equations in the collinear degenerate down-converted configuration, and get the relations of phase-matching angles. Considering the double phase-matching, we compute the phase-matching angles with different wavelength. Furthermore, we simplify the expression of effective nonlinear coefficient out of the principal planes, and numerically calculate it varying with the angle and wavelength. These results indicate that there are three effective phase-matching schemes for SPDC which can be used to construct a system to generate entangled photon pairs. ? World Scientific Publishing Company.Accession Number: 20193607411612 -
Record 188 of
Title:Reconstructed image enhancement of digital holography in contourlet domain based on particle swarm optimization
Author(s):Wu, Yiquan(1,2); Yin, Jun(1)Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 40 Issue: 8 DOI: 10.3788/CJL201340.0809002 Published: August 2013Abstract:Aiming at the problem of low contrast, blurred edges and textures, and speckle noise of reconstructed image in digital holography, an adaptive enhancement method for reconstructed image of digital holography in contourlet domain based on uniform searching particle swarm optimization is proposed. Median filtering algorithm is used to suppress speckle noise of the reconstructed image. After the contourlet decomposition, edge enhancement is performed for the band-pass directional subbands by a nonlinear gain function. While the coefficients of low-pass subbands are adjusted by the gain function based on a gray-scale transform and the local mean. The gray-scale transform aims to expand the dark areas of digital holographic image. The undetermined parameters are found by uniform searching particle swarm optimization. The fitness function takes into account the contrast, definition and peak signal-to-noise ratio of image. A large number of experimental results show that, compared with three existing enhancement methods, the proposed method can more effectively improve the contrast and definition of reconstructed image in digital holography, highlight edges and textures, and suppress speckle noise. As a result, the measurement accuracy of digital holography can be improved.Accession Number: 20134216869130 -
Record 189 of
Title:Development of the fabrication method for novel polymer imaging fiber
Author(s):Kong, Depeng(1); Wang, Lili(1); He, Zhengquan(1); Chu, Jiurong(2); Li, Yulin(1)Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 40 Issue: 1 DOI: 10.3788/CJL201340.0105004 Published: January 2013Abstract:The fabrication method for novel polymer imaging fiber is developed. The theory of light propagation in fiber and fiber design is expatiated, which is the guide for developing imaging fiber. The material of polymethyl methacrylate (PMMA) is heated and extruded in a hexagon mold as microstructured fiber preform. The holes in it are filled with polystyrene (PS) fibers. It is the first preform used for heat-stretch and stack-fusion to form a second preform. Then the second preform is heat-stretched to obtain imaging fiber with diameter of 0.22 mm and single fiber diameter of 3 μm. It is ultrahigh resolution imaging fiber, by which the microscale of 10 μm can be discerned. The method of one-step stack is used to stack 7200 pieces of customized polymer fibers as the multicore imaging fiber preform. The customized fiber with diameter of 0.25 mm and coating thickness of 20 μm is fused together. The preform is heat-stretched to form imaging fiber of 2 mm diameter and 20 μm single fiber diameter. It is found that the dust adsorbed on the fiber face seriously affects fiber's structure and image quality.Accession Number: 20131616213296 -
Record 190 of
Title:Research of X-ray pulsar navigation simulation source
Author(s):Sheng, Li-Zhi(1,2); Zhao, Bao-Sheng(1); Wu, Jian-Jun(3); Zhou, Feng(1); Song, Juan(1,2); Liu, Yong-An(1); Shen, Jing-Shi(4); Yan, Qiu-Rong(1); Deng, Ning-Qin(1,2); Hu, Hui-Jun(4)Source: Wuli Xuebao/Acta Physica Sinica Volume: 62 Issue: 12 DOI: 10.7498/aps.62.129702 Published: June 20, 2013Abstract:As an autonomous navigation method, X-ray pulsar navigation can provide position, timing and attitude information for various spacecrafts. Since the X-rays (1-20 keV) from the pulsar can not penetrate the earth atmosphere, an X-ray source in laboratory needs to be set up to test and calibrate the detector. In this paper an arbitrary X-ray pulse source to simulate the neutron pulsar signal is proposed. The main components of the simulation source are a grid controlled X-ray tube and arbitrary pulse generation electronics. With the arbitrary pulse voltage applied to the tube grid, the X-ray intensity is controlled. Through electron optics design, the tube electrode parameters are optimized. A grid controlled X-ray tube is fabricated and tested. Using a micro-channel plate detector to detect and reconstruct the generated X-ray pulses, the similarity between the accumulated profile and the original pulsar profile is better than 95%. The frequency stability of the pulsar source emulator is about 2×10-11. ? 2013 Chinese Physical Society.Accession Number: 20132916517334 -
Record 191 of
Title:Eyewear-style three-dimensional endoscope derived from microstructured polymer fiber with the function of image transmission
Author(s):Kong, De-Peng(1); Wang, Li-Li(1); He, Zheng-Quan(1); Chu, Jiu-Rong(2); Ma, Tian(1)Source: Chinese Physics B Volume: 22 Issue: 2 DOI: 10.1088/1674-1056/22/2/020701 Published: February 2013Abstract:A method of fabricating multi-core polymer image fiber is proposed. Image fiber preform is fabricated by stacking thousands of polymer fibers each with a 0.25-mm diameter orderly in a die by only one step. The preform is heated and stretched into image fiber with an outer diameter of 2 mm. Then a portable eyewear-style three-dimensional (3D) endoscope system is designed, fabricated, and characterized. This endoscopic system is composed of two graded index lenses, two pieces of 0.35-m length image guide fibers, and a pair of oculars. It shows good flexibility and portability, and can provide the depth information accordingly. ? 2013 Chinese Physical Society and IOP Publishing Ltd.Accession Number: 20130916074010 -
Record 192 of
Title:Comparison of timing noise properties of carbon nanotubes, graphene and graphene oxide as saturable absorbers for a mode-locked Er-doped fiber laser
Author(s):Li, Xiaohui(1,3); Wu, Kan(2); Shum, Perry Ping(2); Wang, Yonggang(3); Wang, Yishan(3); Wang, Qijie(1)Source: CLEO: Applications and Technology, CLEO_AT 2013 Volume: Issue: DOI: 10.1364/cleo_at.2013.jtu4a.06 Published: 2013Abstract:We compare the timing noise properties of three most typical carbon materials, i.e., single walled carbon nanotubes, graphene and graphene oxide as saturable absorbers in a passively mode-locked Er-doped fiber laser as a test platform. ? OSA 2013.Accession Number: 20134717001726