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2017

Record 121 of

Title:Comparative Study of Data Compression Methods for Large Aperture Static Imaging Spectrometer

Author(s):Yu, Lu(1,2,3); Liu, Xue-Bin(1); Li, Hong-Bo(1,3); Liu, Gui-Zhong(2)
Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 37 Issue: 3 DOI: 10.3964/j.issn.1000-0593(2017)03-0939-07 Published: March 1, 2017
Abstract:Facing the problem of choosing different data source as compressing object results in different compression effect, several techniques are investigated to explore a better data source which can reduce the loss of image and spectral information while getting higher compression ratio in the compression work of the large aperture static imaging spectrometer. In this paper the optical path difference dimension data source of LASIS was proposed after analyzing the characteristic of LASIS and then compared with the LASIS and LAMIS data source in detail. The SWIR data collected with the principle prototype of LASIS were used in our experiment. Firstly, three forms of data sources were extracted after detailedly introducing their data characteristic and extracting methods. Secondly, the mature algorithms in engineering JPEG and JPEG2000 were employed to compress and reconstruct the three forms of data sources respectively. Finally, the compression effect was evaluated in the aspect of image content, interference dimension, spectral dimension and compression ratio respectively, and the original spectral curves of three materials choosing from the field of view and those after reconstruction were extracted next, then the loss of spectral information of these three materials were measured by using the SA (Spectral Angle) and RQE (Relative Quadratic Error) values of the spectral curves to evaluate the compression effect. It is demonstrated that using the optical path difference dimension data as compressing object shows obvious advantages compared with LASIS and LAMIS, which achieves a combination of higher compression ratio, lower mean square error, lower peak signal noise ratio and less information loss that is competitive with the best results from the literature. The results show that the proposed optical path difference dimension data source has good performance in preserving the spatial and spectral information during the compression of LASIS than the other two common forms data sources of LASIS. ? 2017, Peking University Press. All right reserved.
Accession Number: 20172203711701
Record 122 of

Title:Design of a common-aperture VIS/LWIR imaging optical system with muti-field of view

Author(s):Jing, Duan(1); Kai, Liu(1); Gang, Li(1,2); Peipei, Yan(1,2); Qiusha, Shan(1); Kai, Jiang(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10256 Issue: DOI: 10.1117/12.2257878 Published: 2017
Abstract:In order to achieve the multi-band and multi-field of view imaging for target and to meet the needs of target detection for large amount of information, a common-aperture visible light/long-wave infrared(VIS/LWIR) imaging optical system with muti-field of view was designed. In this paper, the aperture is 400mm, the working wavelength is 500～700nm and 7.5～10μm, the temperature range is -15°C+50°C, this system can realize 1500mm and 3000mm dual focal length(VIS), the full field of view of short focal length is 1.16° and long focal length is 0.58° respectively, and realize 1400mm focal length(LWIR) and the full field of view of 0.54°, satisfy 100% cold shield efficiency. A re-imaging system was adopted in this designed optical system consists of main optics, VIS projection components and LMIR projection components. First of all, the structural selection and the initial parameter calculation were introduced in detail. Secondly, to improve image quality and environment adaptability, the analysis of temperature change was described particularly and the structural design requirements were put forward according to the analysis of the data. The design results proved that at the spatial frequency of 50 lp/mm, the axis MTF of the VIS system is greater than 0.48, the MTF of the LWIR system approaches the diffraction limit, the system can offer a high resolution and excellent images in whole range of the focal length, and it has the advantages of good adaptability, compact structure and small size, the results satisfy the design requirement. ? 2017 SPIE.
Accession Number: 20171703607570
Record 123 of

Title:Diagnostic Equipment Calibration Platform Based on Sub-Picosecond Ultraviolet Laser

Author(s):Yuan, Zheng(1); Deng, Keli(1); Li, Jin(1); Yang, Zhiwen(1); Wu, Bingjing(2); Chen, Tao(1); Deng, Bo(1); Qi, Wenbo(2); Wang, Qiangqiang(1); Cao, Zhurong(1); Liu, Shenye(1)
Source: Guangxue Xuebao/Acta Optica Sinica Volume: 37 Issue: 6 DOI: 10.3788/AOS201737.0614002 Published: June 10, 2017
Abstract:In order to make full use of output characteristics of high energy, ultrashort pulse width of sub-picosecond ultraviolet lasers, a calibration platform of laser inertial confinement fusion(ICF) diagnostic equipment is established. The calibration platform has such functions as laser energy measurement, optical transmission delay, beam splitting and geometric decline, and sequential optical pulse generator, which can provide the structural support and high vacuum operating environment for the relevant diagnostic equipment. The mechanical and optical design is developed in all parts of the platform, and the platform is used to calibrate the X-ray diode response time, X-ray streak camera sweep speed, X-ray framing camera dynamic range and so on. The results show that the calibration platform matches the sub-picosecond ultraviolet calibration source well, and can achieve precise calibration of various diagnostic equipments. ? 2017, Chinese Lasers Press. All right reserved.
Accession Number: 20173003967968
Record 124 of

Title:Efficient point matching under uneven and dramatic illumination changes

Author(s):Yang, Rui(1,2); Liu, Zhaohui(1); Yang, Tao(1,2); Li, Wenhao(1,2)
Source: Journal of Electronic Imaging Volume: 26 Issue: 1 DOI: 10.1117/1.JEI.26.1.013001 Published: January 1, 2017
Abstract:Point matching under illumination changes is significant for many vision information applications. However, the uneven and dramatic illumination variations model is rarely considered in existing point matching algorithms. Therefore, a method to match features efficiently under uneven and dramatic illumination changes is presented. This method extracts and describes illumination invariant interesting points from matched multibrightness layers that are obtained by a set of contrast stretching functions and prior information based on original images. Layers matching is insensitive to large unevenness of illumination changes and provides similar images in brightness and structure, so the effects of large uneven illumination changes can be reduced greatly. This algorithm is compatible with most detectors and descriptors. To accelerate the computing speed, the features from the accelerated segment test detector and the improved speeded up robust features descriptor are chosen in this paper. In addition, the combination of priority Hamming distance matching and Lowe's matching algorithms is first proposed to increase the matching speed. This method is generic and can be used in most point matching under all varying illumination conditions. Experimental results demonstrate that the proposed method improves the quality of matched points significantly. ? 2017 SPIE and IS&T.
Accession Number: 20170303255295
Record 125 of

Title:Nonnegative Discriminant Matrix Factorization

Author(s):Lu, Yuwu(1); Lai, Zhihui(2); Xu, Yong(3); Li, Xuelong(4); Zhang, David(5); Yuan, Chun(1)
Source: IEEE Transactions on Circuits and Systems for Video Technology Volume: 27 Issue: 7 DOI: 10.1109/TCSVT.2016.2539779 Published: July 2017
Abstract:Nonnegative matrix factorization (NMF), which aims at obtaining the nonnegative low-dimensional representation of data, has received wide attention. To obtain more effective nonnegative discriminant bases from the original NMF, in this paper, a novel method called nonnegative discriminant matrix factorization (NDMF) is proposed for image classification. NDMF integrates the nonnegative constraint, orthogonality, and discriminant information in the objective function. NDMF considers the incoherent information of both factors in standard NMF and is proposed to enhance the discriminant ability of the learned base matrix. NDMF projects the low-dimensional representation of the subspace of the base matrix to regularize the NMF for discriminant subspace learning. Based on the Euclidean distance metric and the generalized Kullback-Leibler (KL) divergence, two kinds of iterative algorithms are presented to solve the optimization problem. The between- and within-class scatter matrices are divided into positive and negative parts for the update rules and the proofs of the convergence are also presented. Extensive experimental results demonstrate the effectiveness of the proposed method in comparison with the state-of-the-art discriminant NMF algorithms. ? 1991-2012 IEEE.
Accession Number: 20172803942203
Record 126 of

Title:Plasma assisted fabrication of multi-layer graphene/nickel hybrid film as enhanced micro-supercapacitor electrodes

Author(s):Ding, Q.(1); Li, W.L.(3,4); Zhao, W.L.(1); Wang, J.Y.(1); Xing, Y.P.(1); Li, X.(2); Xue, T.(2); Qi, W.(5); Zhang, K.L.(1); Yang, Z.C.(1); Zhao, J.S.(1)
Source: IOP Conference Series: Materials Science and Engineering Volume: 182 Issue: 1 DOI: 10.1088/1757-899X/182/1/012014 Published: March 10, 2017
Abstract:A facile synthesis strategy has been developed for fabricating multi-layer graphene/nickel hybrid film as micro-supercapacitor electrodes by using plasma enhanced chemical vapor deposition. The as-presented method is advantageous for rapid graphene growth at relatively low temperature of 650 °C. In addition, after pre-treating for the as-deposited nickel film by using argon plasma bombardment, the surface-to-volume ratio of graphene film on the treated nickel substrate is effectively increased by the increasing of surface roughness. This is demonstrated by the characterization results from transmission electron microscopy, scanning electron microscope and atomic force microscopy. Moreover, the electrochemical performance of the resultant graphene/nickel hybrid film as micro-supercapacitor working electrode was investigated by cyclic voltammetry and galvanostatic charge/discharge measurements. It was found that the increase of the surface-to-volume ratio of graphene/nickel hybrid film improved the specific capacitance of 10 times as the working electrode of micro-supercapacitor. Finally, by using comb columnar shadow mask pattern, the micro-supercapacitor full cell device was fabricated. The electrochemical performance measurements of the micro-supercapacitor devices indicate that the method presented in this study provides an effective way to fabricate micro-supercapacitor device with enhanced energy storage property. ? Published under licence by IOP Publishing Ltd.
Accession Number: 20171403529035
Record 127 of

Title:Optomechanical integrated simulation of Mars medium resolution lens with large field of view

Author(s):Yang, Wenqiang(1,2); Xu, Guangzhou(1); Yang, Jianfeng(1); Sun, Yi(1,2)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10463 Issue: DOI: 10.1117/12.2285582 Published: 2017
Abstract:The lens of Mars detector is exposed to solar radiation and space temperature for long periods of time during orbit, so that the ambient temperature of the optical system is in a dynamic state. The optical and mechanical change caused by heat will lead to camera's visual axis drift and the wavefront distortion. The surface distortion of the optical lens includes the displacement of the rigid body and the distortion of the surface shape. This paper used the calculation method based on the integrated optomechanical analysis, to explore the impact of thermodynamic load on image quality. Through the analysis software, established a simulation model of the lens structure. The shape distribution and the surface characterization parameters of the lens in some temperature ranges were analyzed and compared. the PV/RMS value, deformation cloud of the lens surface and quality evaluation of imaging was achieved. This simulation has been successfully measured the lens surface shape and shape distribution under the load which is difficult to measure on the experimental conditions. The integrated simulation method of the optical machine can obtain the change of the optical parameters brought by the temperature load. It shows that the application of Integrated analysis has play an important role in guiding the designing the lens. ? 2017 SPIE.
Accession Number: 20180304654525
Record 128 of

Title:A new method named as segment-compound method of baffle design

Author(s):Qin, Xing(1); Yang, Xiaoxu(1); Gao, Xin(2); Liu, Xishuang(3)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10256 Issue: DOI: 10.1117/12.2256848 Published: 2017
Abstract:As the observation demand increased, the demand of the lens imaging quality rising. Segment-Compound baffle design method was proposed in this paper. Three traditional methods of baffle design they are characterized as Inside to Outside, Outside to Inside, and Mirror Symmetry. Through a transmission type of optical system, the four methods were used to design stray light suppression structure for it, respectively. Then, structures modeling simulation with Solidworks, CAXA, Tracepro, At last, point source transmittance (PST) curve lines were got to describe their performance. The result shows that the Segment-Compound method can inhibit stay light more effectively. Moreover, it is easy to active and without use special material. ? 2017 SPIE.
Accession Number: 20171703607636
Record 129 of

Title:Target reconstruction algorithm for four-beam sheared coherent imaging

Author(s):Lu, Chang-Ming(1,2,3); Chen, Ming-Lai(1); Luo, Xiu-Juan(1); Zhang, Yu(1); Liu, Hui(1); Lan, Fu-Yang(1,2); Cao, Bei(1)
Source: Wuli Xuebao/Acta Physica Sinica Volume: 66 Issue: 11 DOI: 10.7498/aps.66.114201 Published: June 5, 2017
Abstract:Sheared-beam imaging, which is a nonconventional coherent laser imaging technique, can be used to better solve the problem of taking pictures with high resolution for remote targets through turbulent medium than conventional optical methods. In the previous research on this technique, a target was illuminated by three coherent laser beams that were laterally arranged at the transmitter plane into an L pattern. In order to obtain a high quality image, a series of time-varying scattered signals is collected to reconstruct speckled images of the same object. To overcome atmospheric turbulence, multiple sets of three-beam laser should be emitted, which increases data acquisition time. In this paper, aiming at the quasi real-time problem of conventional sheared beam imaging technique, we use four-beam laser with rectangular distribution instead of the traditional L type sheared three-beam laser to illuminate the target. According to this, we propose a target reconstruction algorithm for four-beam sheared coherent imaging to reconstruct four target images simultaneously in one measurement, which can acquire high quality images by reducing the amount of measurement and the speckle noise. Meanwhile, it can greatly reduce the amount of beam switching in multi-group emission and improve the imaging efficiency. Firstly, the principle of the four-beam sheared coherent imaging technique is deduced. Secondly, in the algorithm, the speckle amplitude and phase difference frames can be extracted accurately by searching for the accurate positions of the beat frequency components. Based on the speckle phase difference frames, four sets of wavefront phases can be demodulated by the least squares method, and wavefront amplitude can be obtained by algebraic operation of speckle amplitude. The reconstructed wavefront is used for inverse Fourier transform to yield a two-dimensional image. A series of speckled images is averaged to form an incoherent image. Finally, the validity of the proposed technique is verified by simulations. From the simulation results, the image quality of the proposed method is better than that of the traditional method in the same amount of measurement. Furthermore, on the premise of the same image quality, the data acquisition amount of the proposed method is 2-3 times as large as that of the traditional method. In other words, compared with that of the traditional method, the data acquisition time of the proposed method is reduced at least by half and the algorithm processing time is less. It can be concluded that the proposed imaging technique can not only improve the efficiency of target reconstruction, but also present a better way of imaging the remote moving targets. ? 2017 Chinese Physical Society.
Accession Number: 20173103998755
Record 130 of

Title:Nonlinear Interference Spectrum Data Reconstruction Algorithm for Image Plane Interference

Author(s):Zhang, Zhinan(1); Li, Libo(1); Hu, Bingliang(1); Chen, Jiejing(1,2); Gao, Xiaohui(1,2); Yang, Fanchao(1)
Source: Guangxue Xuebao/Acta Optica Sinica Volume: 37 Issue: 6 DOI: 10.3788/AOS201737.0630002 Published: June 10, 2017
Abstract:The static Michelson interferometer is an entity type image plane interferometer, which can solve the technical difficulty of large field of view of interferometer. In the sampling process, nonlinear interference error is introduced by the interferometer, which leads to a consequence that the spectrum cannot be recovered accurately, so the nonlinear interference error needs to be corrected. A theoretical model of nonlinear interference error is analyzed, a nonlinear interference spectrum data reconstruction algorithm is presented, and a simulation is carried out. The simulation results indicate that the target spectrum can be recovered successfully by the reconstruction algorithm with numerical fitting, and the nonlinear interference error is eliminated. The reconstruction algorithm using Cauchy dispersion formula fitting is more precise than the reconstruction algorithm using linear fitting, and the relative error between the recovery spectrum and the input spectrum is less than 0.7% at the absorption peak. ? 2017, Chinese Lasers Press. All right reserved.
Accession Number: 20173003967991
Record 131 of

Title:Midinfrared wavelength conversion in hydrogenated amorphous silicon waveguides

Author(s):Wang, Jiang(1,2); Wang, Zhaolu(1); Huang, Nan(1); Han, Jing(1); Li, Yongfang(2); Liu, Hongjun(1)
Source: Optical Engineering Volume: 56 Issue: 10 DOI: 10.1117/1.OE.56.10.107103 Published: October 1, 2017
Abstract:Midinfrared (MIR) wavelength conversion based on degenerate four-wave mixing is theoretically investigated in hydrogenated amorphous silicon (a-Si:H) waveguides. The broadband phase mismatch is achieved in the normal group-velocity dispersion regime. The conversion bandwidth is extended to 900 nm, and conversion efficiency of up to -14 dB with a pump power of 70 mW in a 2-mm long a-Si:H rib waveguides is obtained. This low-power on-chip wavelength converter will have potential for application in a wide range of MIR nonlinear optic devices. ? 2017 Society of Photo-Optical Instrumentation Engineers (SPIE).
Accession Number: 20174304306091
Record 132 of

Title:Fabrication and optical performances measurements of flexible chalcogenide imaging fiber bundles

Author(s):Wang, Xing-Feng(1,2); Yang, Jian-Feng(1); Yan, Xing-Tao(1); Chen, Guo-Qing(1,2); Xu, Yan-Tao(1)
Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 25 Issue: 12 DOI: 10.3788/OPE.20172512.3137 Published: December 1, 2017
Abstract:The academic meanings of infrared imaging fiber bundles were researched and their fabrication technologies were given. A kinds of flexible chalcogenide infrared imaging fiber bundles were fabricated, and their characteristics were tested. By taking As40S58Se2 and As40S60 as the rod and tube materials, the fibers were drawn by rod-in-tube technique. The infrared imaging fiber bundle with a core diameter of 40 μm and a cladding diameter of 50 μm was prepared by man-machine-integration technique and it shows squared arrangement which incorporates 576 individual fibers. A special experimental equipment was constructed. The properties of this imaging fiber bundle including spatial arrangement and shaping, blind-fiber ratio and optical transmission efficiency were measured, and the decrease of Modulation Transfer Function (MTF) in the system caused by infrared imaging fiber bundle were measured. Experimental results indicate that the fiber bundle shows a good spatial arrangement and shaping. The blind-fiber ratio is 2.7%, fiber attenuation loss is lower than 0.5 dB/m, and the optical efficiency is almost 31%. Moreover, The decrease of MTF resulted from the fiber bundle in the system is less than 10%. Finally, an infrared imaging experiment was implemented, and the result shows that fine infrared thermal images have been delivered through this system. ? 2017, Science Press. All right reserved.
Accession Number: 20180504692888

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