2014
2014
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Record 241 of
Title:Lightweight design of the rectangular mirror using topology optimization
Author(s):Xiang, Meng(1,2); Li, Fu(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9280 Issue: DOI: 10.1117/12.2067871 Published: 2014Abstract:That minimizing the mass of space optical remote sensor at the same time guaranteeing of structural rigidity and surface shape accuracy, became a new critical research topic. This paper achieves detailed design of meniscus rectangular lens body structure by taking the choice of materials, design of supporting structure and lightweight form of mirror into account. And we established lightweight concrete of the mirror under self-weight by the method of topological optimization design. For the optimization, we used a 3-D model of the rectangular mirror and calculated based on that making minimum weight of the mirror as an objective function constrained by the displacement of the mirror surface. Finally finite element analysis method was adopted to get the optimization results analyzed and compared with the traditional triangular lightweight model. Analysis results prove that: the new mirror is superior to the traditional model in surface accuracy and structural rigidity, PV value, RMS value and the lightweight rate. With enough high dynamic-static stiffness and thermal stability, this kind of mirror can meet the demand under the self-weight and the random vibration environment respectively. So this article puts forward a new idea in the lightweight design of rectangular mirror. ? 2014 SPIE.Accession Number: 20150800541561 -
Record 242 of
Title:Optical system design of near infrared spectroscopy based on polarized interference
Author(s):Xie, Zheng-Mao(1,2); Gao, Li-Min(1); He, Jun-Hua(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 43 Issue: 12 DOI: 10.3788/gzxb20144312.1222003 Published: December 1, 2014Abstract:Based on polarized interference principle, an optical system of near infrared spectroscopy with single optical path was proposed. For the tungsten halogen source coupled with optical fiber, the collimated and convergent systems using 90° off-axial parabolic mirror were designed. He-ne laser as source for sampling control was introduced, and the beams are combined and split with near infrared by a cold mirror. Two perpendicular Glan-thompson prisms are introduced as polarizers, within the compensated crystal and scanning wedge are set as optical phase compensator of the polarization interference. A near infrared polarization interference-based optical system was designed, whose wavelength band is from 800 nm to 1700 nm, theoretical spectrum resolution is better than 8 cm-1, and clear aperture is Φ10.4 mm. The results of quality evaluation show that the root mean square radius at marginal field of view according to the spot diagram is about 1.7 μm, the lateral chromatic aberration is 0.2 μm, and the geometric encircled energy at all the field of view has reached to 100% within a diameter of Φ14 μm. ?, 2014, Chinese Optical Society. All right reserved.Accession Number: 20150300425650 -
Record 243 of
Title:Real-time implementation of camera positioning algorithm based on FPGA & SOPC
Author(s):Yang, Mingcao(1,2); Qiu, Yuehong(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9282 Issue: DOI: 10.1117/12.2068208 Published: 2014Abstract:In recent years, with the development of positioning algorithm and FPGA, to achieve the camera positioning based on real-time implementation, rapidity, accuracy of FPGA has become a possibility by way of in-depth study of embedded hardware and dual camera positioning system, this thesis set up an infrared optical positioning system based on FPGA and SOPC system, which enables real-time positioning to mark points in space. Thesis completion include: (1) uses a CMOS sensor to extract the pixel of three objects with total feet, implemented through FPGA hardware driver, visible-light LED, used here as the target point of the instrument. (2) prior to extraction of the feature point coordinates, the image needs to be filtered to avoid affecting the physical properties of the system to bring the platform, where the median filtering. (3) Coordinate signs point to FPGA hardware circuit extraction, a new iterative threshold selection method for segmentation of images. Binary image is then segmented image tags, which calculates the coordinates of the feature points of the needle through the center of gravity method. (4) direct linear transformation (DLT) and extreme constraints method is applied to three-dimensional reconstruction of the plane array CMOS system space coordinates. using SOPC system on a chip here, taking advantage of dual-core computing systems, which let match and coordinate operations separately, thus increase processing speed. ? 2014 SPIE.Accession Number: 20150800543874 -
Record 244 of
Title:Optical system design of broadband astigmatism-free Czerny-turner spectrometer
Author(s):Zhao, Yiyi(1,2); Yang, Jianfeng(1); Xue, Bin(1); Yan, Xingtao(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 43 Issue: 4 DOI: Published: April 2014Abstract:For the development trend of miniaturization and high-resolution of spectrometer, an optical design with a simple structure, broadband, astigmatism-corrected micro spectrometer was designed. The principle and correction method of the aberration of crossed beam Czerny-turner spectrometer were analyzed in detail. The broadband astigmatism-corrected theory equations using cylindrical lens were deduced. For example, a micro spectrometer operating in 300-900 nm with an object NA of 0.08 has been designed. This spectrometer adopted crossed beam structure to minish its volume and used a cylindrical lens to remove astigmatism over the full bandwidth. The analyzed results demonstrated that this spectrometer with compact configuration and small volume corrected the astigmatism in the wide spectral region. The resolution of the spectrometer was better than 0.5 nm in the whole spectral region.Accession Number: 20142217774874 -
Record 245 of
Title:The research on measuring the extinction ratio of polarizing prism accurately
Author(s):Hao, Chong(1,2); Wu, Yi-Ming(1); Lu, Wei-Guo(1); Xiao, Mao-Sen(1); Li, Chun-Yan(1,2)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 43 Issue: 12 DOI: 10.3788/gzxb20144312.1223001 Published: December 1, 2014Abstract:In traditional method of testing the extinction rate of polarizing prism, as the incidence is not vertical and the position of extinction can't be located accurately, extinction ratio can be measured accurately neither. To solve this problem, taking Glan-Taylor prism for example, magneto-optic modulation was adopted to define the extinction place accurately, rotating the prism several times to decrease the nonlinear perturbation caused by oblique incidence. Simulation and experiment show that, the minimum and maximum light intensity can be gained, the extinction rate was also obtained and fulfilled the precision requirement. ?, 2014, Chinese Optical Society. All right reserved.Accession Number: 20150300425652 -
Record 246 of
Title:Best slant-plane estimation based stereo matching algorithm
Author(s):Cao, Xiaoqian(1,2); Ma, Caiwen(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 43 Issue: 3 DOI: Published: March 2014Abstract:A novel stereo matching algorithm based on best slant-plane estimation was proposed in this paper in the purpose of eliminating "stair-casing" which showed up frequently in the slant scene matching process where the window -based matching algorithm was used. In this procedure, a slant parameter vector was randomly attributed to every pixel in the reference image firstly, then, those vectors were iteratively propagated between neighbor pixels followed by a recursively slant-plane parameter refinement process for each pixels in the principle of whether a lower cost could be got under the new slant-plane parameter vectors, until the parameter vectors were converged to the best slant-plane parameter vectors while a sub-pixel disparity was got for each pixel in the reference image. Experiment results indicate the effectiveness of the algorithm, the performance of the algorithm on the slant scene is ranked on top of those state-of-art algorithm which is relatively close to the algorithm proposed here, while the performance on the normal scene is comparable with the state-of -art algorithm.Accession Number: 20142217774753 -
Record 247 of
Title:An improvement of embedded zerotree wavelet coding based on compressed sensing
Author(s):Chen, Zhi(1); Mu, Chenhao(1); Xu, Fan(2)Source: Proceedings of the IEEE International Conference on Software Engineering and Service Sciences, ICSESS Volume: Issue: DOI: 10.1109/ICSESS.2014.6933776 Published: October 21, 2014Abstract:Embedded zero-tree wavelet (EZW) is a kind of image compression algorithm which provides high compression rates fast. In order to improve the quality of reconstructed image after decoding, in this research, we put forward an improvement of embedded zerotree wavelet coding and simulate this new algorithm. This method takes full advantages of the Compressed Sensing (CS) theory and EZW. Simulation results demonstrated that the proposed method improved the quality of the unzipped image significantly. ? 2014 IEEE.Accession Number: 20144600195285 -
Record 248 of
Title:Study of push-broom infrared fiber image transmission system
Author(s):Zhao, Yi-Yi(1,2); Yang, Jian-Feng(1); Yan, Xing-Tao(1,2); Li, Fu(1); Xue, Bin(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 43 Issue: 2 DOI: 10.3788/gzxb20144302.0222002 Published: February 2014Abstract:The push-broom infrared remote sensing imaging technology plays an important role in the high-resolution earth observation, but the internal development of infrared imaging technology is baffled by the technical level of long-linear array infrared detector. To achieve high-resolution push-broom infrared imaging, a method by the use of line-plane-switching infrared fiber bundle was proposed. In this method, the linear array end of the imaging fiber bundle was used as a long-linear array infrared detector and the plane array end of the bundle was coupled by a mature small infrared focal plane array with the single fiber corresponding to the pixel of the focal plane. The main problem of the design of the objective lens and coupling lens in the infrared fiber image transmission system was analyzed. And a system with an objective lens and an coupling lens was designed for a kind of fiber bundle which has 4000×6 pixels on its entrance end and has 160×150 pixels on its exit end. The imaging performance of the objective lens and coupling lens were close to the diffraction limits while meeting special requirements of infrared fiber image transmission system. The presented design is a better reference for this kind of fiber image transmission system. The mean transfer function was introduced for evaluating the MTF of the overall optical system, and the simulation results show a good image quality.Accession Number: 20141217496712 -
Record 249 of
Title:Analysis of extinction ratio of a Glan-Taylor prism
Author(s):Li, Chunyan(1,2); Wu, Yiming(1); Gao, Limin(1); Lu, Weiguo(1,2); Wang, Weifeng(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 43 Issue: 1 DOI: Published: January 2014Abstract:The calculation formula of Glan-Taylor prism's transmittance between emanative lights' azimuth, incident angle and structure angle of prism was obtained by using refraction law and Fresnel formula as well as the ray-tracing method. The relationship between the extinction ratio and transmittance was indicated. By computer simulation of Matlab, the characteristic of extinction ratio in the whole azimuth was analyzed; the extinction ratio's transformation relationship along with incident angle and structure angle was investigated. From simulation results, we discover that the extinction ratio is unacted on the incident angle when the angle is in the vertical azimuth of prism's optical axis. And the ratio becomes bad with increasing of the structure angle. The theoretical results are in good agreement with problems appeared from practical system which verifies its correctness, and it explains the problem in project item. The work of this article has great guiding significance in the design and use of Glan-Taylor prism.Accession Number: 20141017420263 -
Record 250 of
Title:Design and simulation of the adaptive optics system based on mixed H2/H∞ control
Author(s):Zhao, Xin(1,2); Ma, Cai-Wen(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 43 Issue: 12 DOI: 10.3788/gzxb20144312.1201003 Published: December 1, 2014Abstract:To achieve small residual wavefront gradient tilt corrected by the adaptive optics system and good robust stability of the system, a mixed H2/H∞ control method for the adaptive optics system was proposed. In order to verify the control performance, the atmospheric turbulence wavefront gradient tilt was simulated, and the residual wavefront gradient tilt corrected by the adaptive optics wavefront gradient tilt correction test platform with the mixed H2/H∞ controller and by the one with the classic integral controller was compared. The robust stability of the two systems was compared as well. The result demonstrated that the test platform with the mixed H2/H∞ controller achieved not only smaller residual wavefront gradient tilt but also better robust stability compared to the one with the classic integral controller, and proved the efficiency of the mixed H2/H∞ control method for the adaptive optics system. ?, 2014, Chinese Optical Society. All right reserved.Accession Number: 20150300425636 -
Record 251 of
Title:Dynamics analysis on adhesive bonds of tilt mirror
Author(s):Cao, Shang(1,2); Ruan, Ping(1); Wang, Chao(1,2); Xu, Guangzhou(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9280 Issue: DOI: 10.1117/12.2068441 Published: 2014Abstract:Adhesive bonding technology has been widely applied in the field of space remote sensing. In order to make the adhesive bonds connecting the mirror and the fixed structures in a satellite launch or operation of dynamic environment without damage, the finite element model of the tilt mirror is essential to be established for dynamic analysis, as well as the experimental verification. There are detailed model and the equivalent stiffness model on the adhesive bonds. The modal, frequency response, random vibration and shock response are analyzed through the detailed model of the bonds. The stress of the three point mirror bonds is compared with the six point support mirror. The mechanics experiment is carried out based on the dynamics analysis. The results of calculation demonstrates that the impact of frequency response and random vibration on adhesive bonds is relatively little, while the impact of the shock response is large. The experimental verification shows that the stress of bonds with three points support mirror under shock response exceeds the shear strength, which leads to the separation of the mirror and the fixed structure and the improved six point support mirror is satisfied to the requirements. The dynamics analysis on adhesive bonds of tilt mirror makes sense for designing, assembling and mechanics experiment. ? 2014 SPIE.Accession Number: 20150800541547 -
Record 252 of
Title:Infrared small target detection based on bilateral filtering algorithm with similarity judgments
Author(s):Li, Yanbei(1,2); Li, Yan(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9300 Issue: DOI: 10.1117/12.2070949 Published: 2014Abstract:Infrared small target detection is part of the key technologies in infrared precision-guided, search and track system. Resulting from the relative distance of the infrared image system and the target is far, the target becomes small, faint and obscure. Furthermore, the interference of background clutter and system noise is intense. To solve the problem of infrared small target detection in a complex background, this paper proposes a bilateral filtering algorithm based on similarity judgments for infrared image background prediction. The algorithm introduces gradient factor and similarity judgment factor into traditional bilateral filtering. The two factors can enhance the accuracy of the algorithm for smooth region. At the same time, spatial proximity coefficients and gray similarity coefficient in the bilateral filtering are all expressed by the first two of McLaughlin expansion, which aiming at reducing the time overhead. Simulation results show that the proposed algorithm can effectively suppress complex background clutter in the infrared image and enhance target signal compared with the improved bilateral filtering algorithm, and it also can improve the signal to noise ratio (SNR) and contrast. Besides, this algorithm can reduce the computation time. In a word, this algorithm has a good background rejection performance. ? 2014 SPIE.Accession Number: 20150800547573