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2015

Record 85 of

Title:Thermal design and analysis for fiber optic gyroscope combination

Author(s):Liu, Ying(1); Fan, Yongqing(1); Xu, Jintao(2)
Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 44 Issue: 12 DOI: Published: December 25, 2015
Abstract:In order to meet the requirements of environmental temperature, complete quickly and reliably the design scheme of FOG combination, the thermal design and analysis of FOG combination were carried out. The combination model and finite element model were established, the boundary conditions and constraints conditions were set, the temperature and the reliability of the key components and assemblies of the combination FOG were analyzed in entire temperature cycles. Finally, the maximum temperature of DSP was reduced by 10℃, the maximum temperature of DC/DC power modules was from the original 90℃ down to 70℃, the all critical components and assemblies were working within their rated temperature range through the way of thermal design, the uniformity of fiber optic gyroscope combination of internal temperature field was improved, from the original 30℃ down to 10℃, a basis was provided to determine the design of scheme. ? 2015, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.
Accession Number: 20160401852703
Record 86 of

Title:Low-cost robust polymer optical fiber temperature sensor based on FIR method for in situ measurement

Author(s):Du, Xin-Chao(1,2); He, Zheng-Quan(1); Lin, Xiao(1); Zhou, Li-Bin(3); Hu, Bao-Wen(1); Luo, Bao-Ke(1); Guo, Xiao-Yi(1); Kong, De-Peng(1); Ren, Li-Yong(1); Li, Yu-Lin(1)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 44 Issue: 4 DOI: 10.3788/gzxb20154404.0406003 Published: April 1, 2015
Abstract:An optical fiber temperature sensor using two fluorescent dyes based on Fluorescence Intensity Ratiometric (FIR) method was proposed. In experiment, Rhodamine B and Rhodamine 110, which were temperature-sensitive and temperature-insensitive respectively, acted as the sensing materials. Polymer optical fibers were utilized to transmit excitation light and collect emitted fluorescence. The two dyes- fluorescence spectra could be separated conveniently since their respective emission peaks were 60 nm apart. The optimal spectral intervals of RH110 and RHB for FIR were identified. By calculating the fluorescence intensity ratio of the two dyes, the calibration curves of intensities ratios vs temperature were obtained with good linearity. The effects of different concentrations of fluorophore on the calibration curves were also studied. When the concentrations of dyes were 0.3 g/L, a minimum rms temperature error of 0.28℃ and a sensitivity of 0.0128/℃ were achieved. Moreover, the influences of illumination source-s fluctuations and dyes- photo-bleaching can be eliminated to some degree. ?, 2015, Chinese Optical Society. All right reserved.
Accession Number: 20152100877442
Record 87 of

Title:A new X-ray framing camera with picoseconds time resolution

Author(s):Gou, Yongsheng(1,2); Bai, Yonglin(1); Liu, Baiyu(1); Bai, Xiaohong(1); Qin, Junjun(1); Wang, Bo(1); Zhu, Bingli(1); Peng, Xu(1); Cao, Weiwei(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9674 Issue: DOI: 10.1117/12.2197312 Published: 2015
Abstract:A new method to get a X-ray framing camera with picoseconds time resolution was proposed based on time amplification. Its principle comes from that we use high voltage electrical pulse to get speed dispersion of the photoelectrons pulse first, and then the photoelectrons pulse will be stretched in axial direction by drift area, at the end the photoelectrons pulse after stretched will be framing imaged by a traditional MCP?1/4 microchannel plate?1/4‰gated framing camera. A model of the camera was built according to this method. Time amplification of the system is about 30, and image magnification of the system is about 0.4. Parameters for designing the camera system were presented after theoretical deriving and model simulation. At last, theoretical time resolution and spatial resolution of the camera were given. ? 2015 SPIE.
Accession Number: 20155201719107
Record 88 of

Title:Application of phase demodulation technique in turbid medium imaging

Author(s):Zhou, Libin(1,2); Du, Xinchao(3); He, Zhengquan(3); Sun, Hao(1); Yuan, Liutong(1); Zhang, Xiaolei(1); Hu, Manli(1); Li, Yulin(3)
Source: Guangxue Xuebao/Acta Optica Sinica Volume: 35 Issue: DOI: 10.3788/AOS201535.s111005 Published: July 10, 2015
Abstract:Multiple light scattering caused by turbid medium can distort the propagation of waves, thus the image will become blurred. A novel method called turbid lens imaging (TLI) is adopted to reconstruct this kind of distorted images. In this method, the complex electric field of output light needs to be obtained to calculate transfer matrix of turbid medium. Only the intensity information is recorded by CCD, the phase information will be merged in recorded images. As speckle images are generated when the incident light transmits through turbid medium, there will be obvious error in the phase retrieved by using Hilbert transform directly on the interference fringe pattern. In order to eliminate the influence of speckle intensity changes, the distorted wave image, reference beam image, light interference fringe image and background image are recorded respectively. According to the interference theory, interference cosine factor can be computed, and it will retrieve phase of distorted waves more accurately by using Hilbert transform on cosine factor. In the above method, the complex electric field of distorted wave and the transfer matrix of the turbid medium are successfully calculated. It is more accurate as the amplitude is measured directly. For speckle fringe, the calculation results are much more accurate than the Hilbert transform phase demodulation results. ?, 2015, Chinese Optical Society. All right reserved.
Accession Number: 20154601546826
Record 89 of

Title:A fiber-optic temperature sensor based on dual fluorescence by using FIR method

Author(s):Du, Xinchao(1,2); Zhou, Libin(3); He, Zhengquan(1); Liu, Feng(1); Lin, Xiao(1,2); Hu, Baowen(1); Guo, Xiaoyi(1); Luo, Baoke(1); Ren, Liyong(1); Li, Yulin(1)
Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 42 Issue: 8 DOI: 10.3788/CJL201542.0805002 Published: August 10, 2015
Abstract:A fiber-optic temperature sensor based on fluorescence intensity ratiometric (FIR) method is proposed and investigated experimentally. Plastic optical fibers are employed for transmitting the excitation light and collecting the Rhodamine B (RHB) and Rhodamine110 (RH110) fluorescence signals. Given that the fluorescence intensity of RHB is temperature-dependent while that of RH110 is temperature-independent, the temperature can be measured by calculating the fluorescence intensity ratio of these two dyes. To achieve a desired performance, the optimal integration ranges of fluorescence intensities of the two dyes are identified via considerable experimental tests. Indeed, a precise measurement is achieved in experiments. The feasible range of temperatures is from 25℃ to 60℃; a minimum rms temperature error of 0.38℃ and a sensitivity of 0.0134/℃ are achieved. Further, the proposed sensor is proved to be insensitive to fiber bending for bend radii exceeding 9 mm. Thus, the sensor can be used for in situ temperature monitoring. ?, 2015, Science Press. All right reserved.
Accession Number: 20153901314710
Record 90 of

Title:A design of digital processing circuit for the duo-lateral PSD

Author(s):Zhou, Weixiang(1,2); Liang, Yanbing(1); Wang, Xiaoyang(1,2)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9674 Issue: DOI: 10.1117/12.2199670 Published: 2015
Abstract:Beam pointing stability control technology detecting the vibration of the optical platform by detectors, using the fast steering mirror compensated the vibration displacement, thereby maintaining a stable beam. Position Sensitive Detector (PSD) as a sensitive position detection system components, its performance significantly affect the overall accuracy of the test system. This article selects Sitek's two-dimensional duo-lateral PSD: 2L20-CP7. By analyzing the measurement principle of the PSD, we designed a reverse bias circuit, I-V converted circuit, A/D converted circuit and control circuit which FPGA as a controller, testing the output current value to verify the reasonableness of the circuit design, and calculate the location information according to formula. We also made a measured grid chart diagram and distortion based on the application of computer, so dose error analysis. We concluded that the linearity of this PSD is better, and it can be applied in the high-precision systems. ? 2015 SPIE.
Accession Number: 20155201719144
Record 91 of

Title:Learning a nonnegative sparse graph for linear regression

Author(s):Fang, Xiaozhao(1); Xu, Yong(1,2); Li, Xuelong(3); Lai, Zhihui(1,4); Wong, Wai Keung(5,6)
Source: IEEE Transactions on Image Processing Volume: 24 Issue: 9 DOI: 10.1109/TIP.2015.2425545 Published: September 1, 2015
Abstract:Previous graph-based semisupervised learning (G-SSL) methods have the following drawbacks: 1) they usually predefine the graph structure and then use it to perform label prediction, which cannot guarantee an overall optimum and 2) they only focus on the label prediction or the graph structure construction but are not competent in handling new samples. To this end, a novel nonnegative sparse graph (NNSG) learning method was first proposed. Then, both the label prediction and projection learning were integrated into linear regression. Finally, the linear regression and graph structure learning were unified within the same framework to overcome these two drawbacks. Therefore, a novel method, named learning a NNSG for linear regression was presented, in which the linear regression and graph learning were simultaneously performed to guarantee an overall optimum. In the learning process, the label information can be accurately propagated via the graph structure so that the linear regression can learn a discriminative projection to better fit sample labels and accurately classify new samples. An effective algorithm was designed to solve the corresponding optimization problem with fast convergence. Furthermore, NNSG provides a unified perceptiveness for a number of graph-based learning methods and linear regression methods. The experimental results showed that NNSG can obtain very high classification accuracy and greatly outperforms conventional G-SSL methods, especially some conventional graph construction methods. ? 2015 IEEE.
Accession Number: 20152400934712
Record 92 of

Title:Haze removal using dark channel for remote sensing images of natural disaster

Author(s):Gan, Yu-Quan(1,2); Wen, De-Sheng(1,2); Wang, Le(1,2); Gao, Xiao-Hui(1,2); Wei, Cui-Yu(1,2)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 44 Issue: 6 DOI: 10.3788/gzxb20154406.0610003 Published: June 1, 2015
Abstract:In order to remove the haze in natural disaster remote sensing images, an approach based on dark channel and hazy image degradation model was presented, which could remove the haze by using guided filter. Firstly, images of natural disaster were divided into fog area and mist area by threshd, and different methods were used to obtain the dark channel of the images.Then, guided filter was used to optimize the transmmission map, and the contrast of the images was stretched to improve the dynamic range of the images. A series of natural disaster remote sensing images were chosen to test the alogrithm of haze removal. Finally, a series of evaluate parameters were proposed to assess the method. The result shows that the proposed algorithm can remove the haze of the images, improve the image quality, and enhance the color and detail of the images, so that the high-quality images can be obtained, which meet the requirements of haze removal for natural disaster remote sensing images to some extent. ?, 2015, Chinese Optical Society. All right reserved.
Accession Number: 20152901043457
Record 93 of

Title:Design and implementation of a Cooke triplet based wave-front coded super-resolution imaging system

Author(s):Zhao, Hui(1); Wei, Jingxuan(2)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9630 Issue: DOI: 10.1117/12.2190814 Published: 2015
Abstract:Wave-front coding is a powerful technique that could be used to extend the DOF (depth of focus) of incoherent imaging system. It is the suitably designed phase mask that makes the system defocus invariant and it is the de-convolution algorithm that generates the clear image with large DOF. Compared with the traditional imaging system, the point spread function (PSF) in wave-front coded imaging system has quite a large support size and this characteristic makes wave-front coding be capable of realizing super-resolution imaging without replacing the current sensor with one of smaller pitch size. An amplification based single image super-resolution reconstruction procedure has been specifically designed for wave-front coded imaging system and its effectiveness has been demonstrated experimentally. A Cooke Triplet based wave-front coded imaging system is established. For a focal length of 50 mm and f-number 4.5, objects within the range [5 m, ∞] could be clearly imaged, which indicates a DOF extension ratio of approximately 20. At the same time, the proposed processing procedure could produce at least 3× resolution improvement, with the quality of the reconstructed super-resolution image approaching the diffraction limit. ? 2015 SPIE.
Accession Number: 20161202113876
Record 94 of

Title:Research and design of portable photoelectric rotary table data-Acquisition and analysis system

Author(s):Yang, Dawei(1); Yang, Xiufang(1); Han, Junfeng(2); Yan, Xiaoxu(3)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9449 Issue: DOI: 10.1117/12.2075398 Published: 2015
Abstract:Photoelectric rotary table as the main test tracking measurement platform, widely use in shooting range and aerospace fields. In the range of photoelectric tracking measurement system, in order to meet the photoelectric testing instruments and equipment of laboratory and field application demand, research and design the portable photoelectric rotary table data acquisition and analysis system, and introduces the FPGA device based on Xilinx company Virtex-4 series and its peripheral module of the system hardware design, and the software design of host computer in VC++ 6.0 programming platform and MFC package based on class libraries. The data acquisition and analysis system for data acquisition, display and storage, commission control, analysis, laboratory wave playback, transmission and fault diagnosis, and other functions into an organic whole, has the advantages of small volume, can be embedded, high speed, portable, simple operation, etc. By photoelectric tracking turntable as experimental object, carries on the system software and hardware alignment, the experimental results show that the system can realize the data acquisition, analysis and processing of photoelectric tracking equipment and control of turntable debugging good, and measurement results are accurate, reliable and good maintainability and extensibility. The research design for advancing the photoelectric tracking measurement equipment debugging for diagnosis and condition monitoring and fault analysis as well as the standardization and normalization of the interface and improve the maintainability of equipment is of great significance, and has certain innovative and practical value.. ? 2015 SPIE.
Accession Number: 20151100635503
Record 95 of

Title:The research on measurement technology of high dynamic range laser focal spot

Author(s):Wang, Zhengzhou(1,2,3); Hu, Bingliang(3); Yin, Qinye(1); Cao, Shikang(3); Wang, Wei(3)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9677 Issue: DOI: 10.1117/12.2197290 Published: 2015
Abstract:In order to obtain the far-field distribution of high dynamic range laser focal spot, the mathematical model of schlieren method to measure the far-field focal spot was proposed, and the traditional schlieren reconstructed algorithm was optimized in many aspects in this paper. First of all, the mathematical model which used to measure the far-field focal spot was created, the amplificatory coefficient K of the main lobe intensity and amplificatory coefficient b of the laser spot area were selected; Secondly, the two important parameters were calibrated and the accurate main lobe spot and side lobe spot were captured by the integrated diagnostic beam fast automatic alignment system; Finally, the schlieren reconstructed algorithm was optimized by circle fitting method to calculate side lobe image center and weighted average method to fuse the joint image edge, and the error of traditional schlieren reconstruction method for side lobe center was reduced and the obvious joint mark of reconstructed image was eliminated completely. The method had been applied in a certain laser driver parameter measurement integrated diagnostic system to measure far-field laser focal spot. The experimental results show that the method can measure the far-field distribution of high dynamic range laser focal spot exactly on the condition that the parameter of mathematical model is calibrated accurately and the reconstructed algorithm of schlieren measure is optimized excellently. ? 2015 SPIE.
Accession Number: 20155201714886
Record 96 of

Title:Research on the high-brightness traffic variable message sign based on laser diodes

Author(s):Feng, Li-Li(1,2); Huang, Hai-Tao(3); Ruan, Chi(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9672 Issue: DOI: 10.1117/12.2196782 Published: 2015
Abstract:Researches indicate that foggy weather is one of the most critical factors that restrict human's traffic activities and cause traffic accidents. It will reduce the visibility of traffic message board, which could cause the insecurity of transportation. Commonly, light-emitting diodes (LEDs) were used as light source for variable message sign, which could not be seen clearly in the foggy low visibility condition. A high-brightness light source which could be used for variable information board was firstly put forward in this paper. And a new type of variable message sign used in low visibility condition was also introduced. Besides, the attenuation characteristics of laser diode (LD) and light-emitting diode (LED) were analyzed respectively. Calculation and simulation show that the attenuation of red light source is fastest, and the yellow LED light has the better transmittance property. In the experiment, LDs were used to make variable message board for verifying image definition. A 16?16 array structure composed of LDs was designed and could display Chinese characters. By comparing the display effect of LDs and LEDs driven with same power, they were placed in fog chamber of the visibility less than 5 meters. And experiment results show that the penetrability of red LD light is better than that of red LED. So traffic variable message sign based on LDs could improve the image definition and the information could be seen more clearly in the foggy weather. In addition to the high-brightness, good coherence, good direction, experimental results show that traffic variable message board based on LD has better visual effect in low visibility condition. ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
Accession Number: 20155201717816