2015
2015
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Record 229 of
Title:Optical system design for wide-angle airborne mapping camera with diffractive optical element
Author(s):Niu, Hai-Jun(1,2); Zhang, Jian(1); Yan, A-Qi(1,2); Leng, Han-Bing(1); Fei, Jia-Qi(1); Wu, Deng-Shan(1); Cao, Jian-Zhong(2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9449 Issue: DOI: 10.1117/12.2085042 Published: 2015Abstract:With the development of the digital airborne photo-grammetry technology, the more performances of the optical system for airborne mapping camera are required, such as the longer focal, the wider field of view (FOV), at the same time, the secondary spectrum correction becomes more important and difficult for the optical system design. A high performance optical system of airborne mapping camera with 200mm focus and2=60°FOV is designed in this paper. The range of work wavelength is from 430nm to 885nm. A two-layer HDOE with negative dispersive characteristic is used to eliminate the secondary spectrum in the process of optical system design. The diffraction efficiency of the designed two-layer HDOE is up to 90%. From the result of design, the MTFs in whole fields are over 0.5 at 90lp/mm, which shows that the system has a great image quality. Meantime, the thermal analysis is done at the temperature range between -20°C and 40°C, and the MTF curves of the system at-20°C ～40°C show that a great image quality is kept, which meets the design requirements. ? 2015 SPIE.Accession Number: 20151100635588 -
Record 230 of
Title:Approved square root Cubature Kalman Filtering and its application to POS
Author(s):Zhao, Bing(1,2); Cao, Jianzhong(1); Yang, Hongtao(1,2); Zhou, Zuofeng(1); Shi, Kui(1); Xu, Weigao(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 44 Issue: 9 DOI: Published: September 25, 2015Abstract:To solve the problems that extended Kalman filter is difficult to obtain the optimal state estimation of complex nonlinear system with fast convergence speed and high estimate accuracy, an improved square root Cubature Kalman Filtering algorithm was proposed by introducing the matrix QR decomposition and Cholesky factorization updating technology to traditional Cubature Kalman Filter, via it can validly avoid the complicated calculating of matrix decomposition and inverse. Moreover, aiming at the uncertainty of system's variable and statistical properties, a weighted adaptive noise covariance matrix estimator was constructed, through integrating the adaptive noise estimator under wavelet Kalman Filtering ideology. A-SRCKF was applied to airborne positioning and orientation system, the simulation results demonstrate that the proposed method can effectively improve the accuracy of POS outputs as well as enhance the efficiency. ?, 2015, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20154501520732 -
Record 231 of
Title:Bit error rate analysis of X-ray communication system
Author(s):Wang, Lü-Qiang(1,2); Su, Tong(1); Zhao, Bao-Sheng(1); Sheng, Li-Zhi(1); Liu, Yong-An(1); Liu, Duo(1,2)Source: Wuli Xuebao/Acta Physica Sinica Volume: 64 Issue: 12 DOI: 10.7498/aps.64.120701 Published: June 20, 2015Abstract:X-ray communication, which was firstly introduced by Keithe Gendreau in 2007, is potential to compete with conventional communication methods, such as microwave and laser communication, against space surroundings. As a result, a great deal of time and effort has been devoted to making the initial idea into reality in recent years. Eventually, the X-ray communication demonstration system based on the grid-controlled X-ray source and microchannel plate detector can deliver both audio and video information in a 6-meter vacuum tunnel. The point is how to evaluate this space X-ray demonstration system in a typical experimental way. The method is to design a specific board to measure the relationship between bit-error-rate and emitting power against various communicating distances. In addition, the data should be compared with the calculation and simulation results to estimate the referred theoretical model. The concept of using X-ray as signal carriers is confirmed by our first generation X-ray communication demonstration system. Specifically, the method is to use grid-controlled emission source as a transceiver while implementing the photon counting detector which can be regarded as an important orientation of future deep-space X-ray communication applications. As the key specification of any given communication system, bit-error-rate level should be informed first. In addition, the theoretical analysis by using Poisson noise model also has been implemented to support this novel communication concept. Previous experimental results indicated that the X-ray audio demonstration system requires a 10-4 bit-error-rate level with 25 kbps communication rate. The system bit-error-rate based on on-off keying (OOK) modulation is calculated and measured, which corresponds to the theoretical calculation commendably. Another point that should be taken into consideration is the emitting energy, which is the main restriction of current X-ray communication system. The designed experiment shows that the detected X-ray energy is 7 × 10-5 mW/m2. This relatively low power level not only restricts the bit rate of transceiver, but also increases the error fraction to some extent. Obviously, OOK modulation can meet the high communication rate and relatively low bit-error-rate requirement of current audio demo system. Current restriction has been pointed out and the potential improvement is also presented. ?, 2015, Chinese Physical Society. All right reserved.Accession Number: 20153001051133 -
Record 232 of
Title:Data correction techniques for the airborne large-aperture static image spectrometer based on image registration
Author(s):Zhang, Geng(1); Shi, Dalian(1); Wang, Shuang(1); Yu, Tao(1); Hu, Bingliang(1)Source: Journal of Applied Remote Sensing Volume: 9 Issue: 1 DOI: 10.1117/1.JRS.9.095088 Published: January 1, 2015Abstract:We propose an approach to correct the data of the airborne large-aperture static image spectrometer (LASIS). LASIS is a kind of stationary interferometer which compromises flux output and device stability. It acquires a series of interferograms to reconstruct the hyperspectral image cube. Reconstruction precision of the airborne LASIS data suffers from the instability of the plane platform. Usually, changes of plane attitudes, such as yaws, pitches, and rolls, can be precisely measured by the inertial measurement unit. However, the along-track and across-track translation errors are difficult to measure precisely. To solve this problem, we propose a co-optimization approach to compute the translation errors between the interferograms using an image registration technique which helps to correct the interferograms with subpixel precision. To demonstrate the effectiveness of our approach, experiments are run on real airborne LASIS data and our results are compared with those of the state-of-the-art approaches. ? 2015 Society of Photo-Optical Instrumentation Engineers.Accession Number: 20151200649030 -
Record 233 of
Title:Feature competition and partial sparse shape modeling for cardiac image sequences segmentation
Author(s):Qin, Xianjing(1,2); Tian, Yan(1); Yan, Pingkun(1)Source: Neurocomputing Volume: 149 Issue: PB DOI: 10.1016/j.neucom.2014.07.044 Published: February 3, 2015Abstract:The segmentation of endocardium and epicardium of left ventricle (LV) in cardiac MR image sequences play a crucial role in clinical applications. Active shape model (ASM) based methods are often used to extract the LV boundaries with the steps of searching and representation. However, due to the challenges, such as interior papillary muscles, complicated outside tissues and weak boundaries, the searching may be partially incorrect and the representation cannot reflect the reliable part of the contour. In this paper, a feature competition based searching strategy is proposed by exploiting both the information of the object and background to reduce the error of searching. Then, we propose a partial sparse shape model to effectively represent the searched shape. This representation is able to retain the partial reliable contour while reconstructing the unreliable part approximating to the real contour. Moreover, the incremental learning algorithm is exploited to construct a patient-specific appearance model to increase the accuracy and efficiency of image sequence segmentation. Experimental results on cardiac MR image sequences demonstrate that the proposed method improves the segmentation performance and also reduces the error accumulation compared to the existing methods. ? 2014 Elsevier B.V.Accession Number: 20150700515274 -
Record 234 of
Title:Application of improved particle-swarm-optimization in stabilized platform based on multiple reference frame model
Author(s):Fan, Xinming(1,2); Cao, Jianzhong(1); Yang, Hongtao(1); Wang, Huawei(1); Yang, Lei(1); Liao, Jiawen(1); Wang, Hua(1); Lei, Yangjie(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 44 Issue: 8 DOI: Published: August 25, 2015Abstract:In the conventional servo system, model analysis according to motor axis and base space is used as a reference. However, when analyzing the stabilized platform, it is not compatible due to in which exists inertial space and base space. In order to solve this problem, the multiple reference frame model was proposed, where direct-current motor model was based on inertial space. On the basis of the multiple reference frame model, an improved Particle Swarm Optimization (PSO) algorithm was also proposed. As a kind of swarm intelligence algorithm, PSO was widely used in parameters optimization. The traditional PSO on inertial weight and slopping-over borders were improved, and then, it was adopted in tuning and optimization of PID parameters. The simulation and experiments results indicate that the improved PSO (IPSO) PID controller can obviously enhance the static precision and effectively isolate the vibration and disturbance of carrier. ?, 2015, Chinese Society of Astronautics. All right reserved.Accession Number: 20153801295239 -
Record 235 of
Title:Optical tracking platform based on umbrella multi-tier distributed structure
Author(s):Qiao, Yongming(1,2); Ma, Caiwen(2); Jin, Humin(2); Hao, Wei(2); Lv, Tao(2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 44 Issue: 12 DOI: Published: December 25, 2015Abstract:The basic features that should be possessed are detecting long-distance target, capturing rapid target and tracking multiple target for a high-performance optical warning system. It is the basic condition to achieve the whole airspace closure detection. Due to inherent structural defects, there are some problems in the application of early warning for traditional optical tracking platform. A new concept of structure called umbrella multi-tier distributed load structure was proposed that was fitted in photoelectric tracking platform applied in optical warning. Through the structural feature of the new type of tracking platform, combining with measurement-mode plan of multi-detector, optimizing control and information processing system, it aims to solve the problems effectively that restricts the performance for optical warning system, such as the small searching field-goal; single target tracking; the top blind of tracking. It will break the bottleneck of optical tracking device application in optical warning system. ? 2015, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20160401852689 -
Record 236 of
Title:Detection of angular tracing precision of rotating mirror house in streak camera
Author(s):Zhao, Huai-Xue(1); Zhao, Jian-Ke(1); Tian, Liu-De(1,2); Xue, Xun(1); Pan, Liang(1); Duan, Jiong(1)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 23 Issue: 12 DOI: 10.3788/OPE.20152312.3303 Published: December 1, 2015Abstract:On the basis of the theoretic deduction and corresponding reasonable assumption, a mathematic model was built according to the flight model of exterior trajectory to improve the angular tracing precision of rotating mirror house in a streak camera. A test device was designed and developed for the angular tracing precision of rotating mirror house in the streak camera. The measuring principle of the test device was introduced, the angular tracing precision was measured by the developed device and the uncertainty factors of the tested device were analyzed. The tested results show that the angular tracing precision of the high speed rotating mirror in the streak camera is (0.34±0.06)°, the relative uncertainty of the tested device is 3.0″ and the main error sources come from interpretation and servo control. It concludes that the tested device designed has higher precision and reliability. ? 2015, Science Press. All right reserved.Accession Number: 20160801975745 -
Record 237 of
Title:Improving coherent field imaging quality by suppressing the influence of transmitting aperture spacing error
Author(s):Cheng, Zhi-Yuan(1,2); Ma, Cai-Wen(1); Luo, Xiu-Juan(1); Zhang, Yu(1,2); Zhu, Xiang-Ping(1,2); Xia, Ai-Li(1)Source: Wuli Xuebao/Acta Physica Sinica Volume: 64 Issue: 12 DOI: 10.7498/aps.64.124203 Published: June 20, 2015Abstract:Coherent field imaging is based on the assumption of equal transmitting apertures spacing and equal spectrum of laser, and high-resolution image is reconstructed by iteratively computing the frequency spectrum. However, the inevitable transmitting aperture spacing error of laser is a key factor to affect the coherent field imaging quality in the application. Aiming at the problem of degrading imaging quality caused by the transmitting aperture spacing error, we discuss the mechanism of influence of aperture spacing error on imaging quality and propose a novel method of improving imaging quality from the perspective of suppressing the influence of transmitting aperture spacing error. Firstly, the mechanism of the influence of aperture spacing error on imaging quality and laser echo spectrum is analyzed in detail. Then we derive a frequency spectrum error propagation model. Based on the model, the iterative effect of frequency spectrum error is investigated and the trend of variation in imaging quality with frequency spectrum error is given. We propose a theoretical equation, in which the transmitting aperture spacing error has no influence on frequency spectrum nor imaging quality. To solve the above equation, an optimized method of linear programming is proposed and the optimized matrix of aperture spacing error is obtained. In practice, the influence of aperture spacing error on imaging quality can be largely counteracted by reasonably allocating aperture spacing error according to the optimized spacing error matrix. The correctness and validity of the theoretical model are verified by a simulation experiment. The results show that the Strehl ratio of imaging quality index can be improved by about 100% through using the proposed method, the greater the aperture spacing error, the higher the Strehl ratio of imaging quality index obtained by the method will be. In addition, the method is easy to use practically and less costly as well. Finally, it is concluded that the proposed method can easily and effectively counteract the degrading effect of aperture spacing error on imaging quality. The research can provide a theoretical basis for improving imaging quality and reasonably assigning transmitter aperture spacing accuracy of coherent field imaging telescope. ?, 2015, Chinese Physical Society. All right reserved.Accession Number: 20153001051142 -
Record 238 of
Title:Investigations on the photoluminescence spectra and its defect-related nature for the ultraviolet transmitting fluoride-containing phosphate-based glasses
Author(s):Feng, Dandan(3); He, Quanlong(1,2); Lu, Min(1); Li, Weinan(1); Song, Weiwei(4); Wang, Pengfei(1); Peng, Bo(1)Source: Journal of Non-Crystalline Solids Volume: 425 Issue: DOI: 10.1016/j.jnoncrysol.2015.06.009 Published: June 15, 2015Abstract:Abstract Two types of fluoride-containing phosphate-based glasses were prepared under the reducing and ambient air atmosphere, respectively. And the interrelation between the micro-defects and luminescence for these glasses was investigated by studying their absorption, photoluminescence emission (PL) and excitation (PLE) spectra as well as electron spin resonance (ESR) spectra. The emission spectra under the excitation at 351 nm and the excitation spectra by monitoring the emission wavelength at 433 nm, 454 nm, 505 nm, 645 nm and 780 nm, together with the absorption spectra of these two types of glasses were investigated through Gaussian peak fitting method. Their photoluminescence spectra exhibit a general character with a broadband emission at around 430 nm and a minor band at around 645 nm. The photoluminescence excitation spectra and absorption spectra indicate that the Gaussian peak fitting of the emission spectra with the maximum at about 433, 455, 505 and 645 nm, respectively, are closely associated with phosphate-related oxygen hole center defects and fluorine-related color centers. In addition, the emission and excitation spectra of the glass samples after the thermal treatment process in hydrogen atmosphere manifest that the reducing conditions promote the formation of phosphate-related oxygen hole center defects, oxygen related hole center defects and fluorine-related non-paramagnetic color centers as well as PO43 - defects, while decrease the concentration level of Fe3 + and PO32 - defects. The investigations on the glasses' photoluminescence properties and their changes with the glass melting and thermal treatment atmosphere will promote the further development in preparation technology of the fluoride-containing phosphate-based glasses. ? 2015 Elsevier B.V.Accession Number: 20152400941786 -
Record 239 of
Title:Inner scale effect on scintillation index of flat-topped beam in non-Kolmogorov weak turbulence
Author(s):Zeng, Zhihong(1,2); Luo, Xiujuan(1); Xia, Aili(1); Zhang, Yu(1,2); Cao, Bei(1)Source: Applied Optics Volume: 54 Issue: 10 DOI: 10.1364/AO.54.002630 Published: April 1, 2015Abstract:A simpler generalized expression of irradiance fluctuation for flat-topped beams is presented based on the Born and Rytov perturbation methods. The theoretical expression of the on-axis scintillation index in non-Kolmogorov weak atmospheric optics links is developed using the generalized von Kármán spectrum model, and using the equivalent structure constant that is different for all power-law exponents. The effect of the inner scale on the on-axis scintillation index is examined comprehensively. It is observed that flat-topped beams happen to possess smaller scintillation indices at larger inner scale. The effects of the power law, flat-topped order, source size of the fundamental Gaussian beam, propagation distance, and wavelength are also analyzed. ? 2015 Optical Society of America.Accession Number: 20152701005014 -
Record 240 of
Title:Preparation and applications of low-loss As-S chalcogenide glass fibers
Author(s):Xu, Yan-Tao(1); Guo, Hai-Tao(1); Yan, Xing-Tao(1); Lu, Min(1); Lin, Ao-Xiang(1); Li, Fu(1); Yang, Jian-Feng(1); Zhan, Huan(1,2)Source: Wuji Cailiao Xuebao/Journal of Inorganic Materials Volume: 30 Issue: 1 DOI: 10.15541/jim20140252 Published: January 1, 2015Abstract:High-purity As-S glasses were prepared by repetitive distillation and open-type dynamic distillation methods. The intensities of impurities' absorptions were obviously reduced at 2.9 μm, 4 μm and 6.3 μm. Chalcogenide glass tubes with precise wall thickness and fine surface properties were prepared by tube-rotating technique and the fibers with core of 40 μm, cladding of 50 μm and error of 1% in diameter were drawn by rod-in-tube method. The fiber had good mechanical and optical performances, which general optical loss was less than 0.5 dB/m and the bending radius was less than 4 mm based on the bending test. The line-plane-switching fiber bundle which format was 64×9 quadrate array to implement 192×3 linear array was made from these chalcogenide glass and long-array infrared push-broom image was successfully demonstrated. The results prove that the fibers and bundle have excellent properties and push-broom infrared system based on the line-plane-switching fiber bundle being feasibility. ?, 2015, Science Press. All right reserved.Accession Number: 20150600502467