2017
2017
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Record 133 of
Title:Discovering diverse subset for unsupervised hyperspectral band selection
Author(s):Yuan, Yuan(1); Zheng, Xiangtao(1); Lu, Xiaoqiang(1)Source: IEEE Transactions on Image Processing Volume: 26 Issue: 1 DOI: 10.1109/TIP.2016.2617462 Published: January 2017Abstract:Band selection, as a special case of the feature selection problem, tries to remove redundant bands and select a few important bands to represent the whole image cube. This has attracted much attention, since the selected bands provide discriminative information for further applications and reduce the computational burden. Though hyperspectral band selection has gained rapid development in recent years, it is still a challenging task because of the following requirements: 1) an effective model can capture the underlying relations between different high-dimensional spectral bands; 2) a fast and robust measure function can adapt to general hyperspectral tasks; and 3) an efficient search strategy can find the desired selected bands in reasonable computational time. To satisfy these requirements, a multigraph determinantal point process (MDPP) model is proposed to capture the full structure between different bands and efficiently find the optimal band subset in extensive hyperspectral applications. There are three main contributions: 1) graphical model is naturally transferred to address band selection problem by the proposed MDPP; 2) multiple graphs are designed to capture the intrinsic relationships between hyperspectral bands; and 3) mixture DPP is proposed to model the multiple dependencies in the proposed multiple graphs, and offers an efficient search strategy to select the optimal bands. To verify the superiority of the proposed method, experiments have been conducted on three hyperspectral applications, such as hyperspectral classification, anomaly detection, and target detection. The reliability of the proposed method in generic hyperspectral tasks is experimentally proved on four real-world hyperspectral data sets. ? 1992-2012 IEEE.Accession Number: 20170703341448 -
Record 134 of
Title:A hydrophobic and abrasion-resistant MgF2 coating with an ultralow refractive index for double-layer broadband antireflective coatings
Author(s):Cui, Xinmin(1,2); Ding, Ruimin(1); Wang, Mengchao(1,2); Wang, Conghui(1,2); Zhang, Jing(1,2); Wang, Jing(1,2); Dong, Wensheng(3); Xu, Yao(4)Source: Journal of Materials Chemistry C Volume: 5 Issue: 12 DOI: 10.1039/c6tc05307f Published: 2017Abstract:An ultralow-index top layer is a prerequisite to preparing high-performance broadband AR coatings. When coupled with hydrophobicity and the abrasion-resistance required in practical applications, the challenge becomes even greater. In this work, a MgF2 AR coating was studied because of the low refractive index of MgF2 and its easily realized strong adhesion through low-temperature heat treatment. In order to obtain an ultralow refractive index and endow the coating with hydrophobicity, we designed several experimental routes and finally adopted MTES/TEOS co-precursors to direct MgF2 particles to form a honeycomb-like network structure without a template. A final refractive index of 1.15 and good hydrophobicity, with a water contact angle of 122°, were obtained using the MgF2-SiO2(CH3) coating. These superior properties were attributed to the incorporation of methyl groups, which not only endowed the coating with hydrophobicity, but also changed the original linear assembly of MgF2 particles to a circular assembly. Using this hydrophobic ultralow-index coating as a top layer, a high-performance double-layer AR coating was fabricated with a high average transmittance of 99.43% in the wavelength range of 400-1000 nm, good abrasion-resistance, and damp heat resistance after a low-temperature heat treatment of 250 °C. This MgF2 double-layer AR coating may be used in display devices or lenses. ? The Royal Society of Chemistry.Accession Number: 20171303500899 -
Record 135 of
Title:Design and Implementation of the Intelligent Streak Camera Control System Based on Internet of Things
Author(s):Lü, Bin(1,2); Pei, Cheng-Quan(3); Tian, Jin-Shou(1); Wen, Wen-Long(1); Wang, Jun-Feng(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 46 Issue: 5 DOI: 10.3788/gzxb20174605.0522002 Published: May 1, 2017Abstract:A distributed intelligent control system was implemented to make streak cameras more protable and intelligent, which achieved the monitoring of working parameters, precise control of the electrode voltage and scanning patterns, additionally, image acquisition and processing. Based on the structure of Internet of things and client-server model, the system realized multimachine collaboration capabilities about wired and wireless devices extension and mobile monitoring. Furthermore, an adjustable self-protection high voltage ringing choke converter was designed for the system. The power supply realized the miniaturization by the simply self-excited topological structure, and its linear adjustment accuracy can reach 1%.The picosecond visible light streak camera with the intelligent control system was calibrated by the Nd:YLF pulse laser (Wavelength of 526.5 nmand pulse width of 8 ps).A dynamic spatial resolution of 20 lp/mm (CTF=14%), a dynamic range of 234:1 and a temporal resolution of 14 ps were reached. ? 2017, Science Press. All right reserved.Accession Number: 20173104014253 -
Record 136 of
Title:Study of visibility enhancement of hazy images based on dark channel prior in polarimetric imaging
Author(s):Zhang, Wenfei(1,2,3); Liang, Jian(1,3); Ju, Haijuan(1,3); Ren, Liyong(1); Qu, Enshi(1); Wu, Zhaoxin(2)Source: Optik Volume: 130 Issue: DOI: 10.1016/j.ijleo.2016.11.047 Published: February 1, 2017Abstract:During past decades, lots of efforts on image dehazing have been made based on either computer vision or physical models. In this paper, based on the combination of the polarimetric imaging and the dark channel prior techniques, we propose a novel haze-removal method. On the one hand, the former technique ensures this method has the advantage of keeping the detailed information which might be almost vanished in hazy images; on the other hand, the latter technique provides a much easier way to precisely estimate the key parameters, such as the global atmospheric light and the degree of polarization of the airlight. Moreover, in order to realize the automatically dehazing process with our method, a dynamic bias factor is creatively introduced into the dehazing process by use of the evaluation function—Entropy, ensuring excellent dehazed image being automatically obtained while not involving any other human-computer interaction. Experimental results indicate that our dehazing method can not only enhance the visibility of the hazy images effectively, but also preserve the details considerably. In addition, it is also found that this method is useful and effective for thin, medium and dense haze conditions, and thus shows a good robustness and universality. ? 2016 Elsevier GmbHAccession Number: 20164803061120 -
Record 137 of
Title:Robust multiframe images super resolution
Author(s):Zong, Caihui(1,2); Zhao, Hui(1); Xie, Xiaopeng(1,2); Li, Chuang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10462 Issue: DOI: 10.1117/12.2285139 Published: 2017Abstract:Super-resolution image reconstruction is a process to reconstruct high-resolution images from shifted, low-resolution, degraded observations. In the last two decades, a variety of super-resolution methods have been proposed. These methods are usually very sensitive to their assumed model of data and noise, which limits their utility. This paper reviews some of these methods and addresses their shortcomings. We propose an alternate approach using 1norm minimization and robust regularization based on a bilateral prior to deal with different data and noise models. This computationally inexpensive method is robust to errors in motion and blur estimation and results in images with sharp edges. Experimental results confirm the effectiveness of our method and demonstrate its superiority to other super-resolution methods. ? 2017 SPIE.Accession Number: 20180404671161 -
Record 138 of
Title:RESEARCH for gate drive technology based on image intensifier
Author(s):Xu, Guangqiang(1,3); Liu, Baiyu(1,2); Gou, Yongsheng(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10255 Issue: DOI: 10.1117/12.2267602 Published: 2017Abstract:In order to improve the dynamic range and the signal-noise ratio of the image intensifier, keep the flux of the screen of image intensifier constant. In the article, introduced a design of the switching power supply and tested its performance. Firstly, used a sampling amplifier amplify the feedback current signals. The feedback signals were converted into square wave signals through a digital circuit. Then, using the MOSFET in the post stage circuit produced high voltage and high speed adjustable square pulses. The frequency of the pulse is 1 kHz, the speed of the cutting edge is 20ns and the amplitude is 200V. The photoelectron emission time of the photocathode is short when the width of the high speed pulse is narrow for strong illumination. On the contrary, the time is long when the width is wide for weak illumination. The number of photoelectron is a constant no matter what kind of the illumination. It keeps the flux reaching the phosphor screen constant. ? 2017 SPIE.Accession Number: 20171403514732 -
Record 139 of
Title:Study of fuzzy PID controller for velocity circuit of optical-electronic theodolite
Author(s):Li, Gengxin(1,2); Yang, Xiaojun(1); He, Saixian(3)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10256 Issue: DOI: 10.1117/12.2257303 Published: 2017Abstract:Two-axis stabilized turntable is an important part of optical-electronic theodolite, it carries various of measuring instruments. In order to improve the response speed of the optical-electronic theodolite when tracking high speed target. In the same time, improve the stability and precision when tracking low speed target. The traditional servo controller is double close-loop structure. On the basis of traditional structure, we use the fuzzy control theory to design the servo control speed loop adjuster as a fuzzy PID controller, and the position loop is designed as a traditional first order adjuster. We introduce the theory and characteristics of PID control and fuzzy control, and discussed the structure of the speed loop fussy controller and the tuning method of the PID parameters. The fuzzy PID controller was studied with simulation on the MATLAB/Simulink platform, the performance indexes and the anti-jamming abilities of the fussy PID controller and the traditional PID controller were compared. The experiment results show that the fussy PID controller has the ability of parameter self-tuning, and its tacking ability is much better than the traditional PID controller. ? 2017 SPIE.Accession Number: 20171703607648 -
Record 140 of
Title:Constrained Low-Rank Learning Using Least Squares-Based Regularization
Author(s):Li, Ping(1); Yu, Jun(1); Wang, Meng(2); Zhang, Luming(2,3); Cai, Deng(4); Li, Xuelong(5)Source: IEEE Transactions on Cybernetics Volume: 47 Issue: 12 DOI: 10.1109/TCYB.2016.2623638 Published: December 2017Abstract:Low-rank learning has attracted much attention recently due to its efficacy in a rich variety of real-world tasks, e.g., subspace segmentation and image categorization. Most low-rank methods are incapable of capturing low-dimensional subspace for supervised learning tasks, e.g., classification and regression. This paper aims to learn both the discriminant low-rank representation (LRR) and the robust projecting subspace in a supervised manner. To achieve this goal, we cast the problem into a constrained rank minimization framework by adopting the least squares regularization. Naturally, the data label structure tends to resemble that of the corresponding low-dimensional representation, which is derived from the robust subspace projection of clean data by low-rank learning. Moreover, the low-dimensional representation of original data can be paired with some informative structure by imposing an appropriate constraint, e.g., Laplacian regularizer. Therefore, we propose a novel constrained LRR method. The objective function is formulated as a constrained nuclear norm minimization problem, which can be solved by the inexact augmented Lagrange multiplier algorithm. Extensive experiments on image classification, human pose estimation, and robust face recovery have confirmed the superiority of our method. ? 2016 IEEE.Accession Number: 20164703043637 -
Record 141 of
Title:Mid-infrared transmitter and receiver modules for free-space optical communication
Author(s):Hao, Qiang(1); Zhu, Guoshen(1); Yang, Song(1); Yang, Kangwen(1); Duan, Tao(2); Xie, Xiaoping(2); Huang, Kun(3); Zeng, Heping(1,4)Source: Applied Optics Volume: 56 Issue: 8 DOI: 10.1364/AO.56.002260 Published: March 10, 2017Abstract:We report on the experimental implementation of single-frequency fiber-laser pumped mid-infrared (mid-IR) transmitter and receiver modules for free-space communications. These modules enable frequency upconversion and downconversion between the 1550-nm telecom wavelength and the mid-IR, thus providing essential free-space transmission links with mid-IR single-frequency lasers in the 3.6 μm region. Specifically, based on difference frequency generation (DFG) in MgO-doped periodically poled LiNbO3 (MgO:PPLN), the mid-IR transmitter produces 9.3-mW power at 3594 nm with 5-W pump power at 1083 nm ( ? 2017 Optical Society of America.Accession Number: 20171103448075 -
Record 142 of
Title:Design of imaging circuitry of space CCD camera based on FPGA
Author(s):Liu, Meiying(1,2); Wen, Desheng(1); Wang, Hu(1); Liu, Yang(1); Zhao, Hui(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10462 Issue: DOI: 10.1117/12.2284098 Published: 2017Abstract:A imaging system of area-Array CCD cameras based on FPGA was designed. The overall structure and design of the system was introduced in detail. According to the working mode and driving timing requirements of this CCD image sensor, the driving schedule under the control of FPGA was designed. The working mode and parameters of such an imaging system were aligned with the control signals in accordance with the general requirements of space CCD cameras. With FPGA device as the platform of hardware design, the hardware of integrated timing and control system was described in VHDL language. The A/D converter AD9945 based on the correlated double sampling was used to realize the analog-digital (A/D) conversion of ICX285AL output signals. The XQR2V3000-4CG717V developed by Xilinx was chosen to accomplish the design of this hardware circuit. Through simulation, the correctness of driving schedule was verified, thus preparing necessary hardware for the final development of space area-Array CCD cameras with high performance. ? 2017 SPIE.Accession Number: 20180404671116 -
Record 143 of
Title:Hyperspectral image band selection via global optimal clustering
Author(s):Zhang, Fahong(1); Wang, Qi(1); Li, Xuelong(2)Source: International Geoscience and Remote Sensing Symposium (IGARSS) Volume: 2017-July Issue: DOI: 10.1109/IGARSS.2017.8126818 Published: December 1, 2017Abstract:Band selection, by choosing a set of representative bands in hyperspectral images (HSI), is concerned to be an effective method to eliminate the 'Hughes phenomenon'. In this paper, we present a global optimal clustering-based band selection (GOC) algorithm based on the hypothesis that all the bands in a cluster are continuous at their wavelengths. After the clustering result is obtained, we propose a greedy-based method to select representative bands in each cluster, trying to minimize the linear reconstruction error. Experiment on a real HSI dataset shows that the proposed method outperforms the state-of-the-art competitors. ? 2017 IEEE.Accession Number: 20180704799262 -
Record 144 of
Title:Study of the characteristics about the digital holography with spherical and plane reference wave
Author(s):Zhu, Meng(1,2); Bai, Jianming(1); Xiao, Maosen(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10464 Issue: DOI: 10.1117/12.2285037 Published: 2017Abstract:In order to design and optimize the optical system of digital holography, rebuild the object field with high quality, the characteristics of imaging system with spherical and plane reference wave are demonstrated respectively based on optical scalar diffraction theory. Based on the discrete Fresnel diffraction integral, recording and reconstruction of hologram with plane reference wave as well as the impact of CCD size and reconstructed distance on holographic imaging have been simulated with matlab. The simulation results show that: zero-order image and twin images are spatially separated when choosing the parameters of recording system properly; the quality of rebuild image suffers as CCD decreases in size and the reconstruction distance deviates from the recording distance. ? 2018 SPIE.Accession Number: 20180304653151