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2019

Record 109 of

Title:Target detection of hyperspectral image based on spectral saliency

Author(s):Zhang, Xiaorong(1,2,3); Pan, Zhibin(1); Hu, Bingliang(3); Zheng, Xi(4); Liu, Weihua(3)
Source: IET Image Processing Volume: 13 Issue: 2 DOI: 10.1049/iet-ipr.2017.1173 Published: February 7, 2019
Abstract:Target detection of hyperspectral image (HSI) is a research hotspot in the field of remote sensing. It is of particular importance in many domains, especially in military application. Unsupervised target detection is usually more difficult because there is no prior information about target. Traditional algorithms exploit spectral information, only. This study introduces the idea of saliency detection from the visual technique into HSI processing domain and proposes a novel approach named spectral saliency target detection (SSD). It establishes a novel salient model, which utilises both spatial saliency and spectral saliency. In the framework of SSD, it combines the model with spectral matching algorithm to make it perform well even in situations where the target is concealed and small. A HSI set comprised of eight different scenes with complex background is setup to evaluate the performance of the proposed algorithm. The final visible detection results demonstrate that the SSD algorithm outperforms the others. The receiver operation characteristic (ROC) curve and area under the ROC curve are applied to evaluate the results. The proposed algorithm shows superior and stable performance. ? The Institution of Engineering and Technology 2018.
Accession Number: 20190906561908
Record 110 of

Title:Design of X-ray Microscope Employing Toroid Mirrors Working at Grazing-incidence

Author(s):Cui, Ying(1,2,3); He, Jun-Hua(1); Wu, Bing-Jing(1); Yan, Ya-Dong(1); Xu, Rui-Hua(1)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 48 Issue: 12 DOI: 10.3788/gzxb20194812.1211002 Published: December 1, 2019
Abstract:In order to diagnose the physical process of laser inertial confinement fusion, a X-ray microscope was established. The imaging characteristics of the toroidal mirrors used in the system, optical design and parameter optimization, aberrations and tolerance analysis of the system and alignment were studied. Firstly, based on the requirements of plasma diagnosis, some optical system parameters were determined, and the the microscope for imaging the X-ray through the basic structure of two tandem toroidal mirrors in u-shaped arrangement and one planar mirror for spectrum selection was designed. The structural parameters of the three mirrors were preliminarily determined according to the anastigmatic focusing. Then the optical design software was used for modeling and optimization. The spherical aberration, coma aberration, field obliquity and astigmatism of X-ray microscope were also analyzed. By analyzing the influence of system parameters change on the image quality and the accuracy requirement of the system, reasonable tolerance was established. Finally, An auxiliary aiming system was designed to solve the off-axis problem of grazing incidence mounting of the toroid mirrors when adjusted offline, also a bidirectional binocular intersection online aiming system was designed to solve the problem of assembling and aiming accuracy of the system. Experiment results show that the resolution of the microscope is less than 5 μm at 500 μm field of view, which basically meets the requirements of large field of view and high resolution in laser plasma hard X-ray imaging. ? 2019, Science Press. All right reserved.
Accession Number: 20200708160477
Record 111 of

Title:Tunable broadband emission from red to blue by gamma radiation in multicomponent phosphate glasses

Author(s):He, Quanlong(1,2); Wang, Pengfei(1); Li, Weinan(1); Sun, Mengya(1,2); Lu, Min(1); Peng, Bo(1)
Source: Journal of the American Ceramic Society Volume: 102 Issue: 1 DOI: 10.1111/jace.15986 Published: January 2019
Abstract:We demonstrate for the first time that the tunable broadband emission from red to blue can be obtained by gamma radiation in multicomponent phosphate glasses. Gamma radiation causes the increased phosphate-related non-bridging oxygen hole center and oxygen hole center defects, which lead to the enhanced emission peaking at 452 nm. Meanwhile, the vibration amplitude of O-P-O chain's internal decrease, resulting in the decreased emission at 660 nm. Besides, the increased isolated phosphate units (Q0 and Q1), as well as the gradual decrease in P atoms that make up the main phosphate chain contribute to the blue-shift of the main emission peak at 616 nm, which directly results in the tunable broadband emission from 616 to 460 nm. The gamma radiation process endows this type of multicomponent phosphate glasses with promising applications in solid-state lighting devices. ? 2018 The American Ceramic Society
Accession Number: 20183505758954
Record 112 of

Title:Improved Method for On-Orbit Modulation Transfer Function Detection of Space Cameras

Author(s):Cheng, Ying(1,2); Yi, Hongwei(1,2); Liu, Xinlong(1,3)
Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 46 Issue: 7 DOI: 10.3788/CJL201946.0704010 Published: July 10, 2019
Abstract:According to the on-orbit working state and imaging characteristics of cameras for space exploration, the lunar-edge method is used to detect its on-orbit modulation transfer function (MTF), combined with the commonly used test method of MTF. This method uses the high-contrast linear edge image formed by the lunar edge and the deep space background as the test target. The simulation is used to analyze the calculation precision and running speed of various processing methods in each link, forming an optimized process of on-orbit MIT detection based on the lunar-edge method. In the link of edge spread function (ESF) processing, a modified Savitsky-Golay filter combined with double Gaussian fitting method is used to obtain an accurate ESF while effectively suppressing the noise. The simulation and experimental results show that the proposed method has an accuracy of 0.02 for images with a signal-to-noise ratio higher than 30 dB, which can achieve accurate calibration of camera focal plane position and MTF. ? 2019, Chinese Lasers Press. All right reserved.
Accession Number: 20193707416574
Record 113 of

Title:Freeway variable speed limit system based on traffic meteorological environment monitoring

Author(s):Kang, Heng(1,3); Li, Yongfang(3); Ruan, Chi(2)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11052 Issue: DOI: 10.1117/12.2521114 Published: 2019
Abstract:In order to reasonably determine the safe speed limit of expressway under several meteorological conditions such as stagnant water, icing, snow, fog, and provide the driver with the maximum acceptable safe speed, this paper proposes a Freeway variable speed limit system based on traffic meteorological environment monitoring. This paper establishes a speed limit model based on visibility, illumination and road surface state. The STM32f103 is proposed as a controller to collect meteorological information in real time using road surface condition monitoring equipment, visibility meter and illumination meter. And use LED information board to prompt the maximum safe speed in real time. This paper is based on QT5 development of the host computer client. QT has the advantages of high modularity and good reusability, and can be extended to other functions as needed. ? 2019 SPIE.
Accession Number: 20190806535036
Record 114 of

Title:Haze-removal polarimetric imaging schemes with the consideration of airlight's circular polarization effect

Author(s):Zhang, Wenfei(2); Liang, Jian(1); Ren, Liyong(1)
Source: Optik Volume: 182 Issue: DOI: 10.1016/j.ijleo.2019.01.048 Published: April 2019
Abstract:The polarimetric dehazing methods have been proven effective in enhancing the quality of images acquired in turbid media, including in hazy weather conditions. However, traditional polarimetric dehazing methods are all based on a hypothesis that the airlight only performs linear polarization property. The circular polarization effect is usually ignored although it may be an essential component of the airlight. In this paper, we report a new polarimetirc dehazing method considering the full polarization effects of the airlight (the linear and circular polarization effects of the airlight). In addition, an effective dehazing method only using the circular polarization effect of the airlight is given. Experimental results verify the effectiveness and the universality of the proposed method, and its dehazing capacity is obviously enhanced. Meanwhile, the circular polarization effect based method also can effectively achieve dehazing result only with one intensity image and one circular polarization image. This method is much easier to implement, although the dehazing results are not comparative to that of the full polarization effects based method. The proposed methods would advance the applications of the polarimetric dehazing methods in dehazing application filed. ? 2019 Elsevier GmbH
Accession Number: 20190806517243
Record 115 of

Title:3G structure for image caption generation

Author(s):Yuan, Aihong(1,2); Li, Xuelong(1); Lu, Xiaoqiang(1)
Source: Neurocomputing Volume: 330 Issue: DOI: 10.1016/j.neucom.2018.10.059 Published: 22 February 2019
Abstract:It is a big challenge of computer vision to make machine automatically describe the content of an image with a natural language sentence. Previous works have made great progress on this task, but they only use the global or local image feature, which may lose some important subtle or global information of an image. In this paper, we propose a model with 3-gated model which fuses the global and local image features together for the task of image caption generation. The model mainly has three gated structures. (1) Gate for the global image feature, which can adaptively decide when and how much the global image feature should be imported into the sentence generator. (2) The gated recurrent neural network (RNN) is used as the sentence generator. (3) The gated feedback method for stacking RNN is employed to increase the capability of nonlinearity fitting. More specially, the global and local image features are combined together in this paper, which makes full use of the image information. The global image feature is controlled by the first gate and the local image feature is selected by the attention mechanism. With the latter two gates, the relationship between image and text can be well explored, which improves the performance of the language part as well as the multi-modal embedding part. Experimental results show that our proposed method outperforms the state-of-the-art for image caption generation. ? 2018
Accession Number: 20184506050720
Record 116 of

Title:A Deep Scene Representation for Aerial Scene Classification

Author(s):Zheng, Xiangtao(1); Yuan, Yuan(2); Lu, Xiaoqiang(1)
Source: IEEE Transactions on Geoscience and Remote Sensing Volume: 57 Issue: 7 DOI: 10.1109/TGRS.2019.2893115 Published: July 2019
Abstract:As a fundamental problem in earth observation, aerial scene classification tries to assign a specific semantic label to an aerial image. In recent years, the deep convolutional neural networks (CNNs) have shown advanced performances in aerial scene classification. The successful pretrained CNNs can be transferable to aerial images. However, global CNN activations may lack geometric invariance and, therefore, limit the improvement of aerial scene classification. To address this problem, this paper proposes a deep scene representation to achieve the invariance of CNN features and further enhance the discriminative power. The proposed method: 1) extracts CNN activations from the last convolutional layer of pretrained CNN; 2) performs multiscale pooling (MSP) on these activations; and 3) builds a holistic representation by the Fisher vector method. MSP is a simple and effective multiscale strategy, which enriches multiscale spatial information in affordable computational time. The proposed representation is particularly suited at aerial scenes and consistently outperforms global CNN activations without requiring feature adaptation. Extensive experiments on five aerial scene data sets indicate that the proposed method, even with a simple linear classifier, can achieve the state-of-the-art performance. ? 1980-2012 IEEE.
Accession Number: 20192707140732
Record 117 of

Title:Range-gated imaging in turbid conditions using a combination of intensity and polarization information

Author(s):Ren, Wei(1); Guan, Jinge(1); Liu, Jiahang(2); Chen, Junyu(2); Feng, Xiaoshan(3)
Source: Physica Scripta Volume: 94 Issue: 10 DOI: 10.1088/1402-4896/ab2683 Published: August 7, 2019
Abstract:Polarization of light is introduced into range-gated imaging (RGI) for target detection and recognition in turbid conditions. The polarimetric RGI system can obtain both intensity and polarization information on objects. The experimental results show that an intensity-based image, when the target part and the background part of an object have similar reflective characteristic, can reveal the contours of the object by minimizing the effect of backscattering from the medium, and a polarization-based image can highlight the target part by common-mode rejection of the background. Furthermore, intensity and polarization components are combined to describe the scene systematically. Four methods - Laplacian pyramid, discrete wavelet transform, contourlet transform and nonsubsampled contourlet transform - are used for image fusion. Favourable information represented in each image can be extracted from image fusion for target detection and recognition. Objective evaluation indices are applied to compare the performance of different image fusion methods. ? 2019 IOP Publishing Ltd.
Accession Number: 20194507646103
Record 118 of

Title:Advanced Adaptive Photonic RF Filters with 80 Taps Based on an Integrated Optical Micro-Comb Source

Author(s):Xu, Xingyuan(1); Tan, Mengxi(1); Wu, Jiayang(1); Nguyen, Thach G.(2); Chu, Sai Tak(3); Little, Brent E.(4); Morandotti, Roberto(5,6,7); Mitchell, Arnan(2); Moss, David J.(1)
Source: Journal of Lightwave Technology Volume: 37 Issue: 4 DOI: 10.1109/JLT.2019.2892158 Published: February 15, 2019
Abstract:We demonstrate a photonic radio frequency (RF) transversal filter based on an integrated optical micro-comb source featuring a record low free spectral range of 49 GHz, yielding 80 micro-comb lines across the C-band. This record high number of taps, or wavelengths for the transversal filter results in significantly increased performance including a QRF factor more than four times higher than previous results. Furthermore, by employing both positive and negative taps, an improved out-of-band rejection of up to 48.9 dB is demonstrated using a Gaussian apodization, together with a tunable center frequency covering the RF spectra range, with a widely tunable 3-dB bandwidth and versatile dynamically adjustable filter shapes. Our experimental results match well with theory, showing that our transversal filter is a competitive solution to implement advanced adaptive RF filters with broad operational bandwidth, high frequency selectivity, high reconfigurability, and potentially reduced cost and footprint. This approach is promising for applications in modern radar and communications systems. ? 1983-2012 IEEE.
Accession Number: 20191106641005
Record 119 of

Title:Low-noise stable millimeter-wave optoelectronic oscillator based on self-regenerative frequency-dividing and phase-locking techniques

Author(s):Liu, Anni(1); Dai, Jian(1,2); Wu, Zhonghan(1); Liu, Jingliang(1); Xu, Kun(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11048 Issue: DOI: 10.1117/12.2518306 Published: 2019
Abstract:A millimeter-wave optoelectronic oscillator employing self-regenerative frequency dividing and phase-locking techniques is proposed. The frequency division of millimeter-wave signal is achieved effectively via self-regenerative frequency divider breaking the frequency limitation of commercial frequency dividers. In virtue of the frequency conversion pair, the phase-locking technique is effectively utilized to stabilize the millimeter-wave optoelectronic oscillator by a commercial analog phase shifter in relative low frequency band. Finally, a 40-GHz millimeter-wave signal is generated with the single-sideband phase noise about -116 dBc/Hz at 10-kHz frequency offset. Besides, the frequency stability of the proposed millimeter-wave optoelectronic oscillator is greatly improved from 1.2×10-6 to 2.96×10-13 at 1024-s averaging time in a lab room without any thermal control. ? 2019 SPIE.
Accession Number: 20191006602368
Record 120 of

Title:Generation of dark solitons in erbium-doped fiber laser based on black phosphorus nanoparticles

Author(s):Liu, Jianyou(1,2); Zhao, Fengyan(2); Wang, Hushan(2); Zhang, Wei(2); Hu, Xiaohong(2); Li, Xiaohui(1); Wang, Yishan(2)
Source: Optical Materials Volume: 89 Issue: DOI: 10.1016/j.optmat.2018.12.055 Published: March 2019
Abstract:We demonstrate the generation of dark solitons (DSs) in erbium-doped fiber (EDF) laser based on black phosphorus nanoparticles (BPNPs) for the first time. The side-polished fiber deposited with BPNPs is embedded into the laser to enhance the birefringence and nonlinearity of the laser cavity. In the paper, the saturable absorption property of BPNPs with an optical modulation depth of 5.7% and a saturable intensity of 21.7 MW/cm2 are experimentally illustrated. After inserting the BPNPs saturable absorber (SA) into EDF laser, the DSs with repetition rate of 14.68 MHz are obtained at a pump power of 90 mW. Our results prove that the BPNPs are the promising candidate materials for generating DSs in EDF laser. ? 2019 Elsevier B.V.
Accession Number: 20190406423163