-
Record 385 of
Title:Study on the key technologies of a high-speed CMOS camera
Author(s):Jiang, Baotan(1,2,3); Pan, Zhibin(1); Qiu, Yuehong(2)
Source: Optik Volume: 129 Issue: DOI: 10.1016/j.ijleo.2016.10.056 Published: January 1, 2017
Abstract:The high-speed CMOS camera can be widely applied in image technology detection, image measurement, video monitoring, and satellite remote sensing. Given the large image data volume, many technical problems may be encountered in acquisition and transfer of image data and real-time processing. CMV4000 from CMOSIS Company has been selected as image sensor to research application problems. The high-frame and high-definition industrial camera has been designed based on CMV4000 image sensor, FPGA, DDR2 SDRAM high-speed memory chip, and USB3.0 technology. The camera is made up of data automatic alignment module, image acquisition module, memory module, and transfer module. These modules have realized data alignment, acquisition, cache, and transfer of high-speed data. An automatic alignment module is proposed which based on the sliding window consists of register for high-speed image sensor with multi-channel LVDS interface. This module can automatically identify training data sent by LVDS serial channel, and lock the sliding window when finding "Training Pattern", then realize automatic alignment and synchronization for high-speed and multi-channel data. ? 2016 Elsevier GmbH
Accession Number: 20164402973003
-
Record 386 of
Title:Influence analysis of satellite drift angle on spectrum recovery precision of large aperture static interferometer spectrometer
Author(s):Li, Siyuan(1,2,3); Liu, Huan(1); Zhang, Geng(1); Zhang, Zhoufeng(1,2,3); Zhao, Qiang(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10256 Issue: DOI: 10.1117/12.2256460 Published: 2017
Abstract:Large aperture static interferometer spectrometer (LASIS) use the method of push-boom to get the geometric and spectral characteristics of ground target, the particularity of principle requires the movement of satellite must be in the same direction with spectrometers detectors. Drift angle of satellite leading to abnormal image shifts in the column direction which should be perpendicular to the detector and can seriously affect the spectrum recovery precision of collected data. This paper analyzes the influence mechanism of drift angle for spectrum recovery precision. Simulation based on the actual on-orbit data analyses the effects of different drift angle of relative mean deviation and relative secondary deviation rehabilitation of the spectrum, besides the influence of spectral angle similarity. These studies have shown that, when the lateral deviation due to the drift angle on the across track is less than 0.3 pixel, the effect for the relative mean deviation of the inversive spectra will be no more than 7%. when the lateral deviation due to the drift angle on the across track is larger than one pixel, even though the resampling correction is proceeded, the restored spectral data cube still shows an relative mean error more than 10%, which seriously affect the availability of spectral data. ? 2017 SPIE.
Accession Number: 20171703607628
-
Record 387 of
Title:Study on nonlinear process of remote sensing camera imaging at visible wavelengths
Author(s):Zhang, Xing(1,2); Liu, Zhaohui(1); Zhou, Liang(1,2); Li, Wenhao(1,2)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10462 Issue: DOI: 10.1117/12.2285180 Published: 2017
Abstract:As the atmospheric environments get more complex, the surface characteristics are diverse, spaceborne remote sensing cameras with the characteristics of large aperture, long focal length, and small size are demanded ever-increasing, and the high-sensitivity photoelectric detectors are required to detect more observing targets, the nonlinear process of remote sensing imaging system is worth consideration. In this paper, time delay integrated charge-coupled device (TDICCD) is used as an example to analyze imaging chains of space remote sensing system at visible wavelengths. The nonlinear process influenced by atmospheric radiation transmission mode, the reflection characteristics of earth surface, ground-Air couping effect, imaging optical system, TDICCD photoelectric detector, imaging electronics system, data transmission/compression system, and ground station system is researched in detail. At the same time, the method to reduce the nonlinear effects of the image is discussed. In order to apply the space remote sensing information to all walks of life effectively, the nonlinear process will be improved by high-precision atmospheric radiation transmission calculation, reducing the move of the image plane and the noise of the electronics system, designing the A/D converter with stable gain coefficient, optimizing the compression/decompression process, and reducing information loss of the remote sensing imaging system from satellite to the ground station system. ? 2017 SPIE.
Accession Number: 20180404671168
-
Record 388 of
Title:Optical fluxes in coupled PT -symmetric photonic structures
Author(s):Ge, Li(1,2); K.G., Makris; L., Zhang
Source: Physical Review A Volume: 96 Issue: 2 DOI: 10.1103/PhysRevA.96.023820 Published: August 9, 2017
Abstract:In this work we first examine transverse and longitudinal fluxes in a PT-symmetric photonic dimer using a coupled-mode theory. Several surprising understandings are obtained from this perspective: The longitudinal flux shows that the PT transition in a dimer can be regarded as a classical effect, despite its analogy to PT-symmetric quantum mechanics. The longitudinal flux also indicates that the so-called giant amplification in the PT-symmetric phase is a subexponential behavior and does not outperform a single gain waveguide. The transverse flux, on the other hand, reveals that the apparent power oscillations between the gain and loss waveguides in the PT-symmetric phase can be deceiving in certain cases, where the transverse power transfer is in fact unidirectional. We also show that this power transfer cannot be arbitrarily fast even when the exceptional point is approached. Finally, we go beyond the coupled-mode theory by using the paraxial wave equation and also extend our discussions to a PT diamond and a one-dimensional periodic lattice. ? 2017 American Physical Society.
Accession Number: 20173604121357
-
Record 389 of
Title:Secrecy-Optimized Resource Allocation for Device-to-Device Communication Underlaying Heterogeneous Networks
Author(s):Zhang, Kecheng(1); Peng, Mugen(1); Zhang, Ping(2); Li, Xuelong(3)
Source: IEEE Transactions on Vehicular Technology Volume: 66 Issue: 2 DOI: 10.1109/TVT.2016.2566298 Published: February 2017
Abstract:Device-to-device (D2D) communications have recently attracted much attention for the potential capability to improve spectral efficiency (SE) underlaying the existing heterogeneous networks (HetNets). Due to no sophisticated control, D2D-worked user equipments (DUEs) themselves cannot resist eavesdropping or security attacks. It is urgent to maximize the secure capacity for both cellular users and DUEs. This paper formulates the radio resource-allocation problem to maximize the secure capacity of DUEs for D2D communication underlaying HetNets, which consist of high-power nodes (HPNs) and low-power nodes (LPNs). The optimization objective function with transmit bit rate and power constraints, which is nonconvex and hard to directly derive, is first transformed into a matrix form. Then, the equivalent convex form of the optimization problem is derived according to Perron-Frobenius theory. A heuristic iterative algorithm based on the proximal theory is proposed to solve this equivalent convex problem through evaluating the proximal operator of the Lagrange function. Numerical results show that the proposed radio resource-allocation solution significantly improves the secure capacity with a fast convergence speed. ? 2016 IEEE.
Accession Number: 20170803367452
-
Record 390 of
Title:A parallel linearized ADMM with application to multichannel tgv-based image restoration
Author(s):He, Chuan(1); Hu, Changhua(1); Li, Xuelong(2)
Source: Proceedings - International Conference on Image Processing, ICIP Volume: 2017-September Issue: DOI: 10.1109/ICIP.2017.8296469 Published: July 2, 2017
Abstract:A parallel linearized alternating direction method of multipliers (PLADMM) is proposed to solve large-scale imaging inverse problems, which involve the sum of several linear-operator-coupled nonsmooth terms. In the proposed method, the proximity operators of the nonsmooth terms are called individually at each iteration and the auxiliary variables existing in the classical ADMM are excluded. Therefore, the proposed method possesses a highly parallel structure and most of its substeps can be executed simultaneously. The application to multichannel total generalized variation (TGV) based image restoration shows the effectiveness of the proposed method. ? 2017 IEEE.
Accession Number: 20181605019536
-
Record 391 of
Title:Optimal design of an earth observation optical system with dual spectral and high resolution
Author(s):Yan, Pei-Pei(1); Jiang, Kai(1); Liu, Kai(1); Duan, Jing(1); Shan, Qiusha(1)
Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10256 Issue: DOI: 10.1117/12.2257219 Published: 2017
Abstract:With the increasing demand of the high-resolution remote sensing images by military and civilians, Countries around the world are optimistic about the prospect of higher resolution remote sensing images. Moreover, design a visible/infrared integrative optic system has important value in earth observation. Because visible system can't identify camouflage and recon at night, so we should associate visible camera with infrared camera. An earth observation optical system with dual spectral and high resolution is designed. The paper mainly researches on the integrative design of visible and infrared optic system, which makes the system lighter and smaller, and achieves one satellite with two uses. The working waveband of the system covers visible, middle infrared (3-5um). Dual waveband clear imaging is achieved with dispersive RC system. The focal length of visible system is 3056mm, F/# is 10.91. And the focal length of middle infrared system is 1120mm, F/# is 4. In order to suppress the middle infrared thermal radiation and stray light, the second imaging system is achieved and the narcissus phenomenon is analyzed. The system characteristic is that the structure is simple. And the especial requirements of the Modulation Transfer Function (MTF), spot, energy concentration, and distortion etc. are all satisfied. ? 2017 SPIE.
Accession Number: 20171703607647
-
Record 392 of
Title:Meta-nanocavity model for dynamic super-resolution fluorescent imaging based on the plasmonic structure illumination microscopy method
Author(s):Cao, Shun(1,2); Wang, Taisheng(1); Sun, Qiang(1); Hu, Bingliang(1); Yu, Weixing(3)
Source: Optics Express Volume: 25 Issue: 4 DOI: 10.1364/OE.25.003863 Published: February 20, 2017
Abstract:Biological research requires dynamic and wide-field optical microscopy with resolution down to nanometer to study the biological process in a sub-cell or single molecular level. To address this issue, we propose a dynamic wide-field optical nanoimaging method based on a meta-nanocavity platform (MNCP) model which can be incorporated in micro/nano-fluidic systems so that the samples to be observed can be confined in a nano-scale space for the ease of imaging. It is found that this platform can support standing wave surface plasmons (SW-SPs) interference pattern with a period of 105 nm for a 532 nm incident wavelength. Furthermore, the potential application of the NCP for wide-field super-resolution imaging was discussed and the simulation results show that an imaging resolution of sub-80 nm can be achieved. ? 2017 Optical Society of America.
Accession Number: 20170903385629
-
Record 393 of
Title:844-fs mode-locked fiber laser by carboxyl-functionalized graphene oxide
Author(s):Duan, Lina(1); Wang, Hushan(2); Bai, Jing(2); Wang, Yonggang(3); Wei, Lianglei(3); Chen, Zhendong(3); Yu, Jia(4); Wen, Jin(1); Li, Yan(1)
Source: Optical Engineering Volume: 56 Issue: 11 DOI: 10.1117/1.OE.56.11.116104 Published: November 1, 2017
Abstract:We had proved that a kind of graphene nanomaterial "carboxyl-functionalized graphene oxide (GO-COOH)" possessed nonlinear saturable absorber (SA) property. The modulation depth of a GO-COOH water solution was measured as ～8%. Moreover, a GO-COOH-based SA device was made and applied in an erbium-doped fiber laser. In this fiber laser, Q-switching pulses and mode-locked pulses were both obtained. With an increase in the pump power, the pulse width of Q-switching pulses decreased from 9.05 to 2.49 μs. The mode-locked pulse width was 844 fs, and the corresponding spectral bandwidth was 3.64 nm. Moreover, polarization adjusting or control was not needed during the whole process of mode locking. It illustrated that the proposed fiber laser incorporating GO-COOH could endure bigger intracavity birefringence. Our results indicated that the GO-COOH nanomaterial was a promising SA for generating high-performance pulse lasers. ? 2017 Society of Photo-Optical Instrumentation Engineers (SPIE).
Accession Number: 20174804477440
-
Record 394 of
Title:A novel PDE-based single image super-resolution reconstruction method
Author(s):Zhao, Xiaodong(1,2); Cao, Jianzhong(1,2); Zhou, Zuofeng(1,2); Huang, Jijiang(1,2)
Source: International Journal of Pattern Recognition and Artificial Intelligence Volume: 31 Issue: 6 DOI: 10.1142/S0218001417540106 Published: June 1, 2017
Abstract:For applications such as remote sensing imaging and medical imaging, high-resolution (HR) images are urgently required. Image Super-Resolution (SR) reconstruction has great application prospects in optical imaging. In this paper, we propose a novel unified Partial Differential Equation (PDE)-based method to single image SR reconstruction. Firstly, two directional diffusion terms calculated by Anisotropic Nonlinear Structure Tensor (ANLST) are constructed, combing information of all channels to prevent singular results, making full use of its directional diffusion feature. Secondly, by introducing multiple orientations estimation using high order matrix-valued tensor instead of gradient, orientations can be estimated more precisely for junctions or corners. As a unique descriptor of orientations, mixed orientation parameter (MOP) is separated into two orientations by finding roots of a second-order polynomial in the nonlinear part. Then, we synthesize a Gradient Vector Flow (GVF) shock filter to balance edge enhancement and de-noising process. Experimental results confirm the validity of the method and show that the method enhances image edges, restores corners or junctions, and suppresses noise robustness, which is competitive with the existing methods. ? 2017 World Scientific Publishing Company.
Accession Number: 20170703338991
-
Record 395 of
Title:Simulation of Light Field Imaging and Refocusing Models Based on Matrix Transformation
Author(s):Xie, Pei-Yue(1,2,3); Yang, Jian-Feng(1); Xue, Bin(1); Chen, Guo-Qing(1,2)
Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 46 Issue: 5 DOI: 10.3788/gzxb20174605.0510001 Published: May 1, 2017
Abstract:Based on the double plane representation of the light field, aimed at the effect of light on the way of description influenced by coaxial translation, off-axis translation, coplanar rotation and off-planar rotation, and lens transformation between two reference plane of light field camera, this paper provided the corresponding matrix transformation equations. And using the transformation equations, the imaging model, sampling model, and radiation model of light field camera are established. Besides, on the view of light field coaxial space distance transformation, the digital refocusing process is deduced which can receive clearly imaging in any target scene point after got the imaging by focusing at a point. And moreover, by using the established model, the object is generated by computer simulation, and the model is used for digital refocusing on generation of features, the consistency of digital refocusing image and the directly focused images are verified. ? 2017, Science Press. All right reserved.
Accession Number: 20173104014263
-
Record 396 of
Title:Bifurcated overtones of one-way localized Fabry-Pérot resonances in parity-time symmetric optical lattices
Author(s):Gaafer, Fatma Nafaa(1); Shen, Yaxi(1); Peng, Yugui(1); Wu, Aimin(2); Zhang, Peng(3); Zhu, Xuefeng(1,2,4)
Source: Chinese Physics B Volume: 26 Issue: 7 DOI: 10.1088/1674-1056/26/7/074218 Published: June 2017
Abstract:Since the first observation of parity-time (PT) symmetry in optics, varied interesting phenomena have been discovered in both theories and experiments, such as PT phase transition and unidirectional invisibility, which turns PT-symmetric optics into a hotspot in research. Here, we report on the one-way localized FabryPerot (FP) resonance, where a welldesigned PT optical resonator may operate at exceptional points with bidirectional transparency but unidirectional field localization. Overtones of such one-way localized FP resonance can be classified into a blue shifted branch and a red shifted branch. Therefore, the fundamental resonant frequency is not the lowest one. We find that the spatial field distributions of the overtones at the same absolute order are almost the same, even though their frequencies are quite different. ? 2017 Chinese Physical Society and IOP Publishing Ltd.
Accession Number: 20172803927384
