2019
2019
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Record 337 of
Title:Analysis and suppression of stray light in phenological network multi-spectral camera
Author(s):Lei, Jiao(1,2); Ma, Xiaolong(1); Yang, Jianfeng(1); Xue, Bin(1); Lv, Juan(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10838 Issue: DOI: 10.1117/12.2511060 Published: 2019Abstract:The phonological network multi-spectral camera has a complicated internal structure. The camera is a composed of eight lenses, and the light path is divided into eight channels. There is a lot of stray light.So deep stray light analysis and suppression design must be performed to reduce the influence of stray light. This paper analyzes the characteristics of phenological network multi-spectral camera system. Two different baffles are designed, and a regional calculation method is proposed to detect the shading performance of the baffle.Then, the stray light analysis was performed on each channel of the phenological network multispectral camera with TracePro. According to the analysis results, PST curves under different conditions are compared, and the appropriate baffle is selected. Finally, shading performance of the baffle was verified through experiments. ? 2019 COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Accession Number: 20190506430705 -
Record 338 of
Title:Structure design and analysis of the secondary mirror bracket for all day star orientation instrument
Author(s):Liu, Yang(1); Wang, Hu(1); Lin, Shangmin(1); Jie, Yongjie Jie(1); Liu, Jie(1); Xue, Yaoke(1); Liu, Meiying(1,2); Wang, Feng(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11052 Issue: DOI: 10.1117/12.2519837 Published: 2019Abstract:In order to improve the stability of the secondary mirror mounting structure and reduce the influence of the position change of the secondary mirror on the imaging quality of the camera, the secondary mirror support structure was studied. Aiming at the problems of traditional secondary mirror support, a new type of secondary mirror bracket is proposed in this paper. The finite element analysis results show that under the same obstruction ratio, the torsional stiffness, the stiffness along the optical axis and the thermodynamic properties of the new secondary mirror bracket are similar to the secondary mirror traditional support structure, but the weight of the new s bracket is only 15.2% of the traditional support structure. The new bracket solves the shortcomings of the traditional secondary mirror support structure, such as high cost, long period and heavy weight, and is easy to assemble. It has been successfully applied in the all-day star orientation instrument. ? 2019 SPIE.Accession Number: 20190806534734 -
Record 339 of
Title:Research on stray light suppression of space debris detection camera
Author(s):Lin, Shangmin(1); Wang, Hu(1); Liu, Yang(1); Shen, Yang(2); Xie, Yongjie(1); Xue, Yaoke(1); Liu, Jie(1); Liu, Meiying(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11341 Issue: DOI: 10.1117/12.2542391 Published: 2019Abstract:The sources of stray light were briefly introduced and the necessity of stray light suppression was analyzed. Strong stray light often directly affected the performance of space debris detection camera and even invalidated it. Therefore, the application of stray light suppression in space debris detection camera was particularly important. The design of stray light suppression for space debris detection camera using baffle was proposed. On the basis of re-searching the source of stray light, the influences of the edge width of the baffle rings and the surfaces coating treatment scheme on the stray light suppression ability were finally determined. The stray light suppression ability of the baffle was greatly improved by exploring the limit of the mechanical processing of the baffle ring and optimizing the surface coating treatment method of the inner cavity of the baffle. At the same time, the stray light flow channel inside the optical system was optimized. The critical surfaces inside the optical system were found. After removing the critical surfaces, the stray light suppression design results showed the stray light rejection ratio reached 10-7 finally when off-axis angle was larger than 35°. The flares appearing on the detector disappeared completely in the experiments, and the signal-to-noise ratio was higher. The stray light suppression optimization obtained good results, which could better satisfy the requirements of space debris detection. ? 2019 SPIE.Accession Number: 20200408063338 -
Record 340 of
Title:A CNN-RNN architecture for multi-label weather recognition
Author(s):Zhao, Bin(1); Li, Xuelong(2); Lu, Xiaoqiang(2); Wang, Zhigang(1)Source: arXiv Volume: Issue: DOI: null Published: April 24, 2019Abstract:Weather Recognition plays an important role in our daily lives and many computer vision applications. However, recognizing the weather conditions from a single image remains challenging and has not been studied thoroughly. Generally, most previous works treat weather recognition as a single-label classification task, namely, determining whether an image belongs to a specific weather class or not. This treatment is not always appropriate, since more than one weather conditions may appear simultaneously in a single image. To address this problem, we make the first attempt to view weather recognition as a multi-label classification task, i.e., assigning an image more than one labels according to the displayed weather conditions. Specifically, a CNN-RNN based multi-label classification approach is proposed in this paper. The convolutional neural network (CNN) is extended with a channel-wise attention model to extract the most correlated visual features. The Recurrent Neural Network (RNN) further processes the features and excavates the dependencies among weather classes. Finally, the weather labels are predicted step by step. Besides, we construct two datasets for the weather recognition task and explore the relationships among different weather conditions. Experimental results demonstrate the superiority and effectiveness of the proposed approach. The new constructed datasets will be available at https: //github.com/wzgwzg/Multi-Label-Weather-Recognition. Copyright ? 2019, The Authors. All rights reserved.Accession Number: 20200278626 -
Record 341 of
Title:Research on PD-type Iterative Learning Control Algorithm of Manipulator Based on Gain Switching
Author(s):Ma, Zihan(1); Liang, Yanbing(1)Source: Proceedings of the 31st Chinese Control and Decision Conference, CCDC 2019 Volume: Issue: DOI: 10.1109/CCDC.2019.8832932 Published: June 2019Abstract:Multi-joint serial manipulator is highly nonlinear and strongly coupled system with multiple inputs and multiple outputs. In addition, there are some problems such as parameter perturbation, external interference and uncertainty are exist. The trajectory tracking control of manipulator has certain difficulties. As the most important part of manipulator system, the design of controller is related to the accuracy and robustness of manipulator to perform tasks. For hydraulically driven manipulators, it is reciprocate in working process, and has the characteristics of long delay time. Aiming at characteristics and problems of multi-joint series manipulator, this paper proposes a PD-type iterative learning control algorithm based on gain switching, it has the robust term, and the linearized residual is considered to realize the control of the mechanical system with uncertain dynamics equation and non-repetitive interference. The first two joints of the six degrees of freedom manipulator XIOPM, which developed by the research group are simulated by MATLAB/SIMULINK using this method. Compared with the traditional iterative learning control, the algorithm proposed in this paper can converge the actual output trajectory of the system to the desired output trajectory at a relatively fast speed with good tracking performance and high tracking accuracy. ? 2019 IEEE.Accession Number: 20194207534027 -
Record 342 of
Title:Research on improved high gain boost converter
Author(s):Yu, Xiaoyang(1); Wang, Rongbin(2); Qiao, Yongming(3)Source: Chinese Control Conference, CCC Volume: 2019-July Issue: DOI: 10.23919/ChiCC.2019.8865087 Published: July 2019Abstract:This paper mainly introduces a hybrid non-isolated DC-DC converter based on voltage lifting technology. This circuit is formed by introducing a new switching inductance structure on the basis of a unique voltage lifting structure. In this paper, the characteristics of this circuit in Continuous Inductor Current Mode (CCM) are studied, and the voltage and current are analyzed respectively. The voltage gain of this improved converter and other DC-DC converters in CCM mode is compared. Finally, this converter is simulated in Multisim to verify the conclusion of calculation. ? 2019 Technical Committee on Control Theory, Chinese Association of Automation.Accession Number: 20194507630177 -
Record 343 of
Title:A Filamentary Plasma Jet Generated by Argon Dielectric-Barrier Discharge in Ambient Air
Author(s):Li, Jing(1,2,3); Lei, Bingying(1,2); Wang, Jing(1,2); Zhang, Tongyi(1,2); Tang, Jie(1,2); Wang, Yishan(1,2); Zhao, Wei(1,2); Duan, Yixiang(1,2,4)Source: IEEE Transactions on Plasma Science Volume: 47 Issue: 7 DOI: 10.1109/TPS.2019.2916187 Published: July 2019Abstract:A filamentary plasma jet was produced by a cylindrical dielectric-barrier discharge (DBD) equipped with a thin quartz tube. This plasma jet consists of many filaments, and the filaments bifurcate into thinner branches close to the ground electrode. Only a single filament is produced in each current pulse, and this filament is distorted in the long gas gap. The maximum electron density in the filament is on the order of 1015cm-3. Optical emission examination shows a decrease of optical emissions from OH and Ar but an increase of optical emissions from N2 along the plasma jet. The vapor in the working gas argon rather than in the ambient air dominates the optical emissions from the de-excitation of OH along the plasma jet. Near the ground electrode, the nitrogen emission spectra mainly resulted from the direct electron effect on the ground state or metastable nitrogen and the collisions between nitrogen metastables. The rotational temperature is lower than the vibrational temperature but much higher than the room temperature. This feature makes the filamentary plasma jet only suitable for processing samples bearing high temperature. ? 1973-2012 IEEE.Accession Number: 20192807177768 -
Record 344 of
Title:Mechanical rotation and bending sensing by chiral long-period grating based on an axis-offset rotating optical fiber
Author(s):Wang, Ruiduo(1,2); Ren, Zhaoyu(3); Kong, Xudong(1,2); Kong, Depeng(1); Hu, Baowen(1); He, Zhengquan(1)Source: Applied Physics Express Volume: 12 Issue: 7 DOI: 10.7567/1882-0786/ab2a20 Published: July 1, 2019Abstract:A chiral long-period fiber grating (CLPFG) was fabricated by rotating the standard single mode fiber that was fixed on two fiber holders with an axis-offset. We investigated the performance of CLPFGs by sensing the mechanical twist, bending, and liquid refractive index experimentally. A wide twist sensing range of ±720° and 26.7 nm wavelength tuning range were achieved. Compared with tapered long-period fiber grating, the bending sensitivity of CLPFG is 5 times higher. Considering the simple and flexible fabrication process and low cost, this CLPFG may offer a simple and alternative choice for sensing mechanical deformation in industrial applications. ? 2019 The Japan Society of Applied Physics.Accession Number: 20193307307493 -
Record 345 of
Title:New algorithm of surface parameter for optical parabolic surface with high-precision
Author(s):Xu, Guangzhou(1); Ruan, Ping(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 48 Issue: 6 DOI: 10.3788/IRLA201948.0617001 Published: June 25, 2019Abstract:Due to the complexity of calculating model for the current optical parabolic surface and to acquire the high -precision surface based on the data of finite element analysis for parabolic surface, a new high-precision algorithm of surface parameter for optical parabolic surface was proposed. Firstly, the discrete error of the optical parabolic surface was proposed, and elimination technique of discrete error was researched, which was also the crucial step for the data preprocessing of the surface parameter calculation. Secondly, the rigid body displacement and surface distortion displacement were distinguished with the data processing algorithm based on rigid body displacement. Lastly, the basic data to obtain parameter, just as the root mean square, was got using the optimal design algorithm. The algorithm realization of the high-precision parabolic surface parameter was discussed and the validity check of the algorithm was performed as well. The result of validity check demonstrated: the high-precision algorithm of parabolic surface parameter is higher, and the check error is about 6%. The precision of new algorithm can satisfy the engineering requirement, and it also provides a new technical reference for the high precision calculation of optical surface parameter under the external thermal load. ? 2019, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20193407357360 -
Record 346 of
Title:Compound denoising method of laser speckle noise in laser inherent field imaging
Author(s):Cheng, Zhi-Yuan(1); Li, Zhi-Guo(1); She, Wen-Ji(1); Xia, Ai-Li(1)Source: Wuli Xuebao/Acta Physica Sinica Volume: 68 Issue: 5 DOI: 10.7498/aps.68.20181578 Published: March 5, 2019Abstract:Noise is an important factor affecting the image quality of laser coherent field high resolution imaging system. And there exists not only background light additive noise but also laser multiplicative speckle noise in a laser coherent field imaging system. Both of the above noise affect the imaging quality of laser coherent field system. In order to improve the imaging quality from the perspective of noise suppression and settle the imaging quality degradation problem of laser multiplicative speckle noise and background additive noise in the laser coherent field imaging system, the model for the influence of multiplicative speckle noise and background additive noise on laser echo field demodulated signal is established in atmospheric downlink. Then, based on the model, a novel homomorphic filter and sparse matrix trace cascade compound de-noising algorithm is put forward. Firstly, based on the homomorphic filtering theory, the laser multiplicative speckle noise in the laser echo demodulated signal is converted into the additive noise by logarithmic transformation. Then the low-frequency laser multiplicative speckle noise is filtered by the high-pass filter, and the high-frequency demodulated signal is retained. The logarithmic inverse transform is used to obtain the laser echo demodulation signal after the multiplicative speckle noise has been filtered out. Next, the phase random disturbance of atmosphere in laser echo demodulated signal is suppressed by phase closure technology and the imaging spectrum component is reconstructed by the spectrum iterative reconstruction method. Then the high resolution image is obtained by spectrum component inverse Fourier transform. Finally, the effect of background additive noise on the image quality is suppressed by the sparse base tracking theory. The simulated and outdoor experiment result are used to verify the denoising effect and image quality enhancement effect of the composite de-noising method. Compared with the existing single denoising method, the composite denoising method is shown to be able to effectively eliminate laser multiplicative speckle noise and background additive noise at one time. The proposed method can improve image contrast and promote the Strehl ratio of imaging quality in a coherent imaging system. It provides a theoretical basis for improving imaging quality and denosing laser multiplicative speckle noise and background additive noise in coherent field imaging system. ? 2019 Chinese Physical Society.Accession Number: 20191906908967 -
Record 347 of
Title:Detecting optical component damage based on neighborhood vector dot contrast image enhancement
Author(s):Wang, Zheng-Zhou(1); Duan, Ya-Xuan(1); Wang, Li(1); Tan, Meng(1); Li, Hong-Guang(1); Wei, Ji-Tong(1)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 27 Issue: 12 DOI: 10.3788/OPE.20192712.2668 Published: December 1, 2019Abstract:To solve the problems of the inability of LCM in detecting damaged targets in local bright areas and its low separation efficiency, a damage detection method based on local contrast image enhancement of a neighborhood vector local dot was proposed in this study. First, a nine-dimensional neighborhood vector was generated from the 3×3 neighborhood of each point in the image, and the maximum value in the neighborhood was extended to the nine-dimensional extreme vector in calculating the dots of the neighborhood vector and extreme vector. Second, the Neighborhood Vector Dot Contrast (NVDC) of each pixel was calculated. Third, the NVDC of the image patch of each pixel was calculated, i.e., the maximum NVDC value of each pixel in a relatively large area(5×5) was taken as the final Neighborhood Vector Dot Local Contrast (NVDLC) of the corresponding pixel. Fourth, the NVDLC image was binarized, and the targets were separated from the background. The experimental results demonstrate that the LSNR of the damaged image is improved from 3.775 to 12.445, and the signal of the damage target is significantly enhanced using the image enhancement method proposed in this study. After the maximum contrast image of NVDLC is enhanced, the damage targets with size of less than 2 pixels can be directly separated from the background using the adaptive threshold formula, which meets the accuracy and efficiency requirements of the weak contrast damage target detection. ? 2019, Science Press. All right reserved.Accession Number: 20200508108441 -
Record 348 of
Title:Deep voice-visual cross-modal retrieval with deep feature similarity learning
Author(s):Chen, Yaxiong(1,2); Lu, Xiaoqiang(1); Feng, Yachuang(1)Source: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) Volume: 11859 LNCS Issue: DOI: 10.1007/978-3-030-31726-3_39 Published: 2019Abstract:Thanks to the development of deep learning, voice-visual cross-modal retrieval has made remarkable progress in recent years. However, there still exist some bottlenecks: How to establish effective correlation between voices and images to improve the retrieval precision and how to reduce data storage and speed up retrieval in large-scale crossmodal data. In this paper, we propose a novel Voice-Visual Cross-Modal Hashing (V2CMH) method, which can generate hash codes with low storage memory and fast retrieval properties. Specially, the proposed V2CMH method can leverage deep feature similarity to establish the semantic relationship between voices and images. In addition, for hash codes learning, our method attempts to preserve the semantic similarity of binary codes and reduce the information loss of binary codes generation. Experiments illustrate that V2CMH algorithm can achieve better retrieval performance than other state-of-the-art cross-modal retrieval algorithms. ? Springer Nature Switzerland AG 2019.Accession Number: 20202008650109