2020
2020
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Record 289 of
Title:Research on a device of eliminating stray light in transceiver of laser communication
Author(s):Song, Yang(1); Chai, Wenyi(1); Hu, Yongming(1); Qu, Enshi(1); Xin, Wei(1); Xu, Yang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11604 Issue: DOI: 10.1117/12.2579470 Published: 2020Abstract:There is a broad application of laser communication. This technology makes a great contribution to information exchanging between a station on ground and a satellite in space or between two satellites in space. Transceiver of space laser communication usually shares one optical path for compact, lightweight, low cost design. The most important thing is that the laser communication should have low wave aberration, low polarization loss and high isolation. Transmitting and receiving signals use one optical path, which makes negative influence on the isolation in system. It is a big challenge for engineers or designers to ensure the high isolation. The paper made a design about the key device in the transceiver, which was sensitive to isolation. The basic idea of this design was using the special structure style and optical material. It could eliminate stray light efficiently. It was proved that the process of manufacturing and assembling was not difficult. The device proposed in this paper could improve the efficiency and quality of laser communication. Moreover, the paper made mechanical simulation of device to prove that the device was safe. ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Accession Number: 20211310156193 -
Record 290 of
Title:A denoising method based on CNN for the measurement of far-field focal spot of high power laser using Schlieren method
Author(s):Li, Gang(1); Wang, Zhengzhou(2); Wang, Li(1); Tan, Meng(1); Wang, Wei(1); Yi, Dongchi(1); Wei, Jitong(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11567 Issue: DOI: 10.1117/12.2579390 Published: 2020Abstract:Schlieren method is an effective method to measure the high dynamic range far-field focal spot of high power laser at present, it has been used in the comprehensive diagnosis system of the host facility of the national large scientific device. However, the background subtraction algorithm is used for denosing process of the main lobe and side lobe images in the experiment, which could not effectively remove the noise under the condition of strong radiation. In order to improve the reconstruction accuracy and reliability of far-field focal spot measurement based on schlieren method, there are two aspects have been proposed and optimized in this paper as follows, the mathematical model for the measurement of high dynamic range far-field focal spot is constructed, the noise of images captured by detected CCD is removed effectively. Firstly, the mathematical model of laser focal spot measurement is constructed, which provided a theoretical basis for the measurement of far-field focal spot based on schlieren method. Secondly, the denoising algorithm based on Convolutional Neural Network (DnCNN) is introduced into the denoising of main lobe and side lobe CCD image, which can effectively remove the noise of different levels (0-75db) of main lobe and side lobe CCD image.The experimental results show that the noise signal of main lobe and side lobe images are removed by using DnCNN algorithm, and the best reconstructed image of far-field focal spot of high power laser is obtained when the influencers of amplified noise of main lobe image is reduced greatly. After the above optimization and improvement, it will meet the requirements for accuracy and efficiency of the measurement of high dynamic range far-field focal spot. ? 2020 SPIE.Accession Number: 20205009602480 -
Record 291 of
Title:Actuation Modeling of Ionic–Polymer Metal Composite Actuators Using Micromechanics Approach
Author(s):Yang, Liang(1); Zhang, Dongsheng(1); Wang, Hong(2); Zhang, Xining(1)Source: Advanced Engineering Materials Volume: 22 Issue: 12 DOI: 10.1002/adem.202000537 Published: December 2020Abstract:Herein, the movement of hydrated cations in ionic–polymer metal composite (IPMC) is analyzed by the micromechanics method. Based on the mechanism of IPMC, the migration of hydrated cations is in a step-by-step order, and the aggregation of hydrated cations on the cathode side results in the bending of IPMC toward the anode. The physical models of the maximum displacement and maximum blocking force of IPMC are established, the Pt IPMCs are prepared by chemical deposition, and the calculated values are compared with the experimental values. The results indicate that there is water electrolysis in the actuation process of IPMC, which inhibits the migration of ions on the electrode surface and has a negative effect on the property of IPMC. By comparing the calculated value of the model with the experimental value, it is found that there is good consistency. The mathematical statistical metrics, mean absolute error, mean relative error, determination coefficient, correlation coefficient, mean square error, root mean square error, and relative root mean square error, are used to assess the model capability, which puts a theoretical foundation for the prediction and simulation of IPMC and promotes the further development and practical application of IPMC. ? 2020 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimAccession Number: 20203109001744 -
Record 292 of
Title:The method for calculating optical target center of weak contrast collimating image in integrated diagnosis system
Author(s):Wang, Zhengzhou(1); Wang, Li(2); Tan, Meng(2); Chen, Yongquan(2); Li, Gang(2); Yi, Dongchi(2); Wei, Jitong(2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11567 Issue: DOI: 10.1117/12.2575512 Published: 2020Abstract:In the process of fast automatic alignment of optical path in the integrated diagnosis system of host laser facility, there are six kinds of different optical target images captured. Because of the different characteristics of optical target, different methods for calculating the center of optical target image must be put forward, which increases the algorithm complexity of calculating the optical target center. In order to improve the efficiency and accuracy of fast automatic alignment of laser beam in the integrated diagnosis system, it is necessary and important to propose a method that can calculate all kinds of optical center of collimating images. In this paper, based on the synthesis of the characteristics of pinhole image, schlieren sphere image and common optical target image, a general method for calculating the optical target center of weak contrast collimating image is proposed. Firstly, multi-dimensional image cubes are constructed by using multi time-sharing images or neighborhood vectors, and the dimension of multi-dimensional data cubes is reduced by using NVPCA transformation to remove the correlation between the various dimensional images, separate and readjust the noise of original image; Secondly, the one-dimensional image data is classified by Kmeans, and the binary image is processed by the mathematical morphology operation to separate the laser target and background respectively; Thirdly, if the optical target image is a schlieren image, it need to obtain the background of schlieren image, the region of schlieren sphere, the edge of schlieren sphere respectively; If the optical target image is a pinhole image, it need to obtain the characteristic points on the circle contour of the pinhole image; Finally, the least square method is used to calculate the circle center of the pinhole image and the schlieren sphere image, and the center of gravity method is used to calculate the center of optical target. The experimental results show that this paper synthesizes the same and different characteristics of all kinds of collimating images, proposes a method to calculate the optical target center of weak contrast collimating images, improves the calculation accuracy of the optical target center of collimating images (less than 1 pixel) effectively, shortens the fast alignment time of the optical path of the integrated diagnosis system, and provides an effective guarantee for the measurement experiment of far-field focal spot of high power laser based on schlieren method. ? 2020 SPIE.Accession Number: 20205009602549 -
Record 293 of
Title:Sequential Evolution of Colored Copper Surface Irradiated by Defocused Femtosecond Laser
Author(s):Ding, Kaiwen(1); Li, Ming(2); Wang, Cong(1); Lin, Nai(3); Wang, Haoran(1); Luo, Zhi(1); Duan, Ji'an(1)Source: Advanced Engineering Materials Volume: 22 Issue: 10 DOI: 10.1002/adem.201901310 Published: October 1, 2020Abstract:Herein, an effective method is proposed for the fabrication of sequential colors on copper by adjusting femtosecond laser defocusing distance. The sequential evolution tendency of induced colors by adjusting laser defocusing distance is conducted. It is revealed that such a change of surface optical response is originated from the gradual evolution of three different kinds of structures. The angle-resolved spectrum of the colored surface is investigated. In addition, the simultaneously derived hydrophobicity of the colored surface is explored. ? 2020 WILEY-VCH Verlag GmbH & Co. KGaA, WeinheimAccession Number: 20201308353441 -
Record 294 of
Title:Design of high-speed imaging circuit of spaceborne LASIS hyperspectral imager
Author(s):Liu, Yongzheng(1); Kong, Liang(1); Liu, Xuebin(1); Chen, Xiaolai(1); Liu, Wenlong(1); Zhang, Xin(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 49 Issue: DOI: 10.3788/IRLA20200096 Published: July 25, 2020Abstract:According to the requirement of high resolution and wide range for hyperspectral imaging in the field of remote sensing, a high-speed spectral imager electronic system with high resolution and high reliability was developed, which was suitable for the application of Large Aperture Interferential Imaging Spectrometer(LASIS). The multiple four channel parallel ADC chips for analog-to-digital conversion was used, with V5 series FPGA as the core processor and high -speed SerDes chip for image data transmission. At last, the imaging performance and reliability of our high -speed imaging circuit were validated. All these measures provide technical support for China to enter the leading position in the field of space remote sensing, and also provide useful reference for further development of high -resolution hyperspectral imaging remote sensing. ? 2020, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20203609139706 -
Record 295 of
Title:The method for calculating weak contrast Schlieren sphere center in integrated diagnostic fast automatic collimation system
Author(s):Wang, Zhengzhou(1); Tan, Meng(1); Wang, Li(1); Wang, Qing(2); Wei, Jitong(1); Li, Gang(1); Yi, Dongchi(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 11427 Issue: DOI: 10.1117/12.2552889 Published: 2020Abstract:Aiming at the characteristics that the contrast of schlieren sphere image is weak, the color of sphere target is black, and the sphere target is surrounded by background area in the fast collimation process of integrated diagnostic system, a method for calculating the schlieren sphere center based on gray stretching and digital morphology is proposed in this paper. Firstly, the original image is transformed by linear gray scale to enhance the contrast between the schlieren sphere target and the background area, and then the linear gray scale image is binarized by using the OTSU method. Secondly, the background area is transformed into a continuous connected region by using digital morphological operations such as corrosion and expansion, and search for the maximal connected area is the background area. Thirdly, the image of using digital morphology method and the image of background area are processed NOR operation to obtain the schlieren sphere target. Finally, on the basis of edge detection by sobel operation, the least square method is used to fit the center and radius of the schlieren sphere. The experimental results show that the algorithm can calculate the center of the schlieren sphere whose gray level difference between the sphere area and the background area is greater than 10(the max gray level is 4095). The error between the center coordinate obtained by circle fitting method and the real center coordinate is less than 2 pixels, which meets the requirement of the integrated diagnostic beam fast automatic collimation system that the accuracy of the schlieren sphere center is less than 3 pixels. ? COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.Accession Number: 20201108282713 -
Record 296 of
Title:Identification of Xinjiang Jujube Varieties Based on Hyperspectral Technique and Machine Learning
Author(s):Liu, Lixin(1,2); He, Di(1); Li, Mengzhu(1); Liu, Xing(3); Qu, Junle(4)Source: Zhongguo Jiguang/Chinese Journal of Lasers Volume: 47 Issue: 11 DOI: 10.3788/CJL202047.1111002 Published: November 10, 2020Abstract:To identify different Xinjiang jujube varieties, a hyperspectral technique and machine learning algorithms were employed to obtain and analyze the spectral data of Jinsi-jujube, Jun-jujube, and Tan-jujube. First, the original spectra were preprocessed using various data preprocessing methods, including multiplicative scatter correction (MSC), standard normal variate transformation (SNV), first-derivative (1-Der), and Savitzky-Golay (SG) smoothing. The effects of the preprocessing methods on modeling were investigated. Then, the samples were divided into calibration and prediction sets using sample set partitioning methods based on joint X-Y distance (SPXY). The jujube variety identification models were established based on linear discriminant analysis (LDA), K-nearest neighbor (KNN), and support vector machine (SVM) algorithms using the preprocessed full-band spectra. The results demonstrate that 1-Der outperformed other preprocessing methods mentioned above. Next, the characteristic bands were extracted from the full-band spectra using principal component analysis (PCA), successive projections algorithm (SPA), and competitive adaptive reweighted sampling (CARS). Then, the jujube variety identification models were established based on the characteristic bands. The CARS-based models achieved the highest accuracy in the models established based on several characteristic band extraction methods. Finally, taking the SVM model as an example, the model runtime was compared. The time required by the SVM model based on the characteristic bands was much shorter than the time required by the model based on the full-band spectra. ? 2020, Chinese Lasers Press. All right reserved.Accession Number: 20210609892221 -
Record 297 of
Title:Wideband high-resolution spectral analysis assisted by soliton micro-combs
Author(s):Hu, Hao(1); Chen, Liao(1); Wang, Ruolan(1); Zhao, Yanjing(1); Wang, Xinyu(2,3); Wang, Weiqiang(2,3); Zhang, Chi(1); Zhang, Wenfu(2,3); Zhang, Xinliang(1)Source: Optics InfoBase Conference Papers Volume: Part F181-CLEO-AT 2020 Issue: DOI: 10.1364/CLEO_AT.2020.JW2B.31 Published: 2020Abstract:A high-resolution and large-bandwidth spectral analysis is demonstrated utilizing tunable laser and micro-comb. Bandwidth is extended by 100 times up to 2.5 THz with 2-MHz resolution and a high-Q resonator is successfully characterized in L-band. ? OSA 2020 ? 2020 The Author(s).Accession Number: 20204509460235 -
Record 298 of
Title:Wideband High-Resolution Spectral Analysis Assisted by Soliton Micro-Combs
Author(s):Hu, Hao(1); Chen, Liao(1); Wang, Ruolan(1); Zhao, Yanjing(1); Wang, Xinyu(2,3); Wang, Weiqiang(2,3); Zhang, Chi(1); Zhang, Wenfu(2,3); Zhang, Xinliang(1)Source: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS Volume: 2020-May Issue: DOI: null Published: May 2020Abstract:A high-resolution and large-bandwidth spectral analysis is demonstrated utilizing tunable laser and micro-comb. Bandwidth is extended by 100 times up to 2.5 THz with 2-MHz resolution and a high-Q resonator is successfully characterized in L-band. ? 2020 OSA.Accession Number: 20204009262705 -
Record 299 of
Title:A novel photochromic ceramics with reversible luminescence modulation and light bleaching behavior: Sm3+-doped KSr2Nb5O15
Author(s):Cao, Shuyao(1); Chen, Qian(1); Liu, Junting(1); Wu, Changying(2); Li, Leilei(1); Xu, Jie(1,3); Cheng, Guanghua(2,4); Gao, Feng(1)Source: Journal of the European Ceramic Society Volume: 40 Issue: 15 DOI: 10.1016/j.jeurceramsoc.2020.07.030 Published: December 2020Abstract:A novel tetragonal tungsten bronze (TTB) type Sm3+-doped KSr2Nb5O15 (KSN-Sm) optical ceramic is fabricated by atmosphere sintering technology. A reversible photochromic effect between faint yellow and olive colors and accompanied luminescence modulation behaviour can be realized by alternating the 395 nm light irradiation and thermal treatment. The thermal stimulus model is introduced to modify the classical resonance energy transfer mechanism. The results show that the optimal luminescence modulation ratio Rt about the red emission (601 nm) intensity amounted to 60.0 %, and the KSN-Sm ceramic exhibits excellent luminescence modulation rate and reproducibility. The colored KSN-Sm ceramic can be partly bleached by external light stimulus (620 nm), and the luminescence emission intensity can be recovered from 45 % to 84.2 %. The light bleaching efficiency is strongly dependent on the irradiation wavelength, exposure duration and irradiation dose. These discoveries pave the way to develop new luminescence materials with TTB structure. ? 2020 Elsevier LtdAccession Number: 20203109001806 -
Record 300 of
Title:Color full stokes polarization fringe projection 3D imaging
Author(s):Liang, Jian(1,2); Tian, Xiaobo(2); Tu, Xingzhou(2); Spires, Oliver(2); Brock, Neal(3); Wang, Daodang(2); Wu, Heng(2); Ren, Liyong(1,4); Yao, Baoli(1); Pau, Stanley(2); Liang, Rongguang(2)Source: Optics and Lasers in Engineering Volume: 130 Issue: DOI: 10.1016/j.optlaseng.2020.106088 Published: July 2020Abstract:In this paper, we propose and demonstrate a new 3D imaging technique which can simultaneously provide surface shape, color, and polarization information of an object. The system employs a custom color full Stokes polarization camera and a digital color fringe projector. The color and polarization data provide additional surface details not possible using conventional fringe projection 3D imaging techniques, but important for target identification. We demonstrate that, for an object with weak spectral dependent polarization properties, it is possible to obtain surface shape, intensity, and polarization information in a snapshot, dramatically improving the imaging speed. ? 2020 Elsevier LtdAccession Number: 20201108305160