2017
2017
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Record 433 of
Title:Identification of the front or rear surface damage of the thin DKDP crystal
Author(s):Wan, Neng(1,2); Da, Zhengshang(1); Li, Hongguang(1); Yuan, Suochao(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 46 Issue: 8 DOI: 10.3788/IRLA201746.0817001 Published: August 25, 2017Abstract:On the basis of total internal reflection edge illumination, a method can be used to identify the damage on front or rear surface of the thin DKDP crystal by the birefringence of DKDP crystal. When an ultraviolet ray incidented upon a DKDP crystal whose thickness was 11 mm, a displacement of 254.738 μm (theoretical value) between o-ray and e-ray on the exit surface will be caused due to the birefringence of DKDP crystal. The damage located on the rear surface of DKDP had double-images, which could be modulated by polarizer placed in front of CCD camera. The damage located on the front surface of DKDP had a single-image, which couldn't be modulated by polarizer. The method had the ability of avoiding extracting the information of a damage repeatedly, and improving the accuracy of damage identification. The experiments demonstrate that the method can distinguish the damage on front or rear surface of the thin DKDP crystal whose thickness is 11 mm. ? 2017, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20174204277914 -
Record 434 of
Title:Laser spot center location algorithm based on sub-pixel interpolation
Author(s):Liu, Tong(1,2); Tian, Yan(1); Wu, Jingyao(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10462 Issue: DOI: 10.1117/12.2285027 Published: 2017Abstract:Precise location of laser spot in laser precision measurement is always an important research direction. Laser has the characteristics of good direction and small divergence, so it is widely used in aerospace, weapon systems and optical measuring and testing instruments. The accuracy of the laser spot center location can directly determine the precision of measurement. Aiming at positioning the center of laser spot, in the foundation of researching the limitation of the practical application of the common laser spot center location algorithm, this paper proposes a method of laser spot center localization based on sub-pixel interpolation, which can effectively improve the signal noise ratio (SNR) of laser spot image, reduce the influence of the background noise and thermal noise. The algorithm firstly uses the threshold value decision to exclude the interference of the light of the image, and then use the improved sub-pixel interpolation algorithm for image edge detection to obtain the edge image, and finally using the circle fitting method to obtain the positioning center. Through the experiment of processing of laser spot image, the results show that improved algorithm proposed in this paper has higher positioning accuracy than the traditional centroid, and satisfies the need of laser precision measurement in reliability, positioning accuracy and noise resistance and other aspects, at the same time, the computational complexity of this algorithm is low, can greatly save the system resources, and it can be used for the processing of the video images in the hardware and software. ? 2017 SPIE.Accession Number: 20180404670995 -
Record 435 of
Title:Characteristis research of diffuser panel in near backscatter measurement system
Author(s):Han, Yang(1,2); He, Junhua(1); Yan, Yadong(1); Wu, Bingjing(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 46 Issue: 9 DOI: 10.3788/IRLA201746.0917002 Published: September 25, 2017Abstract:Based on the analysis of near back scattered light in laser fusion, a method was proposed to collect near back scattered light by using diffuser panel. Based on the analysis of the application scenarios of the diffuser panel, the characteristic of the diffuser panel was presented. A device for measuring the characteristics of diffuser panel was set up. The directional hemispherical reflectance (DHR), bidirectional reflectance distribution function, surface uniformity, vacuum and UV properties were measured and analyzed. The analysis results show that the F4 target panel has a high reflectivity close to 0.99, the spectral flatness, the bidirectional reflectance distribution function (BRDF) of approximate cosine distribution, 0.869 6% of the higher surface uniformity, as well as the smaller UV vacuum influence. Therefore, the F4 target panel meets the measurement requirements of the near back scattered light in laser inertial confinement fusion (ICF), and it is feasible to use the diffuser panel to collect the near back scattered light. ? 2017, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20174504368492 -
Record 436 of
Title:Design and Test of Portable Hyperspectral Imaging Spectrometer
Author(s):Zou, Chunbo(1,2); Yang, Jianfeng(1); Wu, Dengshan(1); Zhao, Qiang(1); Gan, Yuquan(1); Fu, Di(1); Yang, Fanchao(1); Liu, Hong(1); Bai, Qinglan(1); Hu, Bingliang(1)Source: Journal of Sensors Volume: 2017 Issue: DOI: 10.1155/2017/7692491 Published: 2017Abstract:We design and implement a portable hyperspectral imaging spectrometer, which has high spectral resolution, high spatial resolution, small volume, and low weight. The flight test has been conducted, and the hyperspectral images are acquired successfully. To achieve high performance, small volume, and regular appearance, an improved Dyson structure is designed and used in the hyperspectral imaging spectrometer. The hyperspectral imaging spectrometer is suitable for the small platform such as CubeSat and UAV (unmanned aerial vehicle), and it is also convenient to use for hyperspectral imaging acquiring in the laboratory and the field. ? 2017 Chunbo Zou et al.Accession Number: 20173904210946 -
Record 437 of
Title:Mesoporous SiO2/VO2 double-layer thermochromic coating with improved visible transmittance for smart window
Author(s):Zhang, Jing(1,2,5); Wang, Jing(1,2,5); Yang, Chunming(3); Jia, Hongbao(4); Cui, Xinmin(1,2,5); Zhao, Shichao(1,5); Xu, Yao(2)Source: Solar Energy Materials and Solar Cells Volume: 162 Issue: DOI: 10.1016/j.solmat.2016.12.048 Published: April 1, 2017Abstract:Thermochromic vanadium dioxide (VO2) film is a potential material for smart-window. But the high refractive index (>2) of VO2 coating in visible band resulted in strong reflection and low visible transmission. If another coating with a definite low refractive index is laid on VO2 film to construct a gradient index multilayer system, the total reflection could be effectively reduced. Therefore in this paper we designed a mesoporous SiO2/VO2 double-layer system in which the mesoporous SiO2 layer possessed an index adjustable from 1.243 to 1.354 to reduce the surface reflection of VO2-based smart window. The mesoporous structure has been investigated through several techniques including 2D GISAXS, TEM and N2 ad/desorption. More important, a facile, safe and low-cost solution method was employed to prepare VO2 film with 60?nm thickness directly from ammonium citrato-oxovanadate (Ⅳ) compound that was reported by us previously. On this newly designed mesoporous SiO2/VO2 double-layer coating, the integral visible transmittance at 25?°C (Tvis,L) increased to 80.0% from 69.8% of pure VO2 coating while the corresponsive integral visible transmittance at 90?°C (Tvis,H) increased to 78.9% from 67.6% of pure VO2 coating, if the index of mesoporous SiO2 layer was optimized to 1.299. Simultaneously, the near infrared switching ability at 2000?nm (?T2000) reached 29.0% and solar energy modulation (?Tsol) was maintained at 10.2%. The phase transition temperatures (Tt) for VO2 coating and the optimized SiO2/VO2 double-layer coating were 51.9?°C and 53.8?°C respectively, far below 68?°C of bulky VO2. This optical performance should be very attractive for application in the further smart window because of little increased cost and greatly enhanced property. ? 2017 Elsevier B.V.Accession Number: 20170203242082 -
Record 438 of
Title:The cooling control system for focal plane assembly of astronomical satellite camera based on TEC
Author(s):Yuqing, He(1,2); Yunfei, Du(1); Wei, Gao(1); Baopeng, Li(1); Xuewu, Fan(1); Wengang, Yang(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10256 Issue: DOI: 10.1117/12.2257422 Published: 2017Abstract:The dark current noise existing in the CCD of the astronomical observation camera has a serious influence on its working performance, reducing the working temperature of CCD can suppress the influence of dark current effectively. By analyzing the relationship between the CCD chip and the dark current noise, the optimum working temperature of the red band CCD focal plane is identified as -75°C. According to the refrigeration temperature, a cooling control system for focal plane based on a thermoelectric cooler (TEC) was designed. It is required that the system can achieve high precision temperature control for the target. In the cooling control system, the 80C32 microcontroller was used as its systematic core processor. The advanced PID control algorithm is adopted to control the temperature of the top end of TEC. The bottom end of the TEC setting a constant value according to the target temperature used to assist the upper TEC to control the temperature. The experimental results show that the cooling system satisfies the requirements of the focal plane for the astronomical observation camera, it can reach the working temperature of -75°C and the accuracy of ±2°C. ? 2017 SPIE.Accession Number: 20171703607655 -
Record 439 of
Title:Research on implementation of an improved finite state machine model in satellite simulated system
Author(s):Feng, Xu-Bin(1,2); Su, Xiu-Qin(1,2); Wang, Chen(1); Han, Jun-Feng(1); Yang, Yong-Qing(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10605 Issue: DOI: 10.1117/12.2286412 Published: 2017Abstract:Satellite simulated system is a very important sub system of satellite payload ground comprehensive testing system which tests the satellite payload's order and telemetering before delivering the payload to satellite. For all kinds of satellite simulated system, a new implementation which used an improved Finite State Machine (FSM) model can make the whole system modules clear, reduce the coupling between modules, improve the modules' reusability, enhance productivity, and make the research and development of the whole system easier. The engineering applications' experimental results show that the implementation of an improved FSM model can make the satellite simulated system stable and reliable. ? 2017 SPIE.Accession Number: 20181705046999 -
Record 440 of
Title:Inversion of low dynamic vehicle shape and dimension information using non-resolved photometric data in near space
Author(s):Jing, Nan(1,2); Li, Chuang(1); Zhong, Pei-Feng(1,2); Chong, Ya-Qin(1,2)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 25 Issue: 7 DOI: 10.3788/OPE.20172507.1738 Published: July 1, 2017Abstract:In order to obtain the shape and dimension information of low dynamic non-resolved object in near space,an experiment on optical detection of high altitude balloon was performed to investigate how to calculate object shape and dimension information from photometric data. In the experiment, experimental images captured by the ground-based detector were processed by aperture photometry technology, thus obtaining non-resolved photometric data. During the inversion process, two shape representation methods as well as three sets of regularization functions were adopted to describe and restrict object shape, respectively. The methods contained spherical harmonics function and subdivision control points, and the functions involved spherical harmonics regularization function, triangle panel regularization function and physical characteristics regularization function. Based on the Fourier transform of photometric data and model data of the shape representation methods, the shape and dimension information of the non-resolved object was inversed by the Point Spread Function (PSF) of the optical system. The result shows that the prominent features presented in the object shape are similar, which indicates that the features are extracted from the photometric data. The relative errors of object equivalent diameter inversed by spherical harmonics function and subdivision control points are 11.3% and 22.6%, and the relative errors of object length are 11.6% and 21.8%, respectively. The comparison of the relative errors proves that the shape representation method based on the spherical harmonics function has smaller error and is more suitable to represent the low dynamic object shape. ? 2017, Science Press. All right reserved.Accession Number: 20173904205120 -
Record 441 of
Title:Optical system design of space fisheye lens and performance analysis
Author(s):Geng, Dan(1,2); Yang, Hong-Tao(2); Mei, Chao(2); Li, Ya-Hui(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10462 Issue: DOI: 10.1117/12.2285587 Published: 2017Abstract:In order to reduce the number of cameras which are equipped in spacecraft, and using a small amount of cameras to monitor the whole spacecraft, an optical system of fisheye lens is designed based on the principle of non-similarity. The optical system uses a high definition CCD which has 1920×1080 pixels (the size of pixel is 5.5μm×5.5μm). The effective focal length of the fisheye optical system is 5.0 mm, the F number is 5.0, and the full field of view (FOV) is 180°. Its modulation transfer function (MTF) in all FOV is more than 0.5 at 91 lp/mm with great image. And the relative illumination of marginal FOV reaches 85.2%, this guarantees that the optical system has a good of illumination uniformity. Taken into account that the camera will be used in the intricate space environment, the article was analyzed the influence of environmental factors, the changing temperatures and vacuum environment, on the imaging quality of the optical system. The results show that the optical system of fisheye lens still has good imaging performance under the temperature -40?~+60? in vacuum environment. In the imaging process, the stray light which likes a red ring has been found at the edge of the image when the strong light source appeared in the middle of the image, it is similar to a positive ghost. After analysis, the results show that stray light mainly comes from the reflected light among the lens surfaces. So, there is a proposal that the radius of these lens surfaces should be restricted under optimization. Through the further optimizing and experiment, the consequence proves that the stray light was successfully eliminated. ? 2017 SPIE.Accession Number: 20180404671046 -
Record 442 of
Title:Medical Image Fusion Based on Feature Extraction and Sparse Representation
Author(s):Fei, Yin(1,2); Wei, Gao(2); Zongxi, Song(2)Source: International Journal of Biomedical Imaging Volume: 2017 Issue: DOI: 10.1155/2017/3020461 Published: 2017Abstract:As a novel multiscale geometric analysis tool, sparse representation has shown many advantages over the conventional image representation methods. However, the standard sparse representation does not take intrinsic structure and its time complexity into consideration. In this paper, a new fusion mechanism for multimodal medical images based on sparse representation and decision map is proposed to deal with these problems simultaneously. Three decision maps are designed including structure information map (SM) and energy information map (EM) as well as structure and energy map (SEM) to make the results reserve more energy and edge information. SM contains the local structure feature captured by the Laplacian of a Gaussian (LOG) and EM contains the energy and energy distribution feature detected by the mean square deviation. The decision map is added to the normal sparse representation based method to improve the speed of the algorithm. Proposed approach also improves the quality of the fused results by enhancing the contrast and reserving more structure and energy information from the source images. The experiment results of 36 groups of CT/MR, MR-T1/MR-T2, and CT/PET images demonstrate that the method based on SR and SEM outperforms five state-of-the-art methods. ? 2017 Yin Fei et al.Accession Number: 20173804167426 -
Record 443 of
Title:Modeling and research of infrared characteristics of space target based on radiation dissipation
Author(s):Li, Wenhao(1,2); Liu, Zhaohui(1); Mu, You(1); Liang, Dongsheng(1); Yang, Rui(1,2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 46 Issue: 6 DOI: 10.3788/IRLA201746.0604003 Published: June 25, 2017Abstract:Radiators used to maintain space target functioning normal were introduced. Operating mode and working condition were presented. Current used space target infrared characteristics models were summarized. With further analysis, the outside surface of space target were divided into common area and radiator, and energy equations were built separately. Taking FY-1C as an example, and taking account of orbit, materials and structure, temperature field of the outer surface of space target was calculated using finite element method. When dissipation power was 0 W and 100 W, the biggest temperature difference of radiator was 51.49℃. Analyzing the temperature field with orbit, the illumination in entrance pupil of detection system in a distance of 5 km was calculated. When space target was in the shadow of earth, during which the radiation from earth or solar radiation reflected by earth was negligible because of the big incident angle, the illumination of the space target differed by 1-2 orders of magnitude. When space target was under the sun, different dissipation powers can only affect the illumination of long infrared spectra apparently, because of the reflected radiation of target. ? 2017, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20173504100414 -
Record 444 of
Title:Design of High Ratio Middle Infrared Continuous Zoom Optical System
Author(s):Yang, Ming-Yang(1,2); Yang, Hong-Tao(1,2); Qu, Rui(1); Mei, Chao(1); Zhou, Zuo-Feng(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 46 Issue: 5 DOI: 10.3788/gzxb20174605.0522003 Published: May 1, 2017Abstract:Based on the structure of compounding zoom system, a mathematical model of three component continuous zoon design was proposed. Under the guidance of the model, a compact high zoom ratio continuous zoom optical was designed with medium-wave cooling 15μm, 640×512 staring focal plane array. The system works in the range of 3.7~4.8μm and F number is 4. By using this model to distribute the optical power, the initial focal point is calculated to obtain the focal length range of 9~740mm and the zoom ratio is 80×. The whole system used only two kinds of infrared materials of silicon and germanium and eight lenses were used. The system was U-folded by using the secondary imaging and two 45° reflecting mirrors, it effectively achieved 100% cold shield efficiency and controlled the horizontal and vertical dimension. It got the moving lens zoom track and cam curve of each group, and analyzed the continuous zoom optical system from MTF, spot diagram, distortion, narcissus, environment analysis and so on. The design results prove that the zoom system has the advantages of smooth zoom track, great narcissus controlled features and excellent image and it has also been found to apply to infrared imaging system matching with advanced middle wave detector greatly. Finally, the correctness and feasibility of the mathematical model are verified exactly. ? 2017, Science Press. All right reserved.Accession Number: 20173104014254