2015
2015
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Record 241 of
Title:Super resolution optic three-dimensional imaging based on compressed sensing
Author(s):Wang, Feng(1,2); Luo, Jian-Jun(1); Tang, Xing-Jia(3); Li, Li-Bo(3); Hu, Bin-Liang(3)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 44 Issue: 3 DOI: 10.3788/gzxb20154403.0328001 Published: March 1, 2015Abstract:A super resolution optic three-dimensional imaging based on compressed sensing was proposed for better optic imaging, in which imaging system was consisted of object glass, coding template, dispersion element, collimating lens, focus lens, detector in the front, hyperspectral data was reconstructed in the end by sparse reconstruction algorithm, so the most of data processing was transformed to the back-end from the imaging system. Meanwhile, Piece reconstruction, dislocation pretreatment and multi-frame reconstruction were used for improving accuracy of reconstruction, reducing memory of the back-processing, lowing computation complexity. By comparing the spectral curve, signal noise ratio, spectral error of the original and the reconstructed data cube, and doing classification and identification analysis, it was gained that the proposed compressed sensing could realize super resolution optic three-dimensional imaging, which have better property in imaging and data application, it can be used in big breath, high resolution, low power consumption and moving-target imaging observation. ?, 2015, Chinese Optical Society. All right reserved.Accession Number: 20151600765013 -
Record 242 of
Title:Switchable dual-wavelength fiber laser mode-locked by carbon nanotubes
Author(s):Chen, G.W.(1); Li, W.L.(1); Yang, H.R.(1); Kong, Y.C.(1)Source: Journal of Modern Optics Volume: 62 Issue: 5 DOI: 10.1080/09500340.2014.982224 Published: March 12, 2015Abstract:We have proposed a switchable mode-locked fiber laser by means of carbon nanotube saturable absorber and fiber Bragg gratings (FBGs). The single-wavelength mode-locking operation can be switched between 1549.5 and 1559.5 nm, respectively, which correspond to the central wavelengths of two FBGs. With the appropriate setting of polarization controller, the stable dual-wavelength operation can be achieved due to the high stability of saturable absorber based on carbon nanotubes. Our method provides a simple, stable, low-cost, dual-wavelength ultrafast-pulsed source. ? 2014 Taylor & Francis.Accession Number: 20144900287567 -
Record 243 of
Title:Adaptive detail enhancement for infrared image based on bilateral filter
Author(s):Zeng, Qingjie(1); Qin, Hanlin(1); Leng, Hanbing(2); Yan, Xiang(1); Li, Jia(1,3); Zhou, Huixin(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9675 Issue: DOI: 10.1117/12.2202764 Published: 2015Abstract:In order to solve the problem that infrared images usually have a poor visual effect with low contrast and weak detail information, an adaptive detail enhancement method for infrared image based on bilateral filter is proposed in this paper. Firstly, adopting the bilateral filter which has a good filtering performance, the original infrared image is effectively derived into the smoothed component and the detail component. Exactly, the detail component is the difference between the original infrared image and the smoothed component. The major merit of using the bilateral filter is that the abundant and subtle detail contents containing a lot of edges and textures of the original infrared image could be obtained via adjusting the parameters flexibly. Further, the detail component plays a key role in obtaining an adaptive detail enhancement weight which is generated by the normalization of the detail component. The weight is in the range [0, 1] and their magnitudes can be regarded as the intensity of the original image details. As a result, this detail enhancement weight is adaptive and effective for the original infrared image. Finally, a kind of linear weighting strategy is utilized to achieve the image sharpness combing the original image and the adaptive weight. The experimental results show that the proposed method outperforms other conventional methods in terms of visual effect and quantitative evaluation, which provides a new approach for infrared image detail enhancement. ? 2015 SPIE.Accession Number: 20161602266782 -
Record 244 of
Title:Measurement of azimuth by using new polarizer
Author(s):Xiao, Maosen(1); Li, Chunyan(1,2); Wu, Yiming(1); Lu, Weiguo(1); Wang, Haixia(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 44 Issue: 2 DOI: Published: February 25, 2015Abstract:In order to achieve azimuth accurate measurement of polarizer axis in the polarization signal generating unit, a device and its working principle were introduced with the use of magneto-optical modulation, right-angled prism and autocollimator to elicit the axis azimuth, and the ordinary polarization prism problems were pointed out. A new type of polarization device was designed based on Glan-Taylor prism to solve this problem, it uses three calcite crystals with identical material composition, each side can form a Glan-Taylor prism respectively with the middle, that it can be a analyzer when it is turned 180° around; the working principle of the device and installation and ways of working were described in detail, that the new component can eliminate the prism manufacture and installation errors in the work process was analyzed, it can complete polarizer axis azimuth determination. Finally, experiment results verify that the angle measurement precision of the device is 0.5″, and the system has characteristics of high stability, precision and operability, and so on. ?, 2015, Chinese Society of Astronautics. All right reserved.Accession Number: 20151800809876 -
Record 245 of
Title:Optical system design of a co-path Doppler asymmetric spatial heterodyne interferometer with two fields of view
Author(s):Fei, Xiaoyun(1,2); Feng, Yutao(1); Bai, Qinglan(1); Xie, Nian(1,2); Li, Yong(1); Yan, Peng(1); Sun, Jian(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 35 Issue: 4 DOI: 10.3788/AOS201535.0422003 Published: April 10, 2015Abstract:A co-path Doppler asymmetric spatial heterodyne spectroscopy (DASH) interferometer with two fields of view to apply to wind vector observations from satellite is presented. The instrument using mirrors as field combiners, K?sters prism as beam splitter, one grating and imaging lens with focal power in one dimension can observe winds at different elevations in two orthogonal look directions. It is compact, without moving parts and efficient. An exact relation of the path offset Dd to Littrow angle and the size of K?sters prism is derived. A system for observation of the O[1D]630 nm emission form satellite is designed to show the process and result of parameters optimizing. Finally, a simulated result for the system indicate that the co-path DASH interferometer with two fields of view has space resolution ability in one dimension, it can get the interferograms at different elevations in two directions without scanning parts and it is possible to obtain the wind vector for the same volume with the help of satellite's moving. ?, 2015, Chinese Optical Society. All right reserved.Accession Number: 20152300916635 -
Record 246 of
Title:Design and implementation of CCD exposure time control based on driver timing
Author(s):Liu, Hui(1,2); Liu, Xuebin(1); Chen, Xiaolai(1); Kong, Liang(1); Liu, Yongzheng(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 44 Issue: DOI: Published: December 25, 2015Abstract:A new method for exposure time control by driver timing was proposed for non-electronic shutter frame transfer area CCD imaging detector. Based on the Sarnoff's back illuminated frame transfer array CCD sensor, the charge will be drained quickly in the excess period, with the driver timing controlled by the software. Selecting exposure time as 2 ms, 4 ms, 6 ms and 9.96 ms, the CCD output signal amplitude was measured under system frame frequency of 100 fps. The gray value of continuous 100 frame image calculated by the Matlab. Results show that the method can control the CCD exposure time effectively, and can be implemented by software. It can be widely used in the frame transfer area CCD imaging device without electronic shutter. ? 2015, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20160401852778 -
Record 247 of
Title:Microstructure and chemical bond evolution of diamond-like carbon films machined by femtosecond laser
Author(s):Wang, Jing(1); Wang, Chunhui(1); Liu, Yongsheng(1); Cheng, Laifei(1); Li, Weinan(2); Zhang, Qing(1); Yang, Xiaojun(2)Source: Applied Surface Science Volume: 340 Issue: DOI: 10.1016/j.apsusc.2015.02.169 Published: June 15, 2015Abstract:Femtosecond laser is of great interest for machining high melting point and hardness materials such as diamond-like carbon, SiC ceramic, et al. In present work, the microstructural and chemical bond evolution of diamond-like carbon films were investigated using electron microscopy and spectroscopy techniques after machined by diverse femtosecond laser power in air. The results showed the machining depth was essentially proportional to the laser power. The well patterned microgrooves and ripple structures with nanoparticles were formed distinctly in the channels. Considering the D and G Raman band parameters on the laser irradiation, it revealed a conversion from amorphous carbon to nanocrystalline graphite after laser treated with increasing laser power. X-ray photoelectron spectroscopy analysis showed a great decrease of sp3/sp2 after laser treatment. ? 2015 Elsevier B.V. All rights reserved.Accession Number: 20151400717937 -
Record 248 of
Title:A concept design of deployable space membrane diffractive telescope
Author(s):Zheng, Yaohui(1,2); Ruan, Ping(1); Cao, Shang(1,2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9678 Issue: DOI: 10.1117/12.2199492 Published: 2015Abstract:The traditional Space Telescope has a tremendous potential shortcoming for very large aperture space telescopes. The total mass of the conventional monolithic mirror will skyrocket along with the increase of the apertures; even so much as cannot be launched to space even with the best current lightweight mirror designs. The use of a membrane diffractive optical element (DOE) can reduce the mass of large space telescopes and achieve as much as a factor of seven in mass savings per unit aperture area compared to lightweight mirrors. The primary lens of this telescope is a transmissive membrane etched with a diffraction pattern that offers a significant relaxation in the control requirements on the membrane surface figure. In 2012, the meter-scale transmissive membrane DOE was successfully developed. In 2014, the brassboard telescope of 5-meter diameter successfully demonstrates the ability to collect polychromatic high resolution imagery over a representative object using the transmissive DOE technology. All in all, the development of diffractive telescope with apertures in excess of 5 meter diameter has been put on the agenda. In this paper we first discuss the diffractive imaging system. Then some traditional deployable space optical systems are analyzed in the aspects of deployment methods and characteristics and a conceptual design for a 10m-diameter diffraction telescope is proposed. At last we talk about the key technologies for membrane diffractive telescope. ? 2015 SPIE.Accession Number: 20161602271451 -
Record 249 of
Title:Detector noise quantitative ratio modelling in coherent field imaging
Author(s):Cheng, Zhi-Yuan(1,2); Luo, Xiu-Juan(1); Ma, Cai-Wen(1); Zhang, Yu(1,2); Liu, Hui(1); Zhu, Xiang-Ping(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 44 Issue: 4 DOI: 10.3788/gzxb20154404.0407002 Published: April 1, 2015Abstract:In order to settle the problem of quantitativly estimating ratio of detector noise and analyse whether detecoror noise is the main noise in laser coherent field imaging system, a novel method of quantitative analysis detector noise ratio was proposed. The Signalt-to-Noise (SNR) of the system was given by photoelectron statistics method, and estimating equation of SNR intermediate parameter was derived. A quantitative ratio model of detector noise to total noise was established by SNR equation and estimating equation of SNR intermediate parameter. The ratio model was tested and verified by theory analysis and experiment. The results show that in the specific experiment table, detector noise is about 52% of the total noise. Because the experiment was accomplished at night, turbulence noise and background noise had the least influence on the system, detector noise was the main noise source. The conclusion was acquired that the proposed metod can accurately and effectively estimate detector noise ratio to total noise and has the advantage of simplicity and effectiveness. It can be widely applied in quantitative analysing and measuring of detector noise in laser coherent imaging system. ?, 2015, Chinese Optical Society. All right reserved.Accession Number: 20152100877439 -
Record 250 of
Title:Rapid modeling method of LED free-form surface lens based on Scheme language
Author(s):Dai, Yidan(1,2); Qu, Enshi(1); Ren, Liyong(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 44 Issue: 9 DOI: Published: September 25, 2015Abstract:Multiple softwares were required in the traditional design process of LED free-form surface lens. It is obvious that this process is complicated and inefficient. Moreover, when the model was transferred from 3D modeling software to optical simulation software, the file format had to be changed to solve the problem of the software compatibility. Note that some subtle changes were inevitably introduced to the model by such an operation, such as the generation of cracks or tiny deformation which would seriously affect the light efficiency and the degree of illumination uniformity. A new design method was presented in this paper which was used to directly generate model in the optical simulation software by using Scheme language. In this paper, the method of mesh division was applied to design the LED free-form surface lens with rectangular lighting. After the corresponding surface configuration was obtained, 3D modeling software and the Scheme language programming were used to generate lens model respectively. With the help of optical simulation software, a light source with the size of 1 mm in diameter was used in experiment, in which total one million rays were computed. The simulated results could be acquired by both models. It can be seen that the model deformation problems caused by the process of the model transfer could be prevented by using Scheme language, and the degree of illumination uniformity was also increased from 67% to 93.5%. Meanwhile, only 5 seconds were needed in modeling process by Scheme language which was more efficient than 3D modeling software. ?, 2015, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20154501520710 -
Record 251 of
Title:Optimization design of long wave infrared rays and laser optical system with conformance structure
Author(s):Mei, Chao(1); Cao, Jianzhong(1); Yang, Hongtao(1,2); Guo, Zheyuan(1); Liang, Yuanqing(1,2)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 35 Issue: DOI: 10.3788/AOS201535.s122002 Published: July 10, 2015Abstract:In order to improve the precision of small measure equipment, the manuscript presents a structure of common aperture, long wave infrared rays/laser dual-mode measure equipment. Then an optical system is designed to match the system's needs. The long wavelength infrared imaging system and the laser receiver, laser emission system use the same protect window, the far infrared imaging system and the laser receiver use the same aperture and reflector, in this way the size of optical system is reduced. The volume of the whole optical system is 450 mm×164 mm×164 mm, coincident with the requirement of small and light. At last, analysis the performances of each optical systems by the software, the modulation transfer function of the far infrared imaging system is above 0.23 at 30 lp/mm, the optical path difference of the laser receiver is smaller than 1/4 wavelength, the spot diagram of laser emission system is smaller than 10 μm, all of them can match the project requirement. ?, 2015, Chinese Optical Society. All right reserved.Accession Number: 20154601546783 -
Record 252 of
Title:Evaluation and analysis of pre-oxidation extent of polyacrylonitrile fiber
Author(s):Gu, Hongxing(1,2); Wang, Haojing(1); Fan, Lidong(1); Xue, Linbing(1); Zhao, Youjun(1)Source: Huagong Xuebao/CIESC Journal Volume: 66 Issue: 3 DOI: 10.11949/j.issn.0438-1157.20141369 Published: March 1, 2015Abstract:Polyacrylonitrile (PAN) precursor fiber and pre-oxidized fiber were tested with Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) to investigate the accuracy of pre-oxidation extent which was measured by testing. On the basis of the study on influence factors during the FTIR test, FTIR spectra and relative cyclization index (RCI) were analyzed. Furthermore, aromatization index (AI) was also studied via comparing the thermal properties of precursor fiber and pre-oxidized fiber. The pre-oxidation extent of pre-oxidized fiber could be qualitatively evaluated by FTIR and DSC, while RCI by quantitative calculation was not comparable and AI was higher than the true value. ?, 2015, Chemical Industry Press. All right reserved.Accession Number: 20151400720842