2016
2016
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Record 97 of
Title:High-speed, high-voltage pulse generation using avalanche transistor
Author(s):Yong-Sheng, Gou(1,2); Bai-Yu, Liu(1); Yong-Lin, Bai(1); Jun-Jun, Qin(1); Xiao-Hong, Bai(1); Bo, Wang(1); Bing-Li, Zhu(1); Chuan-Dong, Sun(1)Source: Review of Scientific Instruments Volume: 87 Issue: 5 DOI: 10.1063/1.4948727 Published: May 1, 2016Abstract:In this work, the conduction mechanism of avalanche transistors was demonstrated and the operation condition for generating high-speed pulse using avalanche transistors was illustrated. Based on the above analysis, a high-speed and high-voltage pulse (HHP) generating circuit using avalanche transistors was designed, and its working principle and process were studied. To improve the speed of the output pulse, an approach of reducing the rise time of the leading edge is proposed. Methods for selecting avalanche transistor and reducing the parasitic inductance and capacitance of printed circuit board (PCB) were demonstrated. With these instructions, a PCB with a tapered transmission line was carefully designed and manufactured. Output pulse with amplitude of 2 kV and rise time of about 200 ps was realized with this PCB mounted with avalanche transistors FMMT417, indicating the effectiveness of the HHP generating circuit design. ? 2016 Author(s).Accession Number: 20162202428880 -
Record 98 of
Title:Optimization design of two-dimensional magneto optical trap field coils for cold atom interferometer
Author(s):Fan, Pengge(1,2); Wu, Yiming(1); Jia, Sen(1); Wang, Xianhua(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 45 Issue: 6 DOI: 10.3788/IRLA201645.0618003 Published: June 25, 2016Abstract:High flux of cold atoms is one of the key technologies to realize high-precision cold atom interferometer. The approach of concatenation of two-dimensional Magnetic Optical Trap (2D-MOT) and three-dimensional Magnetic Optical Trap (3D-MOT) is generally used to obtain high flux of cold atoms. The magnetic field distribution of 2D-MOT is the key influencing factor in this appliance. In this paper, three different(rectangular, race-track and saddle) mathematical models of Anti-Helmholtz coils in 2D-MOT were established to analyze the magnetic field distribution. Then, the magnetic field zero drift and the change of magnetic field gradient caused by the error of eccentricity, coils asymmetry, parallelism and inside diameter asymmetry were analyzed, which were produced in the manufacture and installation process using finite element analysis. Results show that the magnetic field gradient provided by saddle coils is more conducive to produce high flux of cold atoms when eccentricity error is less than 1.14 mm, coils asymmetry error is less than 0.016 A and parallelism error is less than 1.02°. This work may provide theoretical guidance for the design and fabrication of magnetic system of 2D-MOT of cold atom interferometer. ? 2016, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20162702564089 -
Record 99 of
Title:Wave-front coded super-resolution imaging technique
Author(s):Zhao, Hui(1); Wei, Jingxuan(2); Pang, Zhihai(1); Liu, Meiying(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 45 Issue: 4 DOI: 10.3788/IRLA201645.0422003 Published: April 25, 2016Abstract:Wave-front coding is a classical computational imaging technique and famous for its capability in extending the depth of focus (DOF) of incoherent imaging system. In fact, besides the DOF extension, this technique has the potentials in realizing super-resolution imaging, which is rare to be investigated in existing literatures. On the one hand, the introduction of phase mask makes defocus invariance of optical transfer function (OTF) possible and the dramatic decrease of modulus of OTF alleviates the aliasing effect owned by most digital imaging systems. In this case, a better image data suitable for super-resolution imaging could be provided. On the other hand, the prominent expansion of point spread function (PSF) allows us to obtain the real sampled PSF corresponding to any specific pitch size in a digital way using the ideal continuous optical PSF whose sampling interval could be considered as unlimitedly small. Therefore, based on these two characteristics, an amplification based single image super-resolution reconstruction algorithm was especially designed for wave-front coded imaging system and an experimental prototype camera has been fabricated to verify the effectiveness of the algorithm. The results demonstrate that the extended DOF which is more than 20 times original DOF has been obtained and at least 3X super-resolution reconstruction effect could be achieved. Besides that, the quality of reconstructed image approaches the diffraction limited level. ? 2016, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20162302456302 -
Record 100 of
Title:New light-control technology research of CCD camera
Author(s):Wang, Xiaotao(1,2); Wang, Xu'an(1,2,3,4); Kang, Ning(3,4)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 45 Issue: 1 DOI: 10.3788/IRLA201645.0120003 Published: January 25, 2016Abstract:The exposure time and signal gain can be used to adjust the light intensity for a conventional CCD camera, but both of them can not be configured best. It is also very difficult to maximize the effectiveness of their dimming, especially for the condition of the changed illumination intensity, the large dynamic range and the unclear picture. For the above-mentioned shortages, the histogram equalization certain improvements, the deployment of exposure time and signal gain were optimized through precise deployment of exposure time and optimization of signal gain coefficients. After the test, the screen effect has been significantly improved, the adjustment time is less than 40 ms, and the system is stable and reliable. ? 2016, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20160902037325 -
Record 101 of
Title:Analysis of defocus in space based space optical debris detection
Author(s):Zeng, De-Xian(1); Hu, Bing-Liang(2); Song, Hai-Jun(2)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 45 Issue: 1 DOI: 10.3788/gzxb20164501.0111002 Published: January 1, 2016Abstract:The reasons of the generation of defocus were discussed and the defocus change was analysed from the relative distance, atmospheric pressure and temperature change. The modulation transfer function model was proposed to study the image quality influenced by defocus. Then different defocus value leading image blurry was simulated. The simulation results indicate that the positive and negative defocus value induced by the relative distance, atmospheric pressure and temperature change can be counteracted. This paper provides an effective data to spatial camera design, compensating measure establishment and performance evaluation. ? 2016, Science Press. All right reserved.Accession Number: 20160902037363 -
Record 102 of
Title:Cooled Dyson long-wave infrared push-broom imaging spectrometer by re-imaging
Author(s):Sun, Jiayin(1,2); Liu, Ying(1); Jiang, Yang(1); Li, Chun(1); Sun, Qiang(1); Hu, Xinrong(3)Source: Optics Communications Volume: 367 Issue: DOI: 10.1016/j.optcom.2016.01.067 Published: May 15, 2016Abstract:A cooled long-wave infrared push-broom imaging spectrometer with an F-number of 2 was designed based on the Dyson configuration. A three-mirror off-axis aspherical optical system that provided excellent slit-shaped images was selected as the fore telescope objective. The re-imaging method was applied to obtain a cold stop efficiency of 100%, and the corrector lens in traditional Dyson imaging spectrometers was replaced with re-imaging lenses to correct spherical aberrations. The designed imaging spectrometer provided a spectral resolution of 25 nm at a range of 8-12 μm and possessed a relatively small volume. ? 2016 Elsevier B.V. All rights reserved.Accession Number: 20161202118789 -
Record 103 of
Title:Detecting densely distributed graph patterns for fine-grained image categorization
Author(s):Zhang, Luming(1); Yang, Yang(2); Wang, Meng(1); Hong, Richang(1); Nie, Liqiang(3); Li, Xuelong(4)Source: IEEE Transactions on Image Processing Volume: 25 Issue: 2 DOI: 10.1109/TIP.2015.2502147 Published: February 2016Abstract:Fine-grained image categorization is a challenging task aiming at distinguishing objects belonging to the same basiclevel category, e.g., leaf or mushroom. It is a useful technique that can be applied for species recognition, face verification, and so on. Most of the existing methods either have difficulties to detect discriminative object components automatically, or suffer from the limited amount of training data in each sub-category. To solve these problems, this paper proposes a new fine-grained image categorization model. The key is a dense graph mining algorithm that hierarchically localizes discriminative object parts in each image. More specifically, to mimic the human hierarchical perception mechanism, a superpixel pyramid is generated for each image. Thereby, graphlets from each layer are constructed to seamlessly capture object components. Intuitively, graphlets representative to each super-/sub-category is densely distributed in their feature space. Thus, a dense graph mining algorithm is developed to discover graphlets representative to each super-/ sub-category. Finally, the discovered graphlets from pairwise images are integrated into an image kernel for fine-grained recognition. Theoretically, the learned kernel can generalize several state-of-the-art image kernels. Experiments on nine image sets demonstrate the advantage of our method. Moreover, the discovered graphlets from each sub-category accurately capture those tiny discriminative object components, e.g., bird claws, heads, and bodies. ? 2015 IEEE.Accession Number: 20170303257792 -
Record 104 of
Title:Parameter selection and optical design of all-day star sensor
Author(s):Pan, Yue(1,2); Wang, Hu(1); Jing, Nan(1,2); Shen, Yang(1,2); Xue, Yao-Ke(1); Liu, Jie(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 45 Issue: 1 DOI: 10.3788/gzxb20164501.0122002 Published: January 1, 2016Abstract:Detecting a 4.5 magnitude star in the observation height of 10 km, the radiance of stars between 600~1100 nm was analyzed, the radiance of sky background and the optical transmission of atmosphere were calculated by using Modtran. When the threshold of SNR is 5, typical parameters are selected. With a plane mirror and a silicon material sphere lens, a lighter miniature optical system was designed. The result shows that the optical system spot shape approaches a circle between 600~1100 nm of full field of view, modulation transfer function approaches perfection and have outstanding image of quality. The Ground-based daytime and nighttime detection SNR of the star tracter is calculated and the detection ability limit is estimated in the threshold 5 of SNR, which is 2.5 stellar magnitude G star in daytime on the ground and 6 at night. ? 2016, Science Press. All right reserved.Accession Number: 20160902037365 -
Record 105 of
Title:Design of large field for visible/infrared integrated optical system
Author(s):Wang, Chenchen(1,2); Zou, Gangyi(1,2); Pang, Zhihai(1); Li, Ruichang(1,2); Fan, Xuewu(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 45 Issue: 10 DOI: 10.3788/IRLA201645.1018003 Published: October 25, 2016Abstract:A visible infrared integrated optical system of a large field of view is designed by using optical software, and the FOVs of the visible system and infrared system are 5.2 degrees and 5.12 degrees respectively. The orbit of the system is 675 kilometers, and have a large width of 61.3 kilometers and 60.36 kilometers respectively can be observed. The system uses a partial field to separate the field of visible light and infrared light respectively, and realize dual optical paths, dual bands and double fields of view imaging at the same time, which improve utility of visible light and infrared light by avoid the use of dividing light elements. Visible light system selects a three mirror system with a focal length of 9 000 mm. The infrared system uses two three mirror systems with a total focal length of 2 025 mm, and the entrance pupil of the rear system has the same position and size with the exit pupil of the former system. After optimizing, the modulation transfer function of the visible system is more than 0.45 at 50 lp/mm, and the infrared system's modulation transfer function is above 0.65 at 25 lp/mm respectively. The imaging quality of both systems reaches the diffraction limit. ? 2016, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20164703037172 -
Record 106 of
Title:Calibration of stray light based on point source transmittance measurement system
Author(s):Xu, Liang(1,2); Gao, Li-Min(1); Zhao, Jian-Ke(1); Liu, Feng(1); Zhou, Yan(1); Li, Zhao-Hui(1,2); Yang, Fei(3); Zhao, Qing(1,2)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 24 Issue: 7 DOI: 10.3788/OPE.20162407.1607 Published: July 1, 2016Abstract:To improve the stray light testing ability and calibration accuracy of the stray light equipment used in test of the Point Source Transmittance (PST), a calibration lens was proposed to calibrate the testing range and testing accuracy of the equipment in a large off-axial angle. By using a simple physical model, the calibration lens was designed in a laboratory. The physical parameters of the calibration lens were measured, then these parameters were taken into the TracePro to calculate the PSTs in different off-axial angles. Finally, the calculated result and the tested result of PSTs were compared, and the test accuracy of the equipment were obtained. The experimental results indicate that the difference between calculate results and testing results of the calibration lens is better than lg/0.5, meeting the need of testing accuracy calibration of the stray light equipment in testing PSTs and providing a reliable reference for the absolute measurement of PSTs. This technology solves the problem in testing accuracy calibration of PST measuring systems. ? 2016, Science Press. All right reserved.Accession Number: 20163402721533 -
Record 107 of
Title:Analysis and calibration of precision for point source transmittance system
Author(s):Li, Zhao-Hui(1,2); Zhao, Jian-Ke(1); Xu, Liang(1); Liu, Feng(1); Guo, Yi(1); Liu, Kai(1); Zhao, Qing(1,2)Source: Wuli Xuebao/Acta Physica Sinica Volume: 65 Issue: 11 DOI: 10.7498/aps.65.114206 Published: June 5, 2016Abstract:Owing to space optical system working for a long time outside the field of view, where there is strong background radiation, and the fact that the point source transmittance (PST) is an important evaluation indicator for stray light suppression of this optical system, the development of stray light equipment for testing PST has received more and more attention. Though the development of PST testing system has been extensively studied, none of them elaborate on the calibration of the PST testing system. Besides, most of the PST testing systems are at a laboratory research stage, and the calibration of neither testing stability nor accuracy is recognized. Therefore, on the basis of the PST testing system established, one calibration lens is designed to calibrate the PST testing system. By comparing the measured PST values of the calibration lens with the analyzed values, the PST testing system can be evaluated. The calibration lens model is built to analyze PST values at different off-axis angles by using the ray tracing software Tracepro. We consider the accuracy of modeling, and on the basis of simplifying the structure design, we measure bidirectional reflectance distribution function values of the painted surface of the calibration lens, and then estimate values of lens surface fromHarvey-Shack model and PSD theory by taking these property data into the model of simulation. Ultimately PST analyzed values of calibration lens can be obtained. Finally, by comparing the measured values of calibration lens, which are tested by using PST testing system, with the analyzed values, the calibration of the PST testing system is completed. In the PST testing process of calibration lens, by analyzing the data at different off-axis angles, the accuracy of repeated measurements and threshold of PST testing system can be obtained. At the same time, testing errors caused by the stability of light source, detector linearity, air scattering and structure of double cylindrical chamber are analyzed through the testing data. The data show that when double cylindrical chamber clean class is ISO 7, the PST threshold of this equipment is 10-8, and the accuracy of repeated measurements is 7.9%. Taking into account the detection capability, the PST threshold of this equipment is 10-10 when environmental condition is better than ISO 6. ? 2016 Chinese Physical Society.Accession Number: 20162502522383 -
Record 108 of
Title:Computer-Aided alignment method of optical lens with high accuracy
Author(s):Xing, Song(1); Hou, Xiao-Hua(1); Zhang, Xue-Min(1); Ji, Bin-Dong(2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 9684 Issue: DOI: 10.1117/12.2245129 Published: 2016Abstract:With the development of space and aviation industry, the optical systems with high resolution and better imaging quality are required. According to the alignment technical process, the factors of every step which have big influence to the imaging quality are analyzed. It is detected that the micro-stress assembly of the optical unit and the high co-Axial precision of the entire optical system are the two important factors which are supposed to determine how well the imaging quality of the optical system is; also the technical methods are discussed to ensure these two factors from the engineering view. The reflective interference testing method to measure the surface figure and the transitive interference testing method to measure the wave aberration of the optical unit are combined to ensure the micro-stress assembly of the optical unit, so it will not bring astigmatism to the whole system imaging quality. Optical alignment machining and precision alignment are combined to ensure the high co-Axial precision of the optical system. An optical lens of high accuracy is assembled by using these methods; the final wave aberration of optical lens is 0.022λ. ? 2016 SPIE.Accession Number: 20165003113836