2012
2012
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Record 25 of
Title:Design of a dual-channel Mach-Zehnder lateral shearing interferometer for the large aperture static imaging spectrometer
Author(s):Fu, Qiang(1,2); Xiangli, Bin(3); Lü, Qun-Bo(3); Jing, Juan-Juan(1,2)Source: Guang Pu Xue Yu Guang Pu Fen Xi/Spectroscopy and Spectral Analysis Volume: 32 Issue: 2 DOI: 10.3964/j.issn.1000-0593(2012)02-0553-05 Published: February 2012Abstract:Large aperture static imaging spectrometry (LASIS) is a kind of joint temporally and spatially modulated Fourier transform imaging spectrometry. In such instruments, lateral shearing interferometer is a key element, the most frequently used type of which is the Sagnac interferometer. In this configuration, one half of the light entering the interferometer backtracks and causes a great decrease in energy efficiency. The present paper proposes a modified Mach-Zehnder lateral shearing interferometer structure to tackle this problem. With the ability to produce the same lateral shear, it features the advantage of dual channel output. We present a ray tracing procedure to induce the general expression of the lateral shear as well as analyze the contributions of error sources to the shear accuracy. The results serve as a new idea for the design of large aperture static imaging spectrometers and can be used to instruct the design and optimization of this kind of imaging spectrometer.Accession Number: 20120714766773 -
Record 26 of
Title:Chaos control of gear system with elastomeric web based on multi-parameter multi-step method
Author(s):Liu, Hai-Xia(1,2); Jiang, Bo(3,4); Wang, San-Min(1); Guo, Jia-Shun(1)Source: Journal of Harbin Institute of Technology (New Series) Volume: 19 Issue: 5 DOI: Published: October 2012Abstract:This paper employs a multi-parameter multi-step chaos control method, which is built up on the OGY method, to stabilize desirable UPOs of a gear system with elastomeric web as a high-dimensional and non-hyperbolic chaotic system, and the analyses are carried out. Three types of relations between components of a certain control parameter combination are defined in a certain control process. Special emphasis is put on the comparison of control efficiencies of the multi-parameter multi-step method and single-parameter multi-step method. The numerical experiments show the ability to switch between different orbits and the method can be a good chaos control alternative since it provides a more effective UPOs stabilization of high-dimensional and non-hyperbolic chaotic systems than the single-parameter chaos control, and according to the relation between components of each parameter combination, the best combination for chaos control in a certain UPO stabilization process are obtained.Accession Number: 20130916074516 -
Record 27 of
Title:The time response of exponential doping NEA InGaAs photocathode applied to near infrared streak cameras
Author(s):Tang, Weidong(1); Yang, Wenzheng(2); Cai, Zhipeng(1); Sun, Chuandong(2)Source: Advanced Materials Research Volume: 415-417 Issue: DOI: 10.4028/www.scientific.net/AMR.415-417.1403 Published: 2012Abstract:An exponential doping NEA InGaAs photocathode is theoretically proposed to apply in the near infrared streak camera. The photocathode time response is calculated and analyzed by using a photoelectron non-steady method. The numerical results show that the excited electrons in the InGaAs active layer is accelerated due to the built-in electric field induced by the exponential doping structure, which shortens the transport time of minority carriers in the photocathode and thus, the time response is greatly improved. In addition, the exponential doping InGaAs photocathode possesses time response of less than 10 picoseconds and near-infrared quantum efficiency of 10%.Accession Number: 20115214644791 -
Record 28 of
Title:Theory and method for designing field-widened prism of spatial heterodyne spectrometer
Author(s):Feng, Yutao(1); Bai, Qinglan(1); Wang, Yongmei(2); Hu, Bingliang(1); Wang, Shu'na(3)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 32 Issue: 10 DOI: 10.3788/AOS201232.1030001 Published: October 2012Abstract:It is one of the most important methods to use field-widened prism to increase the throughput or sensitivity for spatial heterodyne spectrometer. This paper borrows idea from the basic principle of traditional Fourier transform spectrometer with field-widened and combines the characteristics of spatial heterodyne spectroscopy, a method based on numerical reduction to design the field-widen prism of spatial heterodyne spectrometer is proposed. The optimum apex angle of field-widened prism and the maximum field are analyzed with certain Littrow angles and scene wave-numbers. The results indicate that numerical induction method can find the optimum solution of prism apex angle by judging the effect of all orders of field angle on the phase difference. Compared with the results obtained by theoretical deduce method, the maximum field angle along dispersive principal cross section increases by 10%-30%, and the numerical induction method is simple and obvious, the influencing factors on the maximum field angle can be analyzed in the process of optimizing field-widened prism angle.Accession Number: 20124815723856 -
Record 29 of
Title:Analysis on the scattering characteristics of two stray light removing metal surfaces
Author(s):Chen, Jianjun(1,3); Ma, Zhen(1); Duan, Xueting(1); Liu, Qiong(2); Han, Juan(1); Fu, Xing(1)Source: Advanced Materials Research Volume: 571 Issue: DOI: 10.4028/www.scientific.net/AMR.571.115 Published: 2012Abstract:For the purpose of stray light suppression, black anodized and sandblasted aluminum alloy is widespread used in spaceborne cameras. Base on the relative measuring method, in the white light irradiation, measure relative backscatter intensity and BRDF of two black anodized and sandblasted sample surfaces. Contrast these surfaces scattering characteristics. Finally BRDF curves have been drawn with measurement data. In the curves, the BRDF of sandblasted aluminum surface is nearly linear relation. Anodized surface curve, it's pulse pattern that BRDF sharply increases among the region of critical angles. It is indicate that in critical angle range, anodized aluminum surface specularity is visible and can be treated as specular reflection which harm for stray light suppression. This experiment research can provide objective reference of these two material's scattering characteristics in specific optical system design. ? (2012) Trans Tech Publications, Switzerland.Accession Number: 20124815717008 -
Record 30 of
Title:System signal-to-noise ratio analysis based on imaging chain model in multispectral remote sensing
Author(s):Fu, Qiang(1,2); Xiangli, Bin(3); Jing, Juanjuan(1,2)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 32 Issue: 2 DOI: 10.3788/AOS201232.0211001 Published: February 2012Abstract:Signal-to-noise-ratio (SNR) is an important index for evaluating multispectral imaging performance. In the early stage of designing a multispectral imager, SNR analysis should be performed for the determination of subsystem parameters. The imaging chain model of multispectral remote sensing is introduced. Characteristics of radiation source, object spectral reflectance, atmospheric radiation transfer, optical imaging, dispersive element, detector spectral responsivity and camera noise are synthesized to come into an end-to-end analysis. A filter array based multispectral imaging system is modeled. Computation of atmospheric radiation transfer is from MODTRAN under conditions of different solar zenith angles and different surface features. The models of charge coupled device are adopted for characterizing the noise features. SNR for different working conditions are shown for the designed multispectral remote sensing system. The SNR analysis is helpful for demonstrating the best operation condition for multispectral remote sensing system of this kind, as well as optimizing related optical system parameters for best performance with lowest cost.Accession Number: 20121014841948 -
Record 31 of
Title:Single image super-resolution with non-local means and steering kernel regression
Author(s):Zhang, Kaibing(1); Gao, Xinbo(1); Tao, Dacheng(2); Li, Xuelong(3)Source: IEEE Transactions on Image Processing Volume: 21 Issue: 11 DOI: 10.1109/TIP.2012.2208977 Published: 2012Abstract:Image super-resolution (SR) reconstruction is essentially an ill-posed problem, so it is important to design an effective prior. For this purpose, we propose a novel image SR method by learning both non-local and local regularization priors from a given low-resolution image. The non-local prior takes advantage of the redundancy of similar patches in natural images, while the local prior assumes that a target pixel can be estimated by a weighted average of its neighbors. Based on the above considerations, we utilize the non-local means filter to learn a non-local prior and the steering kernel regression to learn a local prior. By assembling the two complementary regularization terms, we propose a maximum a posteriori probability framework for SR recovery. Thorough experimental results suggest that the proposed SR method can reconstruct higher quality results both quantitatively and perceptually. ? 2012 IEEE.Accession Number: 20124415619794 -
Record 32 of
Title:Visual attention accelerated vehicle detection in low-altitude airborne video of urban environment
Author(s):Cao, Xianbin(1); Lin, Renjun(2); Yan, Pingkun(3); Li, Xuelong(3)Source: IEEE Transactions on Circuits and Systems for Video Technology Volume: 22 Issue: 3 DOI: 10.1109/TCSVT.2011.2163443 Published: March 2012Abstract:One of the primary goals of the airborne vehicle detection system is to reduce the risks of incident collisions and to relieve traffic jam caused by the increasing number of vehicles. Different from the stationary systems, which are usually fixed on buildings, the airborne systems in unmanned aircrafts or satellites take the advantages of wider view angle and higher mobility. However, detecting vehicles in airborne videos is a challenging task because of the scene complexity and platform movement. The direct application of the traditional image processing techniques to the problem may result in low detection rate or cannot meet the requirements of real-time applications. To address these problems, a new and efficient method composed by two stages, attention focus extraction and vehicle classification is proposed in this paper. Our work makes two key contributions. The first is the introduction of a new attention focus extraction algorithm, which can quickly detect the candidate vehicle regions to make the algorithm focus on much smaller regions for faster computation. The second contribution is a simple and efficient classification process, which is built using the AdaBoost learning algorithm. The classification process, which is a hierarchical structure, is designed to obtain a lower false alarm rate by looking for vehicles in the candidate regions. Experimental results demonstrate that, compared with other representative algorithms, our method can obtain better performance in terms of higher detection rate and lower false positive rate, while meeting the needs of real-time application. ? 2011 IEEE.Accession Number: 20121114861753 -
Record 33 of
Title:Multi-frame image Super-resolution by total-variation regularization
Author(s):Xu, Zhigang(1,2,3); Su, Xiuqin(1); Zhang, Zhanpeng(1)Source: Journal of Information and Computational Science Volume: 9 Issue: 4 DOI: Published: April 2012Abstract:Multi-frame image Super-resolution (SR) reconstruction needs to deal with the recovery of a single high-resolution image from a set of low quality images. Recently, there has been a great deal of work developing multi-frame SR algorithms. In this study, we proposed an efficient SR regularization algorithm. This approach combines the ideas of bilateral filtering and the beyond-digital-total-variation model. A new regularization norm was presented, termed as locally digital bilateral-total-variation, to keep edges and more details. Experimental results were introduced to illustrate the effectiveness of the proposed algorithm. Performance analysis shows that our method is superior to similar existing methods, the peak signal-to-noise ratio improved about 0.1-1.0 dB. Copyright ? 2012 Binary Information Press.Accession Number: 20121614955585 -
Record 34 of
Title:Die bonding of high power 808 nm laser diodes with nanosilver paste
Author(s):Yan, Yi(1); Chen, Xu(2,3); Liu, Xingsheng(3); Mei, Yunhui(4); Lu, Guo-Quan(5)Source: Journal of Electronic Packaging, Transactions of the ASME Volume: 134 Issue: 4 DOI: 10.1115/1.4007271 Published: 2012Abstract:Conduction-cooled high power laser diodes have a variety of significant commercial, industrial, and military applications. For these devices to perform effectively, an appropriate die-attached material meeting specific requirements must be selected. In this study, nanosilver paste, a novel die-attached material, was used in packaging the 60 W 808 nm high power laser diodes. The properties of the laser diodes operating in the continuous wave (CW) mode, including the characteristics of power-current-voltage (LIV), spectrum, near field, far field, near field linearity, spatial spectrum, and thermal impedance, were determined. In addition, destructive tests, including the die shear test, scanning acoustic microscopy, and the thermal rollover test, were conducted to evaluate the reliability of the die bonding of the 60 W 808 nm high power semiconductor laser with nanosilver paste. Thermal analyses of the laser diodes operating at CW mode with different die-attached materials, indium solder, gold-tin solder and nanosilver paste, were conducted by finite element analysis (FEA). According to the result of the FEA, the nanosilver paste resulted in the lowest temperature in the laser diodes. The test results showed that the nanosilver paste was a very promising die-attached material in packaging high power semiconductor laser. ? 2012 American Society of Mechanical Engineers.Accession Number: 20123715415849 -
Record 35 of
Title:Recent developments on radiation resistance properties of chalcogenide infrared glass materials
Author(s):Meng, Wei(1); Guo, Haitao(2); Xu, Yantao(2); Lu, Chunfeng(2); Qiao, Zebang(2); Lu, Yunqing(1); Wei, Wei(1,2)Source: Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society Volume: 40 Issue: 8 DOI: Published: August 2012Abstract:Chalcogenide glass has great prospects and important applications in the aerospace, nuclear reaction monitoring and detection. It has become one of the most concerned materials in the field of photonics technology. This review represents recent developments on the studies of chalcogenide glass irradiation resistance properties, and emphases on the damage mechanism at gamma radiation. The factors influencing the irradiation resistance properties of chalcogenide glass were analyzed and the feasible ways for enhancing the irradiation resistance properties were discussed. In addition, some further studies on this aspect were given.Accession Number: 20123915472843 -
Record 36 of
Title:Solitons in thermal media with periodic modulation of linear refractive index
Author(s):Ma, Xuekai(1); Yang, Zhenjun(1); Lu, Daquan(1); Hu, Wei(1,2)Source: Optics Communications Volume: 285 Issue: 5 DOI: 10.1016/j.optcom.2011.11.002 Published: March 1, 2012Abstract:We address the existence and properties of solitons in thermal media with periodic modulation of linear refractive index. Many kinds of solitons in such optical lattices, including symmetric and antisymmetric lattices, are found under different conditions. We study the influence of the refractive index difference between two different layers on solitons. It is also found that there do not exist cutoff value of propagation constant and soliton power for shifted lattice solitons. In addition, the solitons launched away from their stationary position may propagate without oscillation when the confinement from lattices is strong. ? 2011 Elsevier B.V. All rights reserved.Accession Number: 20120114656784