2012
2012
-
Record 121 of
Title:Noise of CCD reduction based on three-D noise model
Author(s):Lin, Hui(1); Tian, Xinfeng(1); Su, Xiuqin(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 8558 Issue: DOI: 10.1117/12.2001100 Published: 2012Abstract:This paper proposed proper noise reduction methods for the two different noises (i.e. temporal noise and special noise) based on the 3-D noise model of scientific-grade CCD. Noise reduction calculations have been made with these methods. The results show that these methods are effective for the reduction of temporal noise and spatial noise. The experimental data have verified the effectiveness of these methods for scientific-grade CCD. ? Copyright SPIE.Accession Number: 20131516202253 -
Record 122 of
Title:Fabrication and applications of GRIN materials
Author(s):Li, Yulin(1); Hu, Baowen(1); He, Zhengquan(1); Zhang, Minrui(1); Huo, Junmin(1); Yao, Shengli(1)Source: Advanced Materials Research Volume: 586 Issue: DOI: 10.4028/www.scientific.net/AMR.586.215 Published: 2012Abstract:In recent years, a series of gradient index (GRIN) materials including Optical glass and polymer have been Research and developed in our laboratory. The Micro-lenses and arrays with the special optical materials also have been fabricated mainly by using Ion-exchange method through refractive index profile, which are applied to micro-optic devices and other applications-- especially in the coupled and connected devices for fiber communications and medical endoscope or they are used primarily for document scanning equipments. ? (2012) Trans Tech Publications, Switzerland.Accession Number: 20125015787465 -
Record 123 of
Title:Fully affine invariant SURF for image matching
Author(s):Pang, Yanwei(1); Li, Wei(1); Yuan, Yuan(2); Pan, Jing(3)Source: Neurocomputing Volume: 85 Issue: DOI: 10.1016/j.neucom.2011.12.006 Published: May 15, 2012Abstract:Fast and robust feature extraction is crucial for many computer vision applications such as image matching. The representative and the state-of-the-art image features include Scale Invariant Feature Transform (SIFT), Speeded Up Robust Features (SURF), and Affine SIFT (ASIFT). However, neither of them is fully affine invariant and computation efficient at the same time. To overcome this problem, we propose in this paper a fully affine invariant SURF algorithm. The proposed algorithm makes full use of the affine invariant advantage of ASIFT and the efficient merit of SURF while avoids their drawbacks. Experimental results on applications of image matching demonstrate the robustness and efficiency of the proposed algorithm. ? 2012 Elsevier B.V.Accession Number: 20121114867234 -
Record 124 of
Title:Scale invariant image matching using triplewise constraint and weighted voting
Author(s):Pang, Yanwei(1); Shang, Mianyou(1); Yuan, Yuan(2); Pan, Jing(3)Source: Neurocomputing Volume: 83 Issue: DOI: 10.1016/j.neucom.2011.11.008 Published: April 15, 2012Abstract:Due to limited computational resource, image matching on mobile phone places great demand on efficiency and scale invariant. Though spectral matching (SM) with pairwisely geometric constraints is widely used in matching, it is not efficient and scale invariant for applications in mobile phones. The main factor that limits its efficiency is that it requires to eign-decomposition of a large affinity matrix when the number of candidate correspondences is large. It lacks scale invariance because the pairwise constraints cannot hold when large scale variation occurs. In this paper, we attempt to tackle these problems. In the proposed method, each candidate correspondence is considered as a voter and a candidate as well. As a voter it gives voting scores to other candidates and also votes itself. Based on the voting scores, the optimal correspondences are computed by simple addition operations and ranking operations, which results in high efficiency. To make the proposed method scale invariant, we propose a novel triple-wisely geometric constraint formed by three potential correspondences with one being the candidate and the other two being voters. The three correspondences constitute a pair of triangles. The similarity of the two triangles is the core of the triple-wisely constraint, which is robust to scale variation. The information of triple-wise constraints are encoded in a 3-dimensional matrix from which the optimal correspondence can be obtained by simple summation and ranking operations. Experimental results on real-data show the effectiveness and efficiency of the proposed method. ? 2012 Elsevier B.V.Accession Number: 20120614753599 -
Record 125 of
Title:Development of cesium telluride UV cathode with high quantum efficiency and solar-blind characteristics
Author(s):Wei, Yonglin(1); Zhao, Baosheng(1); Sai, Xiaofeng(1); Liu, Yongan(1); Cao, Xibin(1)Source: Zhenkong Kexue yu Jishu Xuebao/Journal of Vacuum Science and Technology Volume: 32 Issue: 7 DOI: 10.3969/j.issn.1672-7126.2012.07.03 Published: July 2012Abstract:A novel type of Cs2Te ultraviolet(UV) cathode with high quantum efficiency and good solar-blind characteristics was developed. The cathode was fabricated mainly in three steps: first, The Ni films of The cathode conductive substrate, were deposited by electron beam evaporation on a quartz window; next, The Te films were grown by Thermal evaporation, via resistive heating, on the Ni-coated quartz window in ultrahigh vacuum; finally, The Cs films, deposited by Thermal evaporation on top of the Te films, were activated with UV light. The impacts of the microstructures and properties of the Ni, Te, and Cs films, including the sheet resistance and transmittance of the Ni films, The Te film thickness, and Cs content, on the performance of The cathode were studied with X-ray diffraction, and energy dispersive spectroscopy. The results show that the Cs2Te cathode, fabricated under optimized conditions, has high quantum efficiency and good solar-blind characteristics. The 1.0 nm thick Ni films have a sheet resistance of 107 Ω/ and a UV transmittance up to 80%; a quantum efficiency of the cathode made of the 2.0 nm thick Te films reaches 12%. Besides, excessive Cs shifts The response towards the long wavelength; but low Cs content decreases The quantum efficiency.Accession Number: 20123715431557 -
Record 126 of
Title:Gain spectrum of a laser-driven tripod-type atom dynamically induced in the presence of spontaneously generated coherence
Author(s):Tian, Si-Cong(1); Wan, Ren-Gang(2); Kang, Zhi-Hui(1); Zhang, Hang(3); Jiang, Yun(1); Cui, Hai-Ning(1); Gao, Jin-Yue(1)Source: Journal of the Optical Society of America B: Optical Physics Volume: 29 Issue: 5 DOI: 10.1364/JOSAB.29.000881 Published: May 1, 2012Abstract:We examine the absorption of a weak probe beam in a laser-driven tripod-type atom with three closely lying ground levels, where both the driving and probe lasers interact simultaneously with the three transitions. The effects of spontaneously generated coherence (SGC) are taken into account. We introduce dipole moments in the dressed-state picture and the Hamiltonian in terms of the dressed states describing the interaction between the probe and the atom. Gain spectrum under various conditions are presented and analyzed. We show that the spectral structure and the gain amplitude of the probe are strongly influenced by the effect of SGC and the frequency separation of the three closely lying ground levels. The tripod-type atomic system with quantum interference in spontaneous emission can be simulated in the dressed-state picture of a coherently driven four-level N-type system where no SGC effect exists. ? 2012 Optical Society of America.Accession Number: 20122215059403 -
Record 127 of
Title:Influence of package structure on the performance of the single emitter diode laser
Author(s):Li, Xiaoning(1,2); Zhang, Yanxin(1,3); Wang, Jingwei(1,3); Xiong, Lingling(1,3); Zhang, Pu(1,3); Nie, Zhiqiang(1,3); Wang, Zhenfu(1,3); Liu, Hui(1,3); Liu, Xingsheng(1,3)Source: IEEE Transactions on Components, Packaging and Manufacturing Technology Volume: 2 Issue: 10 DOI: 10.1109/TCPMT.2012.2207456 Published: 2012Abstract:The package structure critically influences the major characteristics of semiconductor lasers, such as thermal behavior, output power, wavelength, and far-field distribution. In this paper, a new single emitter package structure called F-mount is designed and compared with the conventional package structure C-mount. The influence of package structure on their performances is characterized and analyzed. The thermal resistances of lasers with different package structures are calculated through simulation, and are contrasted with experimental results. Some devices are also tested for the maximum output power level. Under the continuous wave (CW) condition, the maximum power of F-mount reaches 12.6 W at 808 nm while the output power only reaches 10.9 W for C-mount. Under the condition of 0.5% duty cycle (100 μs 50 Hz), the catastrophic optical mirror damage level reaches 58.7 W at 74 A for F-mount, and 54.8 W at 57 A for C-mount are reported for the first time. It is experimentally found that there is an obvious wavelength difference between the two type structure lasers: about 1.37 nm in CW mode and 2.89 nm in quasi CW mode. Theoretical analysis shows that red-shift and blue-shift is a result of external strain in the package process of F-mount and C-mount, respectively. It is also found that the package structure has an effect on the divergence angle of slow axis far fields, but little impact on that of fast axis far fields. The analysis shows that package structure has a strong influence on the performance of the laser; therefore, the package should be optimized to achieve better performance for some special applications. ? 2011-2012 IEEE.Accession Number: 20124115553489 -
Record 128 of
Title:Dynamic optimization of tip/tilt mirror based on adaptable genetic algorithm
Author(s):Wang, Hongwei(1,2); Ruan, Ping(1); Xu, Guangzhou(1); Xue, Bin(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 41 Issue: 2 DOI: Published: February 2012Abstract:In order to meet the strict requirement of surface-shape and realize the ultra-lightweight design of a tip/tilt mirror, the adaptable genetic algorithm optimization method was introduced into the design of a 110 mm round mirror. The size of support part was figured out. Meanwhile, the finite element model was simplified with axisymmetric method, and the efficiency was improved. Structure optimization principle of adaptable genetic algorithm was proposed, and its advantage was introduced. Tow method of calculating surface profile in sinusoidal vibration process was advanced. Compared with other traditional method, structure optimization based on adaptable genetic algorithm was correct and reliable. Results show that it has strong overall search ability, and has significance instructive and reference for optimization of similar engineering structures.Accession Number: 20121514940944 -
Record 129 of
Title:Driving circuit design for high frame rate CCD image sensor
Author(s):Hao, Yajiao(1); Liu, Xuebin(1)Source: 2012 IEEE 5th International Conference on Advanced Computational Intelligence, ICACI 2012 Volume: Issue: DOI: 10.1109/ICACI.2012.6463324 Published: 2012Abstract:In the light of a frame-transfer CCD area array with high frame rate, the paper explains its operation mechanism in detail. In this paper, LM317H and LM337H are chosen to design a variety of bias voltages required for the CCD. The driving pulses for CCD are generated by the FPGA of Xilinx Corporation and the driving circuit is designed by EL7457CL. The 16 output electrical signals from CCD are pre-processed by voltage followers and differential amplifiers. The experimental results show that the design of driving circuit can meet the normal demands for CCD. ? 2012 IEEE.Accession Number: 20131116105441 -
Record 130 of
Title:Machine learning in medical imaging
Author(s):Suzuki, Kenji(1); Yan, Pingkun(2); Wang, Fei(3); Shen, Dinggang(4)Source: International Journal of Biomedical Imaging Volume: 2012 Issue: DOI: 10.1155/2012/123727 Published: 2012Abstract:nullAccession Number: 20121614956481 -
Record 131 of
Title:Space-based optical combination detection system of space non-cooperative target
Author(s):Chang, Lingying(1); Chen, Rongli(2); Wen, Desheng(2); Zhao, Baochang(2); Lei, Guangzhi(2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 41 Issue: 5 DOI: Published: May 2012Abstract:In order to realize detection and imaging on the space-based non-cooperative space target, a space-based optical combination detection system of space non-cooperative target was presented. This combination detection system included two sets of optical subsystem and the turntable subsystem, and the imaging camera subsystem can acquire high resolution image of the key goal provided by wide field camera subsystem. The wide field camera subsystem can detect the space target in large range in LEO, and it also can continuous track and image target when the target is closed to 30 m-150 km. The optical combination detection system can realize survey of the target in the whole area or detailed survey of specific target with the turntable subsystems. By cooperation, these two subsystem could identify, track and image the target far and wide. It is very important for spacecraft safety when used for spacecraft anti-collision system.Accession Number: 20122915259951 -
Record 132 of
Title:Application of moment descriptor and pattern search method in model-based pose estimation
Author(s):Tang, Huijun(1,2); Zhou, Renkui(1)Source: Journal of Computational Information Systems Volume: 8 Issue: 19 DOI: Published: October 1, 2012Abstract:We propose to use shape descriptors and optimal search for fulfilling the pose estimation task based on optical measuring. Certain element of invariant moments is altered to meet the pose estimation requirements. Initial pose angles are acquired from the viewpoint-dependent appearance model of the object. 2-order normalized center moment is taken as the main feature descriptor and pattern search method is used as the search strategy. For simulation, a missile model of Milkshape 3D format is used. A model library of 1° resolution is created. Scale changing and noise adding are tested on 20 test images randomly selected from model library. For initial images, we can arrive at 1° precision. For scaled and noised images, even there appears some outlier, most of the items arrive around the true values. Results show that the method is practical. The method may get better results by improving the resolution of the model library. ? 2012 Binary Information Press.Accession Number: 20124515645086