2010
2010
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Record 181 of
Title:A hyperspectral images compression algorithm based on 3D bit plane transform
Author(s):Zhang, Lei(1,2,3); Xiang, Libin(2); Zhang, Sam(2); Quan, Shengxue(2)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 7658 Issue: DOI: 10.1117/12.867625 Published: 2010Abstract:According the analyses of the hyper-spectral images, a new compression algorithm based on 3-D bit plane transform is proposed. The spectral coefficient is higher than the spatial. The algorithm is proposed to overcome the shortcoming of 1-D bit plane transform for it can only reduce the correlation when the neighboring pixels have similar values. The algorithm calculates the horizontal, vertical and spectral bit plane transform sequentially. As the spectral bit plane transform, the algorithm can be easily realized by hardware. In addition, because the calculation and encoding of the transform matrix of each bit are independent, the algorithm can be realized by parallel computing model, which can improve the calculation efficiency and save the processing time greatly. The experimental results show that the proposed algorithm achieves improved compression performance. With a certain compression ratios, the algorithm satisfies requirements of hyper-spectral images compression system, by efficiently reducing the cost of computation and memory usage. ? 2010 Copyright SPIE - The International Society for Optical Engineering.Accession Number: 20105213525846 -
Record 182 of
Title:Performance of an improved logarithmic phase mask with optimized parameters in a wavefront-coding system
Author(s):Zhao, Hui(1); Li, Yingcai(1)Source: Applied Optics Volume: 49 Issue: 2 DOI: 10.1364/AO.49.000229 Published: January 10, 2010Abstract:In two papers [Proc. SPIE 4471, 272-280 (2001) and Appl. Opt. 43, 2709-2721 (2004)], a logarithmic phase mask was proposed and proved to be effective in extending the depth of field; however, according to our research, this mask is not that perfect because the corresponding defocused modulation transfer function has large oscillations in the low-frequency region, even when the mask is optimized. So, in a previously published paper [Opt. Lett. 33, 1171-1173 (2008)], we proposed an improved logarithmic phase mask by making a small modification. The new mask can not only eliminate the drawbacks to a certain extent but can also be even less sensitive to focus errors according to Fisher information criteria. However, the performance comparison was carried out with the modified mask not being optimized, which was not reasonable. In this manuscript, we optimize the modified logarithmic phase mask first before analyzing its performance and more convincing results have been obtained based on the analysis of several frequently used metrics. ? 2010 Optical Society of America.Accession Number: 20100512680892 -
Record 183 of
Title:Effect of platform attitude stability on image quality of spatially modulated imaging fourier transform spectrometer
Author(s):Jing, Juanjuan(1,2); Wei, Ruyi(1,2); Yuan, Yan(3)Source: Proceedings - 3rd International Symposium on Information Science and Engineering, ISISE 2010 Volume: Issue: DOI: 10.1109/ISISE.2010.52 Published: 2010Abstract:The data acquired by the spatially modulated imaging Fourier Transform spectrometer(SMIFTS) contain one dimensional spatial information, one dimensional interference information, and one dimensional push broom scanning spatial information. This kind of spectrometer theoretically requires that flying platform keeps uniform moving velocity and steady attitude in the imaging mode, as well as the imaging motion in each two neighboring interferograms is one array of pixels. The unsteadiness of platform would not only cause problems such as distortion, mixed pixels and lower signal-noise ratio on acquired spatial images, but also produce deviation and decadence of interferograms away from ideal ones, bringing the distortion of real spectra. The abnormal image motion model between satellite attitude and the data acquired by SMIFTS is built based on the theory that projection center of a sensor, an image point and an object on the ground are in the same line. This paper calculates the image motions between different frames, assuming that the pitch angle and yaw angle are same, And moreover, analyzes the effect of the attitude steadiness on the data quality of SMIFTS. The results show that, pitch angle bringing distortion of neighboring interferograms in along-orbit directions has most serious effect, the image gradient decrease obviouly and the discrepancy between interferogram and spectra is bigger, yaw angle bringing the relative rotation of neighboring interferograms has the less serious effect on images and spectra. To get the real spectra of the object, we should take some measures to correct it. ? 2010 IEEE.Accession Number: 20113214221937 -
Record 184 of
Title:Energy-efficient contour mapping aggregation in wireless sensor networks
Author(s):An, Yuan(1,2,3); Liu, Yan(4); Ma, Caiwen(2); Zhou, Xinyun(3); Sun, Limin(3)Source: 2010 IEEE Sensors Applications Symposium, SAS 2010 - Proceedings Volume: Issue: DOI: 10.1109/SAS.2010.5439392 Published: 2010Abstract:Contour mapping is an energy-efficient method for geographic correlated value monitoring in Wireless Sensor Networks(WSNs), it suppresses reporting nodes by selecting nodes that are on a contour line. A sensor network is often densely deployed in applications such as temperature or humidity monitoring. In these applications, contour mapping plays a crucial role in data aggregation and data transmission reduction when nodes are densely deployed. In this paper, we propose a novel scheme called DABC (data aggregation based on Bezier curves) to implementing contour mapping in WSNs. In DABC algorithm, sensor nodes that play as sources to report to the sink are intelligently selected through method based on Bezier curve. Simulation on a temperature monitoring scenario shows that DABC saves an amount of energy while achieves almost same fidelity of contour mapping, comparing with traditional methods. ? 2009 IEEE.Accession Number: 20102012942113 -
Record 185 of
Title:Extraction of water bodies from remotely sensed images
Author(s):Liu, Jiahang(1,2); Currit, Nate(3); Meng, Xuelian(3)Source: ISPACS 2010 - 2010 International Symposium on Intelligent Signal Processing and Communication Systems, Proceedings Volume: Issue: DOI: 10.1109/ISPACS.2010.5704742 Published: 2010Abstract:Extracting water bodies from remotely sensed imagery is an important procedure for many water related studies. It is considered as a challenging problem of automatically and effectively extracting water bodies from remotely sensed images, and many researchers rely on existing Geoinformation System (GIS) data or manual digitizing to obtain water body boundaries. This work firstly generalizes several water body characteristics in optical remotely sensed images and then proposes a segmentation-based water body extraction method. The proposed algorithm exploits several features and uses a perception machine (PM) of neural network (NN) to build a classifier. An overall classification accuracy of 96% indicates that this method holds promise for extracting water bodies from optical remotely sensed images. ? 2010 IEEE.Accession Number: 20110813689225 -
Record 186 of
Title:A new phase diversity wave-front error sensing method based on genetic algorithm
Author(s):Liang, Shitong(1,2); Yang, Jianfeng(1); Xue, Bin(1)Source: Guangxue Xuebao/Acta Optica Sinica Volume: 30 Issue: 4 DOI: 10.3788/AOS20103004.1015 Published: April 2010Abstract:The basic principles of wave-front sensing based on phase diversity (PD) are expatiated. An improved PD based on genetic algorithm (GA) is proposed for the highly nonlinear character of PD's objective function. The parallel and global search features of GA are suitable for the global optimization of PD by analyzing the characters of GA. A sparse-aperture system composed by three sub-apertures with different piston errors is established. The changes of the optimization objective function are analyzed and the new PD based on GA is used to find the global optimal value of the system. The results of many experimental simulations show that: GA can find the global optimum value of the sparse-aperture system, and the root mean square (RMS) between estimated piston error found by GA and the true piston error is 0.04λ. The new PD has a high accuracy.Accession Number: 20102112958553 -
Record 187 of
Title:The effect of added O2 on the transmittance and radiation resistance of radiation resistant glasses
Author(s):Li, Weinan(1); Lu, Min(1)Source: Optics Express Volume: 18 Issue: 25 DOI: 10.1364/OE.18.026307 Published: December 6, 2010Abstract:One method of hardening optical glasses against radiation-induced darkening has been to add CeO2 to the batch composition. In the present investigation we prepared a series of lanthanum crown glasses with varying degrees of CeO2 additions and melted them at 1, 400°C with and without bubbling oxygen gas. We examined the influence of added oxygen on the optical transmissions of these glasses in the spectral range 460 to 760 nm following gamma irradiations ranging from 10 to 250 krad. The results showed that dose-for-dose the radiation-induced optical attenuations of the oxidized glasses were greater than for the glasses without added O2. ? 2010 Optical Society of America.Accession Number: 20105013492644 -
Record 188 of
Title:Spacing-tunable multi-wavelength fiber laser based on cascaded four-wave mixing in highly nonlinear photonic-crystal fiber
Author(s):Sun, H.B.(1); Liu, X.M.(1); Wang, L.R.(1); Li, X.H.(1); Mao, D.(1)Source: Laser Physics Volume: 20 Issue: 11 DOI: 10.1134/S1054660X10210115 Published: November 2010Abstract:A multi-wavelength fiber laser based on the cascaded four-wave mixing in highly-nonlinear photonic-crystal fiber is proposed and investigated. The cascade operation is initiated by two strong pump waves boosted by multi-mode pumping erbium/ytterbium co-doped double-cladding fiber amplification technique. A segment of highly-nonlinear near-zero-dispersion-flattened photonic crystal fiber is employed to induce highly efficient cascaded four-wave mixing. The wavelength spacing can be continuously tunable by stretching the fiber Bragg grating. Experimental results show that multiple wavelengths with a high optical side-mode suppression-ratio of >30 dB are achieved. Furthermore, the proposed multi-wavelength fiber laser exhibits an excellent stability at room temperature. ? 2010 Pleiades Publishing, Ltd.Accession Number: 20105013476454 -
Record 189 of
Title:A new continuous wave 2500W semiconductor laser vertical stack
Author(s):Li, Xiaoning(1,2); Peng, Chenhui(1); Zhang, Yanxin(1); Wang, Jingwei(1); Xiong, Lgling(1); Zhang, Pu(1); Liu, Xingsheng(1,3)Source: Proceedings - 2010 11th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2010 Volume: Issue: DOI: 10.1109/ICEPT.2010.5582810 Published: 2010Abstract:With the increasing applications of high power semiconductor lasers in industrial, advanced manufacturing, military, aerospace, medical systems, display, entertainment. etc., semiconductor lasers with high power and high performances are required. The performance of semiconductor lasers is greatly affected by packaging structure, packaging process and beam shaping. In this work, a high power semiconductor laser vertical stack was successfully fabricated. A series of techniques such as spectrum control and beam control were used to achieve marrow spectrum and high beam quality. The performances of the semiconductor laser vertical stack were characterized. A high power of 2500 W, a narrow spectrum of 3.11 nm and an excellent rectangular beam shape were obtained. The lifetime of the vertical stack laser was tested as well. ? 2010 IEEE.Accession Number: 20104713410199 -
Record 190 of
Title:A high power light emitting diode module for projection display application
Author(s):Peng, Chenhui(1); Li, Xiaoning(1,2); Wang, Jingwei(1); Xiong, Lingling(1); Zhang, Yanxin(1); Liu, Xingsheng(1,3)Source: Proceedings - 2010 11th International Conference on Electronic Packaging Technology and High Density Packaging, ICEPT-HDP 2010 Volume: Issue: DOI: 10.1109/ICEPT.2010.5582830 Published: 2010Abstract:Light emitting diode (LED) has numerous advantages such as long lifetime, large color gamut, small size and the absence of mercury vapor. In recent years, there has been recognition that LED could be an alternative light source for projection display application. In this work, dielectric compound parabolic concentrators (CPCs) were designed and optimized for multiple-LED array packaging structure for projection display application. The performance of rectangular CPC was studied and compared to theoretical simulations. Rectangular CPC was fabricated as the collector and collimator. A high power green LED module combined with rectangular CPC was fabricated and its performance was characterized. More than 90% light emitted by multiple-LED array can be collected by the CPC and transmit within the designed angle. A high power of 2.09W and a high luminous flux of 800 lm were obtained. ? 2010 IEEE.Accession Number: 20104713410212 -
Record 191 of
Title:The near- and mid-infrared emission properties of Tm3+-doped GeGaS-CsI chalcogenide glasses
Author(s):Shixun, Dai(1,2); Bo, Peng(2); Pengjun, Zhang(1); Tiefeng, Xu(1); Wang, Xunsi(1); Qiuhua, Nie(1); Xianghua, Zhang(1,3)Source: Journal of Non-Crystalline Solids Volume: 356 Issue: 44-49 DOI: 10.1016/j.jnoncrysol.2010.03.020 Published: October 1, 2010Abstract:Serials of chalcogenide glasses based on composition of 72GeS 2-18Ga2S3-10CsI (in mol%) and doped with high Tm3+ content (up to 10,000 ppm) were prepared, and their luminescence properties were investigated under excitation with 800 nm laser. The influences of doping concentration on Judd-Ofelt intensity parameter Ωi, spontaneous transition probability A, fluorescence branching ratio β, and radiative lifetime τrad of Tm3+ in the samples were studied. Four infrared emission bands observed were centered at 1.48, 1.8, 2.3, and 3.8 μm, corresponding to optical transitions 3H4 → 3F4, 3F4 → 3H6, 3H4 → 3H 5 and 3H5 → 3F4, respectively. For 1.0 wt.% Tm3+: doped sample, no concentration quenching was observed and its emission cross-sections at 2.3 and 3.8 μm calculated by using Füchtbauer-Ladenburg equation were 6.85 × 10 -21 and 7.66 × 10-21 cm -2, respectively. ? 2010 Elsevier B.V. All rights reserved.Accession Number: 20104713405302 -
Record 192 of
Title:Structured light sheet fluorescence microscopy based on four beam interference
Author(s):Lei, Ming(1,2); Zumbusch, Andreas(1)Source: Optics Express Volume: 18 Issue: 18 DOI: 10.1364/OE.18.019232 Published: August 30, 2010Abstract:A 3D structured light sheet microscope using a four-faceted symmetric pyramid is presented. The sample is illuminated by the resulting four beam interference field. This approach combines advantages of standing wave and structured illumination microscopy. Examples of micrographs of fluorescently labeled Chinese hamster ovary (CHO) cells as well as of the compound eyes of drosophila are shown and the optical sectioning ability of our system is demonstrated. The capabilities and the limitations of the scheme are discussed. ? 2010 Optical Society of America.Accession Number: 20103713225081