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Bayesian-based Wavelet Shrinkage for SAR Image Despeckling Using Cycle Spinning

Journal of Electronic Science and Technology 2006年第2期000卷 127-131页

作者： ZHANG De-xiang GAO Qing-wei CHEN Jun-ning Key Lab. Of Intelligent Computing and Signal Processing Anhui University Hefei 230039 China School of Electronic Science and Technology Anhui University Hefei 230039 China School of Electronic Science and Technology Anhui University Hefei 230039 China

A novel and efficient speckle noise reduction algorithm based on Bayesian wavelet shrinkage using cycle spinning is proposed. First, the sub-band decompositions of non-logarithmically transformed SAR images are shown. Then, a Bayesian wavelet shrinkage factor is applied to the decomposed data to estimate noise-free wavelet coefficients. The method is based on the Mixture Gaussian Distributed (MGD) modeling of sub-band coefficients. Finally, multi-resolution wavelet coefficients are reconstructed by wavelet-threshold using cycle spinning. Experimental results show that the proposed despeckling algorithm is possible to achieve an excellent balance between suppresses speckle effectively and preserves as many image details and sharpness as possible. The new method indicated its higher performance than the other speckle noise reduction techniques and minimizing the effect of pseudo-Gibbs phenomena.

关键词： discrete wavelet transform Synthetic Aperture Radar (SAR) despeckling cycle spinning BayesShrink

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Video Summarization by Robust Low-Rank Subspace Segmentation

Advances in Intelligent Systems and Computing

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Advances in intelligent Systems and computing 2013年 212卷 929-937页

作者： Tu, Zhengzheng Sun, Dengdi Luo, Bin Key Lab of Intelligent Computing and Signal Processing of Ministry of Education Anhui University Hefei 230039 China School of Computer Science and Technology Anhui University Hefei 230601 China Key Lab of Industrial Image Processing and Analysis of Anhui Province Hefei 230039 China

ISBN: (纸本)9783642375019

Video summarization provides condensed and succinct representations of the content of a video stream. A static storyboard summarization approach based on robust low-rank subspace segmentation is proposed in this paper. Firstly, video frames are represented as multi-dimensional vectors, and then embedded into a group of affine subspaces using low-rank representation according to the content similarity of the frames in the same subspace. Secondly, a series of subspaces are segmented based on the Normalized Cuts algorithm. The video summary is finally generated by choosing key frames from the significant subspaces and ranking these key frames in temporal order. The experimental results demonstrate that the proposed summarization algorithm can produce crucial key frames and effectively reduce the visual content redundancy in summary comparing with the conventional approaches. © Springer-Verlag Berlin Heidelberg 2013.

关键词： Vectors

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Efficient incremental decoding for tree-to-string translation

Efficient incremental decoding for tree-to-string translatio...

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Conference on Empirical Methods in Natural Language processing, EMNLP 2010

作者： Huang, Liang Mi, Haitao Information Sciences Institute University of Southern California 4676 Admiralty Way Marina del Rey CA 90292 United States Key Lab. of Intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences P.O. Box 2704 Beijing 100190 China

ISBN: (纸本)1932432868

Syntax-based translation models should in principle be efficient with polynomially-sized search space, but in practice they are often embarassingly slow, partly due to the cost of language model integration. In this paper we borrow from phrase-based decoding the idea to generate a translation incrementally left-to-right, and show that for tree-to-string models, with a clever encoding of derivation history, this method runs in average-case polynomial-time in theory, and linear-time with beam search in practice (whereas phrase-based decoding is exponential-time in theory and quadratic-time in practice). Experiments show that, with comparable translation quality, our tree-to-string system (in Python) can run more than 30 times faster than the phrase-based system Moses (in C++). © 2010 Association for Computational Linguistics.

关键词： Decoding

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Forest-based translation

Forest-based translation

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46th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies, ACL-08: HLT

作者： Mi, Haitao Huang, Liang Liu, Qun Key Lab. of Intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences P.O. Box 2704 Beijing 100190 China Department of Computer and Information Science Levine Hall University of Pennsylvania 3330 Walnut Street Philadelphia PA 19104 United States

ISBN: (纸本)9781932432046

Among syntax-based translation models, the tree-based approach, which takes as input a parse tree of the source sentence, is a promising direction being faster and simpler than its string-based counterpart. However, current tree-based systems suffer from a major drawback: they only use the 1-best parse to direct the translation, which potentially introduces translation mistakes due to parsing errors. We propose a forest-based approach that translates a packed forest of exponentially many parses, which encodes many more alternatives than standard n-best lists. Large-scale experiments show an absolute improvement of 1.7 BLEU points over the 1-best baseline. This result is also 0.8 points higher than decoding with 30-best parses, and takes even less time. © 2008 Association for Computational Linguistics.

关键词： Syntactics

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High Common-Mode Rejection Differential Filter Based on Coupled Lines

High Common-Mode Rejection Differential Filter Based on Coup...

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IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP)

作者： Zhen Liu Haoran Zhu Information Materials and Intelligent Sensing Laboratory of Anhui Province Anhui University Hefei China Key Lab of Intelligent Computing & Signal Processing Ministry of Education Anhui University Hefei China

In this paper, a differential bandpass filter (BPF) based on enhanced coupling line structure has been suggested in this study. Two out-of-band transmission zeros are added to the differential mode by loading the coupling line at the output terminal, which raises the rectangular coefficient of the filter. Two common mode transmission zeros in the passband are additionally provided by the open/short stub that is already loaded at the output port. To accommodate the demands of various filter performances, the location of the transmission zeros can be modified by altering the values of the coupling lines' and stubs' impedances. Finally, the passband common mode suppression might be as high as 40 dB.

关键词： Band-pass filters Couplings Radio frequency Conferences Loading Microwave circuits Filtering theory

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Fast Calculation of RCS over a Broad Frequency Band Using FDM and AWE technique

Fast Calculation of RCS over a Broad Frequency Band Using FD...

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International Symposium on Antennas Propagation and EM Theory

作者： Tao Sheng Yufa Sun Lingyang Kong Key Lab. of Intelligent Computing & Signal Processing Ministry of Education Anhui University

ISBN: (纸本)9781467317993

The fast dipole method (FDM) in conjunction with the asymptotic waveform evaluation (AWE) technique is presented for fast calculation of radar cross section (RCS) from arbitrarily shaped perfect electric conductor targets over a broad frequency band. The FDM, which is based on the equivalent dipole-moment (EDM) method, is employed to reduce impedance matrix storage and accelerate the matrix-vector multiplications in the solutions of the Taylor coefficients. The application of AWE technique enables fast frequency sweep analysis. The numerical results show that this method greatly increased the computational efficiency without losing accuracy conditions compared with the traditional method of moments (MoM) combined with AWE technique.

关键词： Fast dipole method Equivalent dipole-moment Asymptotic waveform evaluation Radar cross section Method of moments

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Near-surface electromagnetic fields for a chiral cylinder perpendicularly illuminated with an on-axis Gaussian beam

Near-surface electromagnetic fields for a chiral cylinder pe...

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International Symposium on Antennas Propagation and EM Theory

作者： Yuman Zhai Yufa Sun Huayong Zhang Key Lab. of Intelligent Computing & Signal Processing Ministry of Education Anhui University

ISBN: (纸本)9781467317993

An analytical solution is presented to compute the field distribution near a chiral cylinder surface at normal incidence of an on-axis Gaussian beam. The theoretical analysis of the scattering problem is complicated due to the fact that the left and right circularly polarized waves propagate in the chiral medium with different propagation constants. Numerical results for the normalized near-surface field intensity are given and discussed concisely.

关键词： Chiral cylinder Gaussian beam Near-surface field

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Adaptive Interference Cancellation System for TD-SCDMA Networks

Adaptive Interference Cancellation System for TD-SCDMA Netwo...

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International Symposium on Antennas Propagation and EM Theory

作者： Lingyang Kong Yufa Sun Tao Sheng Key Lab. of Intelligent Computing & Signal Processing Ministry of Education Anhui University

ISBN: (纸本)9781467317993

The TD-SCDMA relay (repeater) provide network operators with a cost-effective means of extending coverage to areas of low signal strength. The maximum gain of a TD-SCDMA repeater is, however, limited by the amount of isolation that exists between the donor and coverage antennas. The radio echoes from coverage antennas not only create interference in the incoming signal from the base station, but also cause instability of the repeater. In this paper, we present an interference cancellation system (ICS) for TD-SCDMA networks, which can eliminate these problems. Various characteristic features of the ICS are illustrated using the MATlab.simulation results.

关键词： TD-SCDMA Relay Repeater ICS

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A Metasurface-Based Wideband High Isolation Circularly Polarized Antenna For 5G MIMO Millimeter-Wave Systems

A Metasurface-Based Wideband High Isolation Circularly Polar...

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IEEE MTT-S International Microwave Workshop Series on Advanced Materials and Processes for RF and THz Applications (IMWS-AMP)

作者： Hui Zhu Haoran Zhu Information Materials and Intelligent Sensing Laboratory of Anhui Province Anhui University Hefei China Key Lab of Intelligent Computing & Signal Processing Ministry of Education Anhui University Hefei China

A wideband high isolation circularly polarized antenna for 5G MIMO millimeter-wave systems is presented in this paper. The presented antenna exhibits wideband characteristics due to the resonance of surface waves along the metasurface. The circularly polarized preliminary bandwidth is achieved by truncated corner patches when the truncation can be adjusted to implement the phase and amplitude values of the two quadrature modes. The port isolation is improved by the resonance of double-layer microstrip lines in the frequency. The size of the antenna is 17.8×17.8×1.02 mm 3 , the impedance bandwidth is 30.4% (23.29-31.66 GHz) and the 3-dB axial ratio bandwidth is 20.5% (24.47-30.12 GHz). In addition, the port isolation of the presented antenna is higher than 25 dB, and the peak gain is 8.4 dB. Therefore, the given antenna has the advantages of wideband, circularly polarized and high isolation.

关键词： Microwave antennas Surface impedance 5G mobile communication Surface waves Metasurfaces Broadband antennas Impedance

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Numerical Simulation of GPR based on 3-D High-order FDTD

Numerical Simulation of GPR based on 3-D High-order FDTD

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第九届国际天线、电波传播及电磁理论学术研讨会(ISAPE2010)

作者： Zhi-xiang Huang Hong-mei Du Yi-cai Mei Xin-gang Ren Xian-liang Wu Key Lab of Intelligent Computing & Signal Processing Anhui University Ministry of Education Hefei Department of Physics and Electronic Engineering Hefei Normal University Hefei China

The high-order finite-difference time-domain (HO-FDTD) technique is used in the simulation of ground-penetrating radar modeling in three dimensions (3-D), which can improve accuracy and reduce the error caused by numerical dispersion effectively. To absorb waves reflected from edges we implement convolutional perfectly matched layer (CPML) absorbing boundaries. It can efficiently absorb the reflections and greatly increase the computation efficiency. The surface-based reflection and cross-hole GPR modeling are simulated, and numerical results show the efficiency of the method.

关键词： Materials

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