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Tracking multiple people under occlusion and across cameras using probabilistic models

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Journal of Zhejiang University-Science A(Applied Physics & engineering) 2009年第7期10卷 985-996页

作者： Xuan-he WANG Ji-lin LIU Institute of Information and communication engineering Zhejiang University Hangzhou 310027 China Zhejiang Provincial Key Laboratory of lnformation Network Technology Hangzhou 310027 China

Tracking multiple people under occlusion and across cameras is a challenging question for discussion. Furthermore, the cameras in this study are used to extend the field of view, which are distinguished from the same field of view. Such corre- spondence between multiple cameras is a burgeoning research subject in the area of computer vision. This paper effectively solves the problems of tracking multiple people who pass from one camera to another and segmenting people under occlusion using probabilistic models. The probabilistic models are composed of blob model, motion model and color model, which make the most of the space, motion and color information. First, we present a color model that uses maximum likelihood estimation based on non-parametric kernel density estimation. Second, we introduce a blob model based on mean shift, which segments the body into many regions according to the color of each person in order to spatially localize the color features corresponding to the way people are dressed. Clothes can be any mixture of colors. Third, we bring forward a motion model based on statistical probability which indicates the movement position of the same person between two successive frames in a single camera. Finally, we effectively unify the three models into a general probabilistic model and attain a maximization likelihood probability image, which is used to segment the foreground region under occlusion and to match people across multiple cameras.

关键词： Color model Motion model Blob model People occlusion People tracking Kernel density estimation

A subband excitation substitute based scheme for narrowband speech watermarking

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Frontiers of Information Technology & Electronic engineering 2017年第5期18卷 627-643页

作者： Wei LIU Ai-qun HU School of lnformation Science and engineering Southeast UniversityNanjing 210096China

We propose a new narrowband speech watermarking scheme by replacing part of the speech with a scaled and spectrally shaped hidden signal. Theoretically, it is proved that if a small amount of host speech is modified, then not only an ideal channel model for hidden communication can be established, but also high imperceptibility and good intelligibility can be achieved. Furthermore, a practical system implementation is proposed. At the embedder, the power normalization criterion is first imposed on a passband watermark signal by forcing its power level to be the same as the original passband excitation of the cover speech, and a synthesis filter is then used to spectrally shape the scaled watermark signal. At the extractor, a bandpass filter is first used to get rid of the out-of-band signal, and an analysis filter is then employed to compensate for the distortion introduced by the synthesis filter. Experimental results show that the data rate is as high as 400 bits/s with better bandwidth efficiency, and good imperceptibility is achieved. Moreover, this method is robust against various attacks existing in real applications.

关键词： Analysis filter Linear prediction Narrowband speech watermarking Passband excitation replacement Power normalization Spectral envelope shaping Synthesis filter

Accurate real-time stereo correspondence using intra- and inter-scanline optimization

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Journal of Zhejiang University-Science C(Computers and Electronics) 2012年第6期13卷 472-482页

作者： Li YAO Dong-xiao LI Jing ZHANG Liang-hao WANG Ming ZHANG Institute of Information and communication engineering Zhejiang UniversityHangzhou 310027China Zhejiang Provincial Key Laboratory of lnformation Network Technology Hangzhou 310027China

This paper deals with a novel stereo algorithm that can generate accurate dense disparity maps in real time. The algorithm employs an effective cross-based variable support aggregation strategy within a scanline optimization framework. Rather than matching intensities directly, the use of adaptive support aggregation allows for precisely handling the weak textured regions as well as depth discontinuities. To improve the disparity results with global reasoning, we reformulate the energy function on a tree structure over the whole 2D image area, as opposed to dynamic programming of individual scanlines. By applying both intra- and inter-scanline optimizations, the algorithm reduces the typical 'streaking' artifact while maintaining high computational efficiency. The experimental results are evaluated on the Middlebury stereo dataset, showing that our approach is among the best for all real-time approaches. We implement the algorithm on a commodity graphics card with CUDA architecture, running at about 35 fames/s for a typical stereo pair with a resolution of 384×288 and 16 disparity levels.

关键词： tereo correspondence, Scanline optimization, Real-time

Robust time reversal processing for active detection of a small bottom target in a shallow water waveguide

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第5期11卷 401-406页

作者： Xiang PAN Jian-long LI Wen XU Xian-yi GONG Institute of lnformation and communication engineering Zhejiang University Hangzhou 310027 China Zhejiang Provincial Key Laboratory of Information Network Technology Hangzhou 310027 China

With the spatial-temporal focusing of acoustic energy,time reversal processing(TRP) shows the potential application for active target detection in shallow *** turn the ‘potential’ into a reality,the TRP based on a model source(MS) instead of a physical probe source(PS) is *** uncertain ocean environments,the robustness of TRP is discussed for the narrowband and broadband signal *** channel transfer function matrix is first constructed in the acoustic perturbation *** a steering vector for time reversal transmission is obtained by singular value decomposition(SVD) of the *** verification of the robust TRP,the tank experiments of time reversal transmission focusing and its application for active target detection are *** experimental results have shown that the robust TRP can effectively detect and locate a small bottom target.

关键词： Robustness Time reversal processing Bottom target detection Uncertain environment Sonar

Coupling characteristics between five-layer slab wave-guides including left-handed materials

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Optoelectronics Letters 2008年第6期4卷 419-421页

作者： SHEN Lu- fa WANG Zi-hua Science College Huzhou Normal University Huzhou 313000 China School of communication and lnformation engineering Shanghai University Shanghai 200072 China

To obtain the coupling characteristics between slab wave-guides including left-handed material,we modify the coupled wave equations by using Maxwell’s equations. First,we obtain new-coupled wave equations and new-coupling coefficient. Second,the coupling between two identical five-layer slab wave-guides where their cores are left-handed material,but their claddings are right-handed materials is studied. The coupling coefficient for even TE mode which is more complex than that of the riglt-handed material slab wave guides,is obtained.

关键词：五层组合板波导光学应用左手材料

Enhancement of the Sensitivity of Gas Sensor Based on Microstructure Optical Fiber

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Photonic Sensors 2015年第4期5卷 312-320页

作者： Monir MORSHED Md. Imran HASAN S. M. Abdur RAZZAK Department of lnformation and communication Technology Mawlana Bhashani Science and Technology University Tangail-1902 Bangladesh Department of Electronics & Telecommunication engineering Rajshahi University of Engineering & Technology Rajshahi-6204 Bangladesh Department of Electrical & Electronic engineering Rajshahi University of Engineering & Technology Rajshahi-6204 Bangladesh

This paper proposes the design and characterization of microstructure optical fiber for gas sensing applications. The aim is to detect toxic and colorless gases over a wide transmission band covering 0.80 gm to 2.00gm wavelength. Numerical investigation is carried out by using the finite element method （FEM）. The numerical study shows that sensitivity of the proposed sensor is moderately increased by introducing four non-circular holes around the defected core of photonic crystal fiber and the confinement loss is also reduced. Furthermore, we confirm that increasing the diameter of central air core and size of the non-circular holes can improve the relative sensitivity and the confinement loss is reduced by increasing the diameter of air holes in the cladding. The enhancement of the relative sensitivity is more than 27.58% （0.1323 to 0.1688） at the wavelength 2=1.33gm that is the absorption line of methane （CH4） and hydrogen fluoride （HF） gases. The confinement loss of the fiber is 1.765x 10-8dB/m.

关键词： Confinement loss gas sensor hollow core photonic crystal fiber microstrucmre fiber relativesensitivity

NOISE REDUCTION FOR FAST FADING CHANNEL BY RECURRENT LEAST SQUARES SUPPORT VECTOR MACHINES IN EMBEDDING PHASE SPACES

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维普期刊数据库

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Journal of Electronics(China) 2006年第6期23卷 926-928页

作者： Xiang Zheng Zhang Taiyi Sun Jiancheng dept of lnformation and communication engineering Xi ＇an Jiaotong University Xi ＇an 710049 China

A new strategy for noise reduction of fast fading channel is presented. Firstly, more information is acquired utilizing the reconstructed embedding phase space. Then, based on the Recurrent Least Squares Sup-port Vector Machines (RLS-SVM), noise reduction of the fast fading channel is realized. This filtering tech-nique does not make use of the spectral contents of the signal. Based on the stability and the fractal of the cha-otic attractor, the RLS-SVM algorithm is a better candidate for the nonlinear time series noise-reduction. The simulation results shows that better noise-reduction performance is acquired when the signal to noise ratio is 12dB.

关键词： Fading channel Noise reduction Support Vector Machines (SVM) Chaotic attractor

SMOOTHING OF 1/F SIGNAL WITH ORTHOGONAL MULTIWAVELET

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Journal of Electronics(China) 2006年第2期23卷 318-320页

作者： Yan Xiaohong Zhang Taiyi Liu Feng The dept of lnformation and communication engineering Xi ＇an Jiaotong University Xi ＇an 710049 China

Based on the orthogonal multiwavelet model of 1/f signals, smoothing fractal signals from white Gaussian noise with multiwavelet filter is proposed. The proposed multiwavelet method is very simple and easy to realize. Compared with Wornell's single wavelet method, the new method has r filtering factors at each scale and has higher filtering speed, where r is the multiplicity of multiwavelet. Also due to the advantages of multiwavelet, the multiwavelet method performs better than that of Wornell's. Simulation results verify the analysis, and Wornell's method is the special case of our method when r = 1.

关键词： Fractal Multiwavelet Filtering Signal-to-noise ratio

Simulation Study and Probe on UWB Wireless communication in Underground Coal Mine

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Journal of China University of Mining and Technology 2006年第3期16卷 296-300页

作者： WANG Yan-fen WANG Zheng-gang YU Hong-zhen School of lnformation and Electrical engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

From an analysis of the status of coal mine underground wireless communication, the application of UWB wireless communication system to underground coal mine is proposed. The basic composition of an UWB communication system and application in underground coal mines are introduced. The analyses show that, because of the transmission power being non-limitted in underground coal mines, the use of UWB in coal mines cannot only realize wireless access services of short distance high rate application for transmission of video monitoring signals, but also realize wireless access services of long distance low rate applications for mobile telephones in underground coal mines and parameters of working conditions monitoring, etc. It is emphasized on the simulation of a TH-PPM UWB communication system with traditional underground broadband model and ground CM1, CM3 model. It is shown that the traditional underground broadband model and ground CM1, CM3 models are not applicable to the UWB communication system in underground coal mines. It is necessary to conduct research on the propagation characteristics of UWB in coal mine tunnels, given the characteristics of the underground environment and to find the appropriate UWB model for underground coal mines.

关键词： ultra-wide band system simulation underground coal mine channel model characteristic of propagation.