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International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： M.Z. Coban R.M. Mersereau Center for Signal & Image Processing (CSIP) School of Electrical & Computer Engineering Georgia Institute of Technology Atlanta GA USA

A fast N-step search algorithm for rate-constrained motion estimation is presented. The motion vectors are selected from a search window based on a rate-distortion criterion by successively eliminating the search positions at each step. The performance of the proposed algorithm is identical to the performance of the conventional rate-constrained N-step search algorithm, with considerable reduction in computation. Computational savings increase in parallel with the increase in the rate constraint and the number of steps.

关键词： Motion estimation Bit rate Video coding Computational efficiency Testing Cost function Lagrangian functions Video sequences signal processing image processing

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Sonar resolution-based environment mapping 15

Sonar resolution-based environment mapping

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15th IEEE International Conference on Robotics and Automation, ICRA 1998

作者： Cahut, Leyla Vlavanis, Kimon P. Delic, Hakan Robotics and Automation Laboratory Center for and Advanced Computer Studies University of Southwestern Louisiana LafayetteLA70504 United States Signal and Image Processing Laboratory Department of Electrical Engineering BogaziCi University Bebek 80815 Istanbul Turkey

ISBN: (纸本)078034300X

Ultrasonic range sensors are used to obtain the information required for collision-free navigation of a mobile robot in a semi-structured or unstructured environment. A set of range readings from a ring of sonars are correlated to acquire a 2D map of the robot's environment. The map is continuously enhanced via novel matching and update algorithms as new data are collected while the robot is in motion. The algorithm utilizes confidence measures that are directly obtained from the sonar's resolution or accuracy. There are no additional modeling assumptions and the approach is robust. The algorithms are experimentally tested on the Nomad 200 mobile robot and Nomad's Cognos Software Development Package. © 1998 IEEE.

关键词： Software testing

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A Region-Based Representation of images in MARS

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Journal of VLSI signal processing Systems for signal, image, and Video Technology 1998年第1-2期20卷 137-150页

作者： Servetto, Sergio D. Rui, Yong Ramchandran, Kannan Huang, Thomas S. Beckman Inst. Adv. Sci. and Technol. Univ. Illinois at Urbana-Champaign Urbana IL 61801 United States Universidad Nacional de La Plata Argentina Univ. Illinois at Urbana-Champaign United States Comp. Res. Adv. Applications Group IBM Argentina Argentina Image Formation and Processing Group Beckman Institute UIUC United States Department of Computer Science UNLP Argentina Dept. of Elec. and Comp. Engineering UIUC United States Multimedia Commun. Res. Department Bell Laboratories Murray Hill NJ United States Info. Sciences Research Department AT and T Labs. Florham Park NJ United States Department of Computer Science UIUC United States Southeast University China Tsinghua University China University of Illinois Urbana-Champaign IL United States Image Formation and Processing Group Beckman Inst. Advance Sci. Technol. UIUC United States Vis. Technol. Grp. of Microsoft Res. Redmond WA United States City College of New York United States Columbia University United States AT and T Bell Labs. United States Ctr. for Telecommunications Research Columbia University United States Elec. and Comp. Eng. Department United States Beckman Institute Coordinated Science Laboratory IL United States IEEE Signal Processing Society United States IEEE IMDSP Technical Committee United States IEEE Transactions on Image Proc. United States National Taiwan University Taipei Taiwan Massachusetts Inst. of Technology Cambridge MA United States Department of Electrical Engineering MIT United States School of Electrical Engineering United States Lab. for Info. and Signal Processing Purdue University United States Dept. of Elec. and Comp. Engineering United States Coordinated Science Laboratory United States Image Formation and Processing Group Beckman Inst. Adv. Sci. and Technol. United States MIT Lincoln Laboratory IBM Thomas J. Watson Research Center Rheinishes Landes Museum Bonn Germany Swiss Institutes of Technology Zurich Switzerland Swiss Institutes of Technology Lausanne S

We study the problem of representing images within a multimedia Database Management System (DBMS), in order to support fast retrieval operations without compromising storage efficiency. To achieve this goal, we propose new image coding techniques which combine a wavelet representation, embedded coding of the wavelet coefficients, and segmentation of image-domain regions in the wavelet domain. A bitstream is generated in which each image region is encoded independently of other regions, without having to explicitly store information describing the regions. Simulation results show that our proposed algorithms achieve coding performance which compares favorably, both perceptually and objectively, to that achieved using state-of-the-art image/video coding techniques while additionally providing region-based support.

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Animated Talking Head with Personalized 3D Head Model

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Journal of VLSI signal processing Systems for signal, image, and Video Technology 1998年第1-2期20卷 97-105页

作者： Ostermann, Jörn Chen, Lawrence S. Huang, Thomas S. AT and T Labs.-Research Red Bank NJ 07701 100 Schultz Dr. United States Beckman Institute CSL University of Urbana IL 61801 United States University of Hannover Imperical College London United States University of Hannover Germany Inst. F. Theor. Nachrichtentechnik United States Vis. Commun. Research Department Bell Labs. United States Image Proc. and Technology Research AT and T Labs.-Research United States University of Illinois Urbana-Champaign IL United States University of Illinois United States Beckman Inst. Adv. Sci. and Technol. University of Illinois United States AT and T Labs. United States ATR Media Intgn. and Commun. Labs. Kyoto Japan National Taiwan University Taipei Taiwan Massachusetts Inst. of Technology Cambridge MA United States Department of Electrical Engineering MIT United States School of Electrical Engineering United States Lab. for Info. and Signal Processing Purdue University United States Coordinated Science Laboratory United States Dept. the Image Form. and Proc. Grp. Beckman Inst. Adv. Sci. and Technol. United States MIT Lincoln Laboratory IBM Thomas J. Watson Research Center Rheinishes Landes Museum Bonn Germany Swiss Institutes of Technology Zurich Switzerland Swiss Institutes of Technology Lausanne Switzerland University of Hannover Germany INRS-Telecommunications University of Quebec Montreal Que. Canada University of Tokyo Japan

Natural Human-computer Interface requires integration of realistic audio and visual information for perception and display. An example of such an interface is an animated talking head displayed on the computer screen in the form of a human-like computer agent. This system converts text to acoustic speech with synchronized animation of mouth movements. The talking head is based on a generic 3D human head model, but to improve realism, natural looking personalized models are necessary. In this paper, we report a semi-automatic method for adapting a generic head model to 3D range data of a human head obtained from a 3D-laser range scanner. This personalized model is incorporated into the talking head system. With texture mapping, the personalized model offers a more natural and realistic look than the generic model. The model created with the proposed method compares favorable to generic models.

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On homomorphic deconvolution of bandpass signals

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IEEE TRANSACTIONS ON signal processing 1997年第10期45卷 2499-2514页

作者： Marenco, AL Madisetti, VK Center for Signal and Image Processing (CSIP) Georgia Institute of Technology School of Electrical and Computer Engineering Atlanta GA USA

A convolution may be represented as x(.) = r(.)* w(.). The goal of deconvolution is to extract r(.) and w(.) from a knowledge of x(.) and finds numerous applications in digital signal processing, Of practical interest in oil exploration is the case where w(.) is a seismic pressure wavelet, x(.) is the observed seismic response, and, (.) is the reflectivity of the earth, A number of procedures have been proposed, including predictive, deterministic, and homomorphic deconvolution, Homomorphic deconvolution has been found to be particularly efficient for those cases where x(.) is known to be fullband. This paper presents a robust constructive procedure for efficient homomorphic deconvolution for those cases where x(.) is a bandpass signal, Extensive comparisons with other methods for deconvolving bandpass signals on measured seismic data traces (including the Novaya Zemlya event) illustrate the improvement in the deconvolution.

关键词： Deconvolution Convolution Reflection Digital signal processing Reflectivity Seismic measurements signal processing Pollution measurement Cepstral analysis Cepstrum

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Spatio-temporal wavelet transforms for digital signal analysis

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signal processing 1997年第1期60卷 23-41页

作者： Leduc, JP Georgia Institute of Technology School of Electrical and Computer Engineering Center of Signal and Image Processing Atlanta GA 30332-0250 USA

The goal of this paper is to investigate spatio-temporal continuous wavelet transforms. A new wavelet family, called the Galilean wavelet, has been designed to tune to four main parameters, namely, scale, spatio-temporal position, spatial orientation, and velocity. The paper starts with the theory of motion-compensated wavelet filtering in the discrete realm of image processing. As a major difference from multi-dimensional homogeneous spaces, spatio-temporal signal involves motion that warps the signal along the trajectories. Modeling motion with 2-D affine transformations leads to spatio-temporal generalizations. Decomposition into elementary operators leads to developing transformation groups and exploiting the related representation theory. The construction of continuous spatio-temporal wavelets in R-n x R spaces is then handled with classical techniques of calculation. Close connections may then be established among all the spatio-temporal wavelet transforms through different sets of transformations. This approach generates a general framework for the study of future tools. Frames of wavelets are thereafter investigated to revisit discrete wavelet transforms in a more general way. Eventually, illustrations demonstrate the ability of Galilean wavelet transforms to analyze spatio-temporal signals. (C) 1997 Elsevier Science B.V.

关键词： wavelet transforms spatio-temporal signals image sequences motion analysis group of transformations regions of interest selective feature extraction

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Sinusoidal modeling and modification of unvoiced speech

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IEEE TRANSACTIONS ON SPEECH AND AUDIO processing 1997年第6期5卷 557-560页

作者： Macon, MW Clements, MA Oregon Graduate Institute of Science and Technology Portland OR USA Center for Signal and Image Processing The Georgia Institute of Technology School of Electrical and Computer Engineering Atlanta GA USA

Although sinusoidal models have been shown to be useful for time-scale and pitch modification of voiced speech, objectionable artifacts often arise when such models are applied to unvoiced speech. This correspondence presents a sinusoidal model-based speech modification algorithm that preserves the natural character of unvoiced speech sounds after pitch and time-scale modification, eliminating commonly encountered artifacts. This advance is accomplished via a perceptually motivated modulation of the sinusoidal component phases that mitigates artifacts in the reconstructed signal after time-scale and pitch modification.

关键词： speech coding speech synthesis

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A secure communications system using chaotic switching

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INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS 1997年第6期7卷 1383-1394页

作者： Lee, C Williams, DB Lee, J Center for Signal and Image Processing School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA 30332-0250 USA

Since previous secure communications methods using chaotic systems require very high SNRs, knowledge of the initial conditions, and/or chaotic systems with the self-synchronization property, their application is limited. In this paper, a new secure communications scheme based on chaotic switching is discussed. The proposed scheme makes decisions on the incoming bits by comparing the power level of the dynamical error for each symbol signal after applying a noise reduction method based on the known system dynamics. A multi-user secure communications scheme is also considered where each user's symbol signal is mapped through a unique scramble matrix. We also examine whether these scramble matrices help to combat against smart jamming. The proposed system does not require self-synchronization between the chaotic receiver and transmitter and exhibits Seasonable performance at relatively low SNRs.

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MPEG-2 nonlinear temporally scalable coding and hybrid quantization

MPEG-2 nonlinear temporally scalable coding and hybrid quant...

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International Conference on Acoustics, Speech, and signal processing (ICASSP)

作者： S. Bayrakeri R.M. Mersereau Center for Signal and Image Processing School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta GA USA

In this paper, we investigate the MPEG-2 temporal scalability syntax and introduce a new approach to temporally scalable coding. Temporal scalability is provided by employing various nonlinear prediction and demultiplexing schemes. A nonlinear deinterlacing algorithm is presented and the related issues on interlaced, progressive and mixed mode video processing are addressed. In addition to the considered scalability techniques, a lookahead quantization scheme is presented for P- and B-type picture coding, which improves the coding performance by selective combination of the DCT domain scalar quantization and entropy-constrained vector quantization. Remarkable performance improvement over the simulcast coding is achieved.

关键词： image coding Scalability Spatial resolution Video coding signal processing Discrete cosine transforms Vector quantization image processing Limiting Decoding

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Computationally efficient exhaustive search algorithm for rate-constrained motion estimation

Computationally efficient exhaustive search algorithm for ra...

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IEEE International Conference on image processing

作者： M.Z. Coban R.M. Mersereau Center for Signal & Image Processing (CSIP) School of Electrical & Computer Engineering Georgia Institute of Technology Atlanta GA USA

A computationally efficient exhaustive search algorithm for rate-constrained motion estimation is presented. The motion vectors are selected from a search window based on a rate-distortion criterion by successively eliminating the search positions depending on the rate constraint. The performance of the proposed algorithm is identical to the performance of the rate-constrained full search algorithm, with considerable reduction in computation. The number of matching calculations decreases as the constraint imposed on the rate increases.

关键词： Motion estimation Bit rate Video coding Computational complexity Constraint optimization Lagrangian functions signal processing image processing Electronic mail Rate-distortion

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