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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1998年第7期8卷 838-848页

作者： Howard, PG Kossentini, F Martins, B Forchhammer, S Rucklidge, WJ AT&T Bell Labs Red Bank NJ USA Univ British Columbia Dept Elect & Comp Engn Vancouver BC V6T 1Z4 Canada Tech Univ Denmark DK-2800 Lyngby Denmark Xerox Corp Palo Alto CA USA

The Joint Bi-Level Image Experts Group (JBIG), an international study group affiliated with ISO/IEC and ITU-T, is in the process of drafting a new standard for lossy and lossless compression of bilevel images. The new standard, informally referred to as JBIG2, will support model-based coding for test and halftones to permit compression ratios up to three times those of existing standards for lossless compression. JBIG2 will also permit lossy preprocessing without specifying how it is to be done. In this case, compression ratios up to eight times those of existing standards may be obtained with imperceptible loss of quality, It is expected that JBIG2 will become an international standard by 2000.

关键词： archiving facsimile halftones JBIG lossless bilevel image compression lossy bilevel image compression MMR model-based coding MR printing text

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Two- versus three-dimensional object-based video compression

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1997年第2期7卷 391-397页

作者： Tekalp, AM Altunbasak, Y Bozdagi, G UNIV ROCHESTER CTR ELECT IMAGING SYSTROCHESTERNY 14627

This paper compares two-dimensional (2-D) and three-dimensional (3-D) object modeling in terms of their capabilities and performance (peak signal-to-noise-ratio and visual image quality) for very low bitrate video coding. We show that 2-D object-based coding with affine/perspective transformations and triangular mesh models can simulate almost all capabilities of 3-D object-based approaches using wireframe models at a fraction of the computational cost, Furthermore, experiments indicate that a 2-D mesh-based coder-decoder performs favorably compared to the new H.263 standard in terms of visual quality.

关键词： model-based coding MPEG Phase 4 three-dimensional wireframe two-dimensional mesh video compression

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FAP extraction using three-dimensional motion estimation

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2002年第10期12卷 865-876页

作者： Sarris, N Grammalidis, N Strintzis, MG Aristotle Univ Thessaloniki GR-54006 Thessaloniki Greece

An integral part of the MPEG-4 standard is the definition of face animation parameters (FAPs). This paper presents a method for the determination of FAPs by using three dimensional (3-D) rigid and nonrigid motion of human facial features found from two-dimensional (2-D) image sequences. The proposed method assumes that a 3-D model has been fitted to the first frame of the sequence, tracks the motion of characteristic facial features, calculates the 3-D rigid and nonrigid motion of facial features, and through this, estimates the FAPs as defined by the MPEG-4 coding standard. The 2-D tracking process is based on a novel enhanced version of the algorithm proposed by Kanade, Lucas, and Tomasi. The nonrigid motion estimation is achieved using the same tracking mechanism guided by the facial motion model implied by the MPEG-4 FAPs.

关键词： 3-D motion estimation FAP extraction head tracking model-based coding

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Hierarchical motion estimation with content-based meshes

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2003年第10期13卷 1000-1005页

作者： Al-Regib, G Altunbasak, Y Mersereau, RM Georgia Inst Technol Ctr Signal & Image Proc Atlanta GA 30332 USA

Two-dimensional mesh-based models provide a good alternative to motion estimation and compensation. The estimation of the best node-point motion vectors is a challenging task. To this effect, Nakaya and Harashima proposed a hexagonal matching procedure. Toklu et al improved the hexagonal search algorithm in terms of both motion-estimation accuracy and computational complexity by employing a hierarchy of regular meshes. Recognizing the limitations of regular meshes, Van Beek et al. extended Toklu et al.'s work by utilizing content-based meshes. Here, we provide an alternative hierarchical motion-estimation method with content-based meshes where hierarchical representations are employed for both the images and the irregular meshes in order to provide further improvements in computational complexity as well as motion accuracy. The comparison results are provided with real video sequences.

关键词： hierarchical motion estimation model-based coding two-dimensional mesh two-dimensional mesh-based motion representation video compression

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Facial model adaptation from a monocular image sequence using a textured polygonal model

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2002年第5期17卷 373-392页

作者： Chang, YJ Chen, YC Natl Tsing Hua Univ Dept Elect Engn Hsinchu 30013 Taiwan

Although several algorithms have been proposed for facial model adaptation from image sequences, the insufficient feature set to adapt a full facial model, imperfect matching of feature points, and imprecise head motion estimation may degrade the accuracy of model adaptation. In this paper, we propose to resolve these difficulties by integrating facial model adaptation, texture mapping, and head pose estimation as cooperative and complementary processes. By using an analysis-by-synthesis approach, salient facial feature points and head profiles are reliably tracked and extracted to form a growing and more complete feature set for model adaptation. A more robust head motion estimation is achieved with the assistance of the textured facial model. The proposed scheme is performed with image sequences acquired with single uncalibrated camera and requires only little manual adjustment in the initialization setup, which proves to be a feasible approach for facial model adaptation. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： facial model adaptation model-based coding MPEG-4 SNHC talking head

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Geometry-assisted image-based rendering for facial analysis and synthesis

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2006年第6期21卷 493-505页

作者： Eisert, Peter Rurainsky, Mrgen Heinrich Hertz Inst Nachrichtentech Berlin GmbH Fraunhofer Inst Telecommun D-10587 Berlin Germany

In this paper, we present an image-based method for the tracking and rendering of faces. We use the algorithm in an immersive video conferencing system where multiple participants are placed in a common virtual room. This requires viewpoint modification of dynamic objects. Since hair and uncovered areas are difficult to model by pure 3-D geometry-based warping, we add image-based rendering techniques to the system. By interpolating novel views from a 3-D image volume, natural looking results can be achieved. The image-based component is embedded into a geometry-based approach in order to limit the number of images that have to be stored initially for interpolation. Also temporally changing facial features are warped using the approximate geometry information. Both geometry and image cube data are jointly exploited in facial expression analysis and synthesis. (c) 2006 Elsevier B.V. All rights reserved.

关键词： facial animation image-based rendering model-based coding face tracking 3-D image analysis and synthesis

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MPEG-4 facial animation in video analysis and synthesis

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INTERNATIONAL JOURNAL OF IMAGING SYSTEMS AND TECHNOLOGY 2003年第5期13卷 245-256页

作者： Eisert, P Heinrich Hertz Inst Nachrichtentech Berlin GmbH Fraunhofer Inst Telecommun Image Proc Dept D-10587 Berlin Germany

MPEG-4 supports the definition, encoding, transmission, and animation of 3-D head and body models. These features can be used for a variety of different applications ranging from low bit-rate video coding to character and avatar animation. In this article, an entire system for the analysis of facial expressions from image sequences and their synthesis is presented. New methods for the estimation of MPEG-4 facial animation parameters as well as scene illumination are proposed. Experiments for different applications demonstrate the potential of using facial animation techniques in video analysis and synthesis. A model-based codec is presented that is able to encode head-and-shoulder video sequences at bit-rates of about 1 kbit/s. Besides the low bit-rate, many enhancements and scene modifications can be easily applied, like scene lighting changes or cloning of expressions for character animation. But also for the encoding of arbitrary sequences, 3-D knowledge can help to increase the coding efficiency. With our model-aided codec, bit-rate reductions of up to 45% at the same quality can be achieved in comparison to standard hybrid video codecs. (C) 2004 Wiley Periodicals, Inc.

关键词： MPEG-4 facial animation video compression model-based coding model-aided coding

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Facial feature analysis in dynamic bandwidth environments: a genetic approach

Facial feature analysis in dynamic bandwidth environments: a...

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IEEE Congress on Evolutionary Computation

作者： Larson, Eric C. Yen, Gary G. Oklahoma State Univ Sch Elect & Comp Engn Stillwater OK 74078 USA

ISBN: (纸本)9781424418220

Facial feature tracking for model-based coding has evolved over the past decades. Of particular interest is its application in very low bit rate coding in which optimization is used to analyze head and shoulder sequences. We present the results of a computational experiment in which we apply a combination of non-dominated sorting genetic algorithm (NSGA-II) and a deterministic search to find optimal facial animation parameters at many bandwidths, simultaneously. As objective functions are concerned, peak signal-to-noise ratio is chosen to be maximized while the total number of facial animation parameters is chosen to be minimized. Particularly, the algorithm is tested for efficiency and reliability. The results show that the overall methodology works effectively, but that a better error assessment function is needed.

关键词： Facial feature tracking model-based coding NSGA-II genetic algorithm cyclic optimization

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Global Object Representation of Scene Surveillance Video based on model and Feature Parameters 16th

Global Object Representation of Scene Surveillance Video Bas...

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16th Pacific-Rim Conference on Multimedia (PCM)

作者： Ma, Minsheng Hu, Ruimin Chen, Shihong Xiao, Jing Wang, Zhongyuan Qu, Shenming Wuhan Univ Comp Sch Natl Engn Res Ctr Multimedia Software Wuhan 430072 Peoples R China Collaborat Innovat Ctr Geospatial Technol Wuhan Peoples R China Henan Univ Sch Software Kaifeng Peoples R China

ISBN: (纸本)9783319240756;9783319240749

Scene surveillance video is a kind of video which are captured by stationary camera for a long time in specific surveillance scene. Due to regular movement of vehicles with similarity structures, models and appearances, surveillance video produce amounts of redundancy and needs to be efficiently coded for transmission and storage. In this study, we investigated the video redundancy generation mechanism of scene surveillance, exploit and presents a new redundancy type-Global Object Redundancy (GOR), it is proven that the vehicles occupy the mostly proportion which caused by amounts of vehicles movement. Secondly, aiming at global vehicle objects representation and GOR elimination, a global object representation scheme of scene surveillance video based on model and feature parameters is introduced, by establish a global knowledge dictionary and feature parameter sets, low bitrate with high quality compression can be achieved due to only few vehicle objects individual semantic and feature parametric be transfer and coded. Finally, we carried out preliminary experiments in simulation environment and shows that the object representation scheme can effectively improve the compression of long-term archive surveillance video which with a certain of image quality assurance.

关键词： Scene surveillance video Global objects redundancy Global objects representation Global texture dictionary model-based coding

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3D model-based head tracking

3D model-based head tracking

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1997 Conference on Visual Communications and Image Processing

作者： Colmenarez, A Lopez, R Huang, TS Univ. of Illinois/Urbana-Champaign (United States)

ISBN: (纸本)0819424358

This paper introduces a new approach to feature-based head tracking and pose estimation. Head tracking and pose estimation find their most important applications in motion analysis for model-based video coding. The proposed algorithm employs an underlying 3D head model, feature-based pose estimation, and texture mapping to produce accurate templates for the feature tracking. In this way, the set of templates used for the matching is constantly updated with the pose changes, allowing the algorithm to track the features over a large range of head motion without loss of precision and error accumulation. Given a rough estimate of the head scale, the initial feature identification is performed automatically and the tracking is successful over a large number of video frames. Computational complexity is also considered with the aim towards creating a real-time end-to-end model-based video coding system.

关键词： head tracking feature tracking model-based coding feature extraction

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