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Visual estimation and compression of facial motion parameters - Elements of a 3D model-based video coding system

INTERNATIONAL JOURNAL OF COMPUTER VISION 2002年第2期50卷 111-125页

作者： Tao, H Huang, TS Univ Calif Santa Cruz Dept Comp Engn Santa Cruz CA 95064 USA Univ Illinois Beckman Inst Image Proc & Format Lab Urbana IL 61801 USA

The MPEG4 standard supports the transmission and composition of facial animation with natural video by including a facial animation parameter (FAP) set that is defined based on the study of minimal facial actions and is closely related to muscle actions. The FAP set enables model-based representation of natural or synthetic talking head sequences and allows intelligible visual reproduction of facial expressions, emotions, and speech pronunciations at the receiver. This paper describes two key components we have developed for building a model-based video coding system: (1) a method for estimating FAP parameters based on our previously proposed piecewise Bezier volume deformation model (PBVD), and (2) various methods for encoding FAP parameters. PBVD is a linear deformation model suitable for both the synthesis and the analysis of facial images. Each FAP parameter is a basis function in this model. Experimental results on PBVD-based animation, model-based tracking, and spatial-temporal compression of FAP parameters are demonstrated in this paper.

关键词： nonrigid motion analysis facial animation model-based coding MPEG4

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Smoothing algorithms for clip-and-paste model-based video coding

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 1999年第2期45卷 427-435页

作者： Hao, SS Lee, MF Yang, JF Natl Cheng Kung Univ Dept Elect Engn Tainan 701 Taiwan

model-based video coding has been adopted as a core experiment in ISO MPEG-4 standard. The clip-and-paste technique for putting video objects in line is an important tool to reduce the transmission rate. To assist the clip-and-pasting method fitting into the 2-D model, we propose several smoothing algorithms for improving the quality of the reconstructed images. In this paper, the proposed smoothing algorithms can adjust deformations of zoom, tilt, and rotation object images. Luminance smoothing algorithm is also applied to compensate the light source variations. Simulation results show that the smoothing methods help to improve clip-and-paste images to achieve a satisfactory quality in visual perceptions.

关键词： model-based coding clip-and-paste method smoothing algorithm

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SPEED-UP TREND ANALYSIS FOR H.261 AND model-based IMAGE-coding ALGORITHMS USING A PARALLEL-PIPELINE model

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SIGNAL PROCESSING-IMAGE COMMUNICATION 1995年第4-6期7卷 489-502页

作者： DOWNTON, AC Department of Electronic Systems Engineering University of Essex Wivenhoe Park Colchester CO4 3SQ UK

model-based and object-oriented coding algorithms are generally more computationally complex than current block-based image coding standards such as H.261, due primarily to the complexity of the image analysis they require. In this paper, simulations of H.261 and two model-based coding algorithms are analysed in terms of their computational complexity, and mapped onto a generalised image coder parallel-pipeline model. Example implementations of the H.261 coder and an object-oriented coder using general purpose parallel processor systems are then presented to confirm the validity of the performance trend analyses;these achieve maximum speedups of about 11 and 1.7, respectively, using up to 16 processors. The performance trends shown by the analysis indicate that the complexity of model-based coding algorithms, when combined with their reliance on coding picture differences and content-dependent algorithm execution times, interact to make it very difficult to achieve significant speed-up of sequential algorithms. Furthermore, the algorithm complexity and abstract data structures will make direct hardware implementations increasingly difficult. Overcoming these problems to achieve real-time model-based coders may require significant algorithmic compromises to be made.

关键词： model-based coding OBJECT-ORIENTED coding REAL-TIME IMAGE coding PARALLEL PROCESSING SPEED-UP

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Global motion estimation in model-based image coding by tracking three-dimensional contour feature points

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1998年第2期8卷 181-190页

作者： Pei, SC Ko, CW Su, MS Natl Taiwan Univ Dept Elect Engn Taipei 10764 Taiwan

Recently a new type of video coding method called model-based image coding has attracted much attention as a potential candidate for low bit-rate visual communication services, This technique reconstructs the facial image with a preknown three-dimensional (3-D) human face model and its received model motion parameters, The parameters of the head motion are mainly divided into two parts: global motion parameters describe the rigid movement of the head, such as rotation and translation, and local motion parameters which deal with the nonrigid movements of facial expressions, such as the opening and closing of the mouth and eyes. In this paper, we propose a new approach which can estimate the head global motion more robustly and accurately, Comparing with the existing techniques to match only a few key points, here we extract 3-D contour feature points and use chamfer distance matching to estimate head global motion, This can improve and enhance the contour tracking performance greatly. We also develop another technique called facial normalization transform, It maps the facial region of the current input frame back to the normalized pose of the initial frame, Using this transform, we can analyze facial expressions at the same orientation and fixed region, This simplifies the analysis work a lot, Then, we do our encoding by the clip-and-paste method along with adaptive codebook technique. In the following, the coder and decoder system are briefly described, Since we mainly focus the work on the analysis and synthesis of the facial portion images, background analysis and bitstream coding technique will not be discussed in this paper.

关键词： contour feature points generic facial model global motion estimation model-based coding

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3-DIMENSIONAL PARAMETER-ESTIMATION FROM STEREO IMAGE SEQUENCES FOR model-based IMAGE-coding

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SIGNAL PROCESSING-IMAGE COMMUNICATION 1995年第4-6期7卷 471-487页

作者： PAPADIMITRIOU, DV DENNIS, TJ UNIV ESSEX DEPT ELECTR SYST ENGN COLCHESTER CO4 3SQ ESSEX ENGLAND

It is shown that the analysis of moving image sequences for 3D modelling can be performed in a relatively straightforward manner if the scene is captured in stereo. but put from a stereo disparity estimation process using calibrated cameras gives absolute 3D surface coordinates from a single stereo pair. When combined with monocular motion cues, the true 3D motion parameters of moving objects can be accurately calculated. Further analysis enables segmentation of body elements according to motion while the 3D surface feature structure, although available from the start, can be integrated and checked for anomalies over the sequence. These results are expected to alleviate the known problems of ambiguity suffered by monocular-source model-based coders.

关键词： model-based coding 3D SCENE ANALYSIS STEREO VISION 3D model CONSTRUCTION 3D MOTION ESTIMATION

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A robust model generation technique for model-based video coding

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2001年第11期11卷 1188-1192页

作者： Siu, M Chan, YH Siu, WC Hong Kong Polytech Univ Dept Elect & Informat Engn Ctr Multimedia Signal Proc Hong Kong Hong Kong Peoples R China

In conventional model-based coding schemes, predefined static models are generally used. These models cannot adapt to new situations, and hence, they have to be very specific and cannot be generated from a single generic model even though they are very similar. In this letter, we present a model-generation technique that can gradually build a model and dynamically modify it according to new video frames scanned. The proposed technique is robust to the object's orientation in the view and can be efficiently implemented with a parallel processing technique. As a result, the proposed technique is more attractive to the practical use of model-based coding techniques in real applications.

关键词： model-based coding model synthesis

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Three-Dimensional Point-Cloud Plus Patches: Towards model-based Image coding in the Cloud 1

Three-Dimensional Point-Cloud Plus Patches: Towards Model-Ba...

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IEEE First International Conference on Multimedia Big Data

作者： Liu, Dong Shao, Tong Li, Houqiang Wu, Feng Univ Sci & Technol China CAS Key Lab Technol Geospatial Informat Proc & Ap Hefei 230027 Peoples R China

ISBN: (纸本)9781479986880

In the era of cloud computing, there are many correlated images in the cloud, joint compression of these images may provide much higher compression ratio than individual coding. model-based coding is an appealing approach to image coding in the cloud, as it removes knowledge redundancy among images that share the same model. In this paper, we make an attempt to model-based image coding for landmark images, where our model consists of three-dimensional (3D) point-cloud plus image patches to describe the geometry and surface color of the landmark respectively. The camera parameters of an input image are estimated based on the 3-D point-cloud and the patches in the model, and then prediction image is generated by selecting, warping, and stitching image patches as well as illuminance compensation, the residue between original and prediction images is compressed by P-frame coding in HEVC encoder. We perform experiments on an Internet photo collection to verify the effectiveness of the proposed scheme. Preliminary results display the superior performance of our scheme that achieves as high as 39.9% bits saving compared to HEVC intra on a single image. The proposed scheme indicates a promising approach to image coding in the cloud and is worthy of in-depth investigation.

关键词： 3-D model Cloud Storage Image coding model-based coding Point-Cloud

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Multiple-model coding scheme for electrical signal compression

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SIGNAL PROCESSING 2025年 236卷

作者： Presvots, Corentin Kieffer, Michel Prevost, Thibault Panciatici, Patrick Li, Zuxing Piantanida, Pablo Reseau Transport Elect Paris France Univ Paris Saclay CNRS Cent Supelec Lab Signaux & Syst L2S Paris France Univ Paris Saclay Cent Supelec Int Lab Learning Syst ILLS McGill ETS MILACNRS Paris France

This paper proposes a low-latency Multiple-model coding (MMC) approach to compress sampled electrical signal waveforms under encoding rate constraints. The approach is window-based. Several parametric waveform models are put in competition to obtain a first coarse representation of the signal in each considered window. Then, different residual compression techniques are compared to minimize the residual reconstruction error. The model parameters are quantized, and the allocation of the rate budget among the two steps is optimized. Simulation results show that the proposed MMC approach achieves a higher signal-to-noise ratio than state-of-the-art solutions on periodic and transients signal waveforms.

关键词： Compression Low latency model-based coding Rate-distortion optimization Raw electrical waveform compression Transform coding

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3D object articulation and motion estimation in model-based stereoscopic videoconference image sequence analysis and coding

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SIGNAL PROCESSING-IMAGE COMMUNICATION 1999年第10期14卷 817-840页

作者： Tzovaras, D Kompatsiaris, I Strintzis, MG Aristotelian Univ Salonika Dept Elect & Comp Engn Informat Proc Lab GR-54006 Salonika Greece

This paper describes a procedure for model-based analysis and coding of both left and right channels of a stereoscopic image sequence. The proposed scheme starts with a hierarchical dynamic programming technique for matching across the epipolar line for efficient disparity/depth estimation. Foreground/background segmentation is initially based on depth estimation and is improved using motion and luminance information. The model is initialised by the adaptation of a wireframe model to the consistent depth information. Robust classification techniques are then used to obtain an articulated description of the foreground of the scene (head, neck, shoulders). The object articulation procedure is based on a novel scheme for the segmentation of the rigid 3D motion fields of the triangle patches of the 3D model object. Spatial neighbourhood constraints are used to improve the reliability of the original triangle motion estimation. The motion estimation and motion field segmentation procedures are repeated iteratively until a satisfactory object articulation emerges. The rigid 3D motion is then re-computed for each sub-object and finally, a novel technique is used to estimate flexible motion of the nodes of the wireframe from the rigid 3D motion vectors computed for the wireframe triangles containing each specific node. The performance of the resulting analysis and compression method is evaluated experimentally. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： stereoscopic image sequence analysis model-based coding object articulation non-rigid 3D motion estimation

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A new approach to wire-frame tracking for semantic model-based moving image coding

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2000年第6期15卷 567-580页

作者： Antoszczyszyn, PM Hannah, JM Grant, PM Univ Edinburgh Dept Elect Engn Edinburgh EH9 3JL Midlothian Scotland

Automatic wire-frame fitting and automatic wire-frame tracking are the two most important and most difficult issues associated with semantic-based moving image coding. A novel approach to high-speed tracking of important facial features is presented as a part of a complete fitting-tracking system we have developed. The method allows real-time processing of head-and-shoulders sequences using software tools only. The algorithm is based on eigenvalue decomposition of the sub-images extracted from subsequent frames of the Video sequence. Since each facial feature (the left eye, the right eye, the nose and the lips) is tracked separately, the algorithm can be easily adapted for a parellel machine. The algorithm was tested on numerous widely used head-and-shoulders video sequences containing speaker's head pan, rotation and zoom with remarkably good results. The experiments we have carried out prove that it is possible to maintain tracking even when the facial features are partially occluded. (C) 2000 Elsevier Science B.V. All rights reserved.

关键词： tracking image coding semantic coding model-based coding wire-frame model principal components analysis

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