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MPEG-4 and rate-distortion-based shape-coding techniques

PROCEEDINGS OF THE IEEE 1998年第6期86卷 1126-1154页

作者： Katsaggelos, AK Kondi, LP Meier, FW Ostermann, J Schuster, GM Northwestern Univ Dept Elect & Comp Engn Evanston IL 60208 USA Silicon Graph Mountain View CA 94043 USA AT&T Bell Labs Res Red Bank NJ 07701 USA 3Com Mt Prospect IL 60016 USA

In this paper, we address the problem of the efficient encoding of object boundaries. This problem is becoming increasingly important in applications such as content-based storage and retrieval, studies and television postproduction, and mobile multimedia applications. The MPEG-4 visual standard will allow the transmission of arbitrarily shaped video objects. The techniques developed for shape coding within the MPEG-4 standardization effort are described and compared first. A framework for the representation of shapes using their contours is presented next. Such representations are achieved using curves of various orders, and they are optimal in the rate-distortion sense. Last, conclusions are drawn.

关键词： boundary coding MPEG-4 rate-distortion theory shape coding video coding

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A method for encoding region boundaries based on transition points

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IMAGE AND VISION COMPUTING 1998年第3期16卷 213-218页

作者： Pinho, AJ Univ Aveiro INESC Dept Elect & Telecomunicacoes P-3810 Aveiro Portugal

In this paper we present an encoding algorithm for boundary maps containing only closed contours. The method relies on the location and encoding of 'transition points', i.e., points where rows or columns of edge elements change state. Experimental results show that this technique offers better compression ratios than differential chain-coding for boundary maps having medium or large complexity. (C) 1998 Elsevier Science B.V.

关键词： boundary coding image coding image segmentation

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Joint optimal object shape estimation and encoding

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2004年第4期14卷 528-533页

作者： Kondi, LP Melnikov, G Katsaggelos, AK SUNY Buffalo Dept Elect Engn Buffalo NY 14260 USA Ingenient Technol Rolling Meadows IL 60008 USA Northwestern Univ Dept Elect & Comp Engn Evanston IL 60208 USA

A major problem in. object-oriented video coding and, MPEG-4 is the encoding of object boundaries., Traditionally this problem, is treated separately from the texture encoding problem. In. this paper, we present,a vertex-based shape coding method which is optimal in the operational rate-distortion sense and takes into account the texture information of the video frames. This is accomplished by utilizing a variable-width tolerance band whose Width,is a function of the texture, profile. As an. example, this width is inversely proportional to the magnitude, of the image gradient. Thus, in areas where the confidence in the estimation of the boundary is low and/or coding errors in the boundary will not affect the application (e.g., object-oriented coding and MPEG-4) significantly,. a larger boundary approximation error, is allowed. We present experimental. results which demonstrate the effectiveness of the proposed algorithm.

关键词： boundary coding MPEG-4 operational rate-distortion (ORD) theory shape coding shape-adaptive DCT

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An efficient rate-distortion optimal shape coding approach utilizing a skeleton-based decomposition

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2003年第10期12卷 1181-1193页

作者： Wang, HH Schuster, GM Katsaggelos, AK Pappas, TN Northwestern Univ Dept Elect & Comp Engn Evanston IL 60208 USA Hsch Tech Abt Elektrotech CH-8040 Rapperswil Switzerland

In this paper, we present a new shape-coding approach, which decouples the shape information into two independent signal data sets;the skeleton and the boundary distance from the skeleton. The major benefit of this approach is that it allows for a more flexible tradeoff between approximation error and bit budget. Curves of arbitrary order can be utilized for approximating both the skeleton and distance signals. For a given bit budget for a video frame, we solve the problem of choosing the number and location of the control points for all skeleton and distance signals of all boundaries within a frame, so that the overall distortion is minimized. An operational rate-distortion (ORD) optimal approach using Lagrangian relaxation and a four-dimensional Direct Acyclic Graph (DAG) shortest path algorithm is developed for solving the problem. To reduce the computational complexity from O(N-5) to O(N-3), where N is the number of admissible control points for a skeleton, a suboptimal greedy-trellis search algorithm is proposed and compared with the optimal algorithm. In addition, an even more efficient algorithm with computational complexity O(N-2) that finds an ORD optimal solution using a relaxed distortion criterion is also proposed and compared with the optimal solution. Experimental results demonstrate that our proposed approaches outperform existing ORD optimal approaches, which do not follow the same decomposition of the source data.

关键词： boundary coding object-based video compression rate-distortion optimization shape coding skeleton decomposition skeletonization

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A Review of the Minimum Maximum Criterion for Optimal Bit Allocation Among Dependent Quantizers

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IEEE TRANSACTIONS ON MULTIMEDIA 1999年第1期1卷 3-17页

作者： Schuster, Guido M. Melnikov, Gerry Katsaggelos, Aggelos K. 3Com Carrier Syst Business Unit Adv Technol Res Ctr Mt Prospect IL 60056 USA Northwestern Univ Dept Elect & Comp Engn Robert R McCormick Sch Engn & Appl Sci Evanston IL 60208 USA

In this paper, we review a general framework for the optimal bit allocation among dependent quantizers based on the minimum maximum (MINMAX) distortion criterion. Pros and cons of this optimization criterion are discussed and compared to the well-known Lagrange multiplier method for the minimum average (MINAVE) distortion criterion. We argue that, in many applications, the MINMAX criterion is more appropriate than the more popular MINAVE criterion. We discuss the algorithms for solving the optimal bit allocation problem among dependent quantizers for both criteria and highlight the similarities and differences. We point out that any problem which can be solved with the MINAVE criterion can also be solved with the MINMAX criterion, since both approaches are based on the same assumptions. We discuss uniqueness of the MINMAX solution and the way both criteria can be applied simultaneously within the same optimization framework. Furthermore, we show how the discussed MINMAX approach can be directly extended to result in the lexicographically optimal solution. Finally, we apply the discussed MINMAX solution methods to still image compression, intermode frame compression of H.263, and shape coding applications.

关键词： boundary coding minimum average criterion minimum maximum criterion optimal bit allocation shape coding video coding

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FOURIER coding OF IMAGE BOUNDARIES

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IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 1984年第1期6卷 102-105页

作者： CHELLAPPA, R BAGDAZIAN, R UNIV SO CALIF INST IMAGE PROCLOS ANGELESCA 90089 HUGHES AIRCRAFT CO DIV ADV PROJECTSRADAR SYST GRPEL SEGUNDOCA 90245

A transform coding scheme for closed image boundaries on a plane is described. The given boundary is approximated by a series of straight line segments. Depending on the shape, the boundary is represented by the (x-y) coordinates of the endpoints of the line segments or by the magnitude of the successive radii vectors that are equispaced in angle around the given boundary. Due to the circularity present in the data, the discrete Fourier transform is used to exactly decorrelate the finite boundary data. By fitting a Gaussian circular autoregressive model to represent the boundary data, estimates of the variances of the Fourier coefficients are obtained. Using the variances of the Fourier coefficients and the MAX quantizer, the coding scheme is implemented. The scheme is illustrated by an example.","doi":"10.1109/TPAMI.1984.4767482","publicationTitle":"IEEE Transactions on Pattern Analysis and Machine Intelligence","startPage":"102","endPage":"105","rightsLink":"http://***/AppDispatchServlet?publisherName=ieee&publication=0162-8828&title=Fourier+coding+of+Image+Boundaries&isbn=&publicationDate=Jan.+1984&author=R.+Chellappa&ContentID=10.1109/TPAMI.1984.4767482&orderBeanReset=true&startPage=102&endPage=105&volumeNum=PAMI-6&issueNum=1","displayPublicationTitle":"IEEE Transactions on Pattern Analysis and Machine Intelligence","pdfPath":"/iel5/34/4767466/***","keywords":[{"type":"IEEE Keywords","kwd":["Image coding","Image edge detection","Image segmentation","Cyclones","Area measurement","Satellites","Pixel","Delay","Clouds","Pattern recognition"]},{"type":"Author Keywords ","kwd":["transform coding","boundary coding","circular autoregressive models","image coding"]}],"allowComments":false,"pubLink":"/xpl/***?punumber=34","issueLink":"/xpl/***?isnumber=4767466","standardTitle":"Fourier coding of Image Boundaries

关键词： Image coding Image edge detection Image segmentation Cyclones Area measurement Satellites Pixel Delay Clouds Pattern recognition Author Keywords transform coding boundary coding circular autoregressive models image coding

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