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MPEG-4 standardized methods for the compression of arbitrarily shaped video objects

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1999年第8期9卷 1170-1189页

作者： Brady, N Integral Design Ltd Dublin 14 Ireland

MPEG-4 is the most recent standard for audio-visual representation to be published by the International Organization for Standardization, One of the many new features of MPEG-4 is its ability to represent two-dimensional video objects of arbitrary shape. For this purpose, MPEG-4 uses the conventional motion-compensated discrete cosine transform syntax for color/texture coding and augments this with an explicit compressed representation of the video object's shape. This paper is intended as a tutorial in the means of encoding and decoding arbitrarily shaped video objects as specified by MPEG-4. The major emphasis of the paper is on explaining the compression technology associated dth the normative shape representation, i.e., block-based context-based arithmetic encoding, but some new aspects associated with arbitrarily shaped texture coding are also highlighted, The MPEG-4 specifications are presented in an informal may, and the motivations underlying the algorithm are clarified. In addition, effective methods are suggested for performing many of the nonnormative encoding tasks, and several encoding performance tradeoffs are illustrated.

关键词： context-based arithmetic encoding MPEG-4 shape coding

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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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A BAYESIAN NEURAL-NETWORK FOR SEPARATING SIMILAR COMPLEX HANDWRITTEN CHINESE CHARACTERS

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PATTERN RECOGNITION LETTERS 1994年第4期15卷 403-408页

作者： CHANG, HD WANG, JF KUO, SC NATL CHENG KUNG UNIV INST INFORMAT ENGN1 UNIV RDTAINAN 701TAIWAN NATL CHENG KUNG UNIV DEPT ELECT ENGNTAINAN 701TAIWAN

A Bayesian neural network for separating characters with the same number of linear like strokes and cross-points is proposed. It is trained by an incremental learning vector quantization algorithm which endows this sy... 详细信息

关键词： HANDWRITTEN CHINESE CHARACTER NEURAL NETWORK shape coding RECOGNITION

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shape compression of moving objects using context-based arithmetic encoding

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2000年第7-8期15卷 601-617页

作者： Brady, N Bossen, F Dublin City Univ Teltec Ireland Dublin 9 Ireland EPFL Signal Proc Lab CH-1015 Lausanne Switzerland

This paper deals with an approach to the compression of 2-D shape information. Specifically, the approach utilises a block-based context-based arithmetic encoding method to exploit both spatial and temporal redundancy in sequences of shapes. The method is shown to be highly efficient in comparative tests. In addition, it is demonstrated that context-based arithmetic encoding is easily extended for the coding of interlaced shape sources and for encoding any source in a scalable and/or error resilient manner. The application of the technique is in the compression of video object shapes within the framework of object-based video coding. The proposed algorithm is part of the MPEG-4 video specification. (C) 2000 Elsevier Science B.V. All rights reserved.

关键词： shape coding arithmetic encoding JBIG MPEG-4

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A ROUGH GRAMMAR FOR A LINGUISTIC RECOGNITION OF IMAGE PATCHES

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SIGNAL PROCESSING 1990年第2期19卷 119-138页

作者： WOJCIK, ZM WOJCIK, BE The Division of Mathematics Computer Science and Statistics The University of Texas at San Antonio TX 78285 U.S.A.

This paper introduces a rough grammar involving explicit operators embedded in the production rules. The grammar is capable of: (a) running the operators on a data-driven or on a data-flow type machine; (b) spreading the hypotheses, goals and constraints from the grammar tree root down to the leaves; (c) coming from local object details (leaves of an execution tree) to a purposeful more global representation (the execution tree root) concurrently avoiding redundant computations; (d) avoiding impasses in a top-down execution tree which need to back up to previous decision points. The rough grammar is used with a new method of syntactic and semantic object recognition from region patches delimited on one side. The region patches are identified from secants (intersections of scanning lines with image objects. The nearest neighbor clustering combined with ordering coordinates of secant ends appends an end of a current secant to a cluster of a patch edge in case the end is closest to the most recent element of the patch edge and in case the end satisfies an assumed order of coordinates. The consideration of the following factors: secant beginnings, secant endings, non-ascending order of secant ends and non-descending order of secant ends permits the region patches to be clustered into basic types. Details of the derivation of patches are presented to show how demands can be propagated from higher-level rough-grammar rules down to the clustering operators. To identify a corner patch, two continuous edge patches belonging to different clusters of region patches are merged if the continuous patches are of efficient lengths and if they are close enough to meet each other. Polygons are identified by merging corner patches or three-sided region patches of different types. Examples of identification of simple objects are presented. The process of identification of different objects can be performed in parallel using separate processors. Zusammenfassung Dieser Beitrag stellt ein

关键词： Rough grammar shape analysis patch analysis shape coding image segmentation edge derivation region analysis linguistic recognition parallel recognition edge patch corner patch region patch constraint propagation demand-driven machine demand propagation data driven execution

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shape error concealment using Hermite splines

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2004年第6期13卷 808-820页

作者： Schuster, GM Li, XH Katsaggelos, AK Hsch Tech Rapperswil Abt Elektrotech CH-8640 Rapperswil Switzerland Georgia Inst Technol Sch Elect & Comp Engn Atlanta GA 30332 USA Northwestern Univ Dept Elect & Comp Engn Evanston IL 60208 USA

The introduction of video objects (VOs) is one of the innovations of MPEG-4. The alpha-plane of a VO defines its shape at a given instance in time and hence determines the boundary of its texture. In packet-based networks, shape, motion, and texture are subject to loss. While there has been considerable attention paid to the concealment of texture and motion errors, little has been done in the field of shape error concealment. In this paper, we propose a post-processing shape error-concealment technique that uses geometric boundary information of the received alpha-plane. Second-order Hermite splines are used to model the received boundary in the neighboring blocks, while third order Hermite splines are used to model the missing boundary. The velocities of these splines are matched at the boundary point closest to the missing block. There exists the possibility of multiple concealing splines per group of lost boundary parts. Therefore, we draw every concealment spline combination that does not self-intersect and keep all possible results until the end. At the end, we select the concealment solution that results in one closed boundary. Experimental results demonstrating the performance of the proposed method and comparisons with prior proposed methods are presented.

关键词： error concealment Hermite spline MPEG-4 shape coding

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Effect of silhouetting and inversion on view invariance in the monkey inferotemporal cortex

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JOURNAL OF NEUROPHYSIOLOGY 2017年第1期118卷 353-362页

作者： Murty, Apurva Ratan Arun, S. P. Indian Inst Sci Ctr Neurosci Bangalore Karnataka India

We effortlessly recognize objects across changes in viewpoint, but we know relatively little about the features that underlie viewpoint invariance in the brain. Here, we set out to characterize how viewpoint invariance in monkey inferior temporal ( IT) neurons is influenced by two image manipulations-silhouetting and inversion. Reducing an object into its silhouette removes internal detail, so this would reveal how much viewpoint invariance depends on the external contours. Inverting an object retains but rearranges features, so this would reveal how much viewpoint invariance depends on the arrangement and orientation of features. Our main findings are 1) view invariance is weakened by silhouetting but not by inversion;2) view invariance was stronger in neurons that generalized across silhouetting and inversion;3) neuronal responses to natural objects matched early with that of silhouettes and only later to that of inverted objects, indicative of coarse-to-fine processing;and 4) the impact of silhouetting and inversion depended on object structure. Taken together, our results elucidate the underlying features and dynamics of view-invariant object representations in the brain. NEW & NOTEWORTHY We easily recognize objects across changes in viewpoint, but the underlying features are unknown. Here, we show that view invariance in the monkey inferotemporal cortex is driven mainly by external object contours and is not specialized for object orientation. We also find that the responses to natural objects match with that of their silhouettes early in the response, and with inverted versions later in the response-indicative of a coarse-to-fine processing sequence in the brain.

关键词： object recognition shape coding invariance viewpoint

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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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Supporting adjective learning by children with Developmental Language Disorder: Enhancing metalinguistic approaches

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INTERNATIONAL JOURNAL OF LANGUAGE & COMMUNICATION DISORDERS 2023年第2期58卷 629-650页

作者： Davies, Catherine Ebbels, Susan Nicoll, Hilary Syrett, Kristen White, Sarah Zuniga-Montanez, Cecilia Univ Leeds Leeds England Moor House Res & Training Inst Oxted Surrey England UCL London England Rutgers State Univ Dept Linguist New Brunswick NJ USA Rutgers State Univ Ctr Cognit Sci RuCCS New Brunswick NJ USA Leeds Beckett Univ Leeds England Univ Leeds Sch Languages Cultures & Soc Leeds LS2 9JT England

Background: Adjectives are essential for communication, conceptual development and academic success. However, they are semantically and syntactically complex and can be particularly challenging for children with Developmental Language Disorder (DLD). Surprisingly, language interventions have not typically focused on this important word class. Aims: (1) To provide a supportive and accessible primer on adjectives for practitioners;(2) to explore how the shape coding (TM) system can be adapted to support adjective learning in DLD;and (3) to provide practical recommendations on how to support adjective learning in clinical practice and education. Methods/Procedure: We synthesise linguistic and psychological research on adjective semantics, clinical insights into DLD and pedagogical practice supporting this population. Main Contribution: We address the lack of specific training in the nature and acquisition of adjectives for speech and language therapists (SLTs) by providing an accessible primer. We also provide an innovative guide detailing how an established metalinguistic intervention might be adapted to support adjective learning. Conclusions/Implications: Without targeted support for adjective learning, the communicative potential of children with DLD is compromised. Our recommendations can be used across a range of therapeutic and educational contexts to guide SLTs and teaching staff in developing practice in this area.

关键词： adjectives vocabulary Developmental Language Disorder language intervention shape coding

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Improving comprehension in adolescents with severe receptive language impairments: a randomized control trial of intervention for coordinating conjunctions

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INTERNATIONAL JOURNAL OF LANGUAGE & COMMUNICATION DISORDERS 2014年第1期49卷 30-48页

作者： Ebbels, Susan H. Maric, Natasa Murphy, Aoife Turner, Gail UCL Div Psychol & Language Sci London England

BackgroundLittle evidence exists for the effectiveness of therapy for children with receptive language difficulties, particularly those whose difficulties are severe and persistent. AimsTo establish the effectiveness of explicit speech and language therapy with visual support for secondary school-aged children with language impairments focusing on comprehension of coordinating conjunctions in a randomized control trial with an assessor blind to group status. Methods & ProceduresFourteen participants (aged 11;3-16;1) with severe RELI (mean standard scores: CELF4 ELS = 48, CELF4 RLS = 53 and TROG-2 = 57), but higher non-verbal (Matrices = 83) and visual perceptual skills (Test of Visual Perceptual Skills (TVPS) = 86) were randomly assigned to two groups: therapy versus waiting controls. In Phase 1, the therapy group received eight 30-min individual sessions of explicit teaching with visual support (shape coding) with their usual SLT. In Phase 2, the waiting controls received the same therapy. The participants' comprehension was tested pre-, post-Phase 1 and post-Phase 2 therapy on (1) a specific test of the targeted conjunctions, (2) the TROG-2 and (3) a test of passives. Outcomes & ResultsAfter Phase 1, the therapy group showed significantly more progress than the waiting controls on the targeted conjunctions (d = 1.6) and overall TROG-2 standard score (d = 1.4). The two groups did not differ on the passives test. After Phase 2, the waiting controls made similar progress to those in the original therapy group, who maintained their previous progress. Neither group showed progress on passives. When the two groups were combined, significant progress was found on the specific conjunctions (d = 1.3) and TROG-2 raw (d = 1.1) and standard scores (d = 0.9). Correlations showed no measures taken (including Matrices and TVPS) correlated significantly with progress on the targeted conjunctions or the TROG-2. Conclusions & ImplicationsFour hours of shape coding therapy led to si

关键词： intervention randomized control trial language impairment language disorder receptive language shape coding adolescents

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