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Object-adaptive vertex-based shape coding method

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1997年第1期7卷 251-255页

作者： OConnell, KJ Chicago Corporate Research Laboratories Motorola Schaumburg IL USA

The paper presents a new technique for compactly representing the shape of a visual object within a scene. This method encodes the vertices of a polygonal approximation of the object's shape by adapting the representation to the dynamic range of the relative locations of the object's vertices and by exploiting an octant-based representation of each individual vertex. The object-level adaptation to the relative-location dynamic range provides the flexibility needed to efficiently encode objects of different sizes and with different allowed approximation distortion. At the vertex-level, the octant-based representation allows coding gains for vertices closely spaced relative to the object-level dynamic range. This vertex coding method may be used with techniques which code the polygonal approximation error for further gains in coding efficiency. Results are shown which demonstrate the effectiveness of the vertex encoding method. The rate-distortion comparisons presented show that the technique's adaptive nature allows it to operate efficiently over a wide range of rates and distortions and across a variety of input material, whereas other methods are efficient over more limited conditions.

关键词： image coding image representations multimedia databases object representations piecewise linear approximation shape coding

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Linear rate-distortion models for MPEG-4 shape coding

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2004年第6期14卷 869-873页

作者： Chen, ZZ Ngan, KN Chinese Univ Hong Kong Dept Elect Engn Shatin Hong Kong Peoples R China Nanyang Technol Univ Sch Comp Engn Singapore 2263 Singapore

In this letter, we explore the rate-distortion (R-D) characteristics of binary shape information in the MPEG-4 standard. The shape coding scheme is a block-based context-based arithmetic encoding approach and distortion is introduced by down and up sampling. Generally, the shape bit rate and non-normalized distortion increase in proportion with the number of border blocks. At any given resolution scale, the more complex an object, the more distortion that is introduced. Consequently, we propose an R-D model based on the parameters derived from the border blocks and a block-based shape complexity for the video object. The computational complexity is much lower than other existing methods. Experimental results show that it can accurately predict the bit rate and distortion of the binary shape for rate control purposes.

关键词： MPEG-4 rate distortion (R-D) shape coding

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A shape coding ARRAY

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PATTERN RECOGNITION LETTERS 1986年第1期4卷 57-59页

作者： WOJCIK, ZM ROSENFELD, A UNIV MARYLAND COLLEGE PKMD 20742

An architecture designed for fast serial coding of object shapes is described. It consists of two mutually perpendicular arrays of bidirectional shift registers that are used, respectively, for horizontal and vertical image shifting. Parallel exchange of image data between the two nets is also possible. shape coding operations are applied by a circular set of cells in one of the arrays, having distinguished parallel-out terminals.

关键词： Cellular arrays shape coding shift registers

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Feature point-based multiscale shape coding

Feature point-based multiscale shape coding

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Conference on Image Compression and Encryption Technologies

作者： Shi, XL Zhang, ZY Shanghai Univ Sch Commun & Informat Engn Shanghai 200041 Peoples R China

ISBN: (纸本)0819442798

In this paper, we propose a new fast and efficient method of shape coding called feature point-based adaptive arithmetic encoding algorithm (FPAE). For dealing with video image, we regard a shape as a set of points that are parameterized by arc length and B-spline bases. Then, the evolution of curve at different resolution levels s in B-spline scale space is achieved by convoluting the curve with the dilated B-spline kernel instead of Gaussian kernel. Compared with Gaussian method, this method has an advantage of fast algorithm. By calculating the curvature, the feature-points including significant information of shape contour can be found. But for shape coding, this shape representation will not very efficient when the shape consist of arcs. The modified shape representation also includes the feature-point that lies in arc and the distance from the feature-point to chord is largest. All of the feature-points are encoded by adaptive arithmetic encoding. Experimental results show that our method reduces coded bits by about 25% compared with the context-based arithmetic encoding (CAE) of the MPEG-4 VM and the subjective quality of the reconstructed shape is better than that of CAE at same Dn.

关键词： shape representation feature-points FPAE shape coding curvature scale space feature-points adaptive arithmetic coding B-spline MPEG-4 CAE

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Evaluating the effectiveness of therapy based around shape coding to develop the use of regular past tense morphemes in two children with language impairments

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CHILD LANGUAGE TEACHING & THERAPY 2014年第3期30卷 245-254页

作者： Kulkarni, Amit Pring, Tim Ebbels, Susan Guys & St Thomas Community Hlth Serv London SE11 4TH England Cent London Community Hlth London England City Univ London London EC1V 0HB England UCL London WC1E 6BT England

It has been suggested that difficulties with tense and agreement marking are a core feature of language impairment. Hence, studies are required that analyse the effectiveness of intervention in this area, including consideration of whether changes seen in therapy sessions generalize to spontaneous speech. This study assessed the effectiveness of therapy based around shape coding in developing the use of the regular past tense morpheme -ed in two school-aged children with language impairments. It also considered whether participants benefited from additional generalization therapy in order to start using target forms in their spontaneous speech. The former was assessed using a sentence completion task and the latter by a conversational task with blind assessors. One participant improved markedly in sentence completion but did not gain in the conversation task until after the generalization therapy. The other made more modest gains on the sentence completion task and seemed to generalize to the conversation task without recourse to the generalization therapy. Larger studies are required to confirm these interpretations and to determine whether they are applicable to the wider population of children with language impairments.

关键词： Grammar intervention language impairment morphology school aged shape coding

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Curvature analysis approach to shape coding using B-splines

Curvature analysis approach to shape coding using B-splines

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Conference on Visual Communications and Image Processing 2001

作者： Zaletelj, J Tasic, JF Univ Ljubljana Fac Elect Engn SI-1000 Ljubljana Slovenia

ISBN: (纸本)0819439886

This work presents an algorithm for efficient shape coding using cubic B-splines. In the framework of object-based layered coding of image sequences, shape information is essential for content-based access to video objects, and its efficient encoding needs to be investigated. We present a rate and distortion controlled algorithm for video object share approximation by variable number of cubic B-spline segments and motion compensated inter-frame coding of B-spline control points. Rate-distortion efficiency of the proposed algorithm is compared to MPEG-4 contest arithmetic encoding and two stage motion compensated chain coding.

关键词： shape coding object-based video coding B-splines multi-scale shape analysis

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A Hybrid Admissible Distortion Checking Algorithm for the B-Spline-Based Operational Rate-Distortion Optimal shape coding

A Hybrid Admissible Distortion Checking Algorithm for the B-...

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Data Compression Conference (DCC)

作者： Lai, Zhongyuan Zuo, Zhen Wang, Zhe Liu, Wenyu Huazhong Univ Sci & Technol Elect & Informat Engn Dept Wuhan 430074 Peoples R China

ISBN: (纸本)9780769543529

Existing distortion measurement using chord-length parameterization (DMCLP) is fast but results in the extra bit-rate problem. In contrast, the up to date accurate distortion measurement using analytical model (ADMAM) can achieve the smallest bit-rate but is very time consuming. It motivates us to develop a hybrid admissible checking algorithm that can take full use of each advantage. Observing that the value of DMCLP is always no less than that of ADMAM, we develop a hybrid distortion checking algorithm that evokes ADMAM if and only if the DMCLP value of associate contour point exceeds the admissible distortion. Theoretical analyses and experimental results demonstrate that our proposal can save up to 48% execution time compared with the ADMAM checking algorithm while maintains the smallest bit-rate property. Moreover, we discover and explain that its reduced execution time com-pared with the ADMAM checking algorithm is increasing while its extra execution time compared with DMCLP checking algorithm is decreasing toward zero as the admissible distortion increases.

关键词： Distortion measurement shape coding execution time Checking abnormal shapes Bit rate distortion Rate distortion

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A novel statistical learning based rate distortion analysis approach for multiscale binary shape coding

A novel statistical learning based rate distortion analysis ...

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Conference on Visual Communications and Image Processing 2007

作者： Chen, Zhenzhong Ngan, King Ngi Chinese Univ Hong Kong Dept Elect Engn Hong Kong Hong Kong Peoples R China

ISBN: (纸本)9780819466211

In this paper, we propose a statistical learning based approach to analyze the rate-distortion characteristics of multiscale binary shape coding. We employ the polynomial kernel function and incorporate rate-distortion related features for our support vector regression. epsilon-Insensitive loss function is chosen to improve the estimation robustness. The parameter tuning is also studied. Moreover, we discuss the feature selection which helps to improve the estimation accuracy. Comparing to the traditional method, our proposed framework provides better rate distortion estimation not only on simple shapes but also on complex shapes.

关键词： rate-distortion shape coding statistical learning

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Computation complexity analysis and VLSI architectures of shape coding for MPEG-4

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Conference on Visual Communications and Image Processing

作者： Gong, DN He, Y Tsinghua Univ Dept Elect Engn State Key Lab Microwave & Digital Commun Beijing 100084 Peoples R China

ISBN: (纸本)0819437034

There are huge bit-level operations in shape coding algorithms for MPEG-4. These bit-level operations make it difficult to implement real-time MPEG-4 coding in the general-purpose processor without any hardware support. This paper first gives the analysis of computation complexity in MPEG-4 shape coding algorithms. Then a dedicated VLSI architecture to accelerate shape coding, which is called shape Engine, is proposed. shape Engine is composed of three dedicated but flexible processors element (PE) namely PB-PE, Filtering-PE and CAE-PE. The combination of RISC core and shape Engine leads to a great speed up over pure software implementation of MPEG-4 shape coding.

关键词： MPEG-4 VLSI architectures shape coding computation complexity

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Accurate Distortion Measurement Using Analytical Model for the B-Spline-Based shape coding

Accurate Distortion Measurement Using Analytical Model for t...

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Data Compression Conference (DCC)

作者： Lai, Zhongyuan Zuo, Zhen Wang, Zhe Liu, Wenyu Huazhong Univ Sci & Technol Elect & Informat Engn Dept Wuhan 430074 Peoples R China

ISBN: (纸本)9780769543529

In this paper, we present a new model to measure the contour point distortion for the B-spline-based shape coding, called accurate distortion measurement using analytical model (ADMAM). It models the distortion as the shortest distance of associate contour point from the approximating B-spline. Observing that this shortest path is perpendicular to the tangent vector of the approximating B-spline, we construct a parametric cubic equation by setting their dot product to be zero and address it by using Cartan's formula. The theoretical property and the experiments presented demonstrate that ADMAM can lead to the smallest bit-rate among all the distortion measurements that can guarantee the admissible distortion, when the operational rate-distortion optimal shape coding framework is applied. Moreover, if the original contour has NC points, it takes only O(NC) time for both a peak and mean-squared segment distortion measuring paradigms, which is the lowest complexity among all the existing distortion measurements.

关键词： Distortion measurement shape coding Tangent vector distortion ANALYSIS MODELS abnormal shapes Dot product contour shortest path splines (mathematics)

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