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Compact representation of contours using directional grid chain code

SIGNAL PROCESSING-IMAGE COMMUNICATION 2008年第2期23卷 87-100页

作者： Park, Heechan Martin, Graham R. Yu, Andy C. Univ Warwick Dept Comp Sci Coventry CV4 7AL W Midlands England

An efficient contour-based method for the coding of binary shape information is described. Conventional chain coding techniques show high coding efficiency for lossless compression, but they exploit the coherence of the contour in only a restricted manner. Higher coding efficiency can be achieved by realising the neighbourhood relation as a Markov chain, and this is exploited in a new coding scheme, the directional grid chain coding (DGCC). The method is computationally efficient and the coding process adapts to the inherent changes in the contour. Two schemes are proposed, a lossless and a quasi-lossless method. The lossless scheme achieves 32% saving in bit rate compared with the conventional differential chain code (DCC). The second, quasi-lossless technique achieves 44% bit reduction compared with the DCC and the distortions present in the reconstructed contour are hardly noticeable to the human eye. (c) 2007 Elsevier B.V. All rights reserved.

关键词： chain code contour coding shape coding object-based representation

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shape Error Concealment Based on a shape-Preserving Boundary Approximation

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2012年第8期21卷 3573-3585页

作者： Tsiligianni, Evaggelia Kondi, Lisimachos P. Katsaggelos, Aggelos K. Univ Ioannina Dept Comp Sci GR-45110 Ioannina Greece Northwestern Univ Dept Elect Engn & Comp Sci Evanston IL 60208 USA

In object-based video representation, video scenes are composed of several arbitrarily shaped video objects (VOs), defined by their texture, shape and motion. In error-prone communications, packet loss results in missing information at the decoder. The impact of transmission errors is minimized through error concealment. In this paper, we propose a spatial error concealment technique for recovering lost shape data. We consider a geometric shape representation consisting of the object boundary, which can be extracted from the alpha-plane. Missing macroblocks result in a broken boundary. A B-spline curve is constructed to replace a missing boundary segment, based on a T-spline representation of the received boundary. We use T-splines because they produce shape-preserving approximations and do not change the characteristics of the original boundary. The representation ensures a good estimation of the first derivatives at the points touching the missing segment. Applying smoothing conditions, we manage to construct a new spline that joins smoothly with the received boundary, leading to successful concealment results. Experimental results on object shapes with different concealment difficulty demonstrate the performance of the proposed method. Comparisons with prior proposed methods are also presented.

关键词： COM-ERC error concealment shape coding T-splines

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The detection of duplicates in document image databases

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IMAGE AND VISION COMPUTING 1998年第12-13期16卷 907-920页

作者： Doermann, D Li, HP Kia, O Univ Maryland Ctr Automat Res Language & Media Proc Lab College Pk MD 20742 USA

Document imaging technology has developed to the point where it is not uncommon for organizations to scan large numbers of documents into databases with little or no index information. This may be done for archival purposes with an index as simple as a case number, or with the ultimate goal of automatically extracting index information for content-based queries. Maintaining the integrity of such a database is difficult, however, especially in a distributed environment where copies of the same documents may be scanned at different times. In this paper we present a novel approach to detecting duplicate documents in very large databases using only features extracted from the image. The method is based on a robust 'signature' extracted from each document image which is used to index into a table of previously processed documents. The system is able to deal with differences between scanned document instances such resolution, skew and image quality. The approach has a number of advantages over OCR or other recognition-based methods including speed and robustness to imaging distortions. To justify the approach and demonstrate its scalability, we have developed a simulator which allows us to change parameters of the system and examine performance while processing millions of document signatures. A complete system has been implemented and tested on a collection of technical articles and memos. (C) 1998 Elsevier Science B.V. All rights reserved.

关键词： document image databases duplicate detection shape coding document indexing

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An efficient binary motion estimation algorithm and its architecture for MPEG-4 shape encoding

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2006年第7期16卷 859-868页

作者： Al-Qaralleh, Esam A. Chang, Tian-Sheuan Lee, Kun-Bin Natl Chiao Tung Univ Dept Elect Hsinchu 300 Taiwan

This paper presents a fast binary motion estimation (BME) algorithm and its architecture for MPEG-4 shape encoding. The proposed algorithm explores the property of the binary-value in BME to quickly skip the unnecessary sum of absolute differences (SAD) computation. When comparing with the full search algorithm, simulation results show that it can efficiently save in the search positions to an average -99.58% of that in the full search algorithm with the same PSNR quality. Due to the algorithm's simplicity and regularity, the resulting hardware implementation also exhibits simple and regular control and data flow. It can achieve real-time encoding with only 11582 gate count.

关键词： binary motion estimation(BME) MPEG-4 shape coding video object plane (VOP)

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Reducing control selection errors associated with underground bolting equipment

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APPLIED ERGONOMICS 2010年第4期41卷 549-555页

作者： Burgess-Limerick, Robin Krupenia, Veronica Zupanc, Christine Wallis, Guy Steiner, Lisa Univ Queensland Sch Human Movement Studies Brisbane Qld 4072 Australia NIOSH Min Injury Prevent Branch Pittsburgh Res Lab Pittsburgh PA USA

Selecting the incorrect control during the operation of underground bolting and drilling equipment causes serious injuries. shape coding and the layout of dual control banks are two aspects of control design which require further examination. The aims of this research were: (i) to determine whether arbitrary shape coding was effective in reducing selection error rates in a virtual analogy of roof-bolting;and (ii) to determine whether any advantages exist for mirror or place layouts for dual control situations in this situation. Two experiments were conducted to address these questions. No benefits of arbitrary shape coding were evident while control location remained constant. When control location was altered, shape coding did provide a significant reduction in selection error rate. No differences between mirror or place arrangements were detected and this question remains open. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： Equipment design shape coding Simulation Mining

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A Volumetric Approach to Point Cloud Compression-Part II: Geometry Compression

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2020年 29卷 2217-2229页

作者： Krivokuca, Maja Chou, Philip A. Koroteev, Maxim 8i Wellington New Zealand INRIA Ctr Rech Rennes Bretagne Atlantique F-35042 Rennes France 8i Seattle WA USA Google Inc Seattle WA 98103 USA Imatrex Inc Moscow 141400 Russia

Compression of point clouds has so far been confined to coding the positions of a discrete set of points in space and the attributes of those discrete points. We introduce an alternative approach based on volumetric functions, which are functions defined not just on a finite set of points, but throughout space. As in regression analysis, volumetric functions are continuous functions that are able to interpolate values on a finite set of points as linear combinations of continuous basis functions. Using a B-spline wavelet basis, we are able to code volumetric functions representing both geometry and attributes. Attribute compression is addressed in Part I of this paper, while geometry compression is addressed in Part II. Geometry is represented implicitly as the level set of a volumetric function (the signed distance function or similar). Experimental results show that geometry compression using volumetric functions improves over the methods used in the emerging MPEG Point Cloud Compression (G-PCC) standard.

关键词： Bezier volumes B-splines wavelets point cloud compression geometry coding shape coding multiresolution representations signed distance function graph signal processing

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A JBIG-based approach to the encoding of contour maps

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2000年第5期9卷 936-941页

作者： Pinho, AJ Univ Aveiro Dept Elect & Telecommun P-3810193 Aveiro Portugal Univ Aveiro Inst Engenharia Electr & Telemat Aveiro P-3810193 Aveiro Portugal

Recently, a new technique for the lossless encoding of contour maps was introduced, based on the concept of "transition points." in this paper we show that by using a simple representation for the transition points, i.e., the map of transition points, the problem of encoding arbitrary contour maps can be easily converted into a problem of lossless image coding. Experimental results show that the joint bilevel image experts group (JBIG) image coding standard can be used successfully For encoding maps of transition points, outperforming, in most cases, differential chain-coding. Moreover, if we take into account that JBIG codecs are available as "off the shelf" components, then the effort required to implement the proposed method is small.

关键词： chain coding contour coding partition coding region-based image coding shape coding transition points

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A NATURAL APPROACH IN IMAGE-PROCESSING AND PATTERN-RECOGNITION - ROTATING NEIGHBORHOOD TECHNIQUE, SELF-ADAPTING THRESHOLD, SEGMENTATION AND shape-RECOGNITION

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PATTERN RECOGNITION 1985年第5期18卷 299-326页

作者： WOJCIK, ZM m 6 Warsaw Poland

Sentence description of objects are utilized in the model. The description is transformable into graphs. Fast shape coding is accomplished by an operator translated along linear objects or contours. A separate node of a graph is obtained for each new position of the operator. After a reduction, the graph is equivalent to a sentence describing an object. A technique incorporating a rotating neighbourhood is introduced and utilized for image enhancement and texture derivation. The technique preserves edges of objects. A threshold which adapts itself to an unknown noise level and image segmentation into individual objects are also presented. All the methods discussed satisfy the basic condition on representing images.

关键词： Pattern recognition Image processing shape coding Image segmentation Enhancements Thresholding Texture derivation Tracking Filling Identification

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Spatial and temporal error concealment algorithms of shape information for MPEG-4 video

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2005年第6期15卷 778-783页

作者： Chen, MJ Cho, CC Chi, MC Natl Dong Hwa Univ Dept Elect Engn Hualien 974 Taiwan Novatek Microelect Corp Hsinchu 300 Taiwan

In this paper, new methods for error concealment of shape information are proposed for compressed MPEG-4 bit-streams transmitted over error prone channels. For spatial domain, the proposed approach employs the Bezier curve fitting to approximate and outline the intra-video object plane (I-VOP). For temporal domain, the proposed scheme uses the weighted side matching criterion to reconstruct the inter-video object planes (P-/B-VOPs). The proposed algorithms get better subjective and objective qualities than previous works.

关键词： Bezier curve error concealment MPEG-4 shape coding side match

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Generalized interframe vertex-based shape encoding scheme for video sequences

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2000年第10期9卷 1667-1676页

作者： Kim, KJ Suh, JY Kang, MG Serome Technol Lab Seoul 120749 South Korea Yonsei Univ Dept Elect Engn Seoul 120749 South Korea

The efficiency of shape coding is an important problem concerning content-based image manipulations and object-based coding of the video sequences. In order to encode the shape information of an object, the boundary is approximated by a polygon which can be encoded with the smallest number of bits for maximum allowable distortion. The conventional boundary coding schemes, however, does not successfully remove the temporal redundancy of the video sequences. This paper proposes a new boundary encoding scheme by which the temporal redundancy between two successive frames is efficiently removed, resulting in lower bit-rate than the conventional algorithms. The interframe vertex selection problem is solved by finding the path with the minimum cost in the directed acyclic graph (DAG) and its fast version using a simplified graph is introduced to reduce the computational load. The vertices were selected from both the current frame to be encoded and the previous frame already encoded, and thus, the temporal redundancy was effectively removed.

关键词： directed acyclic graph interframe vertex selection shape coding

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