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Context-Based coding of Adaptive Multiresolution meshes

COMPUTER GRAPHICS FORUM 2011年第8期30卷 2231-2245页

作者： von Tycowicz, Christoph Kaelberer, Felix Polthier, Konrad Free Univ Berlin D-1000 Berlin Germany

Multiresolution meshes provide an efficient and structured representation of geometric objects. To increase the mesh resolution only at vital parts of the object, adaptive refinement is widely used. We propose a lossless compression scheme for these adaptive structures that exploits the parentchild relationships inherent to the mesh hierarchy. We use the rules that correspond to the adaptive refinement scheme and store bits only where some freedom of choice is left, leading to compact codes that are free of redundancy. Moreover, we extend the coder to sequences of meshes with varying refinement. The connectivity compression ratio of our method exceeds that of state-of-the-art coders by a factor of 27. For efficient compression of vertex positions we adapt popular wavelet-based coding schemes to the adaptive triangular and quadrangular cases to demonstrate the compatibility with our method. Akin to state-of-the-art coders, we use a zerotree to encode the resulting coefficients. Using improved context modelling we enhanced the zerotree compression, cutting the overall geometry data rate by 7% below those of the successful progressive Geometry Compression. More importantly, by exploiting the existing refinement structure we achieve compression factors that are four times greater than those of coders which can handle irregular meshes.

关键词： multiresolution subdivision surfaces progressive mesh coding geometry compression wavelets zerotree coding hierarchical representations level-of-detail I 3 5 [Computer Graphics]: Computational Geometry and Object ModelinguGeometric algorithms languages and systems

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Technologies for 3D mesh compression: A survey

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JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2005年第6期16卷 688-733页

作者： Peng, Jingliang Kim, Chang-Su Kuo, C. -C. Jay Univ So Calif Dept Elect Engn Integrated Media Syst Ctr Los Angeles CA 90089 USA Chinese Univ Hong Kong Dept Informat Engn Shatin Hong Kong Peoples R China

Three-dimensional (313) meshes have been widely used in graphic applications for the representation of 3D objects. They often require a huge amount of data for storage and/or transmission in the raw data format. Since most applications demand compact storage, fast transmission, and efficient processing of 3D meshes, many algorithms have been proposed to compress 3D meshes efficiently since early 1990s. In this survey paper, we examine 3D mesh compression technologies developed over the last decade, with the main focus on triangular mesh compression technologies. In this effort, we classify various algorithms into classes, describe main ideas behind each class, and compare the advantages and shortcomings of the algorithms in each class. Finally, we address some trends in the 3D mesh compression technology development. (c) 2005 Elsevier Inc. All rights reserved.

关键词： 3D mesh compression single-rate mesh coding progressive mesh coding MPEG-4

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progressive coding and Illumination and View Dependent Transmission of 3-D meshes Using R-D Optimization

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2010年第4期20卷 575-586页

作者： Guan, Wei Cai, Jianfei Zhang, Juyong Zheng, Jianmin Univ So Calif Dept Comp Sci Los Angeles CA 90089 USA Nanyang Technol Univ Sch Comp Engn Singapore 639798 Singapore

For transmitting complex 3-D models over bandwidth-limited networks, efficient mesh coding and transmission are indispensable. The state-of-the-art 3-D mesh transmission system employs a wavelet-based progressive mesh coder, which converts an irregular mesh into a semi-regular mesh and directly applies the zerotree-like image coders to compress the wavelet vectors, and view-dependent transmission, which saves the transmission bandwidth through only delivering the visible portions of a mesh model. We propose methods to improve both progressive mesh coding and transmission based on thorough rate-distortion analysis. In particular, by noticing that the dependency among the wavelet coefficients generated in remeshing is not being considered in the existing approaches, we propose to introduce a preprocessing step to scale up the wavelets so that the inherent dependency of wavelets can be truly understood by the zerotree-like image compression algorithms. The weights used in the scaling process are carefully designed through thoroughly analyzing the distortions of wavelets at different refinement levels. For the transmission part, we propose to incorporate the illumination effects into the existing view-depend progressive mesh transmission system to further improve the performance. We develop a novel distortion model that considers both illumination distortion and geometry distortion. Based on our proposed distortion model, given the viewing and lighting parameters, we are able to optimally allocate bits among different segments in real time. Simulation results show significant improvements in both progressive compression and transmission.

关键词： Illumination dependent progressive mesh coding progressive mesh transmission rate-distortion analysis semi-regular meshes view dependent

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A progressive view-dependent technique for interactive 3-D mesh transmission

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2004年第11期14卷 1249-1264页

作者： Yang, S Kim, CS Kuo, CCJ Univ So Calif Dept Elect Engn Los Angeles CA 90089 USA Univ So Calif Integrated Media Syst Ctr Los Angeles CA 90089 USA Chinese Univ Hong Kong Dept Informat Engn Shatin Hong Kong Peoples R China

A view-dependent graphics streaming scheme is proposed in this work that facilitates interactive streaming and browsing of three-dimensional (3-D) graphics models. First, a 3-D model is split into several partitions. Second, each partition is simplified and coded independently. Finally, the compressed data is sent in order of relevance to the user's requests to maximize visual quality. Specifically, the server can transmit visible parts in detail, while cutting out invisible parts. Experimental results demonstrate that the proposed algorithm reduces the required transmission bandwidth, and provides an acceptable visual quality even at low bit rates.

关键词： graphics streaming mesh partitioning mesh simplification progressive mesh coding view-dependent

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progressive 3D mesh coder with octree-based space partitioning

Progressive 3D mesh coder with octree-based space partitioni...

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Conference on Multimedia Systems and Applications VII

作者： Peng, JL Yang, S Kuo, CCJ Univ So Calif Integrated Media Syst Ctr Los Angeles CA 90089 USA

ISBN: (纸本)0819455539

A progressive 3D mesh coding scheme using the octree-based space partitioning is proposed in this work, which achieves better coding efficiency than the state-of-the-art kd-tree-based codec [1,2]. Given a 3D mesh, the quantized 3D vertices are first partitioned into an octree structure. The octree is then traversed from the root and gradually to the leaves. During the traversal, each 3D cell in the tree front is subdivided into eight child cells through three orthogonal cell bi-partitionings. For each cell subdivision, the information of nonempty child cells is encoded. To encode the information, two approaches (i.e. the bit-pattern coding approach and the nonempty-child-cell-tuple coding approach) are implemented and compared. In addition to the geometry coding, the local connectivity update associated with each cell subdivision is also encoded. Furthermore, selective cell subdivision is performed in the tree front to provide better rate-distortion performance, especially at low bitrates. It is shown in experimental results that the geometry coding cost is around 4.2 bits per vertex (bpv) for 8-bit coordinate quantization and 14.3 bpv for 12-bit coordinate quantization, and the connectivity coding cost is 3.3 bpv on the average.

关键词： 3D mesh compression progressive mesh coding geometry coding

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Octree-based progressive geometry encoder

Octree-based progressive geometry encoder

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Conference on Internet Multimedia Management Systems IV

作者： Peng, JL Kuo, CCJ Univ So Calif Integrated Media Syst Ctr Los Angeles CA 90089 USA

ISBN: (纸本)0819451258

Among progressive 3D mesh compression algorithms, the kd-tree-based algorithm proposed by Gandoin and Devillers [1] is one of the state-of-the-art algorithms. Based on the observation that this geometry coder has a large amount of overhead at high kd-tree levels, we propose an octree-based geometry coder that demands a less amount of coding bits at high octree levels by applying selective cell subdivision at high tree levels, leading to a better rate-distortion performance for the low bit rate coding. Experimental results show that, compared with the kd-tree-based coder, the proposed 3D geometry coder performs better for an expanded tree of a level less than or equal to 8 but slightly worse for the full tree expansion with 12-bit quantization.

关键词： 3D mesh compression progressive mesh coding octree-based geometry coder

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Lossless Compression of Adaptive Multiresolution meshes

Lossless Compression of Adaptive Multiresolution Meshes

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22nd Brazilian Symposium on Computer Graphics and Image Processing

作者： Kaelberer, Felix Polthier, Konrad von Tycowicz, Christoph Free Univ Berlin D-1000 Berlin Germany

ISBN: (纸本)9781424449781

We present a novel coder for lossless compression of adaptive multiresolution meshes that exploits their special hierarchical structure. The heart of our method is a new progressive connectivity coder that can be combined with leading geometry encoding techniques. The compressor uses the parent/child relationships inherent to the hierarchical mesh. We use the rules that accord to the refinement scheme and store bits only where it leaves freedom of choice, leading to compact codes that are free of redundancy. To illustrate our scheme we chose the widespread red-green refinement, but the underlying concepts can be directly transferred to other adaptive refinement schemes as well. The compression ratio of our method exceeds that of state-of-the-art coders by a factor of 2 to 3 on most of our benchmark models.

关键词： multiresolution subdivision surfaces level-of-detail connectivity coding lossless progressive mesh coding 3D mesh compression

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progressive geometry encoder based on the octree structure

Progressive geometry encoder based on the octree structure

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Conference on Visual Communications and Image Processing 2004

作者： Peng, JL Kuo, CCJ Univ So Calif Integrated Media Syst Ctr Los Angeles CA 90089 USA

ISBN: (纸本)0819452114

A progressive 3D geometry coding scheme based on the octree structure is proposed in this work, which achieves better coding efficiency than the state-of-the-art geometric codec known as the kd-tree-based codec [1]. Given a 3D mesh, the quantized 3D vertices are first partitioned into an octree structure. The octree is then traversed from the root and gradually to the leaves and, during the traversal, each 3D cell in the tree front is subdivided along three orthogonal directions. For each cell subdivision, the order of subdivision directions is adaptively chosen, the neighborhood-prediction is used and the vertex number distribution is efficiently encoded. The final output bit stream contains relevant information associated with each cell subdivision. It is shown in experimental results that the coding cost is around 15.6 bits per vertex (bpv) for 12-bit coordinate quantization and 5.6 bpv for 8-bit coordinate quantization on average.

关键词： 3D mesh compression progressive mesh coding octree geometry coder

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