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 lossl...
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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.
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...
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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.
For transmitting complex 3-D models over bandwidth-limited networks, efficient meshcoding and transmission are indispensable. The state-of-the-art 3-D mesh transmission system employs a wavelet-based progressivemesh...
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For transmitting complex 3-D models over bandwidth-limited networks, efficient meshcoding and transmission are indispensable. The state-of-the-art 3-D mesh transmission system employs a wavelet-based progressivemesh 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 progressivemesh 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.
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. ...
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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.
A progressive 3D meshcoding 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...
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ISBN:
(纸本)0819455539
A progressive 3D meshcoding 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.
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 la...
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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.
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 comb...
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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.
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]. G...
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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.
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