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Flexible zerotree coding of wavelet coefficients

IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 1999年第6期E82A卷 1117-1125页

作者： Joo, S Kikuchi, H Sasaki, S Shin, J Niigata Univ Dept Elect Engn Niigata 9502181 Japan Dongguk Univ Dept Elect Engn Seoul 100715 South Korea

We introduce an extended EZW coder that uses flexible zerotree coding of wavelet coefficients. A flexible parent-child relationship is defined so as to exploit spatial dependencies within a subband as well as hierarchical dependencies among multi-scale subbands. The new relationship is based on a particular statistics that a large coefficient is more likely to have large coefficients in its neighborhood in terms of space and scale. In the flexible relationship, a parent coefficient in a subband relates to four child coefficients in the next finer subband in the same orientation. If each of the children is larger than a given threshold, the parent extends its parentship to the neighbors close to its conventional children. A probing bit is introduced to indicate whether a significant parent has significant children to be scanned. This enables us to avoid excessive scan of insignificant coefficients. Also, produced symbols are re-symbolized into simple variable-length binary codes to remove some redundancy according to a pre-defined rule. As a result, the wavelet coefficients can be described with a small number of binary symbols. This binary symbol stream gives a competitive performance without an additional entropy coding and thus a fast encoding/decoding is possible. Moreover, the binary symbols can be more compressed by an adaptive arithmetic coding. Our experimental results are given in both binary-coded mode and arithmetic-ceded mode. Also, these results are compared with those of the EZW coder.

关键词： image compression wavelet transform zerotree coding

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Low computational complexity enhanced zerotree coding for wavelet-based image compression

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2000年第4期16卷 401-411页

作者： Wu, BF Su, CY Natl Chiao Tung Univ Dept Elect & Control Engn Hsinchu 300 Taiwan Natl Taiwan Normal Univ Dept Ind Educ Taipei 106 Taiwan

The embedded zerotree wavelet (EZW) algorithm, introduced by J.M. Shapiro and extented by A. Said and W.A. Pearlman, has proven to be a computationally simple and efficient method for image compression. In the current study, we propose a novel algorithm to improve the performance of EZW coding. The proposed method, called enhanced zerotree coding (EZC), is based on two new techniques: adaptive multi-subband decomposition (AMSD) and band flag scheme (BFS). The purpose of AMSD is to change the statistics of transformed coefficients so that the coding performance in peak signal-to-noise ratio (PSNR) can be elevated at a lower bit rate. In addition, BFS is used to reduce execution time in finding zerotrees. In BFS the tree depths are controlled, therefore, many unnecessary comparison operations can be skipped. Experimental results show that the proposed algorithm improves the performance of EZW coding and requires low computational complexity. In addition, the property of embedded coding is preserved, which enables a progressive transmission. (C) 2000 Elsevier Science B.V. All rights reserved.

关键词： image coding zerotree coding adaptive multi-subband decomposition band flag scheme

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Novel embedded image compression technique using second generation bandelets and zerotree coding

Novel embedded image compression technique using second gene...

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Symposium on Remote Sensing and GIS Data Processing and Applications;and Innovative Multispectral Technology and Applications

作者： Li, Kun Wang, Shuang Jiao, Licheng Zhao, Yang Xidian Univ Inst Intelligent Informat Proc Xian 710071 Peoples R China

ISBN: (纸本)9780819469540

As a new multiscale geometric analysis tool, second generation bandelets can make full use of intrinsic geometric regularity and provide an optimal representation of the underlying high-dimensional functions adaptively. In this paper, a novel embedded image compression technique is presented, which is based on second generation bandelets and zerotree coding. The method is embedded progressive which can control the actual compression ratio and allow "best" reconstructions during decompression. Objectively, we use peak signal-to-noise ratio and edge preservation properties to measure Image quality. Numerical tests applied on natural images show that compared with other two algorithms, our method provides improvements both in peak signal-to-noise ratio and edge preservation properties. Subjectively, our method avoids visible ringing effects having better image visual fidelity.

关键词： multiscale geometric analysis (MGA) Second Generation Bandelets zerotree coding image compression

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Adaptive vector quantization for efficient zerotree-based coding of video with nonstationary statistics

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2000年第8期10卷 1478-1488页

作者： Fowler, JE Univ Nice Lab I3S Sophia Antipolis France

A new system for intraframe coding of video is described. This system combines zerotrees of vectors of wavelet coefficients and the generalized-threshold-replenishment (GTR) technique for adaptive vector quantization (AVQ). A data structure, the vector zerotree (VZT), is introduced to identify trees of insignificant vectors, i.e., those vectors of wavelet coefficients in a dyadic subband decomposition that are to be coded as zero. GTR coders are then applied to each subband to efficiently code the significant vectors by way of adapting to their changing statistics. Both VZT generation and GTR coding are based upon minimization of criteria involving both rate and distortion. In addition, perceptual performance is improved by invoking simple, perceptually motivated weighting in both the VZT and the GTR coders. Our experimental findings indicate that the described VZT-GTR system handles dramatic changes in image statistics, such as those due to a scene change, more efficiently than wavelet-based techniques employing nonadaptive scalar quantizers.

关键词： adaptive vector quantization image-sequence coding zerotree coding

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3-D geometry compression using multiscale plane based representation and zerotree based coding

3-D geometry compression using multiscale plane based repres...

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IEEE International Conference on Image Processing (ICIP 2006)

作者： Park, Sung-Bum Lee, Sang-Uk Choi, Hyeokho Seoul Natl Univ Sch Elect Engn INMC Seoul 151 South Korea North Carolina State Univ Dept Elect Engn Raleigh NC 32029 USA

ISBN: (纸本)9781424404810

In this paper, we present a novel geometry compression scheme for compactly representing 3-D sampled data. The proposed framework is based on the octree structured multiscale geometry representation, where local surface is expressed by multiscale plane descriptions. To reduce planar redundancy between different scale plane approximations in the multiscale pyramid, the multiscale plane pyramid is decomposed and the resulting refinement pyramid is encoded using the zerotree based coding method. The decomposition captures the geometry innovation to refine coarse geometry. Moreover, the zerotree based coding method offers the ordered bitstream according to the contribution for reconstructing the geometry innovation. Therefore, we demonstrate that the proposed algorithm compactly represents the 3-D point samples yielding progressive refinement of the surface geometry.

关键词： 3-D point geometry plane representation geometry compression zerotree coding

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A new image coding technique with low entropy using a flexible zerotree

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IEICE TRANSACTIONS ON COMMUNICATIONS 1998年第12期E81B卷 2528-2535页

作者： Joo, S Kikuchi, H Sasaki, S Shin, J Niigata Univ Dept Elect Engn Niigata 9502181 Japan Dongguk Univ Dept Elect Engn Joong Gu Seoul 100715 South Korea

A zerotree image-coding scheme is introduced that effectively exploits the inter-scale self-similarities found in the octave decomposition by a wavelet transform. A zerotree is useful for efficiently coding wavelet coefficients;its efficiency was proved by Shapiro's EZW. In the EZW coder, wavelet coefficients are symbolized, then entropy-coded far further compression. In this paper, we analyze the symbols produced by the EZW coder and discuss the entropy for a symbol. We modify the procedure used for symbol-stream generation to produce lower entropy. First, we modify the fixed relation between a parent and children used in the EZW coder to raise the probability that a significant parent has significant children. The modified relation is flexibly modified again based on the observation that a significant coefficient is more likely to have significant coefficients in its neighborhood. The three relations are compared in terms of the number of symbols they produce.

关键词： image compression wavelet transform zerotree coding entropy coding

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List based zerotree wavelet image coding with two symbols

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IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2004年第1期E87D卷 254-257页

作者： Muzaffar, T Choi, TS Kwangju Inst Sci & Technol Dept Mechatron Kwangju 500712 South Korea

This paper presents a novel wavelet compression technique to increase compression of images. Based on zerotree entropy coding method, this technique initially uses only two symbols (significant and zerotree) to compress image data for each level. Additionally, sign bit is used for newly significant coefficients to indicate them being positive or negative. Contrary to isolated zero symbols used in conventional zerotree algorithms, the proposed algorithm changes them to significant coefficients and saves its location, they are then treated just like other significant coefficients. This is done to decrease number of symbols and hence, decrease number of bits to represent the symbols used. In the end, algorithm indicates isolated zero coordinates that are used to change the value back to original during reconstruction. Noticeably high compression ratio is achieved for most of the images, without changing image quality.

关键词： image compression wavelet transform zerotree coding reduced symbol encoding

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Interslice coding for medical three-dimensional images using an adaptive mode selection technique in wavelet transform domain

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JOURNAL OF DIGITAL IMAGING 1999年第4期12卷 173-184页

作者： Cho, HD Kim, JH Ra, JB Korea Adv Inst Sci & Technol Dept Elect Engn Taejon 305701 South Korea Seoul Natl Univ Coll Med Dept Radiol Seoul South Korea

In this article the authors propose a novel interslice coding algorithm especially appropriate for medical 3-dimensional (3D) images. The proposed algorithm is based on a video coding algorithm using motion estimation/compensation and transform coding. In the algorithm, warping is adopted for motion compensation. Then, by using adaptive mode selection, an MC residual image and original image are mixed up in the wavelet transform domain for improvement in coding performance. The mixed image is then compressed by the zerotree coding method. It is proven that the adaptive mode selection technique in the wavelet transform domain is very useful for medical 3D image coding. Simulation results show that the proposed scheme provides good performance, regardless of interslice distance, and is prospective for medical 3D image compression. Copyright (C) 1999 by W.B. Saunders Company.

关键词： interslice coding motion compensation wavelet transform zerotree coding adaptive mode selection technique

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Context-Based coding of Adaptive Multiresolution Meshes

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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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Scalable Intraband and Composite Wavelet-Based coding of Semiregular Meshes

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IEEE TRANSACTIONS ON MULTIMEDIA 2010年第8期12卷 773-789页

作者： Denis, Leon Satti, Shahid M. Munteanu, Adrian Cornelis, Jan Schelkens, Peter Vrije Univ Brussel Dept Elect & Informat B-1050 Brussels Belgium

This paper proposes novel scalable mesh coding designs exploiting the intraband or composite statistical dependencies between the wavelet coefficients. A Laplacian mixture model is proposed to approximate the distribution of the wavelet coefficients. This model proves to be more accurate when compared to commonly employed single Laplacian or generalized Gaussian distribution models. Using the mixture model, we determine theoretically the optimal embedded quantizers to be used in scalable wavelet-based coding of semiregular meshes. In this sense, it is shown that the commonly employed successive approximation quantization is an acceptable, but in general, not an optimal solution. Novel scalable intraband and composite mesh coding systems are proposed, following an information-theoretic analysis of the statistical dependencies between the coefficients. The wavelet subbands are independently encoded using octree-based coding techniques. Furthermore, context-based entropy coding employing either intraband or composite models is applied. The proposed codecs provide both resolution and quality scalability. This lies in contrast to the state-of-the-art interband zerotree-based semiregular mesh coding technique, which supports only quality scalability. Additionally, the experimental results show that, on average, the proposed codecs outperform the interband state-of-the-art for both normal and nonnormal meshes. Finally, compared with a zerotree coding system, the proposed coding schemes are better suited for software/hardware parallelism, due to the independent processing of wavelet subbands.

关键词： Information theoretic analysis intraband and composite coding lifting-based wavelet transform octree coding scalable mesh coding zerotree coding

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