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Geometric compression of a quadrilateral mesh

COMPUTERS & MATHEMATICS WITH APPLICATIONS 2008年第6期56卷 1597-1603页

作者： Chen, Ren Luo, Xiaonan Xu, Hao Sun Yat Sen Univ Inst Comp Applicat Guangzhou 510275 Guangdong Peoples R China Sun Yat Sen Univ Minist Educ Key Lab Digital Life Guangzhou 510275 Guangdong Peoples R China

A new progressive compression algorithm for arbitrary topology with highly detailed triangle meshes is proposed in this paper. We firstly parameterize the original triangle mesh to a regular quadrilateral approximation. A wavelet transform is then applied to the approximation to remove a large amount of correlation between neighboring vertices. Finally, We used low cost zerotree coding and subdivision based reconstruction to build a sequence of progressive models. Our method will greatly reduce the cost of transportation with acceptable quality loss as shown in the experimental results. (c) 2008 Elsevier Ltd. All rights reserved.

关键词： geometry compress zerotree coding wavelets subdivision progressive transmission

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Multiscale Representation and Compression of 3-D Point Data

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IEEE TRANSACTIONS ON MULTIMEDIA 2009年第1期11卷 177-182页

作者： Park, Sung-Bum Lee, Sang-Uk Samsung Elect Co Ltd Digital Media R&D Ctr Multimedia Platform Lab Suwon South Korea Seoul Natl Univ Sch Elect Engn Signal Proc Lab Seoul South Korea

A compact representation scheme is presented for 3-D point data. To describe underlying surface from raw point samples, we dyadically divide a 3-D domain enclosing whole points. Then, local points in each cube are approximated by a plane patch, yielding a multiscale representation of 3-D surface. To reduce the redundancy between different scale models, the geometry Innovation is evaluated between different scale planes, which reveals the Euclidian distance between planes. Finally, the geometry innovation coefficients are compressed by a zerotree-based encoder. Based on the multiscale plane representation of 3-D geometry and the efficient plane decomposition method, the proposed scheme provides a desirable framework for 3-D point geometry processing.

关键词： 3-D representation and compression multiscale representation plane decomposition plane primitive point data zerotree coding

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Progressive space frequency quantization for SAR data compression

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IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING 2002年第1期40卷 3-10页

作者： Gleich, D Planinsic, P Gergic, B Cucej, Z Univ Maribor Fac Elect Engn & Comp Sci Signal Proc Lab SLO-2000 Maribor Slovenia

In this paper, we propose a new wavelet image coding technique for synthetic aperture radar (SAR) data compression called a progressive space-frequency quantization (PSFQ). PSFQ performs spatial quantization via rate distortion-optimized zerotree pruning of wavelet coefficients that are coded using a progressive subband coding technique. We compared the performances of zerotree-based methods: EZW, SPIRT, SFQ, and PSFQ with the classical wavelet-based method (CWM), which uses uniform scalar quantization of subbands followed by recency rank coding. The performances of the methods based on zerotree quantization were better than the CWM in the rate distortion sense. The embedded coding techniques perform better SNR results than the methods using scalar quantization. However, the probability density function (PDF) of the reconstructed amplitude SAR data compressed using CWM, better corresponded to the PDF of the original data than the PDF of the reconstructed data compressed using the zerotree based methods. The amplitude PDF of the reconstructed data obtained using PSFQ compression algorithm better corresponded to the original PDF than the amplitude PDF of the data obtained using the multilook method.

关键词： arithmetic coding compression radar synthetic aperture radar (SAR) wavelet transform zerotree coding

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Group testing for image compression

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2002年第8期11卷 901-911页

作者： Hong, ES Ladner, RE Univ Washington Dept Comp Sci & Engn Seattle WA 98195 USA

This paper presents Group Testing for Wavelets (GTW), a novel embedded-wavelet-based image compression algorithm based on the concept of group testing. We explain how group testing is a generalization of the zerotree coding technique for wavelet-transformed images. We also show that Golomb coding is equivalent to Hwang's group testing algorithm [5]. GTW is similar to SPHIT [2] but replaces SPHIT's significance pass with a new group testing based method. Although no arithmetic coding is implemented, GTW performs competitively with SPHIT's arithmetic coding variant in terms of rate-distortion performance.

关键词： golomb codes group testing image coding variable length codes wavelet transforms zerotree coding

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Linked significant tree wavelet-based image compression

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SIGNAL PROCESSING 2008年第10期88卷 2554-2563页

作者： Muzaffar, Tanzeem Choi, Tae-Sun Gwangju Inst Sci & Technol Dept Mechatron Kwangju 500712 South Korea

This paper proposes a new linked significant tree (LST) wavelet coding method for improved compression of images. The proposed method first links all the significant coefficients together within a wavelet tree to facilitate encoding algorithm. Insignificant parents, with at least one significant child found in the wavelet data, are changed to significant to link them together. Their location is saved for identification, and they are then treated just like any other significant coefficients during encoding. An embedded LST encoding algorithm is proposed to accommodate the processed output for better coding efficiency. It exploits the fact that no descendent of an insignificant coefficient can be significant any more, since all the significant coefficients within a wavelet tree are linked together. This fact eliminates the need to check the descendents of those coefficients that are found as insignificant. Locations of converted coordinates are sent to the decoder after each encoding pass, to change the values back to original during reconstruction. The proposed method shows improvement when applied to gray-scale images. (C) 2008 Elsevier B.V. All rights reserved.

关键词： image compression linked significant tree (LST) wavelet transform zerotree coding

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Non-RAM-based architectural designs of wavelet-based digital systems based on novel nonlinear I/O data space transformations

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IEEE TRANSACTIONS ON VERY LARGE SCALE INTEGRATION (VLSI) SYSTEMS 2005年第1期13卷 58-74页

作者： Peng, DM Lu, M Univ Nebraska Dept Comp & Elect Engn Omaha NE 68182 USA Texas A&M Univ Dept Elect Engn College Stn TX 77943 USA

The designs of application specific integrated circuits and/or multiprocessor systems are usually required in order to improve the performance of multidimensional applications such as digital-image processing and computer vision. Wavelet-based algorithms have been found promising among these applications due to the features of hierarchical signal analysis and multiresolution analysis. Because of the large size of multidimensional input data, off-chip random access memory (RAM) based systems have ever been necessary for calculating algorithms in these applications, where either memory address pointers or data preprocessing and rearrangements in off-chip memories are employed. This paper establishes and follows novel concepts in data dependence analysis for generalized and arbitrarily multidimensional wavelet-based algorithms, i.e., the wavelet-adjacent field and the super wavelet-dependence vector. Based on them, a series of novel nonlinear I/O data space transformations for variable localization and dependence graph regularization for wavelet algorithms is proposed. It leads to general designs of non-RAM-based architectures for wavelet-based algorithms where off-chip communications for intermediate calculation results are eliminated without preprocessing or rearranging input data.

关键词： dependence graph discrete wavelet transform non-RAM-based architectures zerotree coding

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An improved wavelet-based image coder for embedded greyscale and colour image compression

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2017年 73卷 183-192页

作者： Brahimi, Tahar Laouir, Farid Boubchir, Larbi Ali-Cherif, Arab Jijel Univ Dept Elect Res Lab L2EI BP 98 Ouled Aissa Jijel 18000 Algeria Univ Paris 08 LIASD Res Lab 2 Rue Liberte F-93526 St Denis France

The embedded zero-tree wavelet (EZW) coding algorithm is a very effective technique for low bitrate still image compression. In this paper, an improved EZW algorithm is proposed to achieve a high compression performance in terms of PSNR and bitrate for lossy and lossless image compression, respectively. To reduce the number of zerotrees, the scanning and symbol redundancy of the existing EZW;the proposed method is based on the use of a new significant symbol map which is represented in a more efficient way. Furthermore, we develop a new EZW-based schemes for achieving a scalable colour image coding by exploiting efficiently the interdependency of colour planes. Numerical results demonstrate a significant superiority of our scheme over the conventional EZW and other improved EZW schemes with respect to both objective and subjective criteria for lossy and lossless compression applications of greyscale and colour images. (C) 2017 Elsevier GmbH. All rights reserved.

关键词： Embedded greyscale and colour image coding Lossy/lossless image coding EZW algorithm zerotree coding Wavelet transform

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The impact of tree structures on the performance of zerotree-based wavelet video codecs

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2010年第3期25卷 179-195页

作者： Moinuddin, Athar Ali Khan, Ekram Ghanbari, Mohammed Aligarh Muslim Univ Dept Elect Engn Aligarh 202002 UP India Univ Essex Sch Comp Sci & Elect Engn Colchester CO4 3SQ Essex England

In this paper we analyze the impact of tree structures on the performance of zerotree-based wavelet video codecs. Since zerotree approach is based on aggregation of insignificant coefficients in trees, therefore design of a tree structure is the key issue for a better performance. We have considered six different tree structures with characteristics varying from a simple to relatively complex and composite tree structures to code the luminance-chrominance components of a video sequence. Their performances are compared in terms of average number of bits generated per bitplane, number of coded bitplanes for a given bit budget, rate-distortion performance, memory requirements and computational complexity. We observe that in general more complex and longer trees do not necessarily improve the coding efficiency. However, the tree structures encapsulating more elements per tree are memory efficient. Therefore, the rate-distortion performance, memory requirements and computational complexities need to be traded-off while selecting a particular tree structure. It is also observed that the additional improvement due to optional entropy coding is also tree structure dependent. Further, the simulation results show that by designing an efficient tree structure, depending on the picture content, the performance of a video coder can be improved by up to 2.0 dB, while reducing the computational complexity by 45-60% as well as the memory requirements by almost 29-35%. Compared to the standard JPEG2000 (for intra-frame), tree-based coders are found to be efficient in terms of coding and complexity, particularly at lower bit rates. (C) 2010 Elsevier B.V. All rights reserved.

关键词： zerotree coding SPIHT Color image coding Wavelet video Tree structure

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Wavelet-based images compression of color document by fuzzy picture-text segmentation

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JOURNAL OF THE CHINESE INSTITUTE OF ENGINEERS 2003年第1期26卷 113-118页

作者： Wu, BF Chiu, CC Lin, WL Natl Chiao Tung Univ Dept Elect & Control Engn Hsinchu 300 Taiwan

In this paper, we present a new compression method for color document images based on the wavelet transform and fuzzy picture-text segmentation. This approach addresses a fuzzy picture-text segmentation method, which separates pictures and texts by using wavelet coefficients from color document images. The picture components and the text components are encoded by zerotree wavelet coding and by the modified run-length Huffman coding, respectively.

关键词： wavelet transform zerotree coding fuzzy picture-text segmentation color document image compression

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Low-complexity and low-memory entropy coder for image compression

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2001年第10期11卷 1140-1145页

作者： Zhao, DB Chan, YK Gao, W Harbin Inst Technol Dept Comp Sci Harbin 150001 Peoples R China City Univ Hong Kong Dept Comp Sci Hong Kong Hong Kong Peoples R China

In this paper, a low-complexity and low-memory entropy coder (LLEC) is proposed for image compression. The two key elements in the LLEC are zerotree coding and Golomb-Rice (G-R) codes. zerotree coding exploits the zerotree structure of transformed coefficients for higher compression efficiency. G-R codes are used to code the remaining coefficients in a variable-length codes/variable-length integer manner resulting in JPEG similar computational complexity. The proposed LLEC does not use any Huffman table, significant/insignificant list, or arithmetic coding, and therefore its memory requirement is minimized with respect to any known image entropy coder. In terms of compression efficiency, the experimental results show that discrete cosine transform (DCT)- and discrete wavelet transform (DWT)-based LLEC outperforms baseline JPEG and embedded zerotree wavelet coding (EZW) at the given bit rates, respectively. For example, LLEC outperforms baseline JPEG by an average of 2.2 dB on the Barbara image and is superior to EZW by an average of 0.2 dB on the Lena image. When compared with set partition in hierarchical trees, LLEC is inferior by 0.3 dB, on average, for both Lena and Barbara. In addition, LLEC has other desirable features, such as parallel processing support, region of interest coding, and as a universal entropy coder for DCT and DWT.

关键词： computational complexity entropy coding Golomb-Rice codes image compression zerotree coding

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