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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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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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An Efficient Wavelet-Based Image Coder

An Efficient Wavelet-Based Image Coder

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3rd International Conference on Information and Communication Technologies

作者： Brahimi, Tahar Laouir, Farid Kechacha, N. Univ JIJEL Fac Engn Sci Dept Elect Engn Jijel Algeria

ISBN: (纸本)9781424417513

The embedded zero-tree wavelet (EZW) coding algorithm which was first introduced by Shapiro is a very effective technique for low bit-rate still image compression. In the current study, we propose a novel algorithm to improve the performance of EZW coding. To reduce the scanning and symbol redundancy of the existing EZW the proposed method is based on the use of six symbols instead of four. The purpose of this technique is to avoid the encoding of the children of each significant coefficient on the condition that it has no significant descendant. In addition, It is shown that this new technique is not only fast and computationally efficient, but also retains the property of embeddedness and obtains higher coding efficiency when compared with the conventional EZW.

关键词： lossy imag coding Embedded coding wavelet transform zerotree coding

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The programming realization of image compression algorithm in satellite data compression equipment

The programming realization of image compression algorithm i...

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2nd International Conference on Space Information Technology

作者： Wang Jidong Luo Wusheng Qin, Lu Xiao Xuemin Natl Univ Def Technol Coll Mechatron Engn & Automat Dept Instrument Sci & Technol Changsha 410073 Peoples R China

ISBN: (纸本)9780819469601

Satellite remote sensing image compression system is expected high compressing rate, real time dealing and high fidelity. Based on lapped biorthogonal transform (LBT) and its integer algorithm, this paper describes a fixed-point lapped transform algorithm using approximation to trigonometric function, studies the structure of LBT coefficients and presents a modified zerotree coding algorithm. Also, this paper studies the implementation in TMS320C6000 DSP of the algorithm, the processing speed is improved through task combining, complier options, software pipelining, loop unrolling and complex instruction. This algorithm has been used in a prototype of data compression equipment. Image coding experiments show that the algorithm's memory requirement is low and its coding performance is very competitive with SPIHT when its complexity is far lower than SHIHT.

关键词： remote sensing image compression fixed-point lapped transform zerotree coding parallel computing

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A novel image compression algorithm for hardware implementation

A novel image compression algorithm for hardware implementat...

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4th IASTED International Conference on Circuits, Signals, and Systems

作者： Chen, Suting Yang, Shihong Wu, Qinzhang Chinese Acad Sci Inst Opt & Elect POB 350 Chengdu 610209 Peoples R China

ISBN: (纸本)9780889866058

SPIHT is an advanced image embedded zerotree coding algorithm, but it needs too many memories for hardware real-time implementation. LZC requires reduced memories, but the coding order of spatial sub-bands is unreasonable. In this paper, a new image compression algorithm is presented. By using the idea of LZC to reduce the memory and based on a set partition method of SPIHT, this algorithm preserves the high performance of SPIHT algorithm and greatly reduces memories. In order to improve compression ratio further, run-length coding is used simultaneously. The experimental results show that the new algorithm not only has the properties of good vision effect, but also performs better than that of LZC and SPIHT algorithms in the aspects of the quality of image reconstruction and PSNR under the same ratio of

关键词： image compression zerotree coding SPIHT(set partition in hierarchical trees) LZC(listless zerotree coding)

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Study on CCD image compression and mass storage

Study on CCD image compression and mass storage

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20th Congress of the International-Commission-for-Optics

作者： Liu, H Zhai, LP Xiu, JH Zhao, XY Chinese Acad Sci Changchun Inst Opt Fine Mech & Phys Changchun 130033 Peoples R China Chinese Acad Sci Grad Sch Beijing 100039 Peoples R China Aviat Univ Air Force Changchun 130022 Peoples R China

ISBN: (纸本)0819460583

When CCD camera photographs massive images in the air, it is very important to compress and save CCD image timely and validly. This paper designs the CCD image compression and mass storage system. The one part is image compression: this paper introduces a reduced memory still image compression algorithm based on Listless zerotree coding (LZC). Compared with SPIHT, the approach significantly reduced memory requirement and no reducing the quality of the reconstructed image. The other part is image mass storage: this system uses a kind of special hard disk storage devices that can realize faster data transmission to SCSI (Small Computer System Interface) devices even if it separates oneself from PCs. In the faster data acquisition and storage system, data storage is a key technology. Normal approach is saving the data to mass memories, and then processing and saving the data after complete acquisition. The continuous acquisition time is restricted with the storage capacity in the normal method so that it can't receive the requirement of CCD image storage on many occasions. While its price will be geminate increasing, when we increase the storage capacity. So the approach in this paper is better one to use fast disks on data direct mass storage considering the storage capacity, read/write speed and unit cost. The result of the experiment shows that the system has compressed and saved CCD image validly, so it reached the anticipative purpose.

关键词： wavelet transform zerotree coding real-time compress mass storage system SCSI fast data storage

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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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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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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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Highly efficient zerotree wavelet image Coder with reduced symbols

Highly efficient zerotree wavelet image Coder with reduced s...

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Conference on Applications of Digital Image Processing XXVI

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

ISBN: (纸本)0819450766

This paper presents a novel wavelet compression technique to increase compression of images. Based on extension of zerotree entropy coding method, this method initially uses only two symbols (significant & 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 with no change in image quality.

关键词： image compression wavelet transform zerotree coding reduced symbol

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