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IEEE Conference on Visualization

作者： Chuan-Kai Yang T. Mitra Tzi-Cker Chiueh Department of Computer Science State University of New York Stony Brook Stony Brook NY USA

Very large irregular-grid data sets are represented as tetrahedral meshes and may incur significant disk I/O access overhead in the rendering process. An effective way to alleviate the disk I/O overhead associated with rendering a large tetrahedral mesh is to reduce the I/O bandwidth requirement through compression. Existing tetrahedral mesh compression algorithms focus only on compression efficiency and cannot be readily integrated into the mesh rendering process, and thus demand that a compressed tetrahedral mesh be decompressed before it can be rendered into a 2D image. This paper presents an integrated tetrahedral mesh compression and rendering algorithm called Gatun, which allows compressed tetrahedral meshes to be rendered incrementally as they are being decompressed, thus leading to an efficient irregular grid rendering pipeline. Both compression and rendering algorithms in Gatun exploit the same local connectivity information among adjacent tetrahedra, and thus can be tightly integrated into a unified implementation framework. Our tetrahedral compression algorithm is specifically designed to facilitate the integration with an irregular grid renderer without any compromise in compression efficiency. A unique performance advantage of Gatun is its ability to reduce the runtime memory footprint requirement by releasing memory allocated to tetrahedra as early as possible.

关键词： Rendering (computer graphics) Image coding compression algorithms Bandwidth Algorithm design and analysis Streaming media Head Lead compounds Pipelines Chromium

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Efficient representation and streaming of XML content over the Internet medium

Efficient representation and streaming of XML content over t...

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IEEE International Conference on Multimedia and Expo (ICME)

作者： M. Girardot N. Sundaresan Almaden Research Center IBM San Jose CA USA International Business Machines Corp Armonk NY US

As large XML documents with text and multimedia are exchanged and streamed over the Internet medium, techniques for the compact and efficient representation and exchange for this data become essential. We have designed a system called Millau for the efficient encoding and streaming of XML structures. In this paper, we describe the Millau algorithms for the compression and streaming of XML structures and data. In order to be able to transmit the most important information first, Millau builds a solution for fragmenting an XML document, associating a priority to each fragment, streaming each fragment independently, and rebuilding the whole document or parts of the document according to the user's preferences or the browser's capabilities. This solution can be applied to the streaming of structured XML documents with text or multimedia data.

关键词： XML Internet Streaming media compression algorithms Wire MPEG 7 Standard Buildings Bandwidth Communication channels Protocols

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On board strip-based wavelet image coding for future space remote sensing missions

On board strip-based wavelet image coding for future space r...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： C. Parisot M. Antonini M. Barlaud C. Lambert-Nebout C. Latry G. Moury I3s laboratory Biot France CNES-Bpi 1421 Centre National d'Etudes Spatiales Toulouse France

Spacecraft sensor obtained data has to be stored on-board until an opportunity arises for it to be transmitted to the ground. compression algorithms used in space were based first on DPCM and then on DCT. Image quality evaluation determined however that for applications using the adaptive DCT, such as for SPOT 5, the maximum acceptable compression ratio was about 3 for high resolution observation and about 15 for scientific missions. Beyond that compression ratio, the occurrence of block effects in uniform areas and the loss of detail related to compression noise is no more acceptable for scientific use. To overcome these limits and to prepare future generations of Earth observation satellites and scientific missions, the authors propose a novel and efficient strip-based satellite image coder adapted for on board processing. The performances of their method are better than JPEG 2000 with a complexity lower than 60 operations per pixel. Furthermore, their method can be implemented for different image samplings. The authors quickly explain the general compression scheme used and the solution for on the fly DWT computation. They present the dynamic bit allocation and the regulation process chosen for rate control. Then, they evaluate the complexity and performances of their method comparatively to JPEG 2000.

关键词： Image coding Discrete cosine transforms Transform coding Space vehicles compression algorithms Image quality Image resolution Signal to noise ratio Artificial satellites Image sampling

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Wavelet-based coding of three-dimensional oceanographic images around land masses

Wavelet-based coding of three-dimensional oceanographic imag...

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IEEE International Conference on Image Processing

作者： J.E. Fowler D.N. Fox Department of Electrical & Computer Engineering Mississippi State University Starkville MS USA Naval Research Laboratory NASA Stennis Space Center MS USA

We describe an algorithm for the embedded coding of 3D oceanographic images. These images differ from those arising in other applications in that valid data exist only at grid points corresponding to the sea; grid points that cover land or lie beyond the bathymetry have no associated data. For these images, we employ a 3D lifting wavelet transform tailored specifically to the potentially sparse nature of the data by processing only the valid sea data points in between land masses. In addition, we introduce successive-approximation runlength (SARL) coding, an embedded-coding procedure which adds successive-approximation properties to the well known stack-run (SR) algorithm. SARL is a general technique applicable to the oceanographic images considered here as well as to other coding tasks in which embedded coding is desired but for which zerotree-techniques are impractical.

关键词： Image coding Oceans Wavelet transforms Oceanographic techniques compression algorithms Biomedical imaging Land surface Sea surface Embedded computing Laboratories

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Data splitting and compounding technology for a data real-time transmission system

Data splitting and compounding technology for a data real-ti...

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： Li Maotang Xue Yonglin Jang Jingshan Li Mingfeng Center of Space Science and Applied Research Beijing China Tsinghua University Beijing China

A very useful airborne-ground disaster surveying system (AGDSS) is being developed. The sensors of the surveying system consisted of a GPS receiver and some remote sensing instruments. The processed and compressed data are transmitted to ground receiving stations directly. The AGDSS includes an optical sensor that is of large swath width, high resolution and produces a huge quantity of data. So it is very difficult to assemble the sensors, sample, compress and deal with the output data of the sensors in real-time. However, data splitting and compounding technology has been developed and it can solve the thorny problem. The distinguish feature of the data splitting and compounding technology is the multi-CPU parallel working method adopted. There are some advantages for the data splitting and compounding technology, so it is important to the real-time transmission system for huge amounts of data.

关键词： Real time systems Optical sensors Central Processing Unit Signal sampling Space technology Remote sensing Instruments Remote monitoring Error correction compression algorithms

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Visual optimization tools in JPEG 2000

Visual optimization tools in JPEG 2000

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IEEE International Conference on Image Processing

作者： Wenjun Zeng S. Daly Shawmin Lei Sharp Laboratories of America Inc.orporated USA

We review the various tools in JPEG 2000 that allow the users to take advantages of the various properties of the human visual system such as spatial frequency sensitivity and the visual masking effect. We show that the visual tool sets in JPEG 2000 are much richer than what was available in JPEG, where only locally invariant frequency weighting can be exploited.

关键词： Frequency Transform coding Image coding Humans Visual system compression algorithms Video compression Discrete wavelet transforms Laboratories Visual perception

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On sequential universal coding of sequences with limited amount of training data

On sequential universal coding of sequences with limited amo...

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IEEE Convention of the Electrical and ELectronic Engineers in Israel

作者： I. Sutskover J. Ziv Department of Electrical Engineering Technion-Israel Institute of Technology Haifa Israel

ISBN: (纸本)0780358422

The problem of universal coding in the non-asymptotic regime is investigated. In a forthcoming paper, some non-asymptotic lower bounds on the achievable compression are proven by Ziv for the class of stationary sources and a class of admissible algorithms. To these lower bounds we match an achievable upper bound by construction of a proper algorithm. We also extend our results to a case where some prior assumptions can be incorporated into universal algorithms, creating algorithms that are "almost universal".

关键词： Training data Pixel Entropy Random variables Upper bound Statistics Minimax techniques compression algorithms Algorithm design and analysis Encoding

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PBS: a predictive block sampling algorithm for desktop multimedia video applications

PBS: a predictive block sampling algorithm for desktop multi...

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IEEE International Conference on Multimedia and Expo (ICME)

作者： J. Pasquale T. Nguyen J. Kay Department of Computer Science and Engineering University of California San Diego CA USA

Manipulating digital video using desktop computers, especially in uncompressed form, and communicating it over networks can be time-consuming because of its large bandwidth requirements. While the size of a video frame is large, the amount of new information in each video frame is often quite small. We present an algorithm that predicts those parts of the video image that change from frame to frame. This effectively allows the manipulation of uncompressed digital video using common personal computers with no special hardware support. The algorithm uses a statistical technique and takes advantage of locality of change. We show that the algorithm is effective and yet is simple and low-cost.

关键词： Sampling methods Prediction algorithms Video compression Computer displays Computer networks Streaming media Microcomputers compression algorithms Application software Computer science

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Sub-block interchange for lossless image compression

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 1999年第1期45卷 236-242页

作者： Ng, KS Cheng, LM City Univ Hong Kong Dept Elect Engn Kowloon SAR Hong Kong Peoples R China

Lempel-Ziv-Welch (LZW) technique for text compression has been successfully modified to lossless image compression such as GIF. Recently, a new class of text compression, namely, Burrows and Wheeler Transformation (BWT) has been developed which gives promising results for text compression. Here, we propose a sub-block interchange lossless compression method which belongs to this block sorting class. Our compression results have outperformed GIF in compression ratios and BWT in compression times when tested with 512x512 pixel 8-bit grey scale images. The comparison of compression ratios and times with GIF, BWT and other popular LZ based compression methods are discussed.

关键词： Image coding Sorting Testing Pixel compression algorithms Data compression Performance loss Decoding Entropy coding

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Lossless image compression by using gradient adjusted prediction and Burrows-Wheeler transformation

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 1999年第2期45卷 380-386页

作者： Ng, KS Cheng, LM City Univ Hong Kong Dept Elect Engn 83 Tat Chee Ave Kowloon Peoples R China

In generally text compression techniques cannot be used directly in image compression because the model of text and image are different. Recently, a new class of text compression, namely, block-sorting algorithm which involves Burrows and Wheeler transformation (BWT) gives excellent results in text compression. However, if we apply it directly into image compression, the result is poor. Surprisingly, good results can be obtained if we employ a prediction model such as the one defined in JPEG standard before the BWT algorithm. Thus, the predictive model plays critical role - in the compression process. To further improve the compression efficiency, we use Gradient Adjusted Prediction (GAP). Experimental results show that the proposed method is better than lossless JPEG and some LZ-based compression methods.

关键词： Image coding Transform coding Sorting Predictive models compression algorithms Data compression ISO standards IEC standards Entropy coding Performance loss

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