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High-fidelity coding for super high-definition images

Electronics and Communications in Japan (Part I: Communications) 1998年第3期80卷

作者： Yoshimitsu Kuroki Teiji Ohta Faculty of Engineering Kyushu Institute of Technology Kitakyushu Japan 804

The super high-definition images (SHDI) expected to be prominent in the systems of the 21st century consist of approximately 4000 scan lines and have extremely high fidelity. This paper describes a coding scheme for still SHDI. Predictive coding is thought to be a coding technique capable of not spoiling the quality of SHDI images. Thus, an extrapolative/interpolative prediction scheme that has been proposed [1] for high-efficiency coding of HDTV is used for intraframe coding of SHDI. The extrapolative prediction error is coded with a first-order Huffman code. Comparatively, the prediction efficiency of interpolative prediction is superior to that of extrapolative prediction [2]. Furthermore, since the pixel correlations of the images used in this paper are extremely high [9], the probability of the 0 representative level of the quantizer is high. Thus, in this paper, the prediction error is converted to binary levels when interpolative prediction is used and it is proposed that a coding method based on a type of arithmetic code, the QM-Coder [4], which is used in JPEG, be used to code the resulting binary information. When binary information is coded, the resulting conditional entropy of the reference pixels is shown to be rather constant; and, thus, the number of states can be reduced without an increase in the rate. Image coding simulation results show that the coding performance is improved with this method where extrapolative/interpolative prediction is used by 0.350 ∼ 0.458 bits/pel when compared with the case that uses a first-order Huffman code. Accordingly, high-fidelity images whose signal-to-noise ratio (SNR) is greater than 50 dB with rates less than at 1.653 bits/pel are obtained. © 1997 Scripta Technica, Inc. Electron Comm Jpn Pt 1, 80(3): 47–57, 1997

关键词： super high-definition images arithmetic coding QM-coder extrapolative/interpolative prediction quantization

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Improvement of the coding efficiency for the QM-coder

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Electronics and Communications in Japan (Part I: Communications) 1999年第1期83卷

作者： Yoshimitsu Kuroki Teiji Ohta Faculty of Engineering Kyushu Institute of Technology Kitakyushu Japan 804

The QM-coder [1] is an arithmetic code that is used in common in JPEG and JBIG as the binary information source coding. The most remarkable feature of arithmetic code is that dynamic adaptation can easily be realized. In other words, the code has high versatility. The same algorithm is effective for information sources with various statistical properties, and the code is expected to be applied to various kinds of information source coding [1–3]. However, the QM-coder uses a subtraction-type arithmetic code in order to simplify processing, with the augend operation executed only by constant substitution and subtraction. Thus, it is anticipated that the coding efficiency will be degraded. From such a viewpoint, this paper presents a proposal for the improvement of coding efficiency for subtraction-type arithmetic code [11, 12]. The proposed technique is to separate the augend into several states, and the constant to be assigned to the less probable symbol is varied according to the state. The probability estimation table in the proposed method is constructed by a theoretical investigation based on the table used in the QM-coder. As a result of the coding simulation for the binary image, it is seen that the proposed method can reduce the coding complexity by 0.686% to 1.301% compared to the QM-coder. © 1999 Scripta Technica, Electron Comm Jpn Pt 1, 83(1): 1–9, 2000

关键词： arithmetic coding QM-coder Markov model coding

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Mode-based connectivity compression for triangular meshes

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Jisuanji Fuzhu Sheji Yu Tuxingxue Xuebao/Journal of Computer-Aided Design and Computer Graphics 2007年第6期19卷 703-707页

作者： Liu, Ying Liu, Xuehui Wu, Enhua State Key Laboratory of Computer Science Institute of Software Chinese Acad. of Sci. Beijing 100080 China Graduate University Chinese Acad. of Sci. Beijing 100049 China Department of Computer and Information Science Faculty of Science and Technology University of Macau Macao China

We present an efficient connectivity compression algorithm for triangular meshes. It is a face-based, single resolution and lossless connectivity compression method. This method is an improvement to Edgebreaker method. By the method, in the mesh traversal process, we use an adaptive mesh traversing method to generate split operations, so that the number of split operations could be greatly reduced, In the process of entropy encoding, a code-mode scheme is well designed for each operator in the operator series, the result produced in the mesh traversal. Then after a binary representation is obtained, it is encoded by using adaptive arithmetic coding method finally. In comparison with the previous best face-based encoding methods, our method can significantly improve the compression ratio.

关键词： arithmetic coding Code-mode Connectivity compression Decode Edgebreaker Encode Meshes

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