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Improvement of the coding efficiency for the qm-coder

ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 2000年第1期83卷 1-9页

作者： Kuroki, Y Ohta, T Kyushu Inst Technol Fac Engn Kitakyushu Fukuoka 804 Japan

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. (C) 1999 Scripta Technica.

关键词： arithmetic coding qm-coder Markov model coding

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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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Forward-adaptive method for context-based compression of large binary images

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SOFTWARE-PRACTICE & EXPERIENCE 1999年第11期29卷 943-952页

作者： Ageenko, EI Fränti, P Univ Joensuu Dept Comp Sci FIN-80101 Joensuu Finland

A method for compressing large binary images is proposed for applications where spatial access to the image is required. The proposed method is a two-stage combination of forward-adaptive modeling and backward-adaptive context based compression with re-initialization of statistics. The method improves compression performance significantly in comparison to a straightforward combination of JBIG and tiling. Only minor modifications to the qm-coder are required, and therefore existing software implementations can be easily utilized. Technical details of the modifications are provided. Copyright (C) 1999 John Wiley & Sons, Ltd.

关键词： image compression document imaging context modeling JBIG qm-coder

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Improving DC coding models of JPEG arithmetic coder

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IEEE SIGNAL PROCESSING LETTERS 2004年第5期11卷 505-508页

作者： Lakhani, G Texas Tech Univ Lubbock TX 79409 USA

While conducting experiments with JPEG binary arithmetic coding, we noticed that if a natural photographic image is rotated by 90degrees and then coded, the DC code size is reduced in general. This led us to investigate the discrete cosine transform and statistical models of JPEG arithmetic coder, and formulate two modifications to DC coefficient coding. We propose that the DC of a block should be predicted from the block just above. This modification reduces the DC code size further by about 9% on average. This change is more important for arithmetic coding than Huffman DC coding. We also propose a change in the binary decision coding order specified by the DC statistical model;it produces only a minor reduction in the code size.

关键词： arithmetic entropy coding DC coding JPEG discrete cosine transform (DCT) coding qm-coder

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ITU-T T.851: an enhanced entropy coding design for JPEG baseline images

ITU-T T.851: an enhanced entropy coding design for JPEG base...

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Conference on Applications of Digital Image Processing XXXI

作者： Mitchell, Joan L. Hinds, Arianne T. Ricoh IBM InfoPrint Solut Co Boulder CO 80301 USA

ISBN: (纸本)9780819472939

The Joint Photographic Experts Group (JPEG) baseline standard remains a popular and pervasive standard for continuous tone, still image coding. The "J" in JPEG acknowledges its two main parent organizations, ISO (International Organization for Standardization) and the ITU-T (International Telecommunications Union Telecommunication). Notwithstanding their joint efforts, both groups have subsequently (and separately) standardized many improvements for still image coding. Recently, the ITU-T Study Group 16 completed the standardization for a new entropy coder - called the Q15-coder, whose statistical model is from the original JPEG-1 standard. This new standard, ITU-T Rec. T.851, can be used in lieu of the traditional Huffman (a form of variable length coding) entropy coder, and complements the qm arithmetic coder, both originally standardized in JPEG as ITU-T T.81 vertical bar ISO/IEC 10918:1. In contrast to Huffman entropy coding, arithmetic coding makes no assumptions about an image's statistics, but rather responds in real time. This paper will present a tutorial on arithmetic coding, provide a history of arithmetic coding in JPEG, share the motivation for T.851, outline its changes, and provide comparison results with both the 14 baseline Huffman and the original qm-coder entropy coders. It will conclude with suggestions for future work.

关键词： T.851 ITU-T Rec. T.851 JPEG baseline Q15-coder Q-coder qm-coder MQ-coder skew coder

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High-fidelity coding for super high-definition images

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 1997年第3期80卷 47-57页

作者： Kuroki, Y Ohta, T Faculty of Engineering Kyushu Institute of Technology Kitakyushu 804 Japan Kyushu Institute of Technology Japan Kyushu University Japan Television Society of Japan Info. Processing Society of Japan Japan IEEE

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 similar to 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.

关键词： super high-definition images arithmetic coding qm-coder extrapolative, interpolative prediction quantization

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High-fidelity coding for super high-definition images

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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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