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1997 Conference on Visual Communications and Image Processing

作者： Puri, A Schmidt, RL Haskell, BG AT&T Labs. (United States)

ISBN: (纸本)0819424358

We report on recent advances in traditional dct based video coding at low bitrates. These improvements allow either an increase in coding efficiency or an increase in other functionalities. Our investigation is conducted within the framework of the ongoing work towards the MPEG-4 video standard. The ISO Moving Picture Experts Group (MPEG) is currently developing this standard after having completed the MPEG-I and the MPEG-2 standards. The MPEG-4 video standard is addressing a number of content based as well as traditional functionalities. The development process consists of iterative refinement of the Verification Model (which describes the coding method) via a set of well defined core experiments. Our first experiment is on improved coding efficiency of Intra and uses DC and AC predictions and optimized scanning of dct coefficients followed by a separate optimized variable length code table. Our second experiment is the study of bidirectional coding to allow additional functionality such as temporal scalability at low bit-rates. We present results of these experiments and summarize our findings.

关键词： video compression video coding MPEG coding standards MPEG-4 interframe coding dct coding motion compensation motion compensated dct coding

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Variable temporal-length 3-D discrete cosine transform coding

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IEEE TRANSACTIONS ON IMAGE PROCESSING 1997年第5期6卷 758-763页

作者： Chan, YL Siu, WC Dept. of Electron. Eng. Hong Kong Polytech. Univ. Kowloon

Three-dimensional discrete cosine transform (3-D dct) coding has the advantage of reducing the interframe redundancy among a number of consecutive frames, while the motion compensation technique can only reduce the redundancy of at most two frames. However, the performance of the 3-D dct coding will be degraded for complex scenes with a greater amount of motion. This paper presents a 3-D dct coding with a variable temporal length that is determined by the scene change detector. Our idea is to let the motion activity in each block be very low, while the efficiency of the 3-D dct coding could be increased. Experimental results show that this technique is indeed very efficient. The present approach has substantial improvement over the conventional fixed-length 3 D dct coding and is also better than that of the Moving Picture Expert Group (MPEG) coding.

关键词： .transform coding image sequence shown in Fig coder motion activity dct coding MCTC technique

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CONCEALMENT TECHNIQUES FOR DATA-REDUCED HDTV RECORDING

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SIGNAL PROCESSING-IMAGE COMMUNICATION 1995年第2期7卷 173-182页

作者： KHARATICHVILI, M KAUFF, P Heinrich-Hertz-Institut für Nachrichtentechnik Einsteinufer 37 10587 Berlin Germany

Most of all data-reduced HD-VCRs use powerful error protection schemes in order to prevent error propagation. Under normal conditions these schemes are able to correct all errors from magnetic tape channel. However, under bad conditions some uncorrected errors may be left. Therefore, it must be possible to conceal erroneous dct blocks in order to avoid visible degradations in this worst-case situation. In this context four different concealment techniques (spatial, temporal, motion-adaptive and motion-compensated concealment) are discussed and compared with respect to their efficiency. The results of subjective tests and the discussion of some system aspects show that the motion-adaptive approach is the most suitable one for the underlying application.

关键词： MAGNETIC RECORDING CONCEALMENT TECHNIQUES dct coding

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dct-based objective quality assessment metric of 2D/3D image

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MULTIMEDIA TOOLS AND APPLICATIONS 2015年第8期74卷 2803-2820页

作者： Liu, Xingang Sun, Chao Yang, Laurence T. Univ Elect Sci & Technol China Sch Elect Engn High Tech Zone Xiyuan Rd 2006 Chengdu 611731 Sichuan Peoples R China St Francis Xavier Univ Antigonish NS B2G 2W5 Canada

With the increasing growth of multimedia applications over the networking in recent years, users have put forward much higher requirements for multimedia quality of experience (QoE) than before. One of the representative requirements is the image quality. Therefore, the image quality assessment ranging from two-dimension (2D) image to three-dimension (3D) image has been getting much attention. In this paper, an efficient objective image quality assessment metric in block-based discrete cosine transform (dct) coding is proposed. The metric incorporates properties of human visual system (HVS) to improve its validity and reliability in evaluating the quality of stereoscopic image. This is fulfilled by calculating the local pixel-based distortions in frequency domain, combining the simplified models of local visibility properties embodied in frequency domain, which consist of region of interest (ROI) mechanism (visual sensitivity), contrast sensitivity function (CSF) and contrast masking effect. The performance of the proposed metric is compared with other currently state-of-the-art objective image quality assessment metrics. The experimental results have demonstrated that the proposed metric is highly consistent with the subjective test scores. Moreover, the performance of the metric is also confirmed with the popular IRCCyN/IVC database. Therefore, the proposed metric is promising in term of the practical efficiency and reliability for real-life multimedia applications.

关键词： Quality assessment dct coding Stereoscopic image Human Visual System (HVS) Region of Interest (ROI)

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Joint source and channel decoding of compressed still images

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SIGNAL PROCESSING-IMAGE COMMUNICATION 1999年第3期15卷 217-229页

作者： Xu, W Hagenauer, J Hollmann, J Tech Univ Munich Lehrstuhl Nachrichtentech D-80290 Munich Germany

A joins source-channel decoding approach is described, which utilizes the residual redundancy in the bit stream of a source-coded image by employing a modified APRI-SOVA (a priori soft-output Viterbi algorithm) at the channel decoder. The source coders used are the nonadaptive discrete cosine transform (]dct) coding and subband coding with Lloyd-Max quantization. The log-likelihood ratio describing the a priori information is linearized. The reliability of the current bit is computed as a proper linear combination of the soft values characterizing statistical dependency of the zeroth order (probability of 1's or 0's) and the first order (bit correlation among neighboring samples). Substantial subjective and objective performance gains can be obtained by using this method. It is demonstrated that especially in a noisy environment, it may be better to keep the residual redundancy in the data and use it at the receiver side in order to achieve a more reliable decoding, rather than to further remove it by using a variable length coding. The trade-off between the allocation of bits for source and channel coding is also addressed. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： joint source-channel coding dct coding subband coding soft-output viterbi algorithm

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Estimation of Mosquito Noise Level from Decoded Picture

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2009年第12期E92A卷 3291-3296页

作者： Sugiyama, Kenji Sagara, Naoya Kashimura, Yohei Seikei Univ Musashino Tokyo 1808633 Japan

With dct coding, block artifact and mosquito noise degradations appear in decoded pictures. The control of post filtering is important to reduce degradations without causing side effects. Decoding information is useful, if the filter is inside or close to the encoder;however. it is difficult to control with independent post filtering, such as in a display. In this case, control requires the estimation of the artifact from only the decoded Picture. In this work, we describe an estimation method that determines the mosquito noise block and level. In this method, the ratio of spatial activity is taken between the mosquito block and the neighboring flat block. We test the proposed method using the reconstructed pictures which are coded with different quantization scales. We recognize that the results are mostly reasonable with the different quantizations.

关键词： dct coding block artifact mosquito noise non reference estimation

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Non-reference and Absolute Spatial Blur Estimation from Decoded Picture Only

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2012年第8期E95A卷 1256-1258页

作者： Sagara, Naoya Suzuki, Takayuki Sugiyama, Kenji Seikei Univ Musashino Tokyo 1808633 Japan

The non-reference method is widely useful to estimation picture quality on the decoder side. In this paper, we discuss the estimation method for spatial blur that divides the frequency zones by the absolute value of 64 coefficients with an 8-by-8 dct and compares them. It is recognized that absolute blur estimation is possible with the decoded picture only.

关键词： dct coding spatial blur non-reference estimation spatial frequency

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Segmentation-based hybrid coding using luminance masking

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ELECTRONICS LETTERS 1998年第8期34卷 750-751页

作者： Huang, JW Shi, YQ Shantou Univ Dept Elect Engn Guangdong 515063 Peoples R China New Jersey Inst Technol Dept ECE Newark NJ 07102 USA

The authors propose a segmentation-based hybrid image coding algorithm taking the features of the human visual system into account. A novel segmentation criterion based on luminance masking is presented. The image is segmented into blocks of different sizes and different properties. Block mean, polynomial approximation and discrete cosine transform coding are then applied to the blocks accordingly.

关键词： image segmentation dct coding block mean coding polynomials Pattern recognition Interpolation and function approximation (numerical analysis) approximation theory luminance masking discrete cosine transform coding polynomial approximation coding segmentation-based hybrid coding Codes segmentation criterion image coding Optical information, image and video signal processing Computer vision and image processing techniques transform coding Integral transforms Other numerical methods image coding algorithm discrete cosine transforms

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Linearity Improvement of Mosquito Noise Level Estimation from Decoded Picture

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IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 2011年第2期E94A卷 548-551页

作者： Sagara, Naoya Kashimura, Yousuke Sugiyama, Kenji Seikei Univ Musashino Tokyo 1808633 Japan

dct encoding of images leads to block artifact and mosquito noise degradations in the decoded pictures. We propose an estimation to determine the mosquito noise block and level;however, this technique lacks sufficient linearity. To improve its performance, we use the sub-divided block for edge effect suppression. The subsequent results are mostly linear with the quantization.

关键词： dct coding block artifact mosquito noise non reference estimation

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Motion estimation using low-bit oriented edge image for dct-based video compression

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ELECTRONICS LETTERS 2001年第8期37卷 494-495页

作者： Qiu, XH Zhang, WJ Chen, HY Zhou, R Tsing Hua Univ Inst Microelect Beijing 100084 Peoples R China

A novel block-based motion estimation algorithm using a low-bit resolution oriented edge image (LROEI) is proposed. The algorithm produces difference blocks with little texture for dct coding and enhances the encoding efficiency. Simulation based on a hierarchical subsampling telescope search confirms that the quality of the LROEI is superior to that of luminance image compared with HSTS using an 8 bit luminance image The operational loads are also reduced to 75 or 50% without quality degradation.

关键词： Integral transforms in numerical analysis dct coding edge detection dct-based video compression luminance image data compression encoding efficiency hierarchical subsampling telescope search HSTS quality degradation operational loads difference blocks motion estimation Image and video coding low-bit oriented edge image Video signal processing block-based motion estimation algorithm discrete cosine transforms video coding Image recognition

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