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A novel enhancement for hierarchical image coding

JOURNAL OF VISUAL COMMUNICATION AND image REPRESENTATION 2013年第1期24卷 12-22页

作者： Zhu, Shuyuan Zeng, Bing Hong Kong Univ Sci & Technol Dept Elect & Comp Engn Kowloon Hong Kong Peoples R China Univ Elect Sci & Technol China Sch Elect Engn Chengdu Sichuan Peoples R China

hierarchical image coding usually codes a down-sampled version of an original image and then the difference between the original image and a reconstructed version that is interpolated from the down-sampled layer. In this paper, we demonstrate, for the first time, that when the bit-rate used to code the residual layer falls into a critical region (which covers almost all typical bit-rates used in practice), it often happens that all pixels in the down-sampled layer would be deteriorated if the corresponding coded residuals are added into them. To avoid this problem, we first propose a "naive" solution: no coded residuals will be added back into the down-sampled layer;whereas coded residuals will be added only into the interpolated pixels. Then, we propose to apply a constrained quantization technique during the coding of the residual layer so that all residual pixels at the interpolated positions will end up with an improved quality. To verify its effectiveness, we conduct extensive tests to show that the gap between the hierarchical coding scheme and its single-level counterpart (which is typically around 2-3 dB in the 2-level hierarchy) will be filled up by a rather big percentage. (C) 2012 Elsevier Inc. All rights reserved.

关键词： image coding hierarchical image coding R-D coding performance Constrained quantization

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Integrated pre-fetching and replacing algorithm for graceful image caching

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IEICE TRANSACTIONS ON COMMUNICATIONS 2003年第9期E86B卷 2753-2763页

作者： Su, Z Washizawa, T Katto, J Yasuda, Y Waseda Univ Sch Sci & Engn Tokyo 1690072 Japan Canon Inc Canon Res Ctr Atsugi Kanagawa 2430193 Japan

The efficient distribution of stored information has become a major concern ill the Internet. Since the web workload characteristics show that more than 60% of network traffic is caused by image documents. how to efficiently distribute image documents from servers to end clients is an important issue. Proxy cache is an efficient solution to reduce network traffic. 2 And it has been shown that an image caching method (Graceful Caching) based oil hierarchical coding format performs better than conventional caching schemes ill recent years. However, as the capacity of the Cache is limited, how to efficiently allocate the cache memory to achieve a minimum expected delay time is still a problem to he resolved. This paper presents all integrated caching algorithm to deal with the above problem for image databases. web browsers, proxies and other similar applications ill the Internet. By analyzing the web request distribution of the Graceful Caching, both replacing and pre-fetching algorithms are proposed. We also show that our proposal can be carried out based oil information readily available ill the proxy server;it flexibly adapts its parameters to the hit rates and access pattern of users requesting documents in the Graceful Caching. Finally we verify the performance of this algorithm by simulations.

关键词： graceful caching hierarchical image coding content delivery network web performance caching algorithm

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Performance improvement of Graceful image Caching by using request frequency based prefetching algorithms

Performance improvement of Graceful image Caching by using r...

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IEEE Region 10 International Conference on Electrical and Electronic Technology

作者： Su, Z Washizawa, T Katto, J Yasuda, Y Waseda Univ Grad Sch Sci & Technol Shinjuku Ku Tokyo 1690072 Japan

ISBN: (纸本)0780371011

This paper presents a cache scheme for image databases, web browsers, proxies and other similar applications in Internet The current cache system employs a hard strategy: either the image Is stored in a cache or not even its data is quite big. We have proposed a caching scheme featuring human memory mechanism (image database system featuring graceful oblivion), which is called Graceful Caching. The previous work shows that Graceful Caching reduces user response time by assigning a variable amount of memory to each image. Several recent studies suggest that prefetching, techniques could be employed to further improve the cache performance, by anticipating and prefetching future client requests. Some approaches based on request frequency have been proposed to the conventional caching (hard system) and got better results. In this paper, we try to apply a request frequency based approach. to Graceful Caching system, in which a progressive image format is used. Based on the analysis of web request probability in Graceful Caching, we go on to propose a new prefetching algorithm that drastically improves cache performance of system. We verify the performance of this algorithm by simulations.

关键词： graceful caching hierarchical image coding prefetching Web Caching

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hierarchical Lossless image Compression for Telemedicine Applications 11

Hierarchical Lossless Image Compression for Telemedicine App...

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11th International Conference on image and Signal Processing (ICISP)

作者： Sumalatha, R. Subramanyam, M. V. Santhiram Engn Coll Nandyal India G Pullaiah Coll Engn & Technol Kurnool 518002 India

The main aim of hierarchical lossless image compression is to improve accuracy, reduce the bit rate and improve the compression efficiency for the storage and transmission of the medical images while maintain an acceptable image quality for diagnosis purpose. The cost and limitation in bandwidth of wireless channels has made compression is necessity in today's era. In medical images, the contextual region is an area which contains an important information and must be transmitted without distortion. In this paper the selected region of the image is encoded with Adaptive Multiwavelet Transform AMWT) using Multi Dimensional Layered Zero coding (MLZC). Experimental results shows that Peak Signal to Noise Ratio (PSNR), Correlation Coefficient (CC), Mean Structural Similarity Index (MSSIM) performance is high and Root Mean Square Error (RMSE), Mean Absolute Error (MAE) values are low, and moderate Compression Ratio (CR) at high Bits Per Pixel (BPP) when compared to the integer wavelet and multiwavelet transform. (C) 2015 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/4.0/). Peer-review under responsibility of Universal Society for Applied Research

关键词： AMWT Contextual region hierarchical image coding MLZC Multiwavelet

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A ROBUST PRE-FETCHING ALGORITHM FOR SCALABLE WEB CONTENTS AND ITS PERFORMANCE EVALUATION

A ROBUST PRE-FETCHING ALGORITHM FOR SCALABLE WEB CONTENTS AN...

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1st International Symposium on Intelligent Informatics (ISII 2008)

作者： Su, Zhou Katto, Jiro Yasuda, Yasuhiko Waseda Univ Sch Sci & Engn Shinjuku Ku Tokyo 1698555 Japan

In order to deliver multimedia contents to the end-users with low delay and acceptable quality, the pre-fetching technologies have been shown the efficiency if we can predict user's future requests and prefetch the data needed previously. However, because both the network topology and Web access are changed dynamically, whether the pre-fetching can get the stable performance under dynamic environment becomes an important issue. Therefore, this paper talks about the robustness of the pre-fetching algorithm, which has been proposed by us to deliver layered image contents over the Internet. Based on the web access distribution, the request pattern in the scalable imaging delivering system is analyzed in this paper. Furthermore, we check the robustness of our proposal by changing related parameters. Simulation results show that Our proposal is stable against variable conditions even if access patterns are dynamically changed.

关键词： Contents delivery hierarchical image coding Pre-fetching Web caching

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hierarchical Lossless image Compression for Telemedicine Applications

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Procedia Computer Science 2015年 54卷 838-848页

作者： R. Sumalatha M.V. Subramanyam Santhiram Engineering College Nandyal India G. Pullaiah College of Engineering & Technology Kurnool 518 002 India

关键词： AMWT Contextual region hierarchical image coding MLZC Multiwavelet.

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