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基于DCT编码的新进展

鲁业频1, 李凤亭2, 朱仁义1, 陈兆龙1(1.巢湖学院物理系,安徽巢湖 238000;2.清华大学图象图形研究所,北京 100084)

摘 要
目前,DCT编码在JPEG、MPEG、H.26x等编码标准中有着广泛的应用,但随着Shapiro关于小波的嵌入式零树小波编码以及Said等人提出的集合分裂等级树编码的成功应用,使图像及视频信号的压缩编码提高到了新阶段,这虽然对传统的DCT编码提出了挑战,然而,Xiong等人利用嵌入式DCT块变换之间直流系数(DC)的高度相关性也能获得较高的编码性能,因为对DCT后的系数进行重组,同样具有小波多分辨率图像的特性。此外,基于形状自适应DCT、区域支撑DCT以及形态DCT的提出,还有利用DCT系数实现信息隐藏、图像大小调整、模式识别等等,都将DCT功能与性能推向更高层次,使得基于常规的DCT编码有了更大的应用与发展空间。为使人们对DCT编码现状有一概略了解,在对该技术进行深入分析与研究的基础上,对该技术作了概略介绍,并对DCT编码发展进行了展望。
关键词
New Advances Based on the DCT Transforming Coding

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Abstract
DCT(Discrete Cosine Transform) transforming coding has been widely used coding-standards such as JPEG,MPEG and H.26x exclusive of JPEG2000 at present. The compressing codings for image/video signals have been advanced to a new stage since the EZW(Embedded Zerotree Wavelet) had been introduced by Shapiro and the SPIHT(Set partition in hierarchical trees) applied by Said et al,which are a competitive challenge against the conventional DCT's coding. However,DCT's coefficients have a similar multiresolutional attributes after reorganization its datum like wavelet transforming. There are many excellent performances in the based-DCT such as arbitrarily shaped DCT,region support DCT and morphological representation of DCT coefficients are proposed.Digital watermarking,image resizing and pattern cognition can be done through utilizing DCT's coefficients,and so on.The capability and performance of the DCT have further been promoted to a higher phase. For instance,object-based coding for DCT is a promising technique for next-generation coding.Besides,the experiments show that MR-DCT(Morphological representation of DCT) is among the state-of-the-art DCT-based image coders reported in the literature.What mentioned above have been studied and analyzed deeply in this paper.Hereby,the future development of DCT is also conjected.
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