【摘要】 1974年由Ahmed和Rao提出的离散余弦变换,至今已有30年历史。此间,DCT编码已发展成为JPEG、MPEG、H.26x等图像/视频编码标准中的核心。尽管Shapiro的EZW以及Said等人的SPIHT小波编码的成功应用,对传统的DCT编码提出了挑战,但Xiong等人利用嵌入式DCT块变换之间的直流相关性,以及对DCT后的系数进行策略性重组或层式DCT同样具有小波多分辨率图像的分解特性。此外,基于层次嵌入式DCT、形状自适应DCT、截短DCT、感兴趣区域支撑DCT以及形态DCT等改进形式的编码,都是将基于DCT变换编码推向更高层次。就DCT改进的变换,以及DCT系数的应用,如利用DCT系数实现信息隐藏等,也使得基于常规的DCT变换编码有了更广阔的应用与发展空间,文章就此作了广泛的比较和深入的研究,并指出了发展方向。更多还原

【Abstract】 DCT(Discrete Cosine Transform) transforming coding has been widely used in such coding-standards as JPEG、MPEG and H.26x excluding of JPEG2000 at present. With the embedded image coding using zerotree of wavelet coefficients introduced by Shapiro and the successful application based on set partitioning in hierarchical trees by Said entered into the new phase on the video/image compressing coding. However ,Xiong et al have applied the high correlation between DCS by means of a DCT-based embedded image coding and the same multiresolution characteristics as the wavelet transforming after reorganizing the DCT coefficients transformed. DCT by a suitable coding scheme can provide requirements for transmission of image signal in terms of a fine granularity scalability in the internet. Besides, all those based on EZHDCT、SA-DCT、TR-DCT、RS-DCT and MRDCT have improved the conventional DCT transforming coding further to a higher stage. DCT transforming would have further enlarged it抯 an applying scale and leaving more room based on the conventional DCT after the being reorganized DCT coefficients and by the aid of some improved transformations .Object-based coding for DCT is a promising technique for next-generation coding .All mentioned above have been studied deeply in this paper.更多还原