静态图像编码研究进展

多媒体及Internet的迅速发展导致了对图像编码技术更高的要求。首先以波形编码、第二代编码技术和分形编码技术为线索对静态图像编码技术的发展及编码技术中所存在的一些问题进行了讨论，并从图像编解码的观点讨论了图像在有噪信道上传输的误码率情况和适应于传输的一些图像编码技术；同时对即将成为新的静态图像编码标准的JPEG－2000的目标、编码机制、POI编码的Maxshift方法以及对码流的直接操作等情况进行了讨论。尽管压缩效果一直是任何编码方案所追求的目标，但其它特性，像基于内容的编码、可分级性编码以及鲁棒性编码等也是选择一个好的编码方案时应该考虑的，据此最后对图像编码技术的发展方向进行了展望。

RESEARCH PROGRESS ON STILL IMAGE CODING

More requirements for image coding have arisen from the rapid development of multimedia and Internet. In this paper, an overview of major methods already used or under investigation for still image coding based on waveform coding, second-generation coding and fractal coding is first given, and the problem of BRE (bit rate error) in image transmission over noisy channels is analyzed. Also discussed are some techniques to alleviate channel error owing to bit-error in information such as DC coefficients and AC coefficients, desynchronization of block and packet loss from the standpoint of the image codec. In addition, the objectives and coding engine in JPEG-2000, an emerging standard for still image coding, are introduced, and the Maxshift method for ROI coding and the image manipulation based on compressed images in JPEG-2000 are also analyzed. Although the compression efficiency is the most important feature in any compression scheme, other functionalities, such as coding based on content, scalability coding and error resilience etc., should be taken into account when choosing a best coding scheme. Hereby, the future development of still image coding is also analyzed and conjectured.