图像的多描述编码

Multiple Description Coding for Image

图像的多描述编码(MDC)是针对单描述编码(SDC)而言,其编码方法是将图像编码为多个位流(描述),并使每个描述都能恢复可接受质量的图像。其恢复图像的质量只依赖描述的个数,即如果解码器接收到的描述越多,则由这些描述共同形成的图像质量就越高。在图像通信应用中,在无信道编码的情况下,用MDC方法可适应传输条件恶劣的信道,尤其是无线信道和网络信道。为了能在传输信道恶劣的条件下进行有效的图像传输,在对MDC的基本理论及其应用以及近几年MDC的研究现状进行概述和总结的基础上,提出了一种基于EZW编码的MDC方法。实验结果表明,此法简单、有效,其不仅实现了压缩图像传输的健壮性,同时兼顾了压缩效率。

Controposed to single description coding（ SDC）, multiple description coding（MDC） for image is source coding in which several bit streams（descriptions） of original image are produced such that acceptable quality of the reconstructed image can be obtained from each description. The quality of reconstructed image only depends on the number of descriptions, the more descriptions, the higher quality of reconstructed image is obtained from combining these descriptions. MDC scheme is well suited to the channels which transmission conditions are very poor for image communication without channel coding, especially for networks and wireless channels, In this paper, the theoretical and practical techniques of MDC are exposed, the advances of MDC are described for these years. A MDC scheme of image based on EZW（ Embedded Zerotree Wavelet） is presented. The simulation results show that this method is simple and efficient, and implements robust transmission of compressed image considering the compression efficiency.