鉴于数据在不可靠信道传输时，可能会发生数据包丢失或出错的问题，因此在图像与视频信号传输中如何解决由此而产生的图像质量严重下降问题已成为近年来的一个重要研究课题，而多描述编码作为一种可选的解决方案已开始受到关注。由于多描述编码是将信号分解为多个独立的码流，并通过不同的信道进行传输，因而可在较高压缩效率下增强信号的稳健性。在对目前的图像多描述编码文献进行分析和综合的基础上，首先阐述了多描述编码的历史和信息论背景；然后对图像多描述编码方法进行了分类，即分为基于量化、基于变换和基于空间扩展的多描述编码等几类，并对各种方法的数学模型以及适用情况等进行了讨论；最后给出了图像多描述编码的存在问题及研究展望。

Recently, the problem of packet loss and errors in image communication over erasure channels, such as Internet and wireless networks, becomes an important topic. This creates the need for new approaches to image coding, which combine high compression efficiency and robustness. As a new approach, multiple description coding (MDC) is attractive in this field, which separates the source into several equally important bit streams(descriptions) and then transmitted over different channels. Based on many related literatures, an overview on the state of the art of MDC is given in this paper. Firstly, MDC's history and background in information theory are introduced. And then MDC is classified into several categories, including quantizion based, transform based, space expansion based and so on. Each is described respectively from the mathematic model and its applied conditions. Comparisons between MDSQ and MDPCT are made followed. At the end, some conclusions are given, including problems in MDC and what will MDC be in the future.