Centre for Commun. Res., Bristol Univ.
IEEE Trans Image Process. 1996;5(4):565-74. doi: 10.1109/83.491333.
Many source and data compression schemes work by splitting the input signal into blocks and producing variable-length coded data for each block. If these variable-length blocks are transmitted consecutively, then the resulting coder is highly sensitive to channel errors. Synchronization code words are often used to provide occasional resynchronization at the expense of some added redundant information. This paper introduces the error-resilient entropy code (EREC) as a method for adapting existing schemes to give increased resilience to random and burst errors while maintaining high compression. The EREC has been designed to exhibit graceful degradation with worsening channel conditions. The EREC is applicable to many problems and is particularly effective when the more important information is transmitted near the start of each variable-length block and is not dependent on following data. The EREC has been applied to both still image and video compression schemes, using the discrete cosine transform (DCT) and variable-length coding. The results have been compared to schemes using synchronization code words, and a large improvement in performance for noisy channels has been observed.
许多源和数据压缩方案通过将输入信号分成块并为每个块生成变长编码数据来工作。如果这些变长块连续传输，则生成的编码器对信道错误非常敏感。同步码字通常用于提供偶尔的重新同步，代价是一些额外的冗余信息。本文引入了容错熵码 (EREC) 作为一种方法，用于适应现有方案，在保持高压缩率的同时提高对随机和突发错误的弹性。EREC 的设计目的是在信道条件恶化时表现出优雅的降级。EREC 适用于许多问题，并且在更重要的信息在每个变长块的开头附近传输且不依赖于后续数据时特别有效。EREC 已应用于静止图像和视频压缩方案，使用离散余弦变换 (DCT) 和变长编码。结果与使用同步码字的方案进行了比较，观察到在噪声信道上性能有了很大的提高。
