图象传输系统中信道误码影响的检测与修复

本文分析了信道误码对DPCM图象传输系统重建图象的影响。在此基础上,提出一种适用于一阶DPCM系统的检测误码影响的方法,并进行了理论分析和实验。结果表明,这种方法可以较精确地检测出出现误码的象素行及行内误码的起始点;同时,方法本身具有递推性及运算简单等特点,便于在计算机上快速执行。使用这种方法进行检测时无需增加DPCM系统发送设备的复杂性,也无需采用信道纠检错编码。用这种方法与行替换修复方法构成完整的算法,对改善受误码影响的图象的质量比较有效。

DETECTION AND CORRECTION OF THE CHANNEL BIT ERRORS FOR DIGITAL IMAGE TRANSMISSION SYSTEMS

The effects of the channel bit error on the reconstructed images of the Differential Pulse Code Modulation (DPCM) systems are analysed in this paper. Based on this analysis, an error detection algorithm, which is suitable for the One—dimensionaL DPCM systems, is proposed with mathematical analysis and experiments. It is shown from the results that the origin of the erroreous pixel within a scan line can be detected accurately by the algorithm under some certain conditions without adding any auxiliaries to the DPCM encoders. Furthermore, the algorithm may be fast implemented in digital computers due to its simplicity and recursive property. The experiments also demonstrate that comfining this algorithm with the correction method of line replacement is effective in improving the quality of the DPCM reconstructed image which contains the channel bit error effects.