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为了增强视频通信系统在有误码信道的适应能力 ,提出了一种基于数字水印技术的错误检测方法 ,使得解码器可以对误码块进行有效的补偿。其原理为编码器在量化后离散余弦变换 (DCT)系数中嵌入易碎的数字水印 ,解码器可以通过提取水印从而确认错误以及错误发生的首宏块位置。仿真结果证明 :在信道误码率为 5× 10 - 4时 ,与常用的基于语法的方法相比 ,本方法的错误检测率是其的 1.32～ 1.82倍 ,错误正确定位率是其的 2 .95～ 5 .32倍 ,而且 PSNR只有微弱降低 ,同时算法复杂度很低
In order to enhance the adaptability of the video communication system in the presence of error-code channels, an error detection method based on digital watermarking is proposed, which enables the decoder to effectively compensate the error blocks. The principle is that the encoder embeds a fragile digital watermark in the quantized discrete cosine transform (DCT) coefficients, and the decoder can identify the error and the location of the first macroblock by mistake by extracting the watermark. Simulation results show that when the channel error rate is 5 × 10 - 4, the error detection rate of this method is 1.32 ~ 1.82 times higher than that of the common syntax - based method, and the error correct positioning rate is 2. 95 ~ 5 .32 times, and PSNR only slightly lower, while the algorithm complexity is very low