带失真补偿的抖动调制水印算法中的补偿因子研究

带失真补偿的抖动调制水印算法是一种可以获得大容量的量化水印算法,它以量化失真作为补偿来提高抖动调制水印算法的性能,而其中补偿因子是影响该算法性能的关键因素之一.本文从量化水印算法中最小距离解码器的工作原理出发,提出了衡量带失真补偿的抖动调制水印算法鲁棒性的一般模型;在此基础上,应用率失真理论采用高斯信道来模拟有损压缩信道,得到了在有损压缩下使得误码率最低时,选择补偿因子的方法.理论结果表明有损压缩的强度越大时,应该选择的补偿因子越小.实验结果证明了理论结果的正确性.

Study on the Compensation Factor in the Watermarking Algorithm of Dither Modulation with Distortion Compensation

Dither modulation with distortion compensation is a quantization watermarking algorithm that can achieve high capacity,and it uses the quantization error as the compensation to improve the performances of dither modulation, while the compensation factor is one of the key factors that affect its performances. This paper establishes a common model measuring the robustness of the algorithm from the principle of the minimum distance decoder in quantization watermarking algorithms. Then, this paper uses rate distortion theory to model the lossy compression channel, and obtains the method that can get the minimum bit error rate under lossy compression. The theoretical result shows that the larger the compression strength is, the smaller the compensation factor should be. The experimental result confirms the validity of the theoretical result.