数字水印已成为数字作品版权保护的一种手段,而鲁棒性和不可察觉性是其基本要求.为此,提出了一种基于Shamir秘密共享方案的数字水印算法.该算法首先将图象分成n块,并将水印信息也分成n份,然后通过DCT的相邻系数比较法,将每份水印信息嵌入到图象的相应块中,提取时,只要获得其中的任意t(≤n)份水印信息就可以恢复出原始水印.为提高提取水印图象的精度,给出了基于模糊集的改进算法.实验结果表明,该算法的隐藏效果很好,并且对单一攻击及多种复合攻击具有很好的鲁棒性.

Digital watermarks have been proposed in recent literature as a means for copyright protection of multimedia data. The robustness and the imperceptibility are the basic requirements of the digital watermark. In this paper, we propose a digital watermarking algorithm based on Shamir secret sharing scheme. We divide the field of the image into parts, and then we also make the information of digital watermarking into shares by the algorithm. We embed each share of the digital watermarking in the corresponding part of the image by contrasting DCT coefficients， and only need arbitrary shares in the recovery progress. In order to enhance the precision of the extracted watermark, we improve the extracting algorithm based on fuzzy set. Experimental results show that this algorithm has a good hiding effect and is robust for single attack and even collage attacks.