基于混沌序列的多重数字图像水印算法

采用一维混沌映射，根据不同的混沌初始条件生成多个互不相关的混沌实值序列，进而得到性能良好的多重数字图像水印信号，有效地解决了多重数字图像水印信号的构造问题．同时采用二维混沌映射将各水印信号置乱，随机均匀地叠加在图像小波变换的中低频系数上，各水印信号的嵌入和提取可以互不干扰，解决了多重数字图像水印的嵌入问题．实验结果表明，该算法对各种常见的攻击均具备了一定的抵抗能力，可有效地解决数字图像产品的多著作权问题．

A Multiple Watermarking Algorithm for Digital Image Based on Chaotic Sequences

A multiple watermarking algorithm for digital image based on chaotic sequences is proposed. The massive and independent digital watermark signals are generated through 1-D chaotic maps, which are determined by different initial conditions and parameters. The construction of massive digital watermarks is effectively resolved through this chaotic digital watermark signals. Multiple watermarking algorithm is more complex than the single watermarking algorithm in the embedding method. Each watermark is added to the middle frequency coefficients of wavelet domain randomly by exploiting 2-D chaotic system, so that the embedding and extracting of each watermark don't disturb with each other. The watermarks can be protected to be removed malevolently if the parameters of 2-D chaotic system are considered as the key to embedding procedure. Therefore the performance of security is improved. The capacity of the multiple watermarks is also analyzed in this paper. The experimental results demonstrate that this proposed watermarking algorithm is robust against many common attacks and can resolve the problems of multi-copyright claim and the tracing of digital image products in the different phase of publishing, selling and using.