基于混沌映射的小波域数字水印算法

WAVELET DIGITAL WATERMARKING ALGORITHM BASED ON CHAOTIC MAPPING

针对数字水印的不可感知性和鲁棒性之间的矛盾问题,提出了一种基于混沌映射的小波域数字水印算法.该算法在混沌数字水印系统的基础上,对水印增加了置乱处理,并将其初值作为私有密钥以提高安全性能.嵌入水印时,将置乱的水印图像取模运算后再嵌入混沌映射模型进行迭代,再将所选择的图像进行小波变换后的逼近子图和各级细节子图以不同的嵌入因子分别与混沌水印相加.检测时,利用相应的混沌映射模型生成混沌水印序列,并进行相关检测.计算机仿真结果表明该算法具有很好的视觉效果,并对各种图像处理攻击有较强的鲁棒性,是一种简单可行的数字水印算法.

To overcome problem between invisibility and robustness, a robust digital watermarking scheme based on chaotic mapping, where the initial value of a chaotic map as a private key is added to the existing chaotic watermarking systems is proposed. By scrambling, watermarking image embedding the result of the modular operation in the iteration of the chatic generating systems, the chaotic signal is embedded into the selected approach block and details of blocks at all levels by DWT, the same time taking a modular on the sum by different embedded element. The chaotic sequence is retrieved from the watermarking image by using the corresponding chaotic model in the correlative detector. The computer simulation results demonstrate that the watermark is invisible and robust to general image processing techniques and geometric distortions, it is a simple and feasible digital watermarking algorithm.