一种基于分形的鲁棒性数字图像水印算法

A Robust Digital Image Watermark Algorithm Based on Fractal Theory

提出了一种新的数字水印算法,其充分融合了分形压缩和小波零树的特性。载体图像进行小波变换后,对小波系数进行分形零树编码,并在考虑视觉因素的基础上,将水印嵌入到载体图像视觉不敏感的零树和分形的相似域树。同时为了增加安全性,该算法还对水印图像进行混沌置乱。实验结果表明,该算法不仅对JPEG压缩、高斯噪声以及剪切等都有很好的稳健性,而且鲁棒性也很好。

In the paper,a new watermark algorithm that combines the wavelet zero-tree theory with fractal-based compression is presented.At first,the cover image is applied the wavelet transform,and is encoded on the basis of the mixed method that combines the zero-tree of wavelet domain with the fractal theory;Secondly,according to the characteristics of the Human Visual System （HVS）,the positions of embedding the secret image are obtained,and in order to improving the level of information hidden,l apply chaotic sequence transform to the watermark sequence.The experiment proved that the algorithm can not only resist some kinds of transforms such as clipping,JPEG compression and so on,but also ensure the watermark image robustness.