基于归一化图像的抗仿射变换攻击的水印算法

对于鲁棒的数字图像水印技术来说,仿射变换是最难对付的一种攻击。将水印嵌入到基于几何矩的归一化图像中是一种抵抗仿射攻击的方法,但由于原始图像的归一化图像和遭受了仿射攻击后的归一化图像在尺寸上不相同,这就使得嵌入和提取水印很难实现同步。本文提出了一种基于归一化图像的数字水印算法,选择归一化图像中的某个参数作为水印,嵌入水印的过程就是在原始图像的基础上叠加一个原始图像的非线性变换,使得其归一化图像的该参数处于预定的变化范围之中。实验证明此算法对于大多数StirMark攻击来说都是鲁棒的。

Affine Robust Image Watermarking Based on Image Normalization

In image watermarking,affine transforms are among the most challenging problems.Moment based image normalization has been used in watermarking. Embedding the watermark into the normalized image is the idea of this kind of algorithms.However,be- cause the sizes of the normalized original image and the normalized geometrically attacked image are different,the synchronization of the embedding and the extracting is very difficult to be guaranteed.In this paper,we propose a watermarking algorithm based on image nor- malization.We choose a parameter in the normalized image as the watermark.And the watermarked image is the combination of the origi- nal image and a weighted nonlinear transformation of the original.Watermark detection is as simple as computing the parameter of the normalized version of the received image.The proposed algorithm has proved to be robust to many kinds of geometric manipulations that are performed as part of StirMark attacks.