一种基于仿射变换的图像置乱预处理的水印算法

A Watermarking Scheme Based on Image Shuffling Pre-processing Using Affine Transformation

本文提出了一种基于仿射变换迭代生成的混沌序列对图像进行置乱预处理的水印嵌入算法.选取适当的仿射变换参数及给定初值,使用仿射变换迭代得到一个混沌序列,利用该混沌序列排序生成一个置换排列,对载体图像进行置乱的预处理,从而可以增强水印算法的安全性、透明性和抗攻击的鲁棒性.水印算法是在图像空间域实现的,采用一个图像融合的技术.嵌入算法简单,容易操作.实验结果显示,置乱算法比传统的基于仿射变换的置乱算法有更好的置乱效果,置乱加密的密钥空间也更大;嵌入水印的宿主图像能够有效地抵御剪切、噪声、JPEG压缩等水印攻击,具有较好的鲁棒性.

A watermarking scheme based on image shuffling pre-processing using chaotic sequences generated by affine transformation is proposed. Given suitable parameters and initial values for affine transformation, one can get one chaotic sequence and then get one permutation by sorting the chaotic sequence. The permutation is applied to shuffle the host image in the pre-processing stage in watermarking and therefore enhance the security, transparency and robustness. The watermark embedding is performed in spatial domain by an image merging scheme, which is simple and easy to manipulate. The proposed shuffling scheme yields good scrambling effects compared with the conventional shuffling scheme and owns one larger key space. The watermarked images are robust against various attacks, such as cropping, noising, JPEG compression, etc.