基于DWT具有篡改定位的半脆弱水印算法

Semi-Fragile Watermarking Algorithm Based on DWT with Tamper Localization

半脆弱水印因为在多媒体内容认证方面的重要作用而受到人们密切的关注.为了能够区分偶然攻击与恶意篡改,半脆弱水印需要对一般的内容保护图像操作有一定的鲁棒性.根据图像相邻小波高频系数之间的大小关系在JPEG压缩之后大多数没有发生变化这一事实,提出了一种新的基于DWT变换的具有篡改定位的半脆弱水印算法,该算法主要思想是根据图像相邻小波高频系数之间的大小关系来嵌入水印.仿真实验结果表明:该算法嵌入容量大,有很好的抗JPEG压缩性能,同时也能对恶意篡改精确定位.

Semi-fragile watermarking has attracted much attention because of its important role in multimedia content authentic.ation. In order to distinguish accidental attacks and malicious tamperingi semi-fragile watermarks must have the robustness to process general content protection and image manipulation. After JPEG compression, most of the size relationships between the highfrequency coefficients of adjacent wavelets of an image have no changes. According to this fact,this paper proposes a new semi-fragile watermarking algorithm based on DWT transform with tamper localization. The watermark is embedded according to the size relationship between the high-frequency coefficients of the adiccent wavelets of the image. The results of simulation experiments show that the algorithm has large embedded capacity and good anti-JPEG compression performance. At the same time, the positioning for malicious tampering is also very accurate.