窜改认证与内容恢复分离的自嵌入脆弱水印算法

为了提高可恢复水印的认证精度和恢复质量,降低虚警率,提出了一种窜改认证与内容恢复分离的自嵌入水印算法。该算法以2×2的图像块为认证单位,将认证水印与恢复水印分别嵌入到自身图像块和偏移图像块中,使认证虚警率降为0;同时提出一种基于线性函数和混沌映射的偏移值选取方案,使图像的恢复质量得到提高。理论分析和实验结果表明,该算法能在抵抗拼贴和量化攻击的同时,准确定位图像窜改并以较高的质量进行恢复。

Self-embedding fragile watermarking algorithm with tamper authentication and content recovery separated

To improve the accuracy of authentication and the quality of reconstructed image, reduce the probability of false rejection, this paper proposed an authentication and recovery separated self-embedding watermarking algorithm. It defined 2×2 image block as an authentication unit. It embedded the authentication watermark and recovery watermark respectively into the block itself and the corresponding excursion block, reducing the probability of false rejection to 0. It proposed an offset value selection sheme based on linear function and chaos mapping to improve the quality of the reconstructed image. Theoretical analysis and simulation results show that the proposed algorithm can not only thwart the collage and VQ attack, but also locate tampered blocks accurately and restore it effectively.