提出一种基于奇异值分解和混沌映射的图像脆弱认证水印算法,将混沌映射的初值敏感性应用到图像的篡改检测中。对图像子块进行奇异值分解,同时利用Logistic混沌映射产生认证水印;然后利用Logistic混沌映射设计了一个子块与子块之间的映射函数,将认证水印序列嵌入在相应映射块的LSB上。实验结果表明,算法不仅对篡改非常敏感,而且能够有效地抵抗拼贴攻击和区分篡改图像内容与篡改水印。

An image fragile authentication watermark algorithm based on singular value decomposition and chaotic mapping was proposed, trying to apply chaotic mapping’s initial value sensitivity to tamper detection. Singular value decomposition was carried out on each image block, and authentication watermark was produced by using Logistic chaotic mapping. Then Logistic chaotic mapping was used to design a mapping function defined on two separate blocks, and authentication watermark sequence was embedded into the corresponding mapping block’s LSB. The experimental results show that the algorithm is not only very sensitive to tamper, but also resists collage attack and distinguishes image content tamper from watermark tamper.