为了解决奇异值最高位在几何攻击下易敏感性和零水印抗几何攻击性能差的问题,提出一种基于改进奇异值和子块映射的图像零水印技术。首先,对载体图像进行Arnold置乱处理,消除像素间的相关性。然后,进行Curvelet变换、分块以及奇异值分解以获得载体图像的稳定特征。同时,提出一种子块映射机制,将原始的版权图像划分成不同的子块,并通过对子块求和,使用不同的字符表示水印子块。最后,将载体图像的特征与水印子块按位进行逻辑运算生成零水印。实验结果表明,所提出的图像零水印算法在几何攻击、非几何攻击以及组合攻击下具有很强的鲁棒性,并且生成的零水印信息安全性更高。

In order to solve the problem of the sensitivity of the highest singular value bit under geometric attack and the poor anti-geometric attack performance of zero watermark, an image zero watermark technology based on ameliorated singular value and sub-block mapping is proposed. Firstly, the carrier image was Arnold scrambled to eliminate the correlation between pixels, and then Curvelet transformation, partitioning and singular value decomposition were performed to obtain the stable characteristics of the carrier image. At the same time, a seed block mapping mechanism is proposed to divide the original copyright image into different sub-blocks, and by suming the sub-blocks, different characters are used to represent the water imprint block. Finally, the feature of the carrier image and the water imprint block are logically calculated to generate zero watermark by bit. Experimental results show that the proposed zero-watermarking algorithm has strong robustness under geometric attack, non-geometric attack and combined attack, and the generated zero-watermark information is more secure.