To address the security risk caused by fixed offset mapping and the limited recoverability of random mapping used in image watermarking, we propose an image self-embedding fragile watermarking algorithm based on deneighborhood mapping. First, the image is divided into several 2*2 blocks, and authentication watermark and recovery watermark are generated based on the average value of the image blocks. Then, the denighborhood mapping is implemented as, for each image block, its mapping block is randomly selected outside it's neighborhood whose size is specified by a parameter. Finally, the authentication watermark and the recovery watermark are embedded in the image block itself and its corresponding mapping block. Theoretical analysis indicates that in the case of continuous region tampering, the proposed watermarking method can achieve better the recovery rate of the tampered image block than the method based on the random mapping. The experimental results verify the rationality and effectiveness of the theoretical analysis. Moreover, compared with the existing embedding algorithms based on random mapping, chaos mapping and Arnold mapping, in the case of continuous region tampering, the average recovery rate of the tampered region achieved by the proposed algorithm is higher.
翻译:为解决固定偏移绘图和图像水标记中随机绘图的可回收性有限造成的安全风险,我们提议基于邻里绘图的图像自构脆弱水标记算法。 首先,图像分为几个2*2区块,根据图像区块的平均值生成认证水印和回收水标记。然后,对每个图像区块,其绘图区块是随机选取的,因为每个图像区块的绘图区块的大小由参数指定。最后,在图像区块本身和相应的绘图区块中嵌入认证水标记和回收水标记。理论分析表明,在连续进行区域篡改的情况下,拟议水标记法比随机绘图法的回收率要高。实验结果验证了理论分析的合理性和有效性。此外,与基于随机绘图、混乱测绘和阿诺德绘图的现有嵌入算法相比,在连续区域篡改的情况下,拟议算法所实现的被篡改区域的平均回收率更高。