基于图像正则化的抗几何变换的感知哈希算法

图像哈希在内容认证、数据库搜索和水印等领域有广泛的应用。该文提出的新的抗几何变换的感知哈希方法包括三个主要阶段：第一阶段通过图像正则化过程获得一个对任意仿射变换具有不变性的正则图像；第二阶段对随机选择的多个子图像进行小波变换产生一个包括图像主要特征的副图像；第三阶段采用奇异值分解捕获图像的局部感知成分并生成最终哈希。仿真实验表明算法有效抵抗了几何变换、压缩等感知保持操作，内容篡改也被正确检测。批量实验也证明算法有较好的稳健性和抗误分类能力。

Robust Perceptual Hashing Algorithm to Geometric DistortionsBased on Image Normalization

Image hashing functions have extensive applications in content authentication, database search and watermarking, etc. A novel perceptual hashing algorithm is developed which is robust to geometric distortions. The algorithm includes three stages: the first stage obtains the image that is invariant to any affine transforms through a normalization procedure; the second stage applies discrete wavelet transform to pseudo-randomly select sub-images to obtain secondary image including main features; the third stage uses singular value decomposing to capture local perceptual features and to get the final hash. The experiments show the method withstands perceptually preserved manipulations including geometric distortions, compression, and common signal processing operations. The content changes are also can be detected accurately. Thus the proposed method achieves perceptual robustness while avoiding misclassification.