Perceptual hashing for color images based on hybrid extraction of structural features

In this paper, a novel perceptual hashing scheme for color images is proposed with the hybrid feature extraction mechanism. During the stage of pre-processing, image normalization, Gaussian low-pass filtering and singular value decomposition (SVD) are applied on original image to improve the robustness of the scheme. In order to fully extract the structural features, the circle-based and the block-based strategies are exploited to sample the salient edge points with the aid of Canny operator, and then the color vector angles, which can effectively describe color pixel information, are calculated for the sampled points. Finally, after quantizing and scrambling the variances of the color vector angles for these sampled points, the image hash can be generated securely. Experimental results demonstrate that our scheme can achieve satisfactory performances with respect to perceptual robustness and discrimination. (C) 2017 Elsevier B.V. All rights reserved.