Scale-Invariant Moment Based Robust Image Copy Detection in DCT Domain

In this paper, an invariant moment based robust image copy detection algorithm in discrete cosine transformation (DCT) domain is proposed. Low and middle frequency coefficients which are calculated from full DCT transformation on luminance component of image are used as the image eigenvector in DCT domain. The query image and its angle normalized image eigenvector in DCT domain are computed, then correlation values of two eigenvectors of the query image and those of test image are respectively computed and the larger one is used to judge whether the query image is a copy or not. Full DCT coefficients are verified to have high robustness against common signal attacks and regularly vary with scaling attacks, thus the DCT eigenvector constructed by middle and low frequency full DCT coefficients can resist signal attacks and scaling distortion. The characteristic angle estimated by the image scale invariant moment is used to normalize the image to counteract the rotation distortion, so the angle normalized image can resist rotation distortion. The experimental results show that the algorithm is superior to Ling's methods in terms of rotation distortion.