Robust Copy–Move forgery revealing in digital images using polar coordinate system

Abstract

Copy–Move (CM) is a common type of digital image forgery where a part of the original image is copied and pasted at another position in the same image. Sometimes, to increase the invisibility of the copying process, some processing procedures on the copied region are performed before or after pasting. Although block matching (BM) is the common well-used procedure for CM tempering detection, blind CM detection with geometric or intensity transformations is still a challenge. In this paper, we propose an efficient methodology for enhancing BM based Copy–Move forgery detection. The main contribution of this work is the utilization of polar representation to get the representative features for each block. The main feature used in this paper is the frequency of each block based on Fourier transform. The experimental results show the efficiency of the proposed method for detecting CM regions, even when the copied region has undergone severe image manipulations such as rotation, scaling, Gaussian blurring, brightness modification, JPEG compression and noise addition.