A study on features for the detection of copy-move forgeries.pdf

A Study on Features for the Detection of Copy-Move Forgeries Vincent Christlein, Christian Riess, Elli Angelopoulou {sivichri@stud, riess@i5, elli@i5}.informatik.uni-erlangen.de Abstract: Blind image forensics aims to assess image authenticity. One of the most popular families of methods from this category is the detection of copy-move forg- eries. In the past years, more than 15 different algorithms have been proposed for copy-move forgery detection. So far, the efficacy of these approaches has barely been examined. In this paper, we: a) present a common pipeline for copy-move forgery detection, b) perform a comparative study on 10 proposed copy-move features and c) introduce a new benchmark database for copy-move forgery detection. Experiments show that the recently proposed Fourier-Mellin features perform outstandingly if no geometric transformations are applied to the copied region. Furthermore, our experi- ments strongly support the use of kd-trees for the matching of similar blocks instead of lexicographic sorting. 1 Introduction The goal of blind image forensics is to examine image authenticity without the help of an embedded security scheme (like watermarks). In the past few years, a diverse set of meth- ods for blind image forensics has been developed, see e. g. [SM08, NCLS06, Far09a]. The existing methods can be divided into three categories. The first group focuses on detecting the existence of expected artifacts that have been introduced in the process of image sens- ing. The detection of inconsistensies in such artifacts is a cue for the lack of authenticity of an image. Particular examples include the recovery of a camera-specific sensor noise pattern by Lukas et al. [LFG06], the estimation of the camera response function [HC07], demosaicing [GC08], or the extraction of lens properties [JF06]. A second approach is to search for inconsistencies in the scene that have been introduced as a side effect of tampering. Johnson and Farid presented an approach