An efficient expanding block algorithm for image copy-move forgery detection

Image forgery is becoming more prevalent in our daily lives due to advances in computers and image-editing software. As forgers develop more sophisticated forgeries, researchers must keep up to design more advanced ways of detecting these forgeries. Copy-move forgery is one type of image forgery where one region of an image is copied to another region in an attempt to cover a potentially important feature. This paper presents an efficient expanding block algorithm for detecting copy-move forgery and identifying the duplicated regions in an image. Experimental results show that the new method is effective in identifying size and shape of the duplicated region. Furthermore, it allows copy-move forgeries to be detected, where the copied region has been manufactured slightly lighter or darker, under JPEG compression, or with the effect of Gaussian blurring, in an attempt to throw-off detection algorithms.