Comparative study of copy-move forgery detection techniques

Digital images and their applications gained a huge interest around the world in several fields like newspapers, social media, defaming persons, and courts. There are two types of digital image authentication. The first type is active authentication, which uses digital signature and image watermarks. These techniques have certain constraints such as knowing the content of the digital image. They need special equipment like cameras and development software. The second type is passive authentication, which is used to detect digital image forgeries represented in image cloning, image splicing, image resampling, image retouching, and image morphing. Passive authentication has an advantage of not needing any previous knowledge of the image content to detect the forgery. Copy-move forgery is the most famous type, and it is widespread in all image forgeries. Copy-move forgery is easy to perform and the forged part has the same properties of the whole image that makes it difficult to detect. There are many algorithms used to detect copy-move forgery attacks depending on different techniques. This paper covers the directions of copy-move forgery detection and gives a wide coverage of earlier copy-move forgery detection algorithms and techniques.