Digital image forgery — A threaten to digital forensics

Photography is an art. A digital image is a part of the real world formed after cycles of image generation process. From the initial days of photographic images itself, security and authenticity were major issues. With the era of digital images, the process of altering an image became so popular. The supersonic development in this particular field helps a layman to tamper the image effortlessly. Powerful editing software allows even relatively inexperienced users to process digital images in a convenient way which can challenge the authenticity. So it is inevitable to have an image forgery detection tool to prove the genuineness of the digital image. Without any prior information of the source and the details of a forged image, the passive (blind) techniques detect the image forgery by evaluating the changes in the properties of an image. This paper presents a survey on the recent passive methods for image forgery detection.