1 Chapter 1 : Passive - Blind Image Forensics

One of the key characteristics of digital images with a discrete representation is its pliability to manipulation. Therefore, even back in 1989, the sesquicentennial year for photograph when digital images was gaining popularity, 10% of all color photographs published in United States were actually digitally altered and retouched, according to the Wall Street Journal [1]. The recent well-known tampered images are the Iraq soldier picture of the Los Angeles Times (March 2004) and the Internet image showing Jane Fonda and John Kerry sharing the same speaker platform (Feb 2004). The advanced digital image processing techniques provided by the image editing software like Adobe Photoshop are the catalyst for the prevalence of the manipulated digital images in the public domain, which is evident in web sites such as www.worth1000.com, which is a creative competition and Photoshop contest sites hosting as many as 178,582 Photoshop-created images as in Oct 2005. Besides image compositing, computer graphics nowadays can also produce image forgery of high photorealism. To showcase the high photorealism of computer graphics which rivals that of the real camera images, a 3D graphics company has setup a web site www.fakeorfoto.com for challenging viewers to distinguish computer graphics and camera images.