"A picture shows me at a glance what it takes dozens of pages of a book to expound." - Ivan Turgenev The above line written in 1862 are not only true today, but with amplified significance and consequences. The relevance and importance of digital images growing day by day. They are a major source of information exchange in the digital world. Digital images are used to illustrate facts, establish facts and used by the newspapers, magazines and social media to strengthen the perception. Also digital images are used as corroborative evidences in criminal investigation. So it is very much necessary to ensure the truth of what is being believed. The issue of forged images is not new, but technology advancement in hardware and software has made it easier and cheaper to manipulate an original image either to mislead the audience or to form a particular public perspective about famous personalities. Many instances (http://www.fourandsix.com/photo-tampering-history/, n.d.) have been reported in the past to justify the claim. Some of the widely circulated instances of forged images are shown in Figure 1.1. Digital image forgery may be done just for fun or for a grave illegal act. Digital image forgery may impact various aspects of society like evidence tampering, antique faking, political agenda or criminal investigation. With the menace of digital image …show more content…
The very fact about natural images that no significant regions are exactly same in an image is exploited in all such techniques. So if there is a sizable region to hint duplication then that is treated as case of copy move forgery. We have used block based methods, keypoint based methods and statistical method using independent component analysis. In the block based methods discrete cosine transform is used to convert the image information in spatial domain to frequency domain and characteristics of DCT coefficients are