Image Tamper Detection Using Non Alignment of Jpeg Grids

Digital images have a very significant role in various fields like criminal and forensic investigations, medical imaging and journalism. But due to wide availability of powerful editing software, image forgery has become much easier. The aim of this paper is to detect the forgery on JPEG compressed images when splicing (copy-paste) will result in non alignment of JPEG grids. JPEG is widely used image compression format for digital images. Blocking artifacts introduced during this operation can be used as footprints to detect tampering. Detection is based on the fact that blocking artifact grids (BAG) usually mismatches after copy paste operation. An attempt is made to enlist all existing references related to block artifact grid extraction. These techniques have been designed to determine whether the content is authentic or modified without the knowledge of any prior information about the image under analysis and thus are passive in nature. Study of these methods will be helpful in finding out new algorithms to detect image tampering using grids inconsistency.