Tamper Detection Method for Clipped Double JPEG Compression Image

With the development of digital image processing technique the credibility of digital image has been questioned. This paper proposes a new tamper detection method for clipped double JPEG compression image based on the statistical characteristics of DCT coefficients and block effect caused by double JPEG compression. The offset of the two DCT grids can be obtained by computing the loss of information. Then we will trim the image according to the offset, and it will be available to estimate the primary compression quality factor. The tampered area can be located according to the difference of DCT coefficients. Experiments results show that the proposed method is robust and effective in detecting the clipped double JPEG compression image. And the method is also applicable to the unclipped double JPEG compression image.