Tampered Regions Detection for JPEG Images by Using DCT Coefficients of Re-Saved Image

Recently, digital images have been used in various situations. However, development of image editing software has made image editing easier, which has caused the problem of maliciously tampered images. Therefore, in order to ensure the reliability of digital images, it is necessary to detect whether it has been tampered with or not. On the other hand, the JPEG format is the most famous image file format. This is because this compression rate is higher than that of other file formats. In this study, we propose a novel method to detect tampered regions in a JPEG image using its DCT coefficient. The proposed method deteriorates an input image by re-saving it with another JPEG format. The tampered regions are detected by using the difference image obtained from an input image and its re-saved image in the DCT domain. The effectiveness of the proposed method was verified by experimental results.