Detecting Photo Forensics Through Geometrical And Physical Clues

With the development of the digital image and the corresponding image processing tools, more and more multimedia contents make their way into our life and scope, which challenges the authenticity of the multimedia information. How to judge the authenticity of a given image with only the help of the image itself has become a emergency task.This paper aims to find a solution to the above problem, using the perspective image theory and optics information. We propose a new framework to detect forensics of the image. The framework includes copy detection method using feature description and matching algorithm. The proposed blind method, which does not require inserting additional watermark into the target image at the time recording, can be used to judge the authenticity of the image and help making decisions for news, military, laws and economics. We proposed a new set of methods based on geometrical and physical constraints. For the methods based on geometrical clue, we use the epipolar constraint and planar homography constraint. For the methods based on physical clue, we use the shadow matte and lighting source consistence. Considering extracting complex lighting model is difficult for now, shadow matte in graphics is introduced into image copy detection, and the simple lighting source consistence is also proposed as a physical constraint.