Photo Forensics – There Is More to a Picture than Meets the Eye

Abstract

Given an image or a video clip can you tell which camera it was taken from? Can you tell if it was manipulated? Given a camera or even a picture, can you find from the Internet all other pictures taken from the same camera? Forensics professionals all over the world are increasingly encountering such questions. Given the ease by which digital images can be created, altered, and manipulated with no obvious traces, digital image forensics has emerged as a research field with important implications for ensuring digital image credibility. This talk will provide an overview of recent developments in the field, focusing on three problems. First, collecting image evidence and reconstructing them from fragments, with or without missing pieces. This involves sophisticated file carving technology. Second, attributing the image to a source, be it a camera, a scanner, or a graphically generated picture. The process entails associating the image with a class of sources with common characteristics (device model) or matching the image to an individual source device, for example a specific camera. Third, attesting to the integrity of image data. This involves image forgery detection to determine whether an image has undergone modification or processing after being initially captured.