October 2005, Issue #42

Hot Topic:

JETS' Pre-Engineering Times Hot Topics column highlights current research related to the featured engineering discipline each month. JETS wants you to know the new field advances being made through the exciting discoveries of research.

This month's research focuses on trustworthy photographs comes from Columbia University's Digital Video and Multimedia Lab.

Trustworthy photographs play an important role in many applications such as news reporting, intelligence information gathering, criminal investigation, security surveillance, as well as health care. However, with the advent of digital age, the trustworthiness of pictures could no longer be taken for granted. This project will develop a completely blind and passive system for detecting digital photograph tampering. No extra encryption, signature extraction, or information embedding processes are needed. Content tampering operations are detected at the point of checking by analyzing the natural signal/scene characteristics in the image.

We take an innovative approach integrating techniques from signal processing and computer graphics. The signal processing method involves effective use of higher-order signal statistics, signal acquisition device modeling, image decomposition, and image structural analysis to identify tampering artifacts at the signal level. The computer graphics approach includes novel techniques of 3D geometry estimation, illumination field recovery, and scene reconstruction to detect inconsistency at the scene level like shadows, shading, and geometry.

We aim at a successful system that makes any attacking maneuver as difficult as possible. The system will also provide equal emphasis on robustness and informativeness — suspicions will be explained with locations and reasons. To achieve broader impacts, the proposed research will include deployment of a public image forgery detection engine, release of a large original data set, and definitions of evaluation benchmark.

Authors: Professor Shih-Fu Chang (PI), Professor Ravi Ramamoorthi (co-PI), Tian-Tsong Ng, Jessie Hsu, Dhruv Mahajan

Research Sponsor:National Science Foundation Cyber Trust Program, Award No IIS-04-30258.

For additional information: http://www.ee.columbia.edu/dvmm/