Computer graphics rendering software is capable of generating highly photorealistic images that are often very difficult to differentiate from photographic images. We have, however, developed a method for differentiating between photographic and computer generated (photorealistic) images. Specifically, we have shown that a statistical model based on first- and higher-order wavelet statistics reveals subtle but significant differences between photographic and photorealistic images. This work has begun to have interesting legal applications in light of the 2002 United States Supreme Court ruling that effectively legalized "virtual child pornography".

In related work, we have developed techniques to detect traces of digital tampering, and to detect the presence of hidden messages embedded within digital images.

Matlab routines

(Collaborative work with Siwei Lyu)