Exposing digital forgeries in complex lighting environments

The availability of sophisticated digital imaging technology has given rise to digital forgeries that are increasing in sophistication and frequency. We describe a technique for exposing such fakes by detecting inconsistencies in lighting. We show how to approximate complex lighting environments with a low-dimensional model and, further, how to estimate the model's parameters from a single image. Inconsistencies in the lighting model are then used as evidence of tampering.