Abstract: When creating a digital composite of, for example, two people standing side-by-side, it is often difficult to match the lighting conditions from the individual photographs. Lighting inconsistencies can therefore be a useful tool for revealing traces of digital tampering. Borrowing and extending tools from the field of computer vision, we describe how the direction of a point light source can be estimated from only a single image. We show the efficacy of this approach in real-world settings.

@inproceedings{johnson-farid05,
  url          = {http://www.cs.dartmouth.edu/farid/publications/acm05.pdf},
  booktitle    = {ACM Multimedia and Security Workshop},
  author       = {Micah K. Johnson and Hany Farid},
  year         = {2005},
  title        = {Exposing digital forgeries by detecting inconsistencies in lighting},
  address      = {New York, NY},
}