Photoshop Milestone

Well, not so much for Photoshop, but for us poor suckers who believe faked photos.  Dartmouth and UC Berkeley researchers created a software program that can tell if a photo is faked by testing whether the shadows within are consistent with a single light source throughout the photo.

"Our method shifts the dialogue from ‘does the lighting/shadow look correct?,’ which is well known to be highly unreliable, to a discussion of whether an analyst has correctly selected the location of cast and attached shadows in an image, a far more objective task," says senior author Hany Farid, a professor of computer science and head of the Image Science Group at Dartmouth. "In this regard, our method lets humans do what computers are poor at—understanding scene content—and lets the computer do what humans are poor at—assessing the validity of geometric constraints."

The study, titled "Exposing Photo Manipulation with Inconsistent Shadows," was presented last week at the Association for Computing Machinery’s SIGGRAPH conference, to be published in the journal ACM Transactions on Graphics in September.
I wonder how many fakes this technique will catch.