New software to detect forged photos

Scientists have developed a new software to detect forged photos and have used it to debunk claims that the 1969 Apollo 11 lunar landing photo is fake.
The new method by Dartmouth College and University of California, Berkeley researchers uses a geometric algorithm to locate inconsistent shadows that are not obvious to the naked eye.
The technique analyses a variety of shadows in an image to determine if they are physically consistent with a single illuminating light source.
This allows a forensic analyst to determine if a photo is physically plausible or the result of image fakery. This method has, for example, debunked the claims that the lighting and shadows in the famous 1969 moon landing photo are fake, researchers said.

"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," said 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," Farid said.

The study will be published in the journal ACM Transactions on Graphics.