Shown to the right is a painting by Perugino. Like many Renaissance paintings it is likely that Perugino only painted a portion of this work - apprentices did the rest. It is often very difficult to determine how many hands contributed to a painting. We have developed a mathematical technique that can classify various parts of a painting as belonging to one or more artists. Beginning with a high-resolution digital scan, our technique works by looking for statistical differences across the canvas.

We have also applied this technique to detecting art forgeries -- in collaboration with the Metropolitan Museum of Art, we have analyzed drawings by Bruegel and find that we are able to perfectly distinguish between authentic drawings and known forgeries.

(Collaborative work with Siwei Lyu and Dan Rockmore)