Are you ready for CSI: Photoshop?
This is Sandra Tsing Loh with the Loh Down on Science.
Sometimes, you know when a photograph’s been doctored. But other times, a photo’s so expertly altered, the deception’s hidden.
Computer scientists at Dartmouth have a solution. They've developed software that spots fakery undetectable to the naked eye! The software centers on a basic fact: There’s always a direct line between a light source and shadows.
But in photographs, which are two-dimensional, it’s not always easy to match shadow with source. Objects may appear to block light. Shadows may look distorted.
So the software scans digital photographs using geometry-based algorithms. It looks at sections of shadows, and creates wedges pointed to the apparent light source.
In authentic photos, the wedges should intersect. If not? Doctored image!
As a test, the researchers scanned a picture of the 1969 Apollo moon landing. Conspiracy theorists insist that photo is faked. But the software indicated a single light source. So the moon walk really happened!
If only that recent Cabo vacation hadn’t happened. With, unfortunately, the photos to prove it.
***** For more 90-SECOND SCIENCE FACTS, click here.*****
The Loh Down on Science is produced by LDOS Media Lab, in partnership with the University of California, Irvine, and 89.3 KPCC. And made possible by the generous support of the Gordon and Betty Moore Foundation.
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