My Photoshop skills are such that any sighted person could easily figure out if I tried to digitally manipulate an image. But there are plenty of other people in the world with far better abilities, not to mention fewer scruples.
But, as an article in The Christian Science Monitor shows, there are new digital techniques being developed to expose those forgeries.
As head of Dartmouth College’s Image Science Group in Hanover, N.H., he’s developed computer algorithms that can tease out the tiny flaws hidden in phony photos.
“There’s no way to push a button and tell if it’s real, but there are tests we can run that allow us to be pretty sure if it’s a fake,” says Farid.
Some of the investigative techniques are simply teaching a computer to spot what the untrained eye is too lazy to see. If a figure from one photo has been edited into another, there are almost always imperfections — subtle inconsistencies in the physics and geometry of the combined image. The vanishing points might be off, or the shadows cast from two or more objects may contradict one another.
Be sure to watch the video that uses some recent examples to show how you may only need some basic observational powers to detect fraudulent images.
Better yet, show it to your students.