Wednesday, December 14, 2011

Reason #88: Femto Photography


With funding from DARPA, the Army Research Office, and a number of private enterprises, MIT has developed a technique for recording bullet-time images of light in motion. Except "bullet-time" is a horrible way to put it because light moves around a million times faster than a bullet.

Direct, traditional photography is almost impossible at that speed, so what they've actually done is program sensors to take complex mathematical measurements of a subject as a pulse of light one trillionth of a second long is shot through said subject at 186 thousand miles per second. The measurements--the exposure, essentially--are then reconstructed into a more standard "image" of the subject, at a rate of half a trillion frames per second. Photographing a bullet, incidentally, only requires around 20 thousand frames per second.

Because the pulse is so short, the actual "beam" of light is only a millimeter or so long, which ironically makes it look kind of like a bullet, except, you know, all awesome and glowy and stuff. They for some reason chose to test this process with a Coke bottle, resulting in the extremely awesome video below. A lot more can be found on MIT's website here.

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