Tuesday, March 20, 2012
M.I.T. UNVEILS A CAMERA THAT CAN SEE AROUND CORNERS
Back in 2010 we shared that MIT was developing a special camera that uses echos of light to see around corners. Now, two years later, the researchers are finally showing off the camera in action. It works by firing 50 “femtosecond” (quadrillionth of a second) laser pulses 60 times at various spots at an angled wall. A special imaging sensor then collects the scattered light that’s reflected back and uses complex algorithms to piece together the scene based on how long the photons take to return. The process currently takes several minutes, but researchers hope to reduce it to less than 10 seconds, which would make it more useful for military and industrial applications. (via Scientific American) The ability to see objects hidden behind walls could be invaluable in dangerous or inaccessible locations, such as inside machinery with moving parts, or in highly contaminated areas. Now scientists at the Massachusetts Institute of Technology in Cambridge have found a way to do just that. They fire a pulse of laser light at a wall on the far side of the hidden scene, and record the time at which the scattered light reaches a camera. Photons bounce off the wall onto the hidden object and back to the wall, scattering each time, before a small fraction eventually reaches the camera, each at a slightly different time. It's this time resolution that provides the key to revealing the hidden geometry. The position of the 50-femtosecond (that's 50 quadrillionths of a second) laser pulse is also changed 60 times, to gain multiple perspectives on the hidden scene. "We are all familiar with sound echoes, but we can also exploit echoes of light," says Ramesh Raskar, head of the Camera Culture Research Group at the MIT Media Lab which carried out the study.