MIT Photon Camera Can See 3D Objects Around CornersBy: Jonathan Fisher - March 21, 2012
Leave it to the MIT Media Lab to come up with crazy new stuff. Now they’ve made a camera that can see around corners. Well, kind of. It’s not gonna take a picture of you that your Mom would recognize, but it does create 3D images of objects that are in another room.
According to Nature.com, the camera works by exploiting what researcher Ramesh Raskar calls “echoes of light.” Essentially, a very high-speed camera fires a super quick (50-femtosecond) laser pulse at a wall, that pulse breaks up into photons and scatters, and some of those photons hit objects out of view of the camera, ricochet off the objects, bounce back to the wall they first hit, and re-enter the camera lens. The camera’s time resolution is two picoseconds, the time it takes light to travel 0.6 mm, so when photons reach the camera at different times, positions, and angles, a computer is able to determine how far each photon has traveled with an accuracy of less than a millimeter. To adjust for different photons hitting the camera at the same time, the laser’s position is changed 60 times, and the results, processed through a complicated algorithm, yield a 3D image that would otherwise be hidden from view.
Right now the process takes several minutes, but researchers have a goal of speeding up the process to under 10 seconds, reports Nature.
The implications of such a device are all over the place, especially if researchers meet their goal of speeding up the process to someday create realtime images, even of moving objects. Safety is cited as the major advantage of the technology: Nature suggests the camera could be used in dangerous or inaccessible places, like moving machinery or contaminated areas. Beyond that, far more advanced versions of the technology could in the future help rescuers know what’s going on inside a room before they enter. This could be invaluable in fires, hostage-rescue situations, and even bomb scenarios. Of course, if there’s anything that operates faster than the 50-femtosecond laser pulse, it’s governments’ desire to weaponize new technologies. I wouldn’t be surprised to someday see related technologies mounted on gun barrels or military and police vehicles, or integrated into individual warfighters’ heads-up displays. Of course, it could also be used for spying — both on criminals and law-abiding citizens alike.
But that’s a long way off for a camera that still takes several minutes to create a single image. Regardless of the potential for future application or abuse, it’s a really impressive technology. Here’s a video from Nature that shows how the camera works: