MIT camera can 'see around corners'

A prototype camera system can "see around corners" using bursts of light, according to the Massachussets Institute of Technology researchers who designed the device.

The system bounces femtosecond-long bursts of laser light off walls, doors or floors to build 3D images of objects that are out of the camera's line of sight, MIT said in a statement on Wednesday.

"Four years ago, when I talked to people in ultra-fast optics about using femtosecond lasers for room-sized scenes, they said it was totally ridiculous," Ramesh Raskar, an associate professor at the MIT Media Lab, said in the statement.

Using the same principle as a periscope reflecting light, the system fires ultra-short bursts of laser light at a surface such as a wall, to angle the light pulses into a room. The light bounces around inside the room, and is picked up when it emerges by a detector that can take measurements every few picoseconds.

The system gauges how far the bursts of light have travelled by measuring the time taken for the light bursts to get back to the detector, said MIT. This allows the system to build a 3D image of the object.

"Light is scattered not only by transmission through objects, but also by multiple reflection from diffuse surfaces in a scene. This reflected light contains information about the scene that becomes mixed by the diffuse reflections before reaching the image sensor. This mixing is difficult to decode using traditional cameras," the researchers said in a paper published in Nature Communications on Tuesday.

The technology could eventually be used by emergency services to locate people in dangerous situations, said MIT. Further possible applications for such picosecond photography include vehicle navigation systems and endoscopy.

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