A Camera that can take 3D images in dark

In this week’s issue of the journal Science, researchers from MIT’s Research Laboratory of Electronics (RLE) describe a new lidar-like system that can gauge depth when only a single photon is detected from each location. Since a conventional lidar system would require about 100 times as many photons to make depth estimates of similar accuracy under comparable conditions, the new system could yield substantial savings in energy and time — which are at a premium in autonomous vehicles trying to avoid collisions.


The team captured images of objects, using just single particles of light, known as a photons. "Billions" of photons would be required to take a photo using the camera on a mobile phone. The researchers say the technology could be used to help soldiers on combat operations.

Ahmed Kirmani, a graduate student in MIT’s Department of Electrical Engineering and Computer Science and lead author on the new paper, explains, the very idea of forming an image with only a single photon detected at each pixel location is counterintuitive.

 “The way a camera senses images is through different numbers of detected photons at different pixels,” Kirmani says. “Darker regions would have fewer photons, and therefore accumulate less charge in the detector, while brighter regions would reflect more light and lead to more detected photons and more charge accumulation.”

 This camera technology existed as a Lidar System which is used by Google for it's Streetview service. Lidar uses a laser to fire pulses of light towards an object in a grid sequence. Each location on the grid corresponds to a pixel in the final image.

Normally the laser would fire a large number of times at each grid position and detect multiple reflected photons. In contrast the system used by the MIT team moved on to the next position in the grid as soon as it had detected a single photon.

The team say the technology could be used in many different fields. It could help ophthalmologists when they want to create an image of a patient's eye without having to shine a bright light in someone's eye.

The research was part funded by the US Defense Advanced Research Projects Agency which commissions research for the Department of Defense. Mr Kirmani said the military could use the technology to allow soldiers to see in the dark, giving them an advantage in combat situations.