Camera takes 3D photos in the dark

A camera that can create 3D-images in almost pitch black conditions has been developed by researchers at Massachusetts Institute of Technology.

On the left is an image created using current technology - the photo on the right was produced from the MIT team's new camera technology

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, who wrote the paper containing the findings, said the research has been called "counter-intuitive" as normally the number of photons detected would tell you how bright an image was.

"With only one photon per pixel you would expect the image to be completely featureless," he told the BBC.

Combat advantage

The camera technology already existed and is similar to the Lidar system used by Google for its Streetview service he explained.

"We borrowed the principles form this, the detectors can identify single photons but they still need hundreds of thousands to form images. But we took the system to its limit."

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.

A conventional Lidar system would require about 100 times as many photons to make a similar image to the one the team captured which means the system could provide "substantial savings in energy and time".

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.

Current 3D imaging techniques require more than single photons unlike the team's new system

"Any technology that enhances a military's ability to navigate, target or engage in near-total darkness would be highly prized. 3D imagery married with existing imagery and navigation technologies could significantly enhance the capabilities currently possessed," said Reed Foster, a defence analyst at IHS.

Eventually, the researchers explain, the technology could be developed to make 3D cameras for mobile phones. The camera requires less light than the ones currently available and therefore uses less power.