An ultra-sensitive camera that can locate single photons, by firing laser pulses on the ground and imaging return signals at the speed of light, can locate hidden people or objects in real time, say researchers. The system has potential use in preventing car accidents and helping rescuers locate missing persons in disasters. Jim Drury reports.
Polystyrene model Terry appears to be hidden from view. But this camera developed by Scottish researchers can see round corners, and spots him lurking. SOUNDBITE (English) RYAN WARBURTON, HERIOT-WATT UNIVERSITY RESEARCHER, SAYING: "The camera was devised by the University of Edinburgh and the special thing about it is that it's sensitive to single photons, so a single particle of light. It also has the ability, not just to detect that photon but also to accurately time when it arrived." Heriot-Watt University researchers fine-tuned the camera, so it fires laser pulses at 20 billion shots per second to locate objects in real time. SOUNDBITE (English) GENEVIEVE GARIEPY, HERIOT-WATT UNIVERSITY RESEARCHER, SAYING: "We'll send the short pulses of light at the floor and when they reach the floor they will scatter in every direction and it will grow like a big sphere. So we will reach whatever is hidden around the corner and if an object is there or a person it will do the same thing, it will reflect off the object and send a big sphere of light, a bit like an echo. And then the camera is able to capture that echo as it is coming back...So in about a second we have enough signal to be able to say this is where the echo is coming from." Most research aimed at seeing around corners involves bouncing laser beams off static objects and measuring the time this takes, helping to build a 3D graphic. But that can't be done in real time. Auto makers are interested in using this camera technology on car roofs to help drivers avoid collisions with unseen vehicles or pedestrians. It could also be used in aviation or search and rescue missions. The system works at a distance of several metres and the team hopes to increase that. They'll soon test it outside, using real people. For now Terry continues to play Hide and Seek in the laboratory - and with this camera it's a game he's always destined to lose.