- Title: Ultra-sensitive camera sees around corners
- Date: 11th May 2016
- Summary: PROGRAM DATA ON SCREEN VARIOUS OF CHAN, WARBURTON, AND ON-SCREEN DATA
- Embargoed: 26th May 2016 10:28
- Keywords: laser pulse laser camera photon speed of light Daniele Faccio Heriot-Watt Edinburgh
- Location: EDINBURGH, SCOTLAND, UK
- City: EDINBURGH, SCOTLAND, UK
- Country: United Kingdom
- Topics: Science
- Reuters ID: LVA0054HD60D7
- Aspect Ratio: 16:9
- Story Text: A new camera-based system that can see around walls and locate hidden objects with centimetre precision in real time has been developed at the University of Heriot Watt in Edinburgh.
Researchers from the university's Extreme Light group developed their system using a camera created at the nearby University of Edinburgh.
The camera is sensitive to single photons, at a wavelength of light about 500 nanometres (two thousandths of a millimetre) in diameter, as researcher Ryan Warburton explained.
"The camera was devised by the University of Edinburgh and the special thing about it is that it's sensitive to single photons, so to a single particle of light," he told Reuters. "It also has the ability, not just to detect that photon but also to accurately time when it arrived and that's one of the crucial things in our set-up here. So what we got from Edinburgh was a sensor and a board that it was housed on, and we developed the camera around that, so that we can use it in this experiment and any experiment outdoors as well."
It can find a photon in a 32-by-32 grid by using laser pulses fired at 20 billion shots per second, says the team, which used the camera to locate a 30-centimetre-high foam human model dubbed Terry in laboratory experiments.
According to colleague Genevieve Gariepy, the camera is able to track objects moving around corners, even when completely obscured from view, by firing laser pulses at the floor. "What we do is we have those laser pulses and we shoot them at the floor, so if we have an obstacle like a wall or something or a corner that we want to look around, 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," she explained. "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 - and this is very hard to capture because it is a very low signal and moves very quickly because it moves at the speed of light. But our camera is so sensitive that it doesn't need to acquire (information) for a long time to be able to capture the signal. So in about a second we have enough signal to be able to say this is where the echo is coming from."
Previous research aimed at seeing around corners has involved bouncing laser beams off static objects and measuring the time it took those beams to reach them, which helped build a three-dimensional graphic of the scene. No such system works in real time, says the team.
Warburton believes the team's device could be installed on top of cars to help drivers avoid colliding with unseen vehicles or pedestrians around corners.
"We've had quite a lot of interest from the automotive industry whereby you can see that if this would be useful for accident avoidance or for autonomous driving because if you have it mounted on top of a car you can then project the laser pulse out and if there's a car coming, speeding past the junction or coming towards you, you have knowledge of that before you actually see the car itself," he said.
It could also have potential use in aviation or search and rescue missions.
The team has increased the distance from which the camera system works to several metres. Researcher Susan Chan says the next stage of research led by Professor Daniele Faccio, is to increase this distance further and also test the camera outdoors using human volunteers.
"What we're trying to do now is try to push the limits of our system and try to take it out of the lab," she said. "So we're trying to extend the range to tens of metres. We're also trying to work with more laser power. That way we can take it out of the lab and use it in an eye-safe situation. For example, like when you're using it for autonomous driving, to make sure you can detect the signals in a situation where there is people moving around who are not co-operative with the system, so to speak."
The research was published in peer-reviewed scientific journal Nature Photonics last December. - Copyright Holder: REUTERS
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