Hyper-sensitive laser camera sees around corners in real time

 

 You never know what’s around the corner — unless you happen to have a super-advanced camera designed by researchers at Heriot-Watt University in Edinburgh, Scotland. This device has been designed to take extremely sensitive photographs that can detect the minute reflected lights from objects not in its field of vision. The result is a camera that sees around corners, and it works in real time.
The single-photon avalanche diode (SPAD) camera relies upon a type of echo mapping. You can think of it a little like radar, but with light. This part isn’t anything new — other projects have managed to do similar things. However, this camera is so sensitive that it can capture a photo every second. Therefore, you can watch an object move with the SPAD camera even when it’s technically out of sight.
To make this happen, the researchers used a laser ranging technology to provide the photons. The laser pulse is fired at a surface beyond the corner in the same direction the camera is facing. When it strikes the surface, light is reflected in all directions. The camera sees this propagation of photons, then it watches for a response — an echo. That wave will eventually hit the hidden object and reflect back, but weakly. The laser is extremely fast, though, firing as many as 67 million times per second. That feeds a lot of information into the camera because it can detect even a single photon passing through its field of vision.

 
You won’t get a photo-realistic rendering of the hidden object, but the SPAD does offer plenty of data. The photons collected by the camera can be used to calculate the size, speed, and location of the object down to a centimeter or two. It even manages to recognize multiple objects based on the dispersal of photons.
So, this is cool science, but what is it good for in real life? The researchers speculate than a camera able to see around corners in real time could be invaluable for search-and-rescue scenarios. Rescue workers could avoid entering an area unless they were sure it was necessary. It might also be used for collision avoidance in cars in the same way laser rangefinders and sonar are used now. If the car knows there’s something car-sized moving toward you from around the corner, it might prevent you from accelerating into its path. The problem is adapting the technique to real-world conditions. It works fine in a controlled laboratory setting, but there are a lot of photons bouncing around from all different sources outside the lab. If that can be accounted for, we might be onto something.