A group of researchers at Heriot-Watt University of Edinburgh has realized a camera capable of detecting objects placed "behind the corner", hidden from view, tracing the movement in real time even if it is in fact located outside the visual field.

I see and I see.
The system - described in Nature Photonics - is based on a laser and an ultra fast device for image acquisition, said SPAD (single-photon avalanche diode).
As can be seen in the opening movie (in English), when the light beam is directed toward the floor, bounces in every direction, going to hit the shape placed around the corner: in this way the reflected light generates a "echo" that It falls within the visual field of the camera, allowing it to record the position of every single photon.
"By measuring the return time of the signal - in practice, the echo - we also know how far away the object," explains Genevieve Gariepy, coauthor of the study: the sensors kit is capable of detecting the position of each individual photon, working at a speed of 20 billion frames per second.
What is the novelty.
In the past similar monitoring methods we had already been developed, but with very long acquisition times of images.
The camera of the Heriot-Watt University, however, it works (almost) real-time locating persons or within 1 second.
The ability to quickly encode the received information, it also allows to detect if the subject being filmed is in motion.
Applications.
Researchers are now trying to improve the device performance, also focusing on the reconstruction of the images in 3D, with the aim of providing a tool to facilitate rescue operations in hard to reach places.

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