The camera uses the established technique of echo mapping to locate objects around a blind corner. Echo mapping is used already by other cameras to paint a 3D view of a room, but the speed at which Gariepy’s camera can make its measurements is what sets it apart from similar, existing technology. The system developed by Gariepy employs a precise laser and an advanced camera module so sensitive that it can track individual photons of light. Created by researchers at the University of Edinburgh, the camera not only is super sensitive, it also is fast, allowing the system to detect and track hidden objects in near real-time.
It achieves this goal by releasing short laser pulses that are aimed at the floor just in front of a wall. The light then bounces off the floor, hits the wall and radiates across the room. As the light encounters an object in the room, it bounces back to the camera, which is sensitive enough to detect these returning echoes. The laser fires up to 67 million times per second providing a wealth of data for the camera to process. Using information about how the laser light bounces and the characteristic of the echo it returns, the camera can calculate both the size and position of an object. It also is designed to make a new measurement every three seconds allowing it to detect and track movement of the object with near real-time precision.
In laboratory testing, Gariepy and her team were able to detect a one-foot tall human figure that was placed around a corner. It even worked when the object was located around a hairpin turn. When estimating the size of an object, the camera system was able to make a prediction that was within a 20-percent margin of error.
The team also was able to detect and track multiple objects at the same time. Though already impressive, Gariepy hopes to improve the technology by developing an even faster and more sensitive camera. The team also is experimenting with filters to try to isolate and measure just the specific wavelength emitted by the laser.