How a Camera Can See Around a Corner

A laser works like an echo.

While a camera that can see around corners might seem like like magic, researchers working at Heriot-Watt University in Edinburgh, Scotland, are here to tell you exactly how the trick is done. It all comes down to lasers and an extremely sensitive camera. A laser, similar to this handheld pointer, sends short pulses of light to the floor beyond the edge of a wall. The light spreads, bounces off a hidden object around the corner, and, like an echo, is sent back to a special camera capable of capturing single photons. It’s fast, too, recording a movie of the laser echo at an astonishing framerate of 20 billion frames per second. It also measures the time it takes for the laser to bounce back to the camera, allowing the team to note the hidden object’s distance and movement.