A camera that can see round corners

CAMERAS THATTV look round corners already exist. But they rely on specialised lasers which blink on and off trillions of times a second, and light detectors sensitive enough to track individual photons. Something simpler and more robust would be desirable. And, as they describe in , a team at Boston University in Massachusetts, led by Vivek Goyal, think they have the makings of one.In their prototype, Dr Goyal and his colleagues placed an opaque object called an occluder in front of a screen that was hidden around the corner from a digital camera (see diagram). Illuminated by the screen, the occluder cast a partial shadow, known as a penumbra, on a wall that the camera could see. Run through appropriate algorithms, patterns within the penumbra, invisible to the eye but recorded by the camera, could be used to reconstruct cartoon faces, university logos and arrangements of stripes that the screen had displayed.