British researchers have developed a James Bond-style camera that can peer around corners to see people or objects. The technology could someday allow troops to obtain information without breaking cover or be fitted on cars to give advance warnings of obstacles.
The prototype uses short high-intensity bursts of laser light to illuminate a target object and then collects the tiny fraction of that light that is scattered back on to a detector on the camera.
The geometry of the setup is similar to that in a conventional periscope, in which light from the target object turns a corner by bouncing off a reflecting surface. In this case, however, the reflecting surface is simply a wall or the floor and, unlike a mirror, which reflects light in clean, straight lines, the light is scattered in every direction.
To build a picture, the camera fires the laser 4,000 times each second, at many different angles. A computer algorithm is then used to reconstruct the shape and position of hidden objects around the corner. The prototype will soon be tested in the laboratory to see whether it can be used to distinguish basic shapes, such as cut-out letters.
