Seeing hidden objects

People often hear noises from around corners, but seeing around them is much more difficult—it is not impossible, however. As light scatters off surfaces, it carries information that can be reconstructed using computational methods to uncover information about objects hidden from direct view. Reflecting surfaces can therefore play the role of a mirror in a periscope, and this type of imaging technique is known as computational periscopy. This usually requires expensive, specialized equipment, but Vivek Goyal and colleagues now demonstrate an approach to computational periscopy using an ordinary digital camera. Their technique allows them to recover the position of a hidden object, as well as the scene behind it, both of which are out of direct sight.