Researchers at the Massachusetts Institute of Technology have developed a device that can directly image a person through solid walls, in real time. The device, called RF-Capture, transmits regular wi-fi signals into the area being imaged: in the case of their demonstration device, through a wall. When the signals are reflected back by a human body, they are picked up by the device’s receiver, and then they are put through an imaging processor to produce an on-screen image of the individual.