Researchers have taken the concept of radar and sonar imaging a step further to track people, even through walls. Wi-Vi, which Dina Katabi and her graduate student Fadel Adib are developing at MIT’s Computer Science and Artificial Intelligence Laboratory, transmits a low-power Wi-Fi signal and uses its reflections to track human movement. Katabi is a professor in MIT’s Department of Electrical Engineering and Computer Science. The system uses two transmit antennas and a single receiver. Static objects create identical reflections and cancel each other out, so the system can track people’s movement and calculate a person’s location.
Applications for Wi-Vi include allowing law enforcement to pinpoint the number of criminals in a building and their location, and helping search and rescue teams find survivors. The capability also could be used to develop a personal safety device.
Find out more in this YouTube video from Adib's channel: "Wi-Vi: See through walls with Wi-Fi signals."