Reseachers use Wi-Fi to see through walls for 'cheap'

As if we all need another reason to wear a tinfoil hat. "The Wi-FI! It can see you, man." Well, thanks to a pair of researchers at the University of Utah, it can. The trick is in using and excess of signals shooting around a room, and then finding the spots of interruption using receivers placed all over.

From the Technology Review:

"Joey Wilson and Neal Patwari have developed a technique called variance-based radio tomographic imaging that processes the signals to reveal signs of movement… The basic idea is straightforward. The signal strength at any point in a network is the sum of all the paths the radio waves can take to get to the receiver. Any change in the volume of space through which the signals pass, for example caused by the movement of a person, makes the signal strength vary. So by "interrogating" this volume of space with many signals, picked up by multiple receivers, it is possible to build up a picture of the movement within it."
Okay, so maybe it's not the most subtle way to do it, but researchers Joey Wilson and Neal Patwari are pegging it as an inexpensive way to pull it off as all the tech is off the shelf. The duo believes that it would be perfect for emergency responders, military forces, or police, as it could be a cheap, quick and temporary way to peek through walls.

Technology Review, via The Raw Feed