Wi-Fi signals used to see through walls

The researchers say that the variation of radio signals in a wireless network can reveal the movements of people behind closed doors or even a wall.

Joey Wilson and Neal Patwari, from the University of Utah, have used the principle of variance-based radio tomographic imaging. The system works by measuring interference between the nodes of wireless devices. If someone passes through that field, the device registers a change in the levels of resistance, and feeds that information back to a computer.

The system can currently only see about three feet through a wall, and is so far only capable of sensing motion. At this stage, it is not sophisticated enough to generate an actual image of what lies beyond the wall, but the research team is confident that this feature could be developed in time.

You can read the full article 'Wi-Fi signals used to see through walls' at:
http://www.telegraph.co.uk/technology/news/6254646/
Wi-Fi-signals-used-to-see-through-walls.html

Our thanks to Lee, M0HOK for spotting this item