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Researchers from the University of Utah have found a way of harnessing Wi-Fi signals 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.
The researchers said the technology could be used in search and rescue operations, with emergency teams using the same radio technology used by Wi-Fi networks to build a web of sensors around a disaster site, revealing the location of victims and survivors.
"We envision a building imaging scenario similar to the following. Emergency responders, military forces, or police arrive at a scene where entry into a building is potentially dangerous. They deploy radio sensors around (and potentially on top of) the building area, either by throwing or launching them, or dropping them while moving around the building," wrote Wilson and Patwari on the arXiv science forum.
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