To figure out what’s on the other side of a wall or some other opaque barrier, you either need superpowers or a lot of expensive, heavy radar equipment. That might not be the case for long, though. Researchers at MIT’s Department of Electrical Engineering and Computer Science think they’ve sorted out a way to use inexpensive WiFi gear to detect objects and people behind a wall, or even in other rooms.
The technology, known as Wi-Vi, is being developed by professor Dina Katabi and grad student Fadel Adib. The goal is to make this sensor tech as cheap and compact as possible. Yes, gone are the days you have to lug around heavy radar equipment to see through walls. Well, it’s not as simple as that, but using WiFi signals could make Wi-Vi a commodity. It might even start showing up in consumer products that already have WiFi antennas.
Despite the way Wi-Vi is described by MIT, it’s not quite akin to a real x-ray. Wi-Vi is essentially a motion sensing technology that relies on the same principals as x-rays or radar. When an electromagnetic wave encounters an object, there is some amount of reflection. Wi-Vi is designed to detect that with WiFi signals. Wi-Vi is not getting an image of the other side of the wall.
The test rig designed by Katabi and Adib has three WiFi antennas two are for transmission and one is for reception. The transmitting antennas are identical , except that they output inverse signals. This causes the waves to cancel each other out as they propagate outward from the device. Any static object the waves encounter will produce identical reflections, which are also cancelled out.
Read also:
Low-power WiFi system tracks humans, even behind walls (R & D Magazine)
Wi-Vi lets smartphones see through walls (SlashGear)
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