Slashdot Mirror

← Back to Stories (view on slashdot.org)

MIT Researchers Can See Through Walls Using Wi-Fi

Posted by timothy on from the upgrade-your-router dept.

itwbennett writes "MIT Professor Dina Katabi and graduate student Fadel Adib have developed a system they call Wi-Vi that uses Wi-Fi signals to visualize moving forms behind walls. How it works: 'Wi-Vi transmits two Wi-Fi signals, one of which is the inverse of the other. When one signal hits a stationary object, the other cancels it out. But because of the way the signals are encoded, they don't cancel each other out for moving objects. That makes the reflections from a moving person visible despite the wall between that person and the Wi-Vi device. Wi-Vi can translate those faint reflections into a real-time display of the person's movements.'"

6 of 75 comments (clear)

  1. its called radar by Anonymous Coward · · Score: 5, Informative

    It's not exactly new either. The only difference here seems to be that the radar signal source is just a low power wifi AP. Yawn.

    1. Re:its called radar by Anonymous Coward · · Score: 5, Informative

      Standard radar cannot see through walls because the receiver is overwhelmed by the wall reflection (its ADC is saturated). According to the authors, this is a very well known challenge and is called the "Flash" effect. Wi-Vi's new nulling algorithm solves that problem, enabling for the first time narrowband RF to overcome this effect. This link explains their technique: http://people.csail.mit.edu/fadel/wivi/design.html

  2. Re:Code source or it didn't happen by kk49 · · Score: 5, Informative

    The paper http://people.csail.mit.edu/fadel/papers/wivi-paper.pdf

    --
    You can have your god back when you are old enough to handle the responsibility.
  3. Re:NSA Use by Anarchduke · · Score: 5, Informative

    How is that? They are entirely trustworthy; they do what we tell them to do. We gave them every bit of authority they use to spy on us. We threw our privacy at them and cried, "Take this! Save us from the terrorists and spy upon us!"

    --
    who prays for Satan? Who in 18 centuries has had the humanity to pray for the 1 sinner that needed it most? ~Mark Twain
  4. Not Wi-fi by wisnoskij · · Score: 4, Informative

    I am sure they are using the same frequencies as wi-fi. But wi-fi is not just the use of a certain frequency range.

    --
    Troll is not a replacement for I disagree.
  5. Just like T-Rex by Megahard · · Score: 4, Funny

    It can't see you if you don't move.

    --
    I eat only the real part of complex carbohydrates.