Using RF To See Through Walls

This is some seriously cool stuff. Researchers at MIT recently came up with a device that can “see” through walls. It can actually identify a person (or people) behind a solid object.

They call it RF-Capture and it uses radio waves to identify people. Kind of like some high tech radio-frequency sonar. Using a very complex algorithm it can reconstruct the human figure by analyzing the various reflections of the signals transmitted. It’s so accurate it can even distinguish between different people based on size and posture, and even trace a person’s handwriting in the air.

Sounds like whatever they’re doing, it’s probably blasting a lot of radiation to do it. You’d think so, but no.

The transmitted power is actually 10,000 times lower than a cellphone. Crazy!

While it might not be quite the same caliber as this research, did you know you can make a rudimentary sonar device using microphones and piezo elements?

[via BGR]

20 thoughts on “Using RF To See Through Walls

  1. Oh the Kinect has been doing this for years, MS just never got around to telling us that also “sees” through walls, and has identified everyone in your household, their habits, and activity levels and reported back to Redmond…
    B^)

    1. Actually neither is correct, from the paper:

      “It is difficult for RF-Capture to capture reflections from the user’s
      legs. This is because even as the legs move, they deflect the incident
      RF signals away from the antenna array (toward the ground) rather
      than reflecting them back to the array since the normal to the surface
      of the legs stays almost parallel to the ground. (Note that placing
      the antenna array on the ground instead would enable it to capture a
      user’s legs but would make it more difficult for the array to capture
      his head and chest reflections.)”

  2. The good people at one of our national labs can probably say…
    Been there (19 years ago), done that (well, not exactly the same but still w/radio waves):
    https://str.llnl.gov/str/pdfs/01_96.2.pdf
    And if you want to go out and get some tech for your self, I think (some of) Zircon Stud Finders use some similar ideas.

    As for the above effort, by the looks of it, it’s a phased array. So I assume X-direction is controlled by sweeping the beam. And the Y-direction, as Falense points out, is timed. Probably why the array is placed higher then the person. I suspect if you want more resolution you do the things that side-scan-sonar and side-scan-radar people do. Tighter beams and more precise timing.

  3. Complaints aside this could be neat in a home. With a ring to press to activate gesture actions. Combine it with position detection (or one time manual positioning) of in home devices and we could turn things like a TV, heater, fan etc on/off by pointing at them.

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