Forgot your password?
typodupeerror
Wireless Networking Technology

MIT Researchers Can See Through Walls Using Wi-Fi 75

Posted by timothy
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.'"
This discussion has been archived. No new comments can be posted.

MIT Researchers Can See Through Walls Using Wi-Fi

Comments Filter:
  • its called radar (Score:5, Informative)

    by Anonymous Coward on Saturday June 29, 2013 @09:28AM (#44141681)

    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.

    • MIT has already been doing some nice experiments [mit.edu] with WiFi/microwave oven/ISM band radars. I wonder if this isn't an extension of their previous projects. Using unmodified WiFi electronics seems to be a neat trick, though.
    • Re:its called radar (Score:5, Informative)

      by Anonymous Coward on Saturday June 29, 2013 @11:07AM (#44142171)

      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

      • A Through-Wall Gesture Interface

        Wi-Vi leverages its ability to track motion to enable a through-wall gesture-based communication channel.

        That will be great in hostage situations for the cops to check whether the perps are giving them the finger.

        • by peragrin (659227)

          they can tell the difference between moving and non moving objects.

          The next version will be able to tell the difference in general materials, brick, stone, sheetrock, wood, warm bags of no longer potable water.

          The version after that will introduce portability. and thus the tricorder will be born.

  • by Anonymous Coward

    Headline should have been "MIT Researchers Can Track Movement Behind Walls Using Wi-Fi".

    • by gl4ss (559668)

      Headline should have been "MIT Researchers Can Track Movement Behind Walls Using Wi-Fi".

      but then it sounds suspiciously similar to an older headline on the same subject. and is rather boring.

    • I'm not even sure that's accurate. One signal is the "inverse" of the other? Then how is it Wi-Fi?

  • Gimme! Please :)

  • So then I guess we should be looking into ways to prevent government agencies from using this against us. They've already proven to be completely incapable of trustworthiness.
    • Re:NSA Use (Score:5, Informative)

      by Anarchduke (1551707) on Saturday June 29, 2013 @09:46AM (#44141761)
      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!"
    • by AHuxley (892839)
      Yes US seems right up on all the tech average people use and how to track them:
      http://www.wired.com/dangerroom/2012/03/petraeus-tv-remote/ [wired.com]
      Become a domestic “person of interest” and they will use every connected device you have.
      Welcome to a world where you have to change your notions of secrecy and enjoy every connected device been backdoor ready by design.
      • by citizenr (871508)

        Its funny you link to a quote by David Petraeus - he was Character assassinated by very same CIA/private contractors running surveillance show as soon as he announced CIA security audit.

    • Re:NSA Use (Score:4, Interesting)

      by Trepidity (597) <delirium-slashdotNO@SPAMhackish.org> on Saturday June 29, 2013 @10:57AM (#44142127)

      When it comes to viewing the movement of humans through walls, there have already been infrared cameras for years, which in most situations will do anything this wifi approach can do and more. The only real advantage of this wifi approach is that it's cheaper, using ubiquitous commodity hardware.

      So when it comes to government agencies, this doesn't really change the technological situation: they've already had the ability to track movement through walls for years. They're only restricted in using it to the extent that legal restraints are successful. For example in Kyllo v. United States [wikipedia.org] the Supreme Court threw out a conviction that was obtained in part by using infrared cameras to look inside a home without a warrant.

      • by tibit (1762298)

        When it comes to viewing the movement of humans through walls, there have already been infrared cameras for years, which in most situations will do anything this wifi approach can do and more.

        Can we trade user id's? I'd expect a bit more from a 597. What you claim is an unoriginal figment of your imagination. [pr-infrared.com]

        • "I'd expect a bit more from a 597. What you claim is an unoriginal figment of your imagination."

          I'd expect more from someone who expects more. Your argument is irrelevant to what he was saying.

          While thermal imagers may not "see" what is inside a home, in the sense that they can't pick up shapes in any detail through a wall (the signature becomes too diffuses), they still can impart significant information about what is going on, on the other side of those walls. That is the relevant issue here.

          The point being: something that can't see much more than a warm blob is already illegal for the police

          • by tibit (1762298)

            ?!

            When it comes to viewing the movement of humans through walls, there have already been infrared cameras for years

            Infrared cameras can't see movement through walls, and they definitely can't come even into the same performance ballpark, when it comes to detection of humans, as sensing that uses longer waves. Heck, if you're a lone human in a large enough room, a thermal camera can't even tell that you're there. The surface temperature won't rise enough due to large wall area.

  • MIT researchers can become wet using water. Seeing through things by using wavelengths that penetrate them isn't particularly new, and one of the selling points with wi-fi is that it can go through walls Non-news for nerds, stuff that natters

    • It's somewhat more difficult than just 'seeing through things'; walls are not totally transparent to the wavelengths of interest, and reflections from them dominate the signal. Moreover, this technique makes use of equipment that can't do the precise timing of radar measurements (though this means they can only track the angles of moving targets, not their position). It is a neat sort of hack, and interesting for that reason.

      • by wagnerrp (1305589)
        They're actually using SDR units, rather than commodity WiFi gear, so they probably could rig it up to operate as a proper RADAR system. They just don't have the precision necessary to track someone as they move through a small room.
      • by tibit (1762298)

        What they are doing, in fact, is a well known measurement technique. They tweak the transmitted signals so that the receiver sees a null. Then, as soon as you get moving objects introduced into the volume, the receiver get a signal that's mostly related to this object's motion. I have used the same trick with ultrasound transceivers back in high school, I wish I had it written up.

  • Sweet I can finally watch my neighbors T.V. And to think people used to use WINDOWS! hah! so crude.
  • Not Wi-fi (Score:5, Informative)

    by wisnoskij (1206448) on Saturday June 29, 2013 @10:12AM (#44141897) Homepage

    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.

    • by Trepidity (597)

      Ah, good catch. In that case, if they aren't actually using existing wifi hardware, why pick that particular frequency range? It doesn't seem like it has particularly great properties as far as the intended application. Is it just due to regulatory issues, since it's in the mostly-unregulated ISM band?

      • They very well might be using existing hacked wi-fi hardware.

        But if I used wi-fi hardware to fry an egg, that does not mean that I fried an egg with wi-fi.

      • by dissy (172727)

        It looks like they are using standard wifi hardware, two modules actually.
        What they aren't doing is speaking 802.11 over it and are providing their own framing in order to get a reversed signal on the other module. There will be no protocol in that framing to speak IP on top of.

        The major advantage is that a manufacturer can purchase the same wifi chips as they usually do for wifi, but these two chips are configured in software quite differently. I assume they will likely have a different antenna to optimi

        • by tibit (1762298)

          Never mind that at least the transmitters must be running from same reference oscillator, if not all three devices (two transmitters and the receiver).

    • You are correct in the sense that they are not using the upper layer protocols in Wifi, but incorrect in that the signal modulation they are using is that of modern Wifi (OFDM) as is there intended channel width (20MHz) and frequency band (2.4GHz ISM). So basically they are using a flexible R&D H/W solution (The USRP) to transmit and receive a WiFi like signal and demonstrate their innovation. Existing WiFi IC's would not be able to easily do this because they are not designed for new experimentation bu

  • by Dcnjoe60 (682885) on Saturday June 29, 2013 @10:21AM (#44141939)

    What a cop-out! From the article "Like all technologies in the world, it depends on us how we use them," Katabi said.

    People use that excuse all the time. However, when one has a reasonable expectation as to how some technology will be used, you cannot fall back on this reasoning to ease one's conscious over their own culbability in something. The scientists involved in the Manhatten project new full well how that technology would be used and had to deal with the moral implications. Today, though, the notion is technology for technology's sake with no thought of the consequences.

    Well here's news to all my fellow researchers, if you develop some new technology, great, but don't hide behind your mommy's skirts and say, something like the above. You know darn well how it will be used, so take responsibility for it.

    • Any technology that has been invented, eventually would have been (because we now know it's possible). While not a direct quote, it's what Edward Teller said more or less of the Hydrogen Bomb. That, and we would have been speaking Russian now had we (the US) not pursued the H-Bomb program.

      • by Dcnjoe60 (682885)

        Any technology that has been invented, eventually would have been (because we now know it's possible). While not a direct quote, it's what Edward Teller said more or less of the Hydrogen Bomb. That, and we would have been speaking Russian now had we (the US) not pursued the H-Bomb program.

        That is true, but some technologies are much more readily apparent as to their misuse than others. Splitting the atom is a good example. It is hard to think of peaceful applications of such a technology (which is different from, say, nuclear power). In the past 40 years or so, science has focussed more and more on can we do such and such and ignored the question of should we be doing such and such.

        However, we scientists can not hide behind the moral argument that we are only inventing technology it isn't u

  • I tried to tell you people those newfangled WiFi thingamagiggies would mutate your DNA, but did you listen?

    Now you got mutants at MIT seeing through walls and who knows what else.

  • by Megahard (1053072) on Saturday June 29, 2013 @11:06AM (#44142167)

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

  • We already have enough congestion on 2.412~2.482.Why on earth did they choose Wi-dear lord-Fi?
    • by wagnerrp (1305589)
      Small enough to actually track people, large enough to penetrate walls, and free to use within limited output power.
  • ...functional Aliens motion tracker [youtube.com]???
  • There's an inconsistency between what we see in the demo and the description. Supposedly the system tracks the angle of the object. Yet what the graph in the video looks like is nothing like the angle. It looks like a simple Doppler output that goes to zero once the subject stops moving.

    • by tibit (1762298)

      Never mind that their project website is a piece of crap written for the illiterate. Give me a fucking break, it sounds like a something a particularly clueless high-schooler would write upon seeing the project.

  • This research achieves the same and even better (learns and detects multiple states) with an even more interesting approach. http://search.ieice.org/bin/summary.php?id=e95-b_10_3088&category=B&year=2012&lang=E&abst= [ieice.org]

Opportunities are usually disguised as hard work, so most people don't recognize them.

Working...