Stray WiFi Signals Could Let Spies See Inside Closed Rooms (sciencemag.org) 41
sciencehabit quotes a report from Science Magazine: Your wireless router may be giving you away in a manner you never dreamed of. For the first time, physicists have used radio waves from a Wi-Fi transmitter to encode a 3D image of a real object in a hologram similar to the image of Princess Leia projected by R2D2 in the movie Star Wars. In principle, the technique could enable outsiders to "see" the inside of a room using only the Wi-Fi signals leaking out of it, although some researchers say such spying may be easier said than done. Their experiment relies on none of the billions of digital bits of information encoded in Wi-Fi signals, just the fact that the signals are clean, "coherent" waves. However, instead of recording the key interference pattern on a photographic plate, the researchers record it with a Wi-Fi receiver and reconstruct the object in a computer. They placed a Wi-Fi transmitter in a room, 0.9 meters behind the cross. Then they placed a standard Wi-Fi receiver 1.4 meters in front of the cross and moved it slowly back and forth to map out a "virtual screen" that substituted for the photographic plate. Also, instead of having a separate reference beam coming straight to the screen, they placed a second, stationary receiver a few meters away, where it had a direct view of the emitter. For each point on the virtual screen, the researchers compared the signals arriving simultaneously at both receivers, and made a hologram by mapping the delays caused by the aluminum cross. The virtual hologram isn't exactly like a traditional one, as researchers can't recover the image of the object by shining more radio waves on it. Instead, the scientists used the computer to run the radio waves backward in time from the screen to the distance where wave fronts hit the object. The cross then popped out.
Re: (Score:2)
old tech (Score:1)
2013: http://m.slashdot.org/story/188149
2009: http://m.slashdot.org/story/125417
How long until someone else "discovers" the same thing again?
Re:old tech (Score:5, Funny)
2013: http://m.slashdot.org/story/18... [slashdot.org] 2009: http://m.slashdot.org/story/12... [slashdot.org]
How long until someone else "discovers" the same thing again?
According to the pattern, 2021
It's "seeing" blocked RF signals (Score:3)
What this is really showing is that they have worked out how to make an array antenna and composite that data to "see" what is blocking RF signals which is normally metals. I think you would be hardpressed to identify if a person was standing in the room. Still interesting though.
Re: (Score:2)
Re: (Score:2)
It's more like a passive MRI if the logarithm and device sensitivity could be dialed in just right.
Whether screening for disease at the hospital, scanning for weapons at the airport or in public or looking through walls to see people making drugs or bombs it could be useful. Miniaturized enough this could be a precursor to a star-trek tricorder.
There are real possibilities here.
Re: (Score:2)
Yep. And the only interference it can "see" is that of metal. And only a certain distance. And only if it is still for a long time.
Re: (Score:3)
I think you would be hardpressed to identify if a person was standing in the room
Unless they are wearing their tinfoil hat. Think about it...
Re: (Score:1)
Oh, crap - they can ONLY see my if I wear my tinfoil hat !
But if I take it off...
But if I...
But...
NO CARRIER
Re: (Score:2)
Well, it would work on Wolverine.
More "security research" (Score:2, Funny)
Re: (Score:3)
If this is too theoretical for you then perhaps you would like this article titled, Most mammals need only 12 seconds to poop [sciencemag.org] ;)
Re: (Score:2)
Re: (Score:2)
What is next? They can use "light waves" to detect a cross placed in a room? Its like magic and stuff!
If you think light waves are magic, wait until you see what they can do with magnets! #4 will shock you!
Tomography (Score:2)
Tomography [wikipedia.org] has been around for over 80 years. It's why there's no lens when you have a traditional x-ray taken. You just fire the RF rays in a uniform direction (in this case the single WiFi course acts as a point source with all rays radiating radially), and capture them using a flat photographic plate (or in this case, by moving the WiFi receiver around on a plane). What they're doing isn't even as sophisticated
Re: (Score:2)
Re: (Score:2)
MRI competition? (Score:1)