Off the Grid News – by Daniel Jennings
It is now possible to take 3D pictures of the inside of a room or building — from the outside — with Wi-Fi.
The technology, described in the journal Physical Review Letters, is still in the development stage, although its impact on privacy is frightening.
“You could probably use a drone to map out the inside of an entire building in 20 to 30 seconds,” Philipp Holl, an undergraduate at the Technical University of Munich, told Business Insider.
Holl is one of the inventors of the new kind of holography that can turn Wi-Fi into a surveillance tool.
“It can basically scan a room with someone’s Wi-Fi transmission,” Holl said.
How it Works
Wi-Fi devices that can take pictures through walls have been around for years but the image quality was terrible, Business Insider noted. Holl and his academic supervisor, Friedemann Reinhard, discovered how to take higher-resolution pictures through walls using Wi-Fi.
“Our method gives you much better images, since we record much more signal,” Holl said. “We scan the whole plane of a room.”
They use two antennas. One antenna stays in a fixed position to capture the background while the other is moved to get a complete picture.
The data captured is simultaneously fed into a computer, where software sorts out the differences and creates a real-time picture. The software can create many two-dimensional (2D) images that are combined to create a three-dimensional (3D) picture or hologram.
“These antennas don’t need to be big,” Holl said. “They can be very small, like the ones in a smartphone.”
Some uses of the technology could be beneficial, such as finding people in an earthquake rubble. But other uses – such as by spy agencies or police – will be more controversial.
It looks as if those of us who want privacy had better go back to connecting to our devices the old-fashioned way — with cables.
Scum who work on projects like this make me sick. Walls exist for a reason, you c–ksuckers. And I really wish these scumbags would quit trying to sugarcoat all this dystopian technology with their talk of “search and rescue” or “disaster relief.”
I’m a little skeptical of their results as applied to more complicated situations, such as more than one room, lots of clutter for the signals to bounce off, etc. But the threat seems real enough.
Fortunately, all is not lost for privacy, since electromagnetic signals like WiFi can absolutely be blocked. Lining the walls of one’s home, or at least certain rooms, with electromagnetic shielding fabrics, conductive paints, or most conductive materials should do the trick. The tradeoff is the trouble and the expense, and probably degraded cell phone communications inside your home. If you have aluminum siding on your house, that alone may be sufficient to block imaging through the walls, depending on the conductivity of the aluminum alloy used.
It should also be pointed out that their method is using imaging based on WiFi signals that are already being emitted from inside the building. If you aren’t using any WiFi, then their method won’t work. Also, their method appears to be slower than the one d!ck Holl claims.
Still, radars that can see through (nonmetallic) walls have existed for many years. They’re a threat worth considering. A rule of thumb is that the longer the wavelength, the better it penetrates solid materials, but the worse the resolution and overall image quality. Metallic objects around the periphery of a building (e.g., metal shelving stacked around your walls) will tend to screw it up. And again, the earlier comments about blocking electromagnetic waves with conductive materials will always apply. Maybe someday all new homes will be built with metallic linings in the walls or conductive wallpaper (which exists already).
I built a sound booth once and lined it with lead sheets, no RF. And always hardwire.
Lead worked? I guess if it’s thick enough…the problem is it’s so damned heavy and expensive. Personally, I think I’d just give RF-blocking wall paint a try.