Scientists Have Found a Way to Photograph People Through Walls Using Wi-Fi
Wi-Fi can pass through walls. This fact is easy to take for granted, yet it's the reason we can surf the web using a wireless router located in another room.
However, not all of that microwave radiation makes it to or from our phones, tablets, and laptops. Routers scatter and bounce their signal off objects, illuminating our homes and offices like invisible light bulbs.
Now, German scientists have found a way to exploit this property to take holograms, or 3D photographs, of objects inside of a room - from outside of the room.
"It can basically scan a room with someone's Wi-Fi transmission," Philipp Holl, a 23-year-old undergraduate physics student at the Technical University of Munich, told Business Insider.
Holl initially built the device as part of his bachelor thesis with the help of his academic supervisor, Friedemann Reinhard. Later on the two submitted a study about their technique to the journal Physical Review Letters, which published their paper in early May.
Holl says the technology is only in prototype stage at this point, and has limited resolution, but is excited about its promise.
"If there's a cup of coffee on a table, you may see something is there, but you couldn't see the shape," Holl says. "But you could make out the shape of a person, or a dog on a couch. Really any object that's more than 4 centimetres in size."
How to see through walls with Wi-Fi
The ability to see through walls using Wi-Fi has been around for years.
Some setups can detect home intruders or track moving objects with one or two Wi-Fi antennas. Others use an array of antennas to build two-dimensional images. But Holl says no one has used Wi-Fi to make a 3D hologram of an entire room and the stuff inside of it.
"Our method gives you much better images, since we record much more signal. We scan the whole plane of a room," he says.
Holl's method differs from the others in few significant ways.
Full story at site
Wi-Fi can pass through walls. This fact is easy to take for granted, yet it's the reason we can surf the web using a wireless router located in another room.
However, not all of that microwave radiation makes it to or from our phones, tablets, and laptops. Routers scatter and bounce their signal off objects, illuminating our homes and offices like invisible light bulbs.
Now, German scientists have found a way to exploit this property to take holograms, or 3D photographs, of objects inside of a room - from outside of the room.
"It can basically scan a room with someone's Wi-Fi transmission," Philipp Holl, a 23-year-old undergraduate physics student at the Technical University of Munich, told Business Insider.
Holl initially built the device as part of his bachelor thesis with the help of his academic supervisor, Friedemann Reinhard. Later on the two submitted a study about their technique to the journal Physical Review Letters, which published their paper in early May.
Holl says the technology is only in prototype stage at this point, and has limited resolution, but is excited about its promise.
"If there's a cup of coffee on a table, you may see something is there, but you couldn't see the shape," Holl says. "But you could make out the shape of a person, or a dog on a couch. Really any object that's more than 4 centimetres in size."
How to see through walls with Wi-Fi
The ability to see through walls using Wi-Fi has been around for years.
Some setups can detect home intruders or track moving objects with one or two Wi-Fi antennas. Others use an array of antennas to build two-dimensional images. But Holl says no one has used Wi-Fi to make a 3D hologram of an entire room and the stuff inside of it.
"Our method gives you much better images, since we record much more signal. We scan the whole plane of a room," he says.
Holl's method differs from the others in few significant ways.
Full story at site
