A new technology
based on WiFi
would enable us to
see through walls.
The founders say
the device could be attached into
cellular phones and use the same
wireless antenna. Using the gadget you
can see bad guys hiding in a room like
Superman’s X-ray visio The new device developed by MIT
professor Dina Katabi and graduate
student Fadel Adib is called Wi-Vi, stands
for WiFi Vision, as it employs wireless
signals transmitted by a WiFi device – so
it would allow us to see a person moving behind a wall tracked by all the signals bouncing off that person to produce a
kind of X-ray vision. WiFi doesn’t just bounce off humans but
also other objects in a room such as
floors and furniture, so the trick is
eliminating all the interfering signals,
which are 10,000 to 100,000 times more
powerful than the reflections off a human body. To remove the signals of all the
interfering objects, the Wi-Vi device
sends out two wireless signals that keep
canceling each other unless they hit a
moving target – humans. "To silence the
noise, we change the structure of the WiFi signal so all the undesired reflections are canceled," Dina Katabi
said. Their previous works has shown that
subtle reflections of wireless inter
signals bouncing off a human could be
used to track that person's movements,
but those experiments either required
that a wireless router was already in the room of the person being tracked, or a
whole truck just to carry the radio –
contrary to this, the new device is meant
to be portable, said Katabi.

m.digitaljournal.com/article/353387