We could all now have
Superman-like X-ray vision - thanks to researchers at MIT’s Computer Science
and Artificial Intelligence Laboratory.
Researchers
have long attempted to build a device capable of seeing people through walls. However,
previous efforts to develop such a system have involved the use of expensive
and bulky radar technology that uses a part of the electromagnetic spectrum
only available to the military.
Now
a system being developed by Dina Katabi, a professor in MIT’s Department of
Electrical Engineering and Computer Science, and her graduate student Fadel
Adib, could give all of us the ability to spot people in different rooms using
low-cost Wi-Fi technology.
“We
wanted to create a device that is low-power, portable and simple enough for
anyone to use, to give people the ability to see through walls and closed
doors,” Katabi said.
The
system, called “Wi-Vi,” is based on a concept similar to radar and sonar
imaging.
But
in contrast to radar and sonar, it transmits a low-power Wi-Fi signal and uses
its reflections to track moving humans. It can do so even if the humans are in
closed rooms or hiding behind a wall.
To
do this, the system uses two transmit antennas and a single receiver.
The
two antennas transmit almost identical signals, except that the signal from the
second receiver is the inverse of the first.
As
a result, the two signals interfere with each other in such a way as to cancel
each other out.
Since
any static objects that the signals hit — including the wall — create identical
reflections, they too are cancelled out by this nulling effect.
In
this way, only those reflections that change between the two signals, such as
those from a moving object, arrive back at the receiver, Adib said.

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