WiTrack is a new technology that performs 3D motion tracking
of a person purely using radio reflections of her body,
even if the person is moving behind a wall or furniture.
WiTrack is placed behind the wall of this room,
as indicated by the red arrow.
As the person walks around in the room,
it tracks his motion through the wall.
In the adjacent room, WiTrack outputs the location
of the person as a red dot on the screen.
As the person moves around behind the wall,
the red dot moves on the screen, indicating his exact location
at any point in time.
So let us see how WiTrack works.
WiTrack performs 3D motion tracking
using body radio reflections.
It transmits wireless signals whose power
is 100 times less than Wi-Fi and 1,000 times
smaller than cell phone transmissions.
These signals will reflect off the person
and come back to its receive antennas after some delay.
WiTrack measures the delays and maps them
to the distance traveled by the signals.
Based on a geometric model of the antennas,
WiTrack can now accurately determine
the location of the person.
The model incorporates new algorithms
that remove reflections due to walls and furniture
and focus only on the reflections of a human body,
even if the person is behind a wall
or in a completely different room.
In this demo the person walks on a spiral on the ground
as the red dot tracks him in the bottom left corner
of the screen.
Note that the spiral on the ground
is only there to show the accuracy of the system
and is not used to aid localization in any way.
This system has a large number of applications.
For example, it performs highly accurate localization simply
using reflections off a person's body
without requiring the person to hold any device.
It can also be used in gaming, where it can start players
as they run down hallways or hide behind furniture and walls
for video game enemies.
The system not only tracks the location of a person,
but it can also track his body parts.
In this example, the person is controlling different household
appliances, turning them on and off by simply
pointing his hand in their direction.
Because WiTrack works through walls,
it can allow you to control appliances even
from another room.
So you leave a room and forget to turn off the lights.
All you have to do is point your hand
in the direction of that room to turn the lights off.
WiTrack therefore can perform 3D motion tracking of humans
and body parts simply using radio reflections
off a person's body.
And it works even through walls and obstructions.