Posted by: Site Administration Date posted: 11/08/2004
RFID tags,
all the rage it seems these days. However, they could be more
than they seem to be. They could in fact be the key to the
sensor network necessary for augmented reality to truly come
to be.
Researchers from Mitsubishi Electric Research
Labs have brought dynamic, computer-generated labels into the
physical world with a combination of radio frequency
identification (RFID) tags and portable
projectors.
Exactly like in the low-budget film
"Virtual nightmare" in which everything is produced cheaply,
but with a 'tag' that identifies it to the system as whatever
- the system overlays that image on it. If the box says its
actually a briefcase, that is what displays. If a box is an
alarm clock, ikewise. Houses, cars, clothes, all are produced
from generic objects in the film.
The real life system
is a lot simpler, but works in the exact same way. Mitsubishi
Electric Research Labs' RFID tags affix to any object, and use
a system they have termed Radio Frequency Identity and
Geometry (RFIG) which involves a hand-held, or head-mounted
projector which shines onto the tags, projecting dynamic
images onto objects based on which RFID they are marked
with.
The tags themselves are photosensitive, and
identify themselves to the projector via two-way communication
when the light is played over them.
The projector beams
a sequence of about 20 images of horizontal or vertical bars
of varying density, which form unique codes indicating
horizontal and vertical coordinates. Each tag records the
code, then transmits its identity plus the code back to the
radio frequency reader attached to the projector.. This allows
the reader to determine the precise location of each tag in
its range.
The projector's next output signal marks
the tags for the user, highlighting them in different colours
and / or patterns to allow them to see at a glance, what a box
actually contains. The tags and the area arond them glows
brightly, all the rest is dark.
If several RFID tags
are put on the same object, the projector is able to use them
to build out an outline of the object, and even detect if it
has been shifted, or moved.
On top of that, the
projector has a position tracking system for its own location
and orientation at any given time, and when networked, one
user can use the projecttor to find and id a tag, then use a
computer interface to leave a message on it that then pops up
when another user scans the tag.
The system is still in
development, but is practical right now, if somewhat too
expensive for most commercial applications. The researchers
expect the system should be commercially viable within two to
three years.