Accurate
depth perception is critical to future military, medical applications of AR
Sports fans have come to expect some of
the extras they see on their TV screen, such as the yellow lines that appear on
a football field highlighting where the ball needs to go for a first down.
Similarly, NASCAR fans can find their favorite driver in the pack because of
those superimposed car numbers on the screen.
"Anyone who's seen a football game
has seen the virtual first-down line and it looks like it's really something
painted on the field. It's a very compelling graphic. It really looks like it's
there," says computer scientist J. Edward Swan, II.
But most people are probably not
familiar with the technology that makes this all happen.
Augmented reality, or "AR," is
used to superimpose computer-generated virtual objects on our view of the real
world.
With support from the National Science
Foundation (NSF), Swan and his team at Mississippi State University (MSU) are
working to improve depth perception in the augmented reality environment.
"Ed Swan's work on perceptual issues for
AR goes back more than a decade and includes co-authoring a seminal paper in
which computer graphics attributes were shown to be effective in providing a
sense of the depth of occluded objects for mobile AR using a heads-up
display," explains Lawrence Rosenblum, program officer for graphics and
visualization within the NSF Directorate for Computer and Information Science
and Engineering. "As AR continues to develop, with many of the ideas for
mobile AR now being ported to PDAs and improved hardware for medical and other
relatively stationary applications, his ongoing AR perception research is
paving the pathway for working AR systems."
One challenge is aligning an object in
the real word so that it precisely lines up with virtual objects. While
exactness in millimeters may not be all that critical for a TV sporting event,
think about a soldier relying on this tool during battle or a doctor using this
technology in an operating room. The virtual graphics might be located inside
the patient's body.
"Imagine an application where you
have a surgeon trying to align a scalpel in relation to virtual graphics that
are also in view," says Swan.
"The surgeon would look at the
patient and be able to see into their skin. So, instead of looking to one side
and seeing the scanned information on a monitor, they would look at the
patient, but it's as if they're looking into the patient, as if the patient has
become somewhat transparent at that spot," continues Swan.
Think about it as a sort of X-ray
vision!
The most advanced lab that is actually
applying augmented reality to medical applications is located at the Technical
University of Munich, which Swan visited in 2011. There are no scalpels or
heart monitors in Swan's lab at Mississippi State, but there is an augmented
reality haploscope.
"A haploscope is a precision device
used by vision scientists to present a carefully controlled image to each eye,
so it's a stereo image into the right and left eye," he says.
In Swan's lab, volunteers use the
haploscope to position virtual objects and real ones. Graduate student Gurjot
Singh explains to the volunteers that they will see an object that looks
exactly like a physical one, but it will be computer generated. Their goal is
to align those objects.
"The purpose of the head-mounted
display device is to display an image in stereo. I have two transparent screens
in front of my eyes, which display a stereo screen. This thing on my head is a
tracking device, which tracks my head when it moves, and the device sends
information to a computer through this wire. And when the computer receives
this information, it draws the scene on this screen based on this information,
and my location in space. That's how, when I move my head, you can see the
scene is updated on the screen," explains Singh.
He says the equipment has improved
dramatically in just the past few years.
"The last device used to be so
heavy. The optics were made of glass. These are made of plastic, and are much
brighter than our last device. It gives a more compelling immersive experience
than our last one," says Singh.
Accurate depth perception is vital to
military applications of augmented reality. Swan previously worked at the Naval
Research Lab, on a project to develop a mobile augmented reality system.
"The idea is that soldiers would
walk around with an augmented reality display on their head. They would be able
to see the real world with their actual vision and we would be able to show
them graphics that, if we did it right, would look just like they were also
real objects in the world," says Swan.
On a battlefield, soldiers must quickly
assess what's happening on the ground. As AR improves, they will increasingly
need to combine that situational awareness with commands or warnings sent
through their goggles or helmet.
"You don't want to fill someone's
field of view with graphics that are going to block too much of their view of
the real world," notes Swan.
Ryan Ismert is general manager for
augmented reality at Sportvision, the company that's developed this technology
for major league sports broadcasters. And for TV viewers, just like for a
soldier or a surgeon, simplicity is the key.
"It is presented as a natural part
of the game, explaining something that may otherwise be hard to see, like the
first down marker or the path someone took for a reception route," says
Ismert.
Augmented reality is also the tool used
to paint those country flags on the bottom of swimming pools to distinguish
swimmers during the Summer Olympics.
"Visual reasoning adds an extra
layer of understanding and engagement to sports, but industry may also benefit
from augmented reality tools in everything from aircraft maintenance to capping
an underwater oil well," says Ismert.
Swan agrees that industrial applications
of AR could be widespread.
"Boeing was the first company to
try using augmented reality as part of their manufacturing process, in the
early 1990's. One of Boeing's chief scientists recently said that augmented
reality was going to be increasingly used at Boeing and at other high-tech
manufacturing companies in the coming decades," says Swan.
Miles O'Brien, Science Nation
Correspondent
Marsha Walton, Science Nation Producer
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