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Technology
brings computer imaging closer to reality
Even if you don't have the time or means to visit all of the landmarks
and places you want to, you may still be able to experience them
without physically being there.
For example, if you go to the New Orleans Museum of Art's celebration
of the 200th anniversary of the Louisiana Purchase, you'll be able
to get a 3-D sense of what it is like to visit Jefferson's home
of Monticello.
To do that, the museum has enlisted the help of Carolina's Lars
Nyland, research associate professor of computer science, who
has developed a scanner that can create realistic 3-D models of
rooms, buildings, historical landmarks, caves and just about anything
else.
No, not virtual reality. Image-based rendering. Unlike virtual reality,
in which people build the models -- of a table or bookshelf, for
example -- with special software, image-based rendering uses real-world
images, or scans, as its source. Nyland created the scanner, called
the DeltaSphere 3000, because he wanted to include as much detail
as possible in his models, giving people a realistic experience
of a place.
"In
virtual reality, you might see a book shelf, but you won't see all
of the different books on them with their colors and titles because
nobody wants to take the time to build each book," Nyland said.
"With the DeltaSphere, I know where all of the books are, how many
there are, and which books are lying on their sides."
The scanner contains a laser beam, a mirror, a motor and a computer.
Another computer -- a laptop attached to the scanner -- runs software
Nyland created to tell the scanner what to do -- sweep here, take
a scan, store the data, repeat. To scan, the mirror spins around
the laser, and each time the laser hits something, it calculates
how far away the object is. It does this 25,000 times a second,
taking about 20 minutes to do one full revolution. Just after the
laser measures the distances, a camera captures a full-color panoramic
view.
Software running on a laptop computer interprets the data and weeds
out extraneous details. Take a wall, for example, which has a flat
surface. "What you really need to know about walls is where they
end, so you can eliminate all those samples you don't need in between,"
Nyland said.
Nyland has already taken several scans of Monticello and is working
on simplifying the data so that it's ready in April 2003 when the
exhibit "Jefferson's America, Napoleon's France" opens in New Orleans.
"We want to build a compelling 3-D experience, so that visitors
can take away a piece of Monticello with them," Nyland said. The
exhibit will run from April through the end of August, and the museum
is expecting over 400,000 visitors.
Other possible uses Nyland foresees for DeltaSphere include historical
preservation, engineering and construction projects, and forensics.
In old buildings, for example, when the plaster on the walls has
to be torn down due to water damage or to put in new ventilation,
scans of the open wall would help planners and construction workers
know where the studs and channels are located. "You could get some
information with a photograph," Nyland said, "but with a 3-D model
you can figure out exactly how deep a channel is or its actual spacing.
It's hard to predict what you might need to know later on."
The FBI has contacted Nyland to help them with crime-scene investigations.
While still in the preliminary stages of contracting an agreement,
the FBI hopes to be able to use Delta-
Sphere to take scans of crime scenes before they are cleaned up
and the evidence destroyed.
With DeltaSphere you can create a bird's eye view of a room, which
would allow investigators to see the room from a point of view that's
not possible with two-dimensional images. "The detail is incredible,"
Nyland said. "You can see the folds in the sheets and covers, and
you can get very realistic lighting. In a virtual reality model,
there might be a bed, but they wouldn't go to all that trouble."
If investigators want to figure out, for instance, where a shooter
may have been standing during the crime, they can find all of the
bullet holes in the image and then pull up a grid on the computer
screen with exact measurements in inches. Where the lines intersect
is probably where the gun was.
A similar application would be to use DeltaSphere after an automobile
accident before the vehicles are towed away. An accident investigator
could use the scans to project the cause of the crash. Since the
scans are in color, the investigator could see the skid marks and
then use the grid to take measurements. With that information, the
investigator could estimate the speed of the car within about 10
miles per hour. "This becomes an issue of liability," Nyland said.
"Say you called your insurance company up and told them you slid
out of control and wrecked your car and that you want them to replace
it. Well, they could turn around and say, `You were driving 65 in
a 35, so it's your fault.' It's kind of like DNA evidence. It's
not incriminating in itself. It's just the facts until somebody
puts it together and it becomes evidence."
Nyland has licensed the technology for DeltaSphere to 3rd Tech of
Chapel Hill, which oversees the production and sales of DeltaSphere-3000
Scene Digitizer.
The Office of Technology Development (OTD) is the only UNC-CH office
authorized to execute license agreements with companies. For more
information on reporting inventions, contact OTD at 966-3929.
Provided
by Research and Graduate Studies
Writer:
Cate House
Editor:
Neil Caudle
University Gazette
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