Paleontologists and computer scientists
have joined forces to paint fossils with
digital flesh and create dynamic models
that reveal how dinosaurs may have looked,
walked and attacked prey.
Called "augmented reality" (AR), researchers
have used the new techniques to fit muscles
onto a predator's jawbone and to interpret
a mysterious feature in dinosaur footprints.
National Science Foundation (NSF)-supported
paleontologists Stephen Gatesy of Brown
University and Lawrence Witmer of Ohio
University collaborated with Oliver Bimber
of Bauhaus University in Germany and colleagues
at the Mitsubishi Electronic Research
Laboratory in Cambridge, Massachusetts
and the Fraunhofer Center for Research
in Computer Graphics in Providence, Rhode
Island, to develop augmented reality's
paleontology applications.
The researchers used augmented reality
to determine where powerful jaw muscles
may have attached to the skull of Deinonychus,
a predatory dinosaur. The researchers
hypothesized where muscle, skin, and other
parts would fit, based upon observations
of closely-related modern animals, and
stored this information, along with a
3-D scan of the fossil, in a standard
desktop computer.
The computer drives the researchers' "Virtual
Showcase," a half-mirrored, conical chamber
fitted with numerous projectors and lighting
controls into which fossils are placed.
Standing outside of the showcase and wearing
special glasses, the researchers control
the lighting and projected graphics, creating
a 3-D illusion of flesh enveloping original
bone.
Within the Virtual Showcase, "users perceive
real and virtual content within the same
space," said Bimber. "Virtual and real
objects can be anywhere inside the Virtual
Showcase, and multiple users can look
at them from different perspectives, walking
around them," he said.
A simplified application of the Showcase
projects two-dimensional textures and
information onto white casts of fossils.
"Think of the unpainted cast as a kind
of screen upon which the projection is
displayed," said Gatesy.
Called projection-based illumination, the
process is less expensive than the standard
Virtual Showcase and does not require
special glasses or as many graphics components.
However, projection-based graphics can
not augment the fossil in three dimensions.
The researchers also used another 2-D,
augmented reality process called live
video-mixing to study dinosaur locomotion,
superimposing an animated, skeletal foot
onto a footprint cast from a mudstone
in Greenland. The researchers then visualized
the same simulation in 3D within the Virtual
Showcase.
"By interactively shading the cast inside
the Virtual Showcase, the superimposed
animation of the foot can appear in front
of, behind, or within the footprint,"
said Gatesy. "Until you've seen the thing
in stereo as you move around the object,
it's difficult to describe how effective
it is."
The AR findings help explain why some dinosaur
tracks show a backwards-pointing first
toe - the researchers found that a forward
moving foot can actually create the backward-pointing
slash as it plunges down and forward into
mud.
In addition to research, the AR technology
may also have applications in museum exhibits,
augmenting fossils for a variety of educational
purposes and enhancing details on display
specimens. Just as scientists can easily
change data to meet research needs, museums
can change the data guiding a fossil display.
"I'm looking forward to the day when we
can create, test, modify and communicate
our hypotheses about soft tissues and
behavior while holding specimens in our
hands," said Gatesy. "Keyboards, mice,
and desktop monitors still keep us one
step removed from the raw data, the fossil
itself." [Josh Chamot]
For a movie depicting a Deinonychus skull
within the Virtual Showcase, see:
http://www.nsf.gov/od/lpa/news/02/tip021022_video_bimber.htm
The researchers presented the AR system
at the October 2002 Society of Vertebrate
Paleontology meeting and described the
new technique in the September issue of
IEEE Computer Graphics and Applications
- the abstract is available at:
http://www.computer.org/computer/co2002/r9toc.htm
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All images
courtesy:
Oliver Bimber, Bauhaus University, Germany
(formerly of Fraunhofer Center for Research
in Computer Graphics in Rhode Island),
oliver.bimber@medien.uni-weimar.de
Stephen M. Gatesy, Brown University, stephen_gatesy@brown.edu
Lawrence M. Witmer, Ohio University, witmerl@ohio.edu
Ramesh Raskar, Mitsubishi Electric Research
Laboratories, Massachusetts, raskar@merl.com
L. Miguel Encarnação, Fraunhofer CRCG,
me@crcg.edu

Visualization and presentation of the
packing process with the Virtual Showcase.
The physical skull of Deinonychus is placed
inside the 3D display and is then augmented
with the reconstructed soft-tissues:
(a) physical skull of
Deinonychus,
(b) scanned skull geometry
registered to real counterpart,
(c) augmented muscle
groups,
(d) integrated paranasal
air sinuses and sclerotic rings (bony
eye rings),
(e) superimposed skin.
Larger versions
of JPG and TIF available:
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versions of image A (Size: 36KB)
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versions of image B (Size: 40KB)
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versions of image C (Size: 24KB)
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versions of image D (Size: 24KB)
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Animated theropod foot skeleton superimposed
over the real track via video-mixing.
Larger versions
of JPG and TIF available:
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versions of image (Size: 111KB)

Projector-based illumination:
(a) original theropod
track preserved in the Triassic Fleming
Fjord formation of Greenland,
(b) manmade cast of the
shallow track,
(c) texture of original
track and additional annotations that
indicate the imprints of the toes, projected
directly onto the cast via video-projectors.
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of JPG and TIF available:
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versions of image A (Size: 156KB)
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The Virtual Showcase is a multi-user museum
display that offers an imaginative and
innovative way of accessing, presenting,
and interacting with scientific and cultural
content.
Larger versions
of JPG and TIF available:
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versions of this image (Size: 30KB)
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