Nnews
Society | DOI: 10.1145/1629175.1629185
Tom Geller
Rebuilding for eternity
Researchers use computer vision techniques to preserve culturally
significant sites as high-resolution 3D models.
BUiLDinGs CoLLApse. winD and rain beat them, tem- peratures cycle from freez- ing to blistering, and ran- dom strikes of lightning
threaten sudden obliteration. Those in
wet climes face water rot; in the desert,
ceaseless wear by dust and sand. Even
more potent are the human challenges: war, fire, and deliberate destruction. No earthly structure is safe, from
the Ancient Library of Alexandria to
the Twin Towers of New York City.
But digital representations can
survive such dangers, capturing structures forevermore. Digitization provides other benefits, such as the ability to “visit” a structure remotely, to
examine its otherwise inaccessible
details, or to observe how it’s changed
over time. Further, digitized structures
invite researchers to apply computer-based analytic tools to draw out new
discoveries in such fields as archaeology, history, and architecture.
PHoto Gra PH by FlICKr user dee P Warren
Improvements in digital storage,
network access, and processing power
of the past 10 years have encouraged
researchers to capture ever-larger
sites. Now, two distinct methods enable high-resolution, 3D digitization of
structures as large as a city street or a
multi-acre historical site. One method
uses high-end laser scanning equip-
A tourist’s photo, left, of the face of a statue at Bayon temple posted on the flickr Web site.
At right is an image of the same face in the library of the Bayon Digital Archive Project, led by
katsushi ikeuchi of the university of Tokyo.
ment for accurate digitization to the
sub-millimeter level; the other uses
video or photo collections as the basis
for analysis and reconstruction.
mining Tourists’ Photos
By now, many computer-savvy people
have encountered site reconstruction
in the form of Microsoft’s Bing Maps,
Google Earth, or Google Maps’ Street
View feature. All three are the result
of mapping programs that were enhanced with real-world imagery captured through satellite photography,
aerial photography, or at street level.
These efforts, while impressive, produce imagery that sho ws sites from only
one or two aspects. Such views are sufficient for most purposes—to help people find, recognize, and “tour” remote
