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New perspectives to save cultural heritage
Altan, M. Orhan

CIPA 2003 XIX 11 ' International Symposium, 30 September - 04 October, 2003, Antalya, Turkey
Note that these operations are common for 3D modeling
packages, but were previously not supported by multireso
lution techniques. Since we address transmission over low
bandwidth networks, our method is designed to efficiently
represent the desired object information. By exploiting
spatial and hierarchical coherence within the multiresolu
tion data structure, the object assignment can be encoded
with as little as 0.1 bits per triangle, which is negligible
compared to the object geometry.
(a) high resolution
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(b) low resolution
Figure 8: Querying meta-data about objects in the scene.
Objects can be selected and their photographs displayed
independent of the resolution of the rendered mesh res
olution, as illustrated by the two screenshots with higher
resolution (top) and lower lower resolution (bottom).
The object identification subsystem communicates with the
Web browser (embedding the WebCAME plugin) by re
questing URLs to be loaded into new browser windows or
frames. This is a simple, but very general communication
method. It enables the access to arbitrary database content
independent of the momentary object resolution, because
the object ID is propagated with every triangle through the
multiresolution hierarchy. Figure 8 demonstrates a pos
sible application of this technique: an object is selected
by clicking into the multiresolution mesh and the corre
sponding photograph is loaded and displayed. The com
munication framework also directly allows the execution
of JavaScript programs, which gives it great flexibility and
facilitates the design of more complex interaction modes.
Figure 9: Northwest Heroon of Sagalassos with frieze of
dancing girls, one of the objects is extracted from its origi
nal location and viewed at a close distance (at high detail),
while the non-transformed objects in the background are
rendered at low detail.
We will give an example how the ability to distinguish ob
jects in the multiresolution framework also supports inter
action: parts of the mesh can be extracted from their orig
inal location for close inspection by the user. The level-
of-detail selection procedure takes the transformation into
account, so that the examined object, which is closer to the
viewer than in its original position, is presented at a higher
resolution than it would appear in its original, more distant
location. In Figure 9, one of the pieces of the ’dancing girls
frieze’ has been brought to the foreground and rotated by
the user to study it in detail.
We have also examined the possibility to include attribute
data (such as normal vectors) into the CAME framework.
While an efficient and conceptually simple encoding could
be found (Grabner, 2003a), it turned out that the imple
mentation of the encoder/decoder stages is a sophisticated
task due to the different orders of he involved hierarchical
data structures. Decoding normal vectors for the rendering
system is thus left for future work.
We have presented a work-flow for automatic 3D model
ing and fast visualization of artefacts recorded on archaeo
logical excavation sites with a digital camera. A set of ro
bust multi-view-modeling techniques developed in the past
decade in the field of digital photogrammetry and com
puter vision are used to reconstruct a 3D model with mini
mal user interaction, and the CAME data structure, a newly
developed technique for efficient transmission and visual
ization of large models, is used for real-time viewing and
The purpose of the presented work was not to develop new
technology, but to integrate the different state-of-the-art