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Title
New perspectives to save cultural heritage
Author
Altan, M. Orhan

CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey
Figure 2. Cross section of the church: it has been obtained from the editing of photogrammetric restitutions.
It has also been used to have a support for stratigraphic data: USM are represented in red, while the number inside refers to a specific
report. The overlapping symbols in the area indicate positive or negative actions.
on the apse, with mobile scaffolding, obtaining about 1:350 scale of
images. On the transept, twelve stereocouples have been acquired
at about 1:250 scale (longitudinal overlap =80%, transversal
overlap = 40%). Thanks to the scaffolding set for consolidation
works, it has been possible to take photos in the best condition
for stereoscopic restitution. In parallel, a photographic campaign
with digital camera has been performed to have, on one hand,
model of details at greater scale, usable for deeper and particular
elaborations, on the other hand, a collection of oriented images to
use as model texture. The images have been oriented and restituted
with both analytic stereoplotter Digicart 40 (by Siscam) and digital
Stereoview (by Menci Software).
For the surfaces that could be considered approximately flat image
rectification with Archis software (by Siscam) has been used. A
radiometric adjustment has been performed in order to reduce the
different light exposures of the used images. This type of raster data
is very useful to report USM analysis and, in general, for thematic
representation, but geometric constraints of the surface planarity
limit the application fields. Texture data, besides 3D vector data,
enhance the users cognition and is the direct transposition in the
3D world of what is already consolidated in 2D world.
2.3 Laser scanner survey
Different from the above-mentioned techniques, acquired points
are generally more than necessary to obtain a meaningful shape
representation. Anyway, a kind of interpolation from measured
data was performed when we pass from a discrete (cloud of points)
description to a continuous one (surfaces). Data processing is
mainly based on reducing cloud point data, by filtering, and on
mesh optimisation. This is like saying that, in front of a great
number of acquired points, only a percentage of them will belong
to the final model. The level of details of the models obtained from
low resolution scanning is not comparable to that obtained from