- 119 - 
non contact active sensing (no interference with excavation 
activities and no need to signalise the object); 
immediate results and easy measurements on the model. 
Laser scanning peculiar characteristics are also the practicability 
of object replication (mould), and the support for virtual 
exploration and study via Internet, with a different approach in 
respect to photogrammetry and visual photographic reality 
(Bitelli et al., 2001). 
In applications like those shown, laser scan could be a good 
solution to detect and model ‘out of vertical’ walls, providing a 
valuable support for structural monitoring and intervention. 
On the other hand, archaeologists sometimes require from the 
survey a traditional product, in the form of a vector drawing 
with the main features well individuated, i.e. subordinate to a 
preliminary subjective filtering; the derivation of such a result 
from the laser model requires very powerful software and high 
skills where complex and not elementary geometrical shapes are 
involved, as is the case for numerous archaeological 
applications. 
The choice of appropriate software is a crucial point for data 
processing, where strategies for data decimation and filtering, 
merging of cloud datasets and meshes, TIN tessellation, and 
finally generation of a polygonal model can produce quite 
different results (Fangi et al, 2001). 
Photographic richness provided by photogrammetric image 
products is surely of high importance for archaeologists and 
architects, and true-colour imagery generated as a product of a 
laser scan, when available, is sometimes inadequate in quality 
and radiometric characteristics. 
The integration of the two techniques, on the other hand, could 
provide very interesting results, starting from simple 
combinations: for instance, a stereoscopic model could permit 
the editing and integration of a incomplete laser acquisition (fig. 
12), or the laser data could supply the coordinates for exterior 
orientation of photogrammetric images. 
Fig. 12 - House of the Big Fountain: (a) effect of shadowing 
and edges on laser data; (b) the errors are clearly 
visible and editable by superimposing the point cloud 
data on the photogrammetric stereoscopic model. 
As depicted by other experiences, the use of laser derived DSM 
as a support for digital orthophoto generation do not directly 
provides satisfying results (see for instance figure 13 compared 
with figure 5), depending also on the object shape, data density, 
etc.; it requires at least an appropriate editing of the 3D model. 
Furthermore, complex shapes require multiple scans and an 
accurate survey planning. 
In this context, photogrammetry could play a relevant role to 
complement laser surveys, in order to detect or correct 
erroneous or missing parts of the datasets and to describe 
discontinuities by means of breaklines and points. 
3D texture mapping of the clouds of points can be performed by 
using calibrated instruments and cameras (Kern, 2001), and the 
combination of laser scanning and photogrammetric systems 
could produce a complete object modelling, with highly 
accurate geometric and colour characteristics. 
In the next future the integration of these techniques will play 
therefore a fundamental role in surveying for cultural heritage 
recording. 
Fig. 13 - House of the Small Fountain: particular of orthophoto 
obtained by using surface model provided by laser 
scanning. 
4. REFERENCES 
Baratin L., Bitelli G., Unguendoli M., Zanutta A., 2000. Digital 
orthophoto as a tool for the restoration of monuments. In: 
International Archives of Photogrammetry and Remote 
Sensing, Vol. XXXIII, Part B5, 62-69, Amsterdam. 
Beraldin J.A., Blais F., Coumoyer L., Rioux M., El-Hakim 
S.H., Rodella R., Bernier F., Harrison M., 1999. 3D Digital 
Imaging and Modeling. Proc. 2 nd Int. Conf. on 3D digital 
imaging and modeling, Ottawa, Canada, 33-43. 
Bitelli G., Tini M.A., Vittuari L., 2001. Low-cost systems for 
metrical documentation and virtual reality representation of 
small objects in archaeology. Proceedings Workshop on 
“3D Digital Imaging and Modeling Application of heritage, 
industry, medicine & land”, Padova (CD-Rom). 
Bitelli G., Capra A., Zanutta A., 2001. Photogrammetric 
Surveying of Nymphaea in Pompei. Proceedings CIPA 
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Böhler, W., Heinz, G., Marbs, A., 2001. The potential of non- 
contact close range laser scanners for cultural heritage 
recording. Proceedings CIPA 2001 International 
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Bomaz L., Lingua A., Rinaudo F., 2002. A new software for the 
automatic orientation of 3D digital models acquired using 
laser scanner devices. Int. Workshop on Scanning for 
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Fangi G., Fiori F., Gagliardini G., Malinvemi E.S., 2001. Fast 
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