104 
Fig. 5 - Overlay of the automatically acquired 
D.E.M.. 
was the application characteristic of DPW (Digital 
Photogrammetric Workstation), that is the 
construction of D.E.M. with image automatic 
correlation and the production of orthopnoto. 
For this purpose a S/W was used, newly produced 
and commercialised by Siscam of Firenze; that is 
to say the Stereometric Pro and in particular the 
A.D.A., D.E.M. Manager and Orthomap modules. 
The first one, whose aim is the production of 
D.E.M. with image matching techniques, gave 
acceptable results of the collimated points along a 
grid of 10x1 Ocm (about 3500 points) in the 75% of 
cases. The result may not seem optimal, but it has 
to be considered in relation to: 
• the kind of images (grey scale b&w); 
• the masonry texture much larger than the 
acquisition grid (about 20x40 cm against 10x10 
cm); 
• the low roughness and uniform grey tones ail 
over the images (the low superficial porosity of 
the stone and the daylight reflected and 
diffused from the light floor). 
For the remaining stereoscopic coiiimations the 
operator acted manually completing, in this way, the 
D.E.M. of the surface to be orthoprojected. 
The orthoprojection operations became, with totally 
digital systems, extremely simple and, with WS of 
Fig. 6 - Digital orthophoto and graphic vector 
superimposition.