Boccardo, Piero 
  
  
4. RESL 
The 3D : 
good po 
processit 
and refr: 
the featu 
In order 
phase a 
orthopro 
discrepeti 
Figure 12 — First taking position Figure 13 — Second taking position "eroding 
   
DEED 
funcion: | (Cancel 
   
Figure 14 — Third taking position Figure 15 — Fourth taking position 
Acquisition time has been varied from few seconds to couple of minutes; for all the acquisitions, taking also into 
account the instrument moving, less than one hour was necessary. 
3 POST PROCESSING 
  
Figure 
white) 
The post-processing phase include the 3D reconstruction by 
station using reflective stickers (fig. 16). 
means of tie points, materialized onto the underground 
4 CON 
Accordir 
friendlin 
photogra 
infrastru 
In additi 
surveyin 
few year: 
Future st 
future su 
scan wit] 
    
ACKNC 
Figure 16 — Reflective sticker Figure 17 — 3D reconstruction in Cosmos 3D viewer We like 
not be pe 
The software, by means of an autocorrelation procedure is capable to locate the 3D position of the reflective stickers E 
(characterized by a high reflectivity in the near-infrared wavelength), imposing the correspondence of the coordinates REFER 
(in a given reference system) of them in the different images (tie points). 
The 3D reconstruction generates 3D files (in a 3DD fi 
le format) that can be easily viewed using free-of-charge internet 
downloadable software such as COSMOS (fig. 17). 
P. Wald 
Vienna, 
Internet 
  
  
  
74 International Archives of Photogrammetry and Remote Sensing 
. Vol. XXXIII, Part B5. Amsterdam 2000.