Nearest Natural neightborg 
Linear Triangulation 
  
Figure 6: Gridding elaborations using different algorithm of interpolation 
Some of the processing on the points cloud surveyed on the 
Basilica di S. Marco show how difficult it is to create mesh 
without preliminary treatments (Figure 6). 
The work presented in this paper was finalised at programming 
and successive application of a software programme able to 
handle the process of creating orthophotos. 
Orthophotos are a product frequently requested of surveyors by 
those making up analyses of buildings for the sake of 
cataloguing, conservation and restoration. 
OrthoLaser software requires laser scanning and non-metric 
digital images as input. 
The cloud of input points is comprised of lines of points which 
have: 
Code, X X Z, I RGB 
where / is the intensity of the return signal normalised on 1 byte 
(0-255), RGB is the radiometric value of 3 bytes (Red, Green, 
Blue). 
The software is structured on 4 modules described below. 
1. Module LASER 
Enables uploading and handling the points surveyed using laser 
scanner instruments. An image is viewed in the LASER 
window that we can define as polar from a geometric 
perspective, since each square pixel is defined by a constant 
angle respectively in azimuth and zenith. The radiometric value 
can be either the value of intensity of the return signal or the 
RGB trio. 
For each pixel, the co-ordinates obtained by the conversion of 
spherical to rectangular co-ordinates are known. 
It is possible to roto-translate the reference system in planimetry 
keeping the Z axis parallel to the vertical. 
Roto-translation is necessary because the orthophoto- projection 
always occurs on a plane parallel to the X,Z axes. (Figure 7) 
  
  
  
  
  
  
  
: itl xf 
load imm nf | load3D | load photo | load DLT 
1624 numero colonne (meas / line} oka | 
575 humero righe [lines / image) [ xov 
traslazione 1 3,841 {6.652 | -0,331 
  
  
rotazione | |277 205341 ticalcola punti 1 & 2 | 
  
  
     
  
radiom | Indietro | Fieset ruotato su originale | 
rototransiation seine 
11 3,841 -6,652 10,331 set punta 1 
|-17,992 4,484 10,213 set punto 2 
  
  
  
  
[2772053412 ang dat [1166506357 otras 
Salva | Carica | 
  
  
  
  
  
  
x lastta y lastta calore id 
1388 1465 ]3552822 — | 
A teneno Y terreno Z terreno intensità 
|1.977735672 |5,362985885 [1.835 {56 
Dist Zenit Azimut Numero 
120.777 193.35 {22093 {290548 
I" eroce | | Distorxe © 
[. comeggi distor | | Punto principale 
Dist principale x e v 
| Dist principale 
Esci ottho | dati | A2-Ze| Prepara fot 
  
  
  
  
Figure 7: Screenshot of the I Module. Reflecting targets are clearly visibile in the range map loaded 
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