each set which 
"he homographic 
the double set of 
re then projected 
parameters. For 
nearest point of 
described in the 
ITAL IMAGE 
E 
been performed 
f the statue of 
[useum — Turin, 
ition parameters 
image has been 
a provided by a 
the automatic 
d on the statue 
1e laser internal 
[m] 
-0,771 
-0,832 
-0,094 
0,819 
1,057 
-0,682 
-0,665 
-0,440 
-0,074 
0,113 
0,239 
0,412 
0,553 
  
  
th the camera 
cquisition; the 
assumed as X 
p and k angles 
d by means of 
ind y are listed 
the reflecting 
bed before, the 
centres of the 
| the fiducial 
founded using 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Target x 
# [mm] [mm] 
20 -7,271 -16,983 
21 3,298 -18,512 
22 -5,853 -8,145 
24 2,714 15,970 
25 0,619 20,658 
60 -7,208 -14,748 
61 4,176 -14,409 
62 4,678 -7,838 
63 -0,606 0,468 
65 0,584 3,577 
66 -4,736 5,823 
67 0,440 9.212 
68 4,474 10,880 
Table 11 
Target € n 
# [mm] [mm] 
20 -8,862 -19,854 
21 3,198 -21,823 
22 -6,476 -9,024 
24 4,037 17,469 
25 1,924 22,248 
60 -8,724 -17,253 
61 4,214 -17,050 
62 5,165 -8,881 
63 -0,282 0,617 
65 1.522 4,578 
66 -4,093 7,056 
67 1,444 10,471 
68 5,856 12.329 
Table 12 
The last step of the software was that of looking for the 
homologous of the obtained reflecting targets. Following the 
described procedure, points 24, 60, 61 and 66 were selected by 
the software for the estimation of the homographic 
transformation between the two planes (one of the virtual image 
[xy]of the scanner and the other of the digital image [£n]). 
Using these parameters, all the obtained reflecting targets were 
transferred into the [$n] reference system . 
Table 13 lists the “point set 1" coordinates of table 12 
trasformed in [En] reference system and table 14 shows the 
resulting distances between the transformed points and the 
image points, wich were chosen by the software as homologous. 
The average distance was of 0.330 mm; considering that the 
average scale of the image was of 1:35, the homographic 
transformation placed “point set 1" with an approximation of 
about 1 cm on the object. 
Finally, table 15 compare the results of the orientation of the 
image using the calibration certificate parameters and manual 
collimation of the targets (row “Photogr.”) with those obtained 
using the data coming from the described procedure (row 
“Laser calibr.”). 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Target E 
# [mm] [mm] 
20 -9.050 -20.198 
21 2.990 -22.511 
22 -6.525 -8.940 
24 4.037 17.469 
25 2.202 21.995 
60 -8.724 -17.253 
61 4.214 -17.050 
62 5.075 -8.730 
63 -0.185 1.121 
65 1.256 4.578 
66 -4.093 7.056 
67 1.425 10.617 
68 5.597 12.333 
Table 13 
Target AE An Distance 
# mm mm mm 
20 -0.188 -0.344 0.392 
21 -0.207 -0.688 0.718 
22 -0.049 0.083 0.097 
24 
25 0.278 -0.253 0.376 
60 
61 
62 -0.090 0.151 
63 0.097 0.504 
65 -0.266 0.000 
66 
67 -0.018 0.146 
68 -0.259 0.004 
Table 14 
Xc Yc Zc © © K 
[m] [m] [m] [gon] [gon] [gon] 
  
Photogr. |20,564]100,206/21,424! 0,2546. 0,3820 0,9549 
  
  
  
  
  
  
  
  
Laser calibr.[20,562/100,200{21,430| 0.2689| 0.4012] 1,0342 
  
Table 15 
The differences are negligible in all cases, than the calibration 
of a digital image using laser scanner data and the proposed 
automatic procedures can be considered as a new opportunity 
for the laser scanner integration with photogrammetry. 
6. CONCLUSIONS 
The implemented software allows the automatic orientation of a 
digital image using only the information which can be extracted 
from the DTM produced by a laser scanner device. 
The described procedure makes it possible to orientate the entire 
—325—