International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B5. Istanbul 2004 
  
with the distances obtained using the results of the topographic 
  
  
  
  
  
survey. 
Distances - Scan 1 (m) 
Target 4 6 7 5 
4 
6 3.14215 
7 2.21378| 2.00654 
5 2.16967| 2.27762, 2.98541 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Distances Differences - Topographic/Scan2 (m) 
Target 4 5 6 7 8 
4 
5 0.00038 
6 -0.00061| -0.00008 
7 -0.00026| 0.00108| 0.00059 
8 -0.00133| -0.00123| -0.00150| -0.00122 
9 -0.00134| -0.00155| -0.00191| -0.00138| -0.00046 
  
  
  
  
  
  
  
Table 9. Distances among the common targets — Scan 1 
Distances - Scan 2 (m) 
  
  
  
  
  
Target 4 6 7 5 
4 
6 3.14035 
7 2.21356| 2.00545 
5 2.16776| 2.27829| 2.98538 
  
  
  
  
  
  
  
Table 10. Distances among the common targets — Scan 2 
Differences between 
distances (m) 
  
  
  
  
  
Target 4 6 7 5 
4 
6 0.00180 
7 0.00022, 0.00109 
5 0.00191, -0.00067, 0.00003 
  
  
  
  
  
  
  
Table 11. Differences between distances ( Scanl — Scan 2) 
Table 12 shows the differences between the distances obtained 
from scan 1 and the topographic survey. 
Table 13 shows the differences between the distances obtained 
from scan 2 and the topographic survey. 
It is possible to observe that the average difference is about 1 
mm, whilest the maximum difference is about 3 mm (scan 1), 
and 2 mm (scan 2). Also in this case, the differences are less 
than the scanner accuracy. 
  
Distances Differences - Topographic/Scan1 (m) 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Target| 1 2 3 4 5 6 
1 
2  |-0.00297 
3  |-0.00040|-0.00042 
4  |0.00121|-0.00045| -0.00007 
5 | 0.00019|-0.00126|-0.00038| 0.00238 
6  |-0.00187|-0.00311|-0.00252 -0.00130]-0.00187 
7  |-0.00142|-0.00270|-0.00245|-0.00259| 0.00119/0.00210 
  
  
Table 12. Differences between the distances obtained from the 
first scan and from the topographic survey 
Table 13. Differences between the distances obtained from the 
second scan and from the topographic survey 
6. FUTURE WORK 
A comparison between the proposed targets and radiometric 
plane targets will be carried out. 
Other tests will be performed to evaluate the effectiveness of 
the method when several mergings are executed. 
7. CONCLUSIONS 
The use of volumetric targets for the automatic merging and 
orientation of laser scanner acquisitions has been experimented. 
The targets. have been scanned with higher resolution. An 
automatic procedure for the vertices individuation, based on the 
least square method, has been proposed. A test has been 
performed on the facade of the faculty of engineering of the 
Padua University (Figures 14, 15). The results show errors less 
than the laser scanner accuracy. 
  
  
  
  
  
  
  
  
Figure 14. View of the central window (multiresolution scan) 
with the common targets 
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