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The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B5. Beijing 2008 
Figure 6. Means of intensity values for different coloured 
sheets 
Histogram (day) 
Intensity 
5.2 Intensity analysis 
Due to the specific characteristics of natural material like wood, 
remarkable colour discrepancies occurred with regard to the 
different species. The lowest intensity values were obtained for 
oak (about 140) with increasing intensities for beech, pine, fir 
and spruce with the highest values (about 220). Compared to 
the differences of the mean intensities the MSE values are quite 
high (Figure 9) and therefore, it can not be distinguished 
between these species by analysing the intensity values. 
Figure 9. Histograms of five different species of wood 
6. ANALYSIS OF METAL PLATE 
Figure 7. Histograms of the intensity values for different 
coloured sheets 
5. ANALYSIS OF DIFFERENT TYPES OF WOOD 
At one area of the main test board five different species of 
wood had been positioned: pine, fir, beech, oak and spruce. All 
pieces are of the same roughness. 
5.1 Geometric accuracy 
The MSE values of range measurements lie nearly in the same 
domain and vary only between MSE = ± 2.5 mm for pine and 
MSE = ± 3.3 mm for spruce (Figure 8). Therefore, no 
significant effect of the species could be verified. 
Least square adjustment 
4,00 
3,50 
Rne Fir Beech Oak Spruce 
Since metal is also a possible material covering building 
façades, a metal plate was centred in front of the laser scanner 
in order to keep an incidence angle normal to the object surface 
in the first status. Due to the fact that metal is not a Lambertian 
reflector, the board v has then been rotated stepwise (in 
increments of 10 gon) around the vertical axis to study the 
influence of different incidence angles. 
6.1 Geometric accuracy 
For every rotation angle of the metal plate - as mentioned 
before - an adjusted plane has been estimated and the residuals 
of the original laser points have been used to determine the 
MSE values. The results for every incidence angle are compiled 
in Table 2. 
Incidence 
Angie [ gon 1 
MSE 
[mm| 
Number 
of points 
100 
±7.0 
63 602 
90 
±4.3 
72 086 
80 
±3.1 
66 779 
70 
±2.4 
65 247 
60 
± 1.9 
56 756 
50 
± 1.6 
51 783 
40 
± 1.4 
44 214 
30 
± 1.2 
33 791 
20 
± 1.0 
23 424 
10 
±0.9 
11 009 
Table 2. MSE values of the metal plate for different incidence 
angles 
Figure 8. Range accuracy for different species of wood 
The obtained values of Table 2 show a dependence on the 
incidence angle: with smaller angles also the MSE values