The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B5. Beijing 2008 
1066 
dry piece of wood has a mean intensity of about 160 the same 
piece in wet condition delivers a value of about 75. 
Nevertheless the MSE values of range measurements don’t 
differ significantly and approve the independence on wetness 
conditions. Similar results can be obtained by the test with 
concrete walls, but in contrast to wood material the change of 
the mean intensity values was not relevant (Figure 12). The 
MSE value for wet condition was determined as ± 1.37 mm and 
the one for dry condition as ± 1.31 mm. 
Histogram 
omoinomoinomoinomomom 
T-(0^(ÛSO)OCMCOin(ÛCOro^-CNlTtin 
r-T-T-T-T-T-r-CNJCMCNCN 
Intensity 
Figure 12. Histogram of intensities of dry and wet concrete wall 
10. CONCLUSION 
A special aspect of quality assessment - the influence of 
different materials on the measurements of a terrestrial laser 
scanner - was presented in this paper. Besides the geometric 
accuracy of the range measurements for different materials also 
the simultaneously recorded intensity values have been an 
integral part of our investigations. For the test series grey scaled 
and coloured sheets, different species of wood, a metal plate, 
plasters of different particle size, light-transmissive slides and 
objects in different conditions of wetness have been scanned. 
The selection was based on those materials commonly used at 
building façades. 
The analysis of our results led to some general statements. First 
of all the producer’s specification concerning the range 
accuracy of an extracted plane could be verified. An interesting 
aspect was the increase of measurement accuracy at night-time 
and on bright materials. The influence of different wood species 
and of wetness seems to be marginal while light-transmissive 
material and metal plates induces enormous MSE values much 
higher than the general range accuracy of the laser scanner. 
In the future these test series should be repeated with other 
types of terrestrial laser scanners, especially with systems based 
on phase measurement principle. Furthermore additional 
materials should be included like surfaces of industrial and 
cultural heritage objects. The presented results emphasize the 
need for such investigations. 
REFERENCES 
Amiri Parian, J., Gruen, A. 2005. Integrated Laser Scanner and 
Intensity Image Calibration and Accuracy Assessment. In: 
International Archives of Photogrammetry, Remote Sensing and 
Spatial Information Sciences, Vol. 36, Part 3/W19. 
Boehler, W., Bordas V., M., Marbs, A., 2004. Investigating 
Laser Scanner Accuracy. In: Proceedings of XIXth CIPA WG 6, 
International Symposium, Antalya, Turkey, 30. September-4. 
October, pp. 696 -702. 
Clark, J., Robson, S., 2004. Accuracy of measurements made 
with CYRAX 2500 laser scanner against surfaces of known 
colour. In: International Archives of Photogrammetry, Remote 
Sensing and Spatial Information Science, Vol. XXXV, Comm. 
IV, Part B4, pp. 1031-1037. 
Hanke, K., Grussenmeyer, P., Grimm-Pitzinger, A., Weinold, 
T., 2006. First Experiences with the Trimble GX Scanner. In: 
International Archives of Photogrammetry, Remote Sensing and 
Spatial Information Sciences, Vol. XXXVI, Part 5, ISSN 1682- 
1750, ISPRS Comm. V Symposium, Dresden, Sept. 25-27, 
Germany. 
Kersten, T.P., Sternberg, H. and Mechelke, K., 2005. 
Investigations into the accuracy behaviour of the terrestrial laser 
scanning system Mensi GS100. In: Optical 3-D Measurement 
Techniques VII, Vienna, Austria, Vol. I, pp. 122 - 131. 
Lichti, D., Harvey, B., 2002. The Effects of Reflecting Surface 
Material Properties on Time-of-Flight Laser Scanner 
Measurements. Symposium on Geospatial Theory, Processing 
and Applications, Ottawa. 
Lichti, D.D., Licht, M.G., 2006. Experiences with terrestrial 
laser scanner modelling and accuracy assessment. In: 
International Archives of Photogrammetry, Remote Sensing and 
Spatial Information Sciences, Vol. 36, Part 5, pp. 155-160. 
Pfeifer, N., Dominger, P., Haring, A., Fan, H., 2007. 
Investigating terrestrial laser scanning intensity data: quality 
and functional relations. In. International Conference on Optical 
3-D Measurement Techniques VIII, 2007, ISBN: 3-906467-67- 
8,pp.328-337.