The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part Bl. Beijing 2008
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Figure 9. Test of environmental conditions
Figure 8. Test of influence of surface reflectivity
(3) Test of influence of surface reflectivity
While we captured 3D data of our researching room, we found
that the data of black chairs is entire. So we used the portable
3D laser scanner to scan a black car, the 3D point cloud data of
the black car is very good (Figure 8(a)). The portable 3D laser
scanner can measure black objects, and it is easy applied to
measure terrains coal piles. We used it to acquire the 3D data of
the coal piles in Tianjin Huanghua, built 3D model of the coal
piles, gave the profile maps of the coal piles, and compute the
volumes of the coal piles, just like figure 8(b)-8(c).
(4) Test of environmental conditions
Lasers operate in a very limited frequency band. Therefore
filters can be applied in the receiving unit allowing only this
frequency to reach the receiver resp. the camera. If the radiation
of the illumination source (sunlight, lamps) is strong as
compared to the signal, enough of this ambient radiation will
pass the filter and influence the accuracy or prevent any
measurements at all[Boehler, w., 2003]. We employed a glass
plate with the black and white chessboards to test the influence
of environmental conditions. To prevent from the interference
of environment, we put the glass plate on the playground. We
found that dust is present lead to the edge blur (figure 10(a)).
We also found that the angle between the laser beam and the
light lines of sun is to effect on the scanned data, while the
angle is closer to 0°, the scanned data is very bad (figure 10(b)),
while the angle is more than 90°, there is a little negative
influence on the scanned data (figure 10(c)), and the angle less
than 90° is the most ideal (figure 10(d)). Figure 10(e)-(h) are the
corresponding photos described above.
6. CONCLUSIONS
We developed a 360° continuous scanning, portable 3D laser
scanner, which can be applied to many fields, such as city
planning, industrial survey, virtual reality, and digital
preservation of cultural heritage. The comparison of its all
Technical data with those of foreign 3D laser scanner is shown
in Table 1. It shows technical data of our 3D laser scanner
(AX200) reaches these of foreign products of this kind. In
addition, it has the advantages of small volume and low weight
about only 6 kg, so it is easy to take, and it only costs about one
fifth of the price of the foreign commercial 3D laser scanner.