CIP A 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
The scans were made with a MENSI S-25 laser scanner which 
is based on the triangulation technique from two different 
locations, parallel to the rock face. 
Triangulation measurement system works by geometric relation 
with angle of laser beam, recorded position of laser spot on the 
CCD and distance of CCD base (Figure 2). 
Figure 2. Triangulation methods for range acquisition (Beraldin 
et. al., 2000) 
Triangulation system performs more accurate and fast 
measurement at moderate range (0.8-10m) and a CCD camera 
of scanner must detect structured light. Thus the measurement 
distance was set about 5m and the experiment was conducted 
under the cloudy sky. 
This measurement system consists of computer hardware and 
software which are for backup the large point data, and laser 
scanner. The type of data being returned by a laser scanner is a 
dense point cloud which means 3D position of object. The file 
(format is *.pts) in X, Y and Z coordinates which are relative to 
the scanner’s position are taked by Rapidform2002 which is 
software to visualize and to generate DSM with the point data 
(Figure 3). To avoid the shadow, scanning is conducted from 
two positions and the two stereo images were obtained. It must 
be conformed a complete image. 
. * * S *. lì 4. * < 
. - -Jir-i *s* f ” -> OS. S 
pmi» ~"E ■ » «, 
Figure 3. Screen capture from Rapidform2002 program for 
building digital surface model using the data 
acquired from laser scanner 
2.2 Digital Photogrammetry 
For estimating the accuracy of digital stereo photogrammetry, 
the stereo image was obtained for the same area where laser 
scanning was conducted. To decrease the radial distortion 
which becomes larger and larger where located far from the 
center of lense, we took stereo images in the position where 
triangular shape was made at the center of image. 
Canon EOS D30 was used with 22.7 x 15.1 mm CCD. The 
resolution of image was 2,160 x 1,440 pixel and focal length 
was about 5.6 m. 
15 targets were attached around the triangular shape of image 
for the control points and the check points and the 3D 
coordinate of the points was measured by 5” theodolites DT5S). 
Initial position to take the images and targets are shown at 
Figure 4. The origin was positioned behind the rock face to 
prevent Z-coordinate being negative number. 
To obtain interior and exterior orientation which establishes 
the position and orientation of the bundle of rays with respect to 
the object space coordinate system, bundle adjustment was 
applied (Mikhail et. al., 2001). Table 1 shows the results. 
Left Camera 
(0,1490,8000) 
Left Theodolite 
* ^(0,1415,8000) 
Jf 
Right Camera 
(2077.1690.8000) 
Right Theodolite 
(2077.1612.8000) 
Figure 4. Three dimensional coordinate system : distributed 
solid circles represent targets (units are mm) 
Camera 
Parameters 
Left 
Right 
• 
0.227811 rad 
0.201134 rad 
• 
-0.139705 rad 
0.205790 rad 
• 
0.040883 rad 
-0.052426 rad 
X« 
-21.581 mm 
2068.103 mm 
Y 0 
1497.158 mm 
1704.751 mm 
Z 0 
8045.914 mm 
8019.272 mm 
x 0 
5.956283 pixel 
0.154158 pixel 
yo 
-2.359040 pixel 
-0.895909 pixel 
Zo 
27.908419 mm 
28.15702227 mm 
Table 1. Interior and exterior orientation parameters of 
reference surface determined by EOS D30 
camera(units are radian and mm, respectively)