CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
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. An in- 
house developed application, named CCDINT (Tournas et al, 
2001) was used. The calculation of the approximate values of 
the unknown parameters is made by the software using the 
Direct Linear Transformation (DLT). After the bundle 
adjustment the final results for the focal length and the principal 
point’s location were (in pixels): 
c = 951 , o c = ±32.3 
x 0 = -9.2 , o x0 =±77.5 
y o =0.8, o y0 =±86.7 
As it comes from the results of the adjustment, the stability of 
the digital camcorder is very poor. The variability of the 
estimated parameters is higher than expected. The main reason 
for the large standard deviations of the above parameters is the 
low accuracy of the image coordinates measurements due to 
poor image quality (Lerma et al, 2002). The pixel size can be 
estimated by comparing the focal length in pixels and in mm, 
equal to 3.8 pm. The first two coefficients of the radial 
distortion were also computed : 
k,= 0.006, k 2 =-1.028 1 O' 9 
The estimated radial distortion was not used to produce new 
corrected digital images. Instead it was inserted in the 
photogrammetric procedure, as parameters of the interior 
orientation of the images. Although a wide-angle lens was used, 
the tangential distortion was neglected. 
4. APPLICATION 
4.1 Field work 
For the video recording of the façade of the Gate of Adrianos, 
the experience derived from the editing of the testfield images 
was taken into consideration, according which: 
• object details that lie longer than 3m away from the camera 
are not clearly shown 
• point coordinates could be measured with low accuracy. 
The dimensions of the column capital are lm width x 0.6m 
height and it lies approximately 5m from the ground level. In 
order to approach it and for the video recording, too, an 
especially stable metallic scaffolding was used, which is built 
around the whole façade of the monument for the purposes of a 
conservation project of the Hellenic Ministry of Culture. The 
scaffolding had in total 7 horizontal levels of a width of 2m 
approximately, in contact with the monument. The particular 
column capital lied almost in the middle of the interval between 
two levels. 
The video recording was made following a predefined path, 
almost parallel to the object’s surface, along the scaffolding 
level. The distance between the camcorder and the object was 
not greater than 1.5 m in order to overcome the low resolution 
of the still images and to be able to distinguish architectural 
details. The movement of the camcorder had to be slow, so that 
“fuzzy” images could be avoided. The area of coverage was 
rather narrow, thus a sequence of stereo frames had to be 
created. The base of the sequential still images was 
approximately 0.20 m. Thus the B/H ratio was approximately 
1:8. 
I 
Figure 5. Initial still frame of the central part of the column 
capital 
4.2 Orthoimage Creation 
Three sequential approx. 70% overlapping still images, 
covering part of the column capital and establishing two 
stereomodels, were chosen to generate an orthoimage. All the 
usual photogrammetric procedure was accomplished through 
the SSK Z/I Imaging digital photogrammetric workstation. 
Since the pixel size was not quite known, but computed, it was 
preferred to treat the digital camcorder as an analogue camera. 
Interior orientation consisted of collimating the corners of the 
cropped (output from the Adope Premier) images. Natural detail 
control points were already available with an accuracy better 
than 1 cm. The interior orientation had no significant errors, not 
greater than 2 pm. The relative orientation was also easy to be 
solved. The remained y-parallax was 3 pm. The stereoscopic 
vision was good, and the sense of object’s depth was clear. 
Unfortunately, triangulation of the three images could not be 
solved. Hence the exterior orientation was computed for each 
model separately. Therefore distinct medium-density DTMs 
were created manually for each model. The given output pixel 
size of the orthoimages was set at 1 mm (Ioannidis et al, 2001). 
Model a Model b 
Figure 6. Dgn files of the area of interest