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CIPA 2003 XIX th International Symposium, 30 September - 04 October, 2003, Antalya, Turkey 
the centre of the modern city. 
Grayscale orthoimages of both sides of the whole monument 
were previously generated by the Laboratory of 
Photogrammetry of the School of Rural and Surveying 
Engineering of NTUA, during a research programme funded by 
the Hellenic Ministry of Culture (Figure 1). The images had 
been acquired using metric cameras such as UMK 13x18, P31, 
and Rolleiflex 6006. 
For the application needs in this paper, a detailed close range 
video recording of the eastern side of the Gate of Adrianos was 
made. Finally only a small part of this side was selected for 
editing, testing and production of an ortho-photomosaic. That 
part is a column capital, shown magnified on the lower part of 
Figure 1 (inside the red circle). 
The comparison of the orthoimages coming from the two 
different image sources, metric cameras and digital camcorder, 
and the evaluation of geometrical accuracy and radiometric 
quality will be examined. 
2. THE DIGITAL CAMCORDER 
For the application purposes a Sony DCR-TRV140E (Figure 2) 
supporting the Digital8 standard was used. It is one of the 
cheapest digital camcorders in the market. The connection with 
the computer is achieved through the DV-OUT port supporting 
the IEEE 1394 protocol. The effective part of the 14" CCD 
provides more or less 350K actual pixels. The focal length 
varies from 3.6 mm to 72 mm according to the manufacturer’s 
specifications. The zoom has no fixed positions but a 
continuous range and it is manually controlled. Thus it is almost 
impossible to achieve a known and repeatedly steady focal 
length. Hence it was determined that the lens should be fully 
retracted in order to have the focal length at its shortest length. 
The focus was fixed manually at infinity. A Pinnacle Studio 
video card was used in order to create captured clips in AVI 
format from the camcorder. The captured videos and the 
grabbed still frames were created by using Adobe Premiere. 
The video speed e.g. the frame rate was 25 fps and the average 
data rate 4,28 MB/sec. 
The change of image’s aspect ratio from 1.25 to 1.28 should 
also be considered. 
3. CALIBRATION OF THE CAMCORDER 
The low image resolution in combination with the usual needs 
of archaeological applications demand the achievement of 
maximum accuracy possible from the photogrammetric 
procedures, thus the accurate determination of inner orientation 
parameters, i.e. principal distance, principal point coordinates, 
radial and possibly tangential distortion parameters. For the 
calibration of the particular camcorder, video images of a three 
dimensional testfield were taken. The testfield was placed in a 
room at the School of Rural and Surveying Engineering of 
NTUA, and its dimensions are 6x6x3 m 3 area, consisting of 
targets which are attached to a metallic board and on 8 digit 
columns (Figure 3). The coordinates of the targets had been 
calculated by topographic intersections of high accuracy, better 
than 3mm. The testfield was video recorded from several 
distances varying from lm to 5m, and from different angles. 
The result was a great number of different scale images with 
and without overlap, with and without convergence. 
The influence of the radial distortion is more than obvious, 
looking at the curved appearance of the vertical columns (see 
Figure 3). It was expected, since a wide-angle lens was used. 
(Devernay et al, 2001; Karras et al, 2001).Twelve images were 
chosen and most of the visible targets were measured with pixel 
accuracy. Initially the images were inserted in AutoCAD® 
environment, and the image coordinates of the targets were 
measured. Through an affine transformation the measured 
coordinates in ‘screen’ units were transformed in pixel units. 
Some of the distant targets appeared fuzzy and they were 
rejected. (Figure 4). 
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The file type of the still images is uncompressed TIFF. The 
quantity of 350K pixels is inadequate and leads to an a priori 
poor quality. Although the video card provides -during the 
frame grabbing process- an image size of 720x576 pixels, part 
of the original image is cropped out. Thus the size of all the 
images of the present work is 706x550 pixels. The image loss 
of 2% and 4.5% at horizontal and vertical direction respectively 
is significant not only for the coverage of the recorded object 
but also for the overestimation of the computed focal length. 
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Figure 4. Detail of distant targets 
The determination of camera calibration parameters was made 
simultaneously with the calculation of the exterior orientation 
elements of each image in a bundle adjustment solution. An in-