Dataset 2 - stillvideo images 
For a pilot study on the applicability of high resolution 
digital stillvideo cameras in aerial photogrammetry a 
block of 5 x 10 images was taken with a Kodak DCS200 
(8 bit monochrome 1524 x 1012 pixel sensor, format 
14mm x 9mm, pixel 
spacing 9um x 9um, 
internal harddisk for 50 
uncompressed images, 
18mm lens) from a heli- 
copter over a village in 
Grisons. The average 
image scale was 
1:18'000, the average 
overlap was 70% in both 
directions, with large 
deviations due to 
handling difficulties 
with the hand-held 
  
camera in the unsteady 
helicopter. The orientation data of the images was taken 
from a self-calibrating bundle block adjustment after semi- 
automatic measurement of the image coordinates of 36 
signalized points. Checkpoint accuracies of 2cm for the 
planimetry coordinates and 4cm for the height coordinate 
were achieved in this aerotriangulation (Kersten, 1996). 
  
Figure 5: DCS200 aerial overview image of a village 
An average of 7000 points per image was extracted by the 
Foerstner-operator. Due to the geometric quality of the 
data a maximum tolerance of 10 micron (~ 1 pixel) to the 
epipolar line was found to be appropriate for the accep- 
tance of possible matches. Applying the epipolar line 
intersection routine with the requirement that each point 
has to be matched in at least 5 images, a total of 6860 
object points could be reconstructed. The maximum 
number of images a single points was successfully 
matched in was 21. The average standard deviation of the 
reconstructed points was 0.027/0.027/0.109m in X/Y/Z. 
An contour line plot generated from the 6860 object 
488 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B3. Vienna 1996 
points is shown in Figure 6. Again, no post processing 
was applied to the raw data provided by the routine. The 
plot looks quite good in the surroundings of the village, 
but rather chaotic within the village. 
  
  
    
            
hele a S 
Si 
Figure 6: Urmein test area, 1m contour lines (orientation and 
scale do not correspond to Figure 5) . 
   
    
* * 
Some problematic regions inside the village are shown in 
parts of a digital orthophoto mosaic with contour line 
overlay in Figure 7: As no information on buildings, trees, 
etc. was a priori given or explicitly extracted by the tech- 
nique, a large number of successfully matched points are 
not situated on the terrain surface, but on objects above 
the surface. Due to the characteristics of the interest oper- 
ator and the loss of points caused by the probability of the 
interest operator detecting identical points in all involved 
images, however, buildings are often modeled only rather 
incompletely. In some cases only one or two points of a 
roof were matched, and terrain points at the foot of build- 
ings are often missing. 
  
   
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x NZ 
blunders 
Figure 7: Insuffently modeled ehurch,steeple: 
parts (orthophoto 
with matched points 
and 2.5m contour line 
overlay) 
  
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