the Opportunity oi. 
7 order Whatsoeve, h 
sibilities Opened uy h 
very advanced and i 
uce the very best top 
OW the terrain exact 
relation to the Dum 
Xt that the Photog, 
since photogramyg, 
dress may have Set 
I would have failed + 
m ideas and oni, 
with my life itself, 
positions. Corrections to the elements 
puted according to formulas, derive 
be determined for five different 
drawn and are shown in figure 1. 
been compared to the curve 
  
Communication to 
VIII International Congress for Photogrammetry 
Reprint from 
Svensk Lantmäteritidskrift 
Congress Number 1956 
Commission II 
INVESTIGATION OF SOME SYSTEMATIC DEF( IR MA- 
TIONS OF THE PENCILS OF RAYS IN A 
STEREOPLANIGRAPH 
by 
Lars Ottoson, Civil Engineer, Stockholm 70. 
The projection of the stereoplanigraph is based on the 
Porro-Koppe 
system. The lenses used in the planigr 
aph projectors should consequent- 
ly have the same optical properties as the camera-lens. 1f this is not the 
case, the models will be systematically deformed. The kind of lenses in 
question 1s the Topogon lens which, as known is impaired by quite a 
large radial distortion. The purpose of this investigation was i. a. to 
make clear whether the distortion of the Topogon lens is compensated 
by plotting with the Stereoplanigraph, which is now used by the Geo- 
graphical Survey Office. 
The radial distortion of a projector lens can easily be found out ac- 
cording to a method published in [1]. By this investigation a high-pre- 
cision grid was placed in the right projector of the planigraph. The pro- 
jector was brought into zero-position according to the scales. A princi- 
pal distance of 100 mm was used. The machine coordinates of the grid 
points were measured at base — 0 at the projection distances of 200 and 
300 mm respectively. The measurements were performed at two diffe- 
rent heights in order to determine an accurate value of the projector 
constant. The machine coordinates of the grid were also measured at 
base out and base in 120 mm at a projection distance of 200 mm, cor- 
responding to an overlap of 62,5 %. 
The measurements at base = 0 were made at points in symmetric 
of orientation could then be com- 
d in [2]. The radial distortion could 
radii. The distortion curves were 
The estimated distortion curves have 
given by the manufacturer. The standard 
error of the coordinate measurements according to the adjustment was 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
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