The scheme of Fig. 3 can be used for a digital mono-comparator 
(Fig. 4). After selection of a specified réseau grid the 
corresponding image frame is displayed on a monitor screen. 
By cursor, points are measured in the image frame 
coordinate system, which can be converted to the scan-réseau 
system by use of the according transformation parameter set. 
Automatic point determination is possible by means of 
on-line digital image processing, if sufficient initial 
values of the point's coordinates are available. These 
coordinates can be obtained by an auxiliary system and can then 
be transformed into the scan-réseau system to move the sensor 
to the corresponding réseau grid (Fig. 5). After 
transformation into the image frame system these 
approximate coordinates can be used as initial values 
for automatic point determination. 
Fig. 6 shows the principle of Fig. 4 applied to a 
digital mono image-recording and measuring camera system. 
The matrix sensor is moved behind a réseau plate, 
which is located in the image plane of the camera. 
The schemes of Fig.3 - 6 are realized in the Rollei- 
metric RS1 and RSC1 systems. Further concepts of 
réseau-scanning systems like stereo and multi-image 
recording are presented by WESTER-EBBINGHAUS [1986]. 
analogous photograph 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
scen-réssau 
solid state matrix sensor 
sensor control 
image recording 
memory 
digital image frame image frame detection of réseau targets 
—————— 
transformation parameter set 
réssau coordinates 
in frame system 
o ,0 
Xg* Yg 
scan-résseu fit coordinates of 
of located targets an TOR 
x^, y 
RR 
"Tw. transformation parameter set 
image frame - scan-ressau 
Y. rectification | 
  
  
  
total image mosaic 
  
Fig.3 A/D - conversion system 
113 
  
  
  
  
  
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