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
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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
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