and in another example the maximum image blur in the cen
troid of exposure would, for the instantaneous oscillatio-
nal state: uj = — o* , occur approximately along
the entire left and right frame margins, and the minimum
along the entire frame centre line in flying direction.
With a real photographic shutter (efficiency between 70 7.
and 80 7., the practical image motion will be reduced by
about 25 7. relative to the theoretical motion of 50 jL\m with
an ideal shutter (efficiency = 100 7.) /1/. In combination
with the increase of 25 7. mentioned earlier, image motion
can, in practice, be deduced only from roll, in a first
approximation. In any case, however, image motion varies
from one exposure to the next subject to a random process
involving all angular motion components, since there is no
connection between the temporal characteristic of the
angular velocity amplitude and the moment of exposure.
Consequently, an image with intolerable blur may directly
follow an image with high or extra-high resolution in case
of long shutter speeds. Thus, even with an exposure time
limitation as mentioned above, there is still a statistic
distribution of well defined and less defined images, but
even the maximum image blur will remain within tolerance.
In consideration of these findings, techniques of motion
compensation have been proposed and, together with the
cooperating parties, developed up to the level of inventive
merit. These techniques contain a dynamically attitude-
stabilized platform according to /4/ for all sensing sy
stems, the selection of the moment of exposure in phases of
minimal angular motion according to /5/ for cameras and
according to /6/ for scanners with electronic pixel selec
tion from a matrix to form an instantaneous nominal scan
ning line which corresponds to the desired flying attitude
(Fig. 2).
A platform dynamically stabilized in three axes has been
integrated into the new Jena-made photographic system LMK-
2000 and tested in flight by INTERFLUG.
Fig. 2 :
Detector array (1) with a no*i-
y nal scan line directed verti
cally downward (5) and looking
a head with the »otion
ranges (2,3,4,7 and 10)
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