OPERATIONAL ASPECTS OF DATA AQUISATION FOR BUNDLE BLOCK ADJUSTMENT
Karsten Jacobsen
Universitat Hannover
Hannover, F.R. Germany
ABSTRACT
Advanced technics of dataaquisition for block adjustment can increase
the cost-effectiveness very much. Using the possibilities of computer
supported automatical approximate pointing, the structure of blocks for
precise point determination can be changed. The used methods for on-line
data check and the different possibilities for automatic pointing by
analytical plotters of a program, used for production in different places,
are described. This program is integrated into the program system for
block adjustment BLUH of the University Hannover, but it can be used
also together with other programs for bundle or independent model block
adjustment.
1. PROGRAM B159 FOR AQUISITION OF PHOTO COORDINATES
The program B159 has been developed by the University Hannover for opti-
misation of the aquisation of photo coordinates with the analytical
plotter Planicomp. The results of a detailed calibration of the instru-
ment, based on grid measurements, can be used for a correction of the
plate coordinates. With this correction the same accuracies of highly
accurate bundle block adjustments have been achieved with analytical
plotter measurements like with precise comparator measurements. That
means, it is not necessary to use time consuming comparator measurements,
even if the comparator is more accurate than the analytical plotter.
The accuracy limits are caused by the point definition in the photos
and the geometric quality of the photo itself, so the slightly lower
accuracy of analytical plotters with spindles is negligible. Also the
influence of temperature, which is usually not negligible at the Plani-
comp, can be reduced by the measurement sequence, so finally there is
no reason to use a precise comparator instead of an analytical plotter
for getting higher accurades. The data of the inner orientation can be
read from a special camera file, so up to 25 fiducial marks can be used
for transformation from plate to photo coordinates. The location of the
principal point is free, that means, it is also possible to use the
outer parts of a Large Format Camera. In addition to the fiducial mark
coordinates, up to 125 reseau point coordinates can be read from file,
which are not used for the transformation from plate to photo coordina-
tes. This special group of reseau points is necessary for a reseau
which is projected from the back of the film and where the cartridge is
moved during exposure. That means, the reseau has a different coordinate
system than the fiducial marks and it is not known with respect to the
principal point, like in the case of the Large Format Camera.
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