Ad UNIVERSAL ALGORITHH FOR THE REAL-TIZE PROCESS OF Al
ANALYTICAL PLOTTER
Dr. Rolf-Peter lark
Kombinat VEB Carl Zeiss JENA
Jena, German Democratic Republic
ABSTRACT
At present analytical plotters (AP) are used mainly, if digi-
tal evaluation results are necessary (aerotriangulation, Gi-
gital elevation models etc.). Special tasks as e.g. plotting
in cylindrical coordinates, two-media photogrammetry or plot-
ting from visualised scanning data cannot be solved with the
usual real-time algorithm fixed an central perspective.
To overcome these problems an algorithm is proposed,which is
based on the application of the Taylor formula. In that case
the model coordinate system is subdivided in Spatial segments
each using its own transformation parameters for the left-
hand and for the right-hand photograph. The application of
this algorithm to central perspective photographs leads to a
rigorous solution for the computation of coordinate differen-
ces, which is very important with regard to the requirements
for an AP. ;
The algorithm may be extended by replacing the spatial carte-
sian model coordinate system by other coordinate systems. It
will be demonstrated, that a non-cartesian coordinate system
may be introduced by special programs, whicn can be counted
among the group of orientation programs, without any inter-
ference in the real-time process.
Systematic image errors, the non-straight course of light
rays or the change of orientation elements with time can be
considered in a similar way.
For the evaluation of visualised data from mechanical scan-
ners polynomial transformations are used very often. Even
these may be taken as a basis for the algorithm described in
the paper.
The proposed algorithm makes it possible to the user of an
AP to introduce his special problems in the real-time process
using special application programs without interfering with
the real-tine process himself.
1. INTRODUCTION
Since 1976 an ever increasing number of analytical plotters
has been used in practice and it turned out that their appli-
cations primarily concerned digital restitution techniques
(aerotriangulation, terrestrial photogrammetry, data collec-
tion for digital height models), while the percentage of
graphical map production was rather low.
It is the object of this paper to present an algorithm for
the real-time process which universally applies to all types
of images and optional object and model coordinate systems
and in which the differences of the individual mathematical
models can be allocated to the process of image orientation.
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