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FOTOCAD: A SIMPLE PHOTOGRAMMETRIC PACKAGE FOR NON-PHOTOGRAMMETRISTS
Dr. A. Georgopoulos
Asst.
Professor
Laboratory of Photogrammetry, NTU of Athens
A. Spinou
Surveying Engineer
GREECE
Commission V
ABSTRACT
In this paper a simple integrated modular software package is presented. The
package performs basic analytical
calibration to automated on-screen
simple digitizer and the package runs
photogrammetric operations from camera
restitution. Data collection requires a
under DOS on a PC compatible without
special requirements. The automated restitution takes place in AutoCAD envi-
ronment, thus enabling on-screen editing. No photogrammetric instrument is
required, thus the system is amiable to non-photogrammetrists. An application
of the package is briefly presented using non-metric balloon photography, and
the results are evaluated in terms of accuracy and effectiveness.
KEY WORDS: Analvtical Photogrammetry,
1. LOW COST PHOTOGRAMMETRIC SOFTWARE
PACKAGES
The impressive progress of the computer
industry during the last decade has
altered the way traditional Photogram-
metry was applied until then. Our profes-
sion has passed swiftly from the analo-
gue, through the analytical to the digi-
tal era.
This process has caused an immense change
of attitude towards the way various
photogrammetric problems were approached.
Speed and accuracy have, no doubt, been
greatly improved, but the main benefit
lies in the simplification of the various
procedures. "Alien" processes, such as
camera calibration, relative and absolute
orientations, contour interpolation and
plotting, are performed simply at the
touch of a button. In this way Photogram-
metry has become available for the non
expert.
Archaeologists, Architects, Geologists
and other scientists are now able to
extract reliable quantitative information
on their own from photographs they them-
selves have acquired. They just need to
perform a few simple measurements on the
images (analogue or digital) with the
help of a digitizing tablet and the com-
puter takes over. Several software pack-
ages have greatly contributed to this
end. These packages vary in concept, in
complexity, in cost and in usage. In the
following a brief description and com-
parison of the currently known available
systems will be attempted.
Low Cost System, AutoCAD, Software
1.1 Elcovision 10
ELCOVISION 10 is an integrated package
offered initially from WILD Heerbrugg and
lately distributed by PMS AG. The system
includes a Leica R6 35mm reseau camera,
which is recommended by the manufacturers
for use with it and^ a digitizing tablet,
where all measurements are performed. It
allows for photos taken by hand from ar-
bitrary camera stations, although practi-
cal experience has shown that near normal
case performs better. Interior orienta-
tion is carried out with the help of sui-
table transformations to the original
reseau, or, in special cases, according
to the already known camera calibration
data. Measurements are performed monosco-
pically on paper prints with the help of
the digitizer. The restitution is carried
out pointwise on screen within a not so
friendly editing environment. There is
however the possibility of interfacing
the system with commercially available
CAD packages such as AutoCAD or Microsta-
tion at extra cost and proceed to the
editing off-line (Wild — Leitz 1989).
1.2 Rolleimetric MR2
ROLLEIMETRIC MR2, distributed by Rollei
Fototechnik GmbH, is a similar package
which combines the use of a Rollei semi-
metric camera (6006, or SLX with, reseau
plate) of larger format (60x60mm) with
the software. It claims a similar but
more versatile approach, allowing for
more photographs to be measured simulta-
neously on. the digitizer. tablet. The
photo-grammetric operations are executed
in a similar way as with ELCOVISION 10.
