AUTOMATIC PHOTOGRAMMETRIC PROCESSING OF SPOT IMAGERY FOR POINT DETERMINATION,
DTM GENERATION AND ORTHOPROJECTION
C. Heipke!, W. Kornus!, G. Strunzl, R. Thiemann?, I. Colomina?
! Chair for Photogrammetry and Remote Sensing, Technical University Munich
Arcisstr. 21, D-8000 Munich 2, Germany
Tel: + 49-89-2105 2671; Fax: + 49-89-280 95 73; Telex: 522854 tumue d
E-mail: heipke@photo.verm.tu-muenchen.de
z Department ITG, Industrieanlagen-Betriebsgesellschaft mbH
Einsteinstr. 20, D-8012 Ottobrunn, Germany
Tel: 4- 49-89-6088 3356; Fax: + 49-89-6088 3365
? Institut Cartografic de Catalunya
Balmes, 209-211, E-08006 Barcelona, Spain
Tel: 093/218-8758; Fax: 093/218-8959
Commission IV
ABSTRACT:
For the photogrammetric processing of SPOT imagery
a completely automatic procedure is described. It inclu-
des a sophisticated region growing image matching al-
gorithm, point determination using a polynomial ap-
proach for orbit modelling, the generation of digital
terrain models (DTM) and the computation of ortho-
photos. Only the image coordinates of a number of
ground control points must be measured interactively.
The procedure is evaluated by means of two practical
projects. In contrast to many other investigations of
SPOT the whole images were processed and ample
independent control information for a sound statistical
accuracy check was available. The achieved empirical
height accuracy of better than 10 m is a very good result
considering the small base-to-height ratios of 0.4 and 0.6
respectively.
Key words: SPOT, automatic evaluation, image mat-
ching, point determination, DTM, orthoimage
1. INTRODUCTION
Since 1986 the French SPOT satellites (SPOT = satél-
lite pour l'observation de la terre) provide digital topo-
graphic imagery on a regular commercial base. The
images are taken from a near-polar orbit at an altitude
465
of approximately 830 km and an image scale of roughly
1:800.000. Due to the oblique viewing capabilities, stereo
images - one from each orbit - can be acquired with an
acceptable base-to-height ratio. It is this feature, which
makes SPOT images interesting to the photogrammetric
community.
SPOT 1 has already reached the end of its anticipated
life time, but continues its service. SPOT 2, a version
identical to SPOT 1, is presently the main source for
image data. With SPOT 3 ready for launch in early 1993
and SPOT 4 and 5 having been announced and financi-
ally secured, the longtime availability of SPOT imagery
seems to be guaranteed.
It is behind this background, that the Chair for Photo-
grammetry and Remote Sensing, Technical University
Munich and the Industrieanlagen-Betriebsgesellschaft
mbH, Ottobrunn (IABG) have decided to develop digi-
tal photogrammetric processing tools for SPOT image-
ry. This paper describes the current status of develop-
ment. Earlier reports have been given in /Heipke 1990;
Heipke, Kornus 1991/.
The aim of the development is the automatic derivation
of digital terrain models (DTM) and orthoimages. This
involves a number of different steps. The main ones are:
- identification and measurement of ground control
points (GCP) in the stereo images,
