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1 Models. In
SURFACE RECONSTRUCTION
F. Leberl, M. Gruber, W. Kellerer-Pirklbauer, A. Pinz, P. Uray
Institut für Computerunterstützte Geometrie und Grafik, Technical University Graz, Austria
E-Mail: leberl@icg.tu-graz.ac.at
and
G. Paar
Institut für Digitale Bildverarbeitung, Joanneum Research, Graz, Austria
Invited Paper
Commission III, Working Group 2
KEYWORDS: Photogrammetry, Stereoscopy, Interferometry, Surface, Three-Dimensional, Graphics,
Visualization, Fusion
ABSTRACT
Classical 3-dimensional photogrammetry has traditionally relied on stereoscopy to obtain the geometry of surfaces.
This focus on stereoscopy has recently been broadened to include interferometry with radar sensors, single image
measurements in urban modeling, shape-from-shading to refine the surface description, or ranging in planetary and
industrial settings. The generalization of the problem domain occurs also from a mere consideration of surface geo-
metry to include surface visualization. This in turn causes one to need surface properties other than geometry. We re-
view current thinking and present some recent study results, particularly with satellite remote sensing images and
industrial object reconstruction.
ZUSAMMENFASSUNG
Die klassische Photogrammetrie fokussierte sich auf die Oberflächenmessung mittels Stereoskopie. Dies hat sich in
den letzten Jahren zu einer etwas ganzheitlicheren Betrachtung erweitert. Interferometrie, Einzelbildmessung in urba-
nen Anwendungen, Shape-from Shading, Lauflingenmessung in planetaren und industriellen Problemstellungen und
anderer Methoden der Geometrieerfassung werden durch die Generalisierung der Betrachtungsweise um die Frage der
Visualisierung ergänzt. Dies verursacht ein Interesse an den nicht-geometrischen Eigenschaften einer Oberfläche. Wir
betrachten diese neue Denkweise und zeigen einige neuere Arbeitsergebnisse, besonders aus dem Bereich der Satelli-
tenfernerkundung und der industriellen Oberflächenerfassung.
1 THE EVOLUTION OF SURFACE
RECONSTRUCTION
The concept of „surface reconstruction“ traditionally
consists of the creation of a geometric model of a sur-
face by stereo-photogrammetric means. We have en-
tered an age of coping with vast amounts of digital
visual data where this traditional concept no longer
applies. Instead we deal with a model of a surface in
terms of (a) a digital data base describing a surface’s
geometry and denote this a the geometric model; and
(b) an accompanying description of surface properties
such as texture, roughness or material properties; (c)
combining such data with a so-called ,,graphics pipe-
line to serve specific applications. Modeling and ren-
dering become thus elements of one and the same
system. The underlying ideas apply whether one deals
with an entire planet such as Venus or with micro-
scopic structures such as the surface of steel probes.
1.1 From 2.5-Dimensional to 3-Dimensional Surfaces
Photogrammetric tradition focusses on the surface of
the Earth. Information is extrated from aerial photo-
graphy and the object has a wide extent in planimetry
but only a small range of elevation. This is the reason
why one often refers to terrain as a 2.5-dimensional
object. A vast range of literature and procedures exists
421
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B3. Vienna 1996
to automatically extract the surface shape of terrain
from aerial photography. The result is a respresenta-
tion of the so-called ,,bald Earth“. The procedures work
successfully, provided the bald Earth is accessible and
not obstructed by objects such as trees or man-made
objects.
Recently this problem domain has been generalized to
one where fully 3-dimensional objects need to be
modelled. In the topographic application this may be
objects on top of the bald Earth. In industrial settings
this may be parts that need to be inspected. In
entertainment or architecture this may be the inside of
buildings. In medicine this may be the anatomy of a
human. In physics this may be the nano-structure of
objects. The very well-defined topographic applica-
tion of traditional photogrammetry has therefore re-
cently been expanded significantly and so has the
range of methods that are applicable to surface re-
construction.
1.2 From Stereoscopy to the Reconstruction
of Surface Geometry
Photogrammetry has tradionally relied on stereoscopy
for modeling the geometry of a topographic surface.
Also industrial and architectural applications have tra-
ditionally relied on stereoscopy. A more modern view
is not focussing on stereoscopy to reconstruct a sur-
eee
TE C
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