Figure 4: An example of the results of the new algorithm: (a) Situation after performing the Hough transform with two thresh-
olds. Breakline meshes are illustrated in white, the potential breakline meshes in gray and non-breakline meshes in black.
(b-c) Results of the whole algorithm. Non-breakline meshes are shown in white. Line segments approximating locations of
breaklines within meshes are shown in (b) and the corresponding orthoimage in (c). See text for explanations of the labels.
suitable for breakline modelling than modelling breaklines
with continuous line segments forming edges of triangles.
7 SUMMARY
In this paper an video image data acquisition system for
mapping applications was presented. The acquisition sys-
tem, still under development, consists of two parts:
1. First, a huge amount of true colour video images are
captured from an aircraft. GPS-coordinates of the
camera are included in the image headers, and are
also used by the pilot in navigation via the real-time
plot of the planned and real flight routes.
2. The digital images are transfered from the digitizing
PC to a UNIX workstation, which is the host machine
for a transputer based parallel computer. The system
automatically creates a large orthoimage mosaic and
a digital elevation model of the area.
The "3D-image-mosaic" will be made using the methods of
global matching or global object reconstruction, a general
model for digital photogrammetry, integrating area based
multi-image matching, point determination, object surface
reconstruction and orthoimage generation. As it is very com-
putation intensive, a parallel computation is used.
REFERENCES
Ebner, H., D. Fritsch, W. Gillessen & C. Heipke 1987, In-
tegration von Bildzuordnung und Objektrekonstruktion
innerhalb der digitalen Photogrammetrie, Bildmessung
und Luftbildwesen, 55, (5), 194—203.
Ebner, H. & C. Heipke 1988, Integration of digital image
matching and object surface reconstruction, Interna-
tional Archives for Photogrammetry and Remote Sens-
ing, 27 (B11/IIl), 534—545.
Ebner, H., C. Heipke & M. Holm 1993. Global image
matching and surface reconstruction in object space us-
ing aerial images. In: Barrett, E.B., McKeown, D.M.
Jr (eds.) Integrating photogrammetric techniques with
scene analysis and machine vision. Proceedings of
SPIE conference, Orlando, Florida, 14-15 April 1993.
Vol. 1944, pp. 44—57.
336
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B3. Vienna 1996
Geist, A. A. Beguelin 1994. PVM: Parallel Virtual Machine -
A User's Guide and Tutorial for Networked Parallel Com-
puting, The MIT Press.
George & Liu 1981. Computer Solution of Large Sparse
Positive Definite Systems, Prentice - Hall, Englewood
Cliffs, 1981
Hahn, M. 1992. Towards Automatic DTM Verification Ex-
ploiting Stereo Orthophotos. International Archives for
Photogrammetry and Remote Sensing, Vol. 29, Com. 3,
B3, pp. 233-240.
Heipke, C. 1990, Integration von digitaler Bildzuordnung,
Punktbestimmung, Oberflachenrekonstruktion und
Orthoprojektion in der digitalen Photogrammetrie,
Deutsche Geodàtische Kommission, Reihe C, 366.
München 1990.
Heipke, C. 1992, A global approach for least squares image
matching and surface reconstruction in object space,
Photogrammetric Engineering and Remote Sensing, 58
(3), pp. 317-323.
Helava, U. V. 1988, Object-space least-squares correlation,
Photogrammetric Engineering and Remote Sensing, 54,
(6), pp. 711—714.
Holm, M. 1994, Global image matching and surface recon-
struction in object space using three aerial images. Pro-
ceedings of ISPRS Commission Ill Symposium: Spatial
Information from Digital Photogrammetry and Computer
Vision. 5.—9. September 1994, pp. 379—386.
Pissanetzky 1984. Sparse Matrix Technology, Academic
Press Inc., London.
Rumbaugh J., M. Blaha et a/. 1991. Object-Oriented Mod-
eling and Design, Prentice-Hall.
Shen, J., S. Castan 1992. An Optimal Linear Operator for
Step Edge Detection. CVGIP: Graphical models and im-
age processing, Vol. 54. No. 2, pp. 112—133.
Weisensee M. 1992 Modelle und Algorithmen für das
Facetten-Stereosehen, Deutsche Geodätische Kom-
mission, Reihe C, 374.
Wrobel, B. 1987. Facets Stereo Vision (FAST Vision) — À
new approach to computer vision and to digital pho-
togrammetry, Proceedings of ISPRS Intercommission
Conference on "Fast Processing of Photogrammetric
Data", pp. 231—258.
KEY W
ABSTR
A new «
approacl
automat;
An emp
test bloc
accuracy
point ar
complet:
observat
further i
During |
process
photogr:
automat
The con
the area:
Corresps
matchin
unknow.
measure
used in
image Ir
There ar
automat
determir
accuracy
(Honka
the bloc
of obser
To hand
the tie p
l.
2
3
4.
5.
6
T
Tie
Cori
Bloc
Qua
Tree
Proc
hese ta
The rese
been co
