percentages hebben en de hoogte van
rivieren alleen stroomopwaarts toe
neemt. Ook de omgeving van de te
meten objecten dient gemodelleerd te
worden. Zo moet een algoritme voor
de kartering van wegen „weten" dat er
op- en afritten en kruisingen voor
komen en dat een wegrand af en toe
door bomen verdekt kan zijn. Derge
lijke kennis blijkt zeer moeilijk te mo
delleren. Het is dan ook de ver
wachting dat óók op de lange termijn
de operateur een belangrijke rol blijft
toebedeeld voor de controle en correc
tie van de semi-automatische karte
ringen.
Semi-automatic mappitig in aerial
photographs
Since the introduction of digital photo
grammetry several parts of the photo-
grammetric production processes, like
interior orientation and tie point trans
fer, have been automated. Some other
parts, in particular the mapping of topo
graphy, are difficult to automate, since
computer algorithms for image under
standing lack the excellent interpreta
tion skills of a human operator. To im
prove the efficiency of mapping in digi
tal photographs, semi-automatic me
thods are developed, that combine the
speed and precision of measurements by
computer algorithms with the image in
terpretation of the operator. This paper
reviews several methods for the semi
automatic measurement of point, line
and area features and complex three-
dimensional objects in digital imagery.
With image processing techniques like
feature extraction and image matching
the speed ofsome of the mapping proces
ses can be doubled.
[1] Davis, L. S., A purvey of Edge Detection Techniques.
Computer Graphics and Image Processing, vol. 4,
p.248-270, 1975.
[2] Firestone, L., S.,Rupert, J. Olson, en W. Mueller,
Automated Feature Extraction: The Key to Future
Productivity, Photogrammetric Engineering and
Remote Sensing, vol. 62, no 6, p. 671 - 674,
1996.
[3] Förstner, W. en; E. Giilch, A Fast Operator for
Detection and Precise Location of Distinct Points,
Corners and Centers of Circular Features. Proceedings
ISPRS Inter-commission Workshop on „Fast
Processing of Photogrammetric Data", Interlaken,
juni 1987.
[4] Fua, P., Model-fased Optimization: Accurate and
Consistent Site Modeling, International Archives for
Photogrammetry and Remote Sensing, vol. 31
deel B3, p. 222-233, 1996.
[5] Kraus, K. and P. Waldhausl (Eds.), International
Archives of Photogrammetry and Remote Sensing,
vol. 31, part B3, 1996.
[6] Lang, F. en W. Förstner, 3D-City Modelling with a
Digital One-Ey\ Stereo System. International Archives
of Photogrammetry and Remote Sensing, vol. 31,
deel B3, p. 415 -420, 1996.
[7] Lowe, D., Fitting Parameterized Three-Dimensional
Models to Images. IEEE Transactions on Pattern
Analysis and Machine Intelligence, vol. 13, no. 5,
p. 441 -450, 1991.
[8] Neuenschwander, W., P. Fua, G. Székely en O.
Kiibler, From Zip lock Snakes to Velcro Surfaces.
Ascona Workshop on Automatic Extraction of
Man-Made Objects from Aerial and Space Images,
Birkhauser Verlag, p. 105 - 114, 1995.
[9] Rosenfeld, A., Picture processing by computer.
Computational Surveys, vol. 1, no. 3, p. 147 - 176,
1969.
[10] Trinder, J. en H. Li, Semi-Automatic Feature
Extraction by Snakes. Ascona Workshop on
Automatic Extraction of Man-Made Objects from
Aerial and Space Images, Birkhauser Verlag,
p. 95 - 104, 1995.
[11] Vosselman, G. en J. de Knecht, Road Tracing by
Profile Matching and Kalman Filtering. Ascona
Workshop on Automatic Extraction of Man-Made
Objects from Aerial and Space Images, Birkhauser
Verlag, p. 265 -274, 1995.
549
GEODESIA
1998-12
Summary
Literatuur
