CMRT09: Object Extraction for 3D City Models, Road Databases and Traffic Monitoring - Concepts, Algorithms, and Evaluation 
the shape of central islands within the level set framework can 
potentially provide a solution to these problems. 
Figure 13. Example of a central island that cannot be extracted 
due to heavy occlusions caused by trees and shadows. 
Boichis, N., Cocquerez, J.-P., Airault, S., 1998. A top down 
strategy for simple crossroads extraction. In: IntArchPhRS., 
Vol. XXXII, Part 2/1, pp. 19-26. 
Boichis, N., Viglino, J.-M., Cocquerez, J.-P., 2000. Knowledge 
based system for the automatic extraction of road intersections 
from aerial images. In: IntArchPhRS., Vol. XXXIII, 
Supplement B3, pp. 27-34. 
Caselles, V., Catte, F., Coll, T., Dibos, F., 1993. A geometric 
model for active contours in image processing. Numer.Math., 
Vol. 66, pp. 1-31. 
Cohen, L.D., 1991. On active contours models and balloons. In: 
IEEE Transactions on Computer Vision, Graphics, and Image 
Processing: Image Understanding, Vol. 53, No. 2, pp. 211-218. 
Courant, R., Hilbert, D., 1953. Methods of Mathematical 
Physics. Wiley-Interscience, New York. 
De Gunst, M., 1996. Knowledge-based interpretation of aerial 
images for updating of road maps. Ph.D. thesis, Delft 
University of Technology, the Netherlands. 
Gerke, M., 2006. Automatic Quality Assessment of Road 
Databases Using Remotely Sensed Imagery. PhD thesis, 
Leibniz Universität Hannover, Germany, No. 261; also in: 
Deutsche Geodätische Kommission, Reihe C, No. 599, 105 p. 
Heipke C., Mayer H., Wiedemann C., Jamet O., 1998: External 
evaluation of automatically extracted road axes, PFG 2, pp. 81- 
94. 
Kass, M., Witkin, A., Terzopoulos, D., 1988. Snakes: Active 
contour models. Int. J. Computer Vision, 1(4), pp. 321-331. 
Li, H., Xu, C., Gui, C., Fox, M.D., 2005. Level Set Evolution 
Without Re-initialization: A New Variational Formulation. In: 
Proceedings of IEEE conference on Computer Vision and 
Pattern Recognition (CVPR), IEEE Computer Society Press., 
pp. 430-436. 
Malladi, R., Sethian, J. A., Vemuri, B. C., 1995. Shape 
modeling with front propagation: a level set approach. IEEE 
Trans. Patt. Anal. Mach. Intel!, Vol. 17, pp. 158-175. 
Neuenschwander, W. M., Fun, P., Iverson, L., Szekely, G., 
Kubier, O., 1997. Ziplock snakes. Int. J. Comput. Vis., 25(3), 
pp. 191-201. 
Osher, S., Fedkiw, R., 2002. Level Set Methods and Dynamic 
Implicit Surfaces. Sringer-Verlag, New York. 
Ravanbakhsh, M., 2008. Road junction extraction from high 
resolution aerial imagery assisted by topographic database 
information. PhD thesis, Leibniz Universität Hannover, 
Germany, No. 273; also in: Deutsche Geodätische Kommission, 
Reihe C, No. 621, 90 p. 
Ravanbakhsh, M., Heipke, C., Pakzad, K., 2008. Road junction 
extraction from high resolution aerial imagery. The 
Photogrammetric Record, 23(124), pp. 405-423. 
U.S. Federal Highway Administration, 2000. Roundabout: An 
Information guide. FHWA-RD-00-67, http://www.tfhrc.gov/. 
Xu. C., Prince, J., 1998. Snakes, shapes, and gradient vector 
flow. IEEE Trans. Imag. Proc., Vol. 7, pp. 359-369.