K.U.Leuven > ESAT > PSI > Visics > Research > Topics > Item 1.8

Image processing for automatic cartographic tools (IMPACT)

L. Van Gool, T. Moons, D. Frère, J. Vandekerckhove

This European project aimed at producing 3D city models from multiple, overlapping aerial photographs. The photographs were orthogonal views (i.e., taken from nadir viewpoints). They had a high resolution (one pixel had the size of about 10 cm on the ground) and they were colour images. The goal was to reconstruct the 3D structures and heights of the roofs of the buildings. The scenes were urban, i.e. buildings were packed together and of a wide diversity of shapes. A system has been developed that starts with the extraction of straight lines as basic features. These are grouped into coplanar structures. Coplanar structures are combined into hypotheses about possible roof topologies. The corresponding wire frames are corrected on the basis of back projections into the images; this yields 3D roof models with sufficient precision for a number of applications. These include the planning of GSM antenna placement, the prediction of field of view of surveillance cameras, etc. The project also investigated into the combination of visual and laser range cues, the use of different colour spaces, the effect of image enhancement prior to feature extraction, and the exploitation of texture as well as colour. The project partners were the Universities of Leuven (coordinator), Oxford, and Bonn, as well as ENST, and Eurosense NV. More information about the project can be found on its home page.

The figure above shows one of a series of aerial images of Brussels (left) used to generate the 3D model (right)