Building 3-D city models from multiple unregistered profile maps

The paper presents an approach for building 3-D city models for virtual environments from multiple 3-D data sets acquired from different viewpoints by light striping. The raw data sets are represented as single valued parametric surfaces called the 3-D profile maps. The profile maps are registered to the same coordinate system by an iterative surface matching algorithm developed previously. The registration proceeds hierarchically from low to high resolution and all the data sets are matched simultaneously but an initial registration is assumed to be known. After having segmented each map by a region growing algorithm, the maps are integrated into a piecewise planar surface model by merging compatible segments in the overlapping areas. The borders of the segments are also traced an the parametric domains of the maps as a step for building a wireframe model. Test results are shown in the case of a scale model of an urban area digitized in laboratory conditions