Modeling Urban Scenes from Pointclouds

We present a method for Modeling Urban Scenes from Pointclouds (MUSP). In contrast to existing approaches, MUSP is robust, scalable and provides a more complete description by not making a Manhattan-World assumption and modeling both buildings (with polyhedra) as well as the non-planar ground (using NURBS). First, we segment the scene into consistent patches using a divide-and-conquer based algorithm within a nonparametric Bayesian framework (stick-breaking construction). These patches often correspond to meaningful structures, such as the ground, facades, roofs and roof superstructures. We use polygon sweeping to fit predefined templates for buildings, and for the ground, a NURBS surface is fit and uniformly tessellated. Finally, we apply boolean operations to the polygons for buildings, buildings parts and the tesselated ground to clip unnecessary geometry (e.g., facades protrusions below the non-planar ground), leading to the final model. The explicit Bayesian formulation of scene segmentation makes our approach suitable for challenging datasets with varying amounts of noise, outliers, and point density. We demonstrate the robustness of MUSP on 3D pointclouds from image matching as well as LiDAR.