Robust Extraction of Exterior Building Boundaries from Topographic Lidar Data

Methods for generating accurate building models from lidar data have received considerable attention in the recent literature. Many of the proposed techniques examine the data to define dominant planes in the structure, then intersect these planes to determine the location of internal edges and vertices. However, since most airborne lidar datasets are collected from near-nadir orientations, there are usually very few data points that lie on vertical surfaces. As such, it is usually difficult to determine the planes corresponding to exterior walls using data points on these walls. However, if we assume that exterior walls are oriented directly under the outer boundary of the roof structure, we may identify the geometry of these walls by modeling the 2D shape of the building exterior. This paper presents a robust approach for extracting this exterior boundary directly from the lidar data.