Building extraction from LIDAR data

A strategy for building reconstruction relying on LIDAR data only is presented. Roofs are modeled as plane surfaces, connected along ridges and bordered by the eaves lines. Edge pixels and plane surfaces are detected and labelled as roof slopes based on gradient orientation and plane fitting by RANSAC; a similar procedure applies to eaves lines. Based on geometric reasoning, the topology of the roof slopes and walls is reconstructed, deriving also roof ridges and roof corners. Constraints to be enforced in order to obtain a building shape consistent with the geometric evidence are established. The final reconstruction is performed by a global l.s. adjustment where all raw data contribute to a determination of the building faces while the constraints are satisfied. Preliminary results from a laser scanning survey with a ground resolution of 1 m are presented.