Building Detection and Structure Line Extraction from Airborne LiDAR Data

Because of the blind characteristics of laser signals from the airborne LiDAR system, we can not directly get the 3D coordinates of object’s features such as the roof corners, edges, and complete object’s faces of buildings, etc. which could be obtained by processing the LiDAR data. The goal of this research is to detect the locations of buildings and then extract the structure lines of buildings from the raw LiDAR data. The basic idea is to use the visible information, the elevation, and the hidden information, geometry and physic properties of buildings to obtain the locations and structure lines of buildings. In the aspect of building detection, the wavelet analysis was used firstly to build up the multi-resolution edges, and then a set of edges at an apposite wavelet scale was chosen. Secondly, the initial locations of buildings were obtained by searching the closed edges and the detection results were refined by the elevation, area and texture of buildings. Finally, the locations of independent buildings were obtained. In the aspect of structure line detection, the main idea is to separate the roof structure lines into two parts, one is for external contours and the other is for internal structure lines. The external contours were extracted using Hough transform and other geometric conditions. The internal structure lines were extracted by any two adjacent roof faces intersecting each other. Finally, the two kinds of structure lines were combined to construct the roof shapes. The experiment results showed that the classic roofs such as plane roofs, gabled roofs and L-shape roofs could be reconstructed successfully without any auxiliary information.