Detecting repetitive structures on building footprints for the purposes of 3D modeling and reconstruction

Repetitive structures of a building share features in terms of geometries and appearance and,therefore,the 3D information for these structures can be transferred from one specification to another for the purpose of 3D modeling and reconstruction once they are identified as repetitive structures.In this paper,a novel approach is proposed for the detection of the repetitive structures specified by the polygons of a building’s footprints.Instead of directly operating on the polygon in 2D space,the polygon is converted into a bend angle function representation in 1D space,whereby an extrusion is represented as a closed polygon intersected by the x-axis and located above it,while an intrusion is represented as a closed polygon below the x-axis.In this way,a polygon of a footprint is decomposed into a number of extrusions and intrusions which can in turn be processed.The task of detecting any repetitive structures specified in a building’s footprints then becomes the task of clustering the intersected polygons in the bend angle function space.The extrusions/intrusions which can be placed in the same clusters can be regarded as repetitive structures.Experiments show that this proposed approach can detect repetitive structures with different sizes,orientations and complexities.