RECONSTRUCTION OF SCAFFOLDING COMPONENTS FROM PHOTOGRAMMETRIC POINT CLOUDS OF A CONSTRUCTION SITE
Keywords: Scaffolding components, Photogrammetric point clouds, 3D shape descriptor, Object recognition, Object modelling
Abstract. This paper presents a data-driven workflow for the detection of scaffolding components from point clouds. The points belonging to the scaffolding components are identified and separated from the main building structures and two basic elements, namely the toeboard and the tube, are reconstructed. The workflow has four main processing steps. Firstly, the raw point clouds are preprocessed by statistical filtering and voxel girding. In the second step, the planar surfaces of the building surface and scaffoldings are extracted via RANSAC and then grouped by their parallelity and distance to separate the building façade. In the third step, the 3D shape descriptor FPFH and random forest classification algorithm are applied to classify the point data of building façades into classes belonging to different elements. Finally, by the use of linear fitting algorithm and matching using SHOT shape descriptor, the tubes and toeboards are reconstructed with their geometric parameters. It is shown that the points belonging to these objects are identified and then reconstructed with cylinder and cuboid models. The final results show that over 60% of the tubes and nearly 90% of the toeboards are reconstructed in the investigated façade, and more than 40% of the reconstructed objects are well rebuilt.