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Filtering Surfaces in Surveys with Multiple Overlapping:Sagrada Familia

2019; IOP Publishing; Volume: 471; Linguagem: Inglês

10.1088/1757-899x/471/8/082044

1757-899X

Juan Corso Sarmiento, Adrià Marco Bercero, Daniel López Jiménez, Jordi Casals Fernández, M. Pilar Garcia-Almirall,

Conservation Techniques and Studies

The heritage survey with the Terrestrial Laser Scanner (TLS) allows the document of the geometry of the building and to constitute a 3D point cloud as a register of its conservation state. When complex buildings with architectural and sculptural elements are scanned, there are a lot of captured data that is not valid, because of the instrumental error and foreign elements of the buildings. For that reason, the point cloud must be cleaned with the objective to obtain a final model from which different products could be created, such as plans, technical documents and 3D models to print. For this cleaning process, in this article with the case of study is Antoni Gaudi's Sagrada Familia (Fachada del Nacimiento), we propose a methodology based on applying some filers, considering the fact that more than 3000 positions were realized, 750 of them belong to the same facade with positions that have a lot of overlapping data. Therefore, in a same zone of the building there is data scanned from multiple positions in different ways, so we can find there any kind of error, such as the noise from boundary effects, glass flections and mobile objects, and scans realized from a scissor lift, that have been previously validated. Different point cloud filtering processes have been studied, through the point cloud itself (position by position and with a unitary cloud), and by meshing it. Every process requires the knowledge of how the scan was realized, what type of error dominates in each zone is analyzed. Therefore, each filtering option accomplish the requirements established after the analysis.