TLS AND IMAGE-BASED ACQUISITION GEOMETRY FOR EVALUATING SURFACE CHARACTERIZATION

Abstract

In the framework of cultural heritage documentation projects, it is very frequent the use of dense and detailed 3D models derived from range-based or image-based techniques. These reality-based models represent an effective and powerful solution to document the geometries, the surfaces and the characteristic of heritage assets. In fact, these technologies allow us to accurately describe the level of detail and the surface characterization of the materials, and also to provide precious support for the evaluation of the conservation status of the surveyed structures. In particular, the object studied in the presented research experience is the Morano sul Po arch (Morano sul Po, AL, Piedmont, Italy), a valuable example of an industrial archaeology asset. For the knowledge process of the arch, both LiDAR systems and photogrammetric strategies have been used, in order to properly document the geometry, the consistency of the material and the decays. The specific aim of the research presented in this paper is the evaluation of the advantages and the critical issues of using a telescopic pneumatic pole to raise the position of the scans from the ground and decrease the angle of incidence of the laser beam on the surveyed object. For this reason, the study also takes into consideration the use of mini UAVs and their flexibility to effectively acquire vertical surfaces even at elevated heights, comparing the density and the roughness of the derived model with the data obtainable by using TLS systems.