Point Clouds from different Photographic Sensors for Cultural Heritage Surveying

In this paper it has been investigated the implementation of a Structure from Motion (SfM) using a reflex camera with integrated GPS for documentation and conservation of Cultural Heritage. The SfM provides a non-invasive approach for the structure representation, without the interaction between the structure and any operator. In order to verify the suitability of this technique it has been carried out a terrestrial photogrammetry survey and compared the results with and without use of the Ground Control Points (GCP) surveyed with the total station and GNSS receiver. The study has been conducted on an ancient Aragonese watchtower of the seventeenth century, located near the Abbey of San Vito in the countryside of Polignano a Mare (in the province of Bari, Southern Italy). The elaborations have been carried out in Agisoft PhotoScan and CloudCompare softwares. The first one has been used for extracting the point cloud and the second one for comparing the point clouds: point cloud from integrated GPS and point cloud from GCP. The use of reflex camera with integrated GPS can release 3D modeling but the results can be applied for small scales of representation and not for monitoring or metric analysis