SfM Photogrammetric Techniques Applied in the Building Archaeology Works of the Old Cloister of the Monastery of San Francisco from the 16th Century (Cazalla de la Sierra, Seville)

Abstract

The cloister from the old monastery of San Francisco (Cazalla de la Sierra, Seville) has 12 been suffering a series of remodelling and transformations from its original construction, in the 16th 13 century, to the current day. Thus, a study of building archaeology needed to be accomplished by 14 using photogrammetric techniques by SfM (Structure from Motion) and laser scanning or TLS (Ter- 15 restrial Laser Scanning) that ensure a geometric exactitude and high resolution of the facings sur- 16 veying. For that, over 500 images were taken for the 4 existing facings (about 78 lineal metres) from 17 which a photogrammetric model was obtained of over 50 million polygons; as well as a cloud of 18 over 40 million points from the laser scanning. It can be concluded that by using the techniques of 19 SfM, the task of documenting, analysing and studying the facings of the historical buildings in order 20 to establish its evolutional process, gains, not only in precision and exactitude, but also opens the 21 possibility to go further by obtaining products that are capable in the labour of conservation, resto- 22 ration and protection of the historical heritage, as well as the generation of 3D virtualizations, 23 planned for the diffusion.