Workflow for high definition documentation of the roman archaeological site of Herrera (Seville)

Abstract

Structure from Motion (SfM) photogrammetry has become in the last years one of the most used methodologies for three-dimensional recording in many scientific fields thanks to its great precision, low cost and speed. The aim of this paper is to present a workflow methodology to obtain precise results for the graphical documentation of an archaeological site with complex structures (Rouco & Benavides, 2023) The improvement of photogrammetric hardware and software has provided us with a tool of great value for archaeological research and survey. SfM photogrammetry has been widely applied to cultural heritage studies in a variety of ways, such as digitizing historical buildings, archaeological sites and artefacts. Improvement in UAV-mounted camera technology and calibration methods of non-metric cameras have expanded the use of photogrammetric modelling to non-professional and semi-professional users (Westoby et al. 2012). Although the potential of SfM photogrammetry allows obtaining 3D models with a very good graphic appearance using almost any type of camera, these models need certain calibration and adjustment processes in order to achieve enough precision for professional use. This paper focuses on discussing some important data capture workflow recommendations, as well as the new processing workflows implemented in Agisoft Metashape version 2.0, which improve 3D digital reconstruction and graphical documentation to make it complete and precise. The Herrera Roman Baths site offers an excellent opportunity to explore the complex casuistry in the record of cultural heritage due to the complexity in the registration of the structures and the high degree of precision and graphic resolution that the project required for the tasks of restoration of decorative elements. The existence of a roof structure that protects them has forced us to carry out a manual flight with a UAV at a very low altitude (4m), and to develop different modeling strategies to guarantee metric precision and a high level of detail. © 2023 University of LAquila, Department of Civil Construction, Building and Architecture, Environmental Engineering. All rights reserved.