Photogrammetry is for everyone: Structure-from-motion software user experiences in archaeology

In this study, Structure-from-Motion (SfM) photogrammetric software was used to create 3D models of the Tyler house (Mound, TX) and Eyrie house (Holyoke, MA), both mid-19th century ruins. We compared the resulting models to evaluate the user experience for non-specialists between two different but popular software options for SfM modeling used by archaeologists. We addressed the differences in rendered models by acquisition method, UAV (unmanned aerial vehicle) or terrestrial photography and, compared models using metric and interpretive outputs. We used AgiSoft's PhotoScan (v. 1.4, now Metashape) and Autodesk ReCap Photo (v. 2018) to generate models for this study. Using CloudCompare (v.2.9.1), we calculated cloud-cloud distances, average distances between points, and the standard deviation between model pairs. Clouds were accurate to within 0.03 cm with varying degrees of standard deviation. This result is likely due to differences in methodology, such as the degree of photo overlap between acquisition methods and software rendering parameters. These results may help the archaeological community in selecting software, increasing awareness of point cloud and user-induced variations, and refining acquisition methods when recording archaeological sites. This paper is targeted towards informing non-specialists about options when selecting SfM software.