Effect of photography method and analysis settings in SfM without GCP by using RTK-UAV : investigation using along-road experiment data

Abstract

UAV (Unmanned aerial vehicle)-based photogrammetry without GCP (Ground control point), which combines SfM (Structure from Motion) and RTK-UAV (i.e., UAV capable of RTK-GNSS positioning of shooting position), has been studied around the world in recent years. While some studies show that the photography method and analysis settings have large effects on survey accuracy, there are only a few such studies and it is desirable to accumulate cases. In this study, experimental data simulating 14 types of photography methods, including oblique ones, were analyzed by using Agisoft Metashape with 216 SfM settings. As a result, it was confirmed that the analysis settings in addition to the photography method have complex effects on the accuracy of SfM. In addition, the accuracy did not always improve by adding images, and the analysis settings that can obtain high accuracies differed depending on the photography method.