A Study on the Creation of 3D Models of Cultural Properties by SfM Using an Elaborate Diorama of a Non-Existing Excavation Site

Abstract

In order to protect local cultural properties, it is important for citizens to know the vivid views of the excavation sites. However, it is difficult to recreate the situations of the old excavation sites and make them available as digital archives for citizens to view at any time. When the Tateiwa Site in Iizuka City was excavated in 1963, there was no technology for 3D digital recording of the situations at the excavation site. Also, it was not possible to accurately record the 3D situation with paper drawings. Instead, the excavators of the time took the effort to create an elaborate diorama. This diorama has preserved the 3D situation of the excavation site to the present. Nowadays, SfM (Structure from Motion) can be used to generate a 3D model of an object using photographic images from many viewpoints. Therefore, we attempted to create a 3D model of the excavation site using SfM in order to generate a good quality 3D model at a low cost. In SfM, the processing time and the quality of the created 3D model vary depending on the number of photos used, so we investigated the relationship between the number of photos and the quality of the model. In addition to creating a 3D model using images of a diorama taken with a DSLR(Digital Single Lens Reflex) camera, as is commonly done in SfM, we also experimented with creating a 3D model using images from a smartphone camera. We evaluated the differences in the 3D models generated by the expensive DSLR camera and the smartphone camera that many people carry around. In this evaluation, we confirmed that we could create 3D models with the same quality as those of DSLR cameras even with images from smartphone cameras. Finally, we created a VR (Virtual Reality) system using the 3D model created in this study, and evaluated the quality of the 3D model for VR use.