Using of virtual reality (VR) in underground spaces

Abstract:

The objective of this contribution is to use close range photogrammetry and create a modern visualization of a part of a former underground mine in Dolní Rožínka, today The Bukov Underground Research Facility (URF). The practical part consists of creating a 3D model of the former underground mine and converting it into a virtual reality (VR) environment. The data used for creating the model was collected using two non-metric photogrammetric cameras and was processed using the IBMR method. Component to the project was the creation of a virtual environment using the software Unreal Engine 4 (UE4).

Keywords:

URF Bukov, uranium mine, virtual reality, photogrammetry, IBMR, Unreal Engine 4

Introduction:

Virtual reality (VR) is a technology that is often used for a modern and effective way of documenting and visualizing 3D spatial data these days. The VR is becoming more and more affordable and technologically accessible, which is why its use is expanding into the GIS or photogrammetry field. The main purpose of this project is to create a 3D model using the IBMR method of the URF Bukov, situated in the former Rožná 1 uranium mine in the east of the Vysočina region in Czechia (Fig. 1), as well as its modern visualization in the VR. The place is inaccessible to the public and that is why it is needed to map or present the place in a contactless way.

URF Bukov:

URF is located on the 12th floor of the uranium mine at a depth of 550 metres below the Earth‘s surface. It is a test site for collecting data on the behavior of the rock environment for the future deep repository for radioactive waste.

Fig. 1 Study area

Methods:

1. Selection of area — URF Bukov managed by SÚRAO (Radioactive Waste Repository Authority)
2. Data acquisition — Using two non-metric photogrammetry cameras (Nikon D3100, Canon EOS 7D); External lightning
3. IBMR — Data processing in Agisoft Metashape Professional (Sparse point cloud → GCP‘s → Dense point cloud Mesh with texture)
4. Model preparation for VR — Filling holes in 3D model in Geomagic Wrap; Re-export 3D model in Blender to *.fbx file
5. Unreal Engine 4 — Creating VR environment for the presentation of the URF Bukov 3D model (Fig. 2)

Fig. 2 3D model with texture (Agisoft Metashape Professional)

Results:

An aspect of this project was to compare the authenticity of the model created in Agisoft Metashape Professional (AMP) with both reality and virtual reality (Fig. 3). The model created in AMP software was computationally intensive and still not perfect. In the photogrammetry processing errors can be caused by water surfaces, metal and glazed objects, shiny materials or moving objects.

Therefore, occasional inequality of certain parts of the model or missing data can be seen. The model was partially eliminated from these imperfections in Geomagic software. However, in Geomagic, the model was not extremely interfered in order not to violate the authenticity and methodology of photogrammetric work. Subsequently, the surrounding environment was created in the UE4 processed 3D object so that the virtual experience after using the VR headset was as large and realistic as possible. The final result is a virtual environment, thanks to which it is possible to browse the premises of URF Bukov which are otherwise completely inaccessible to the public.

Fig. 3 Comparison of realities

Conclusion:

The goal of this project was to create a virtual environment URF Bukov, to which the public is denied access. Based on images obtained from fieldwork, a 3D photogrammetric model was created using the affordable IBMR method which, after appropriate repairs and modifications, was installed in the virtual reality environment using UE4 software (Fig. 4). There the environment was created so that the VR user was absorbed in the mine environment as much as possible and thus had the opportunity to experience the most realistic perception.

Fig. 4 Another view to the VR