3D Multi-view Stereo Modelling of an Open Mine Pit Using a Lightweight UAV

Abstract

Digital elevation models have been evolved in decades, their resolution and accuracy have improved vividly. Geological, structural and geomorphological benefits of those high-quality digital elevation models enhanced the quality of the research and engineering and unfold the visibility of the data. Modern techniques such as laser scanners provide a quantum leap on digital modelling, however the cost of those methods limits their widespread usage. Improvements in stereo-photogrammetry did not decelerate. On the contrary, the evolution of Structure from Motion–Multi-view stereo-photogrammetry (SfM-MVS) method is accelerated by the continuous developments in digital photography and computer vision technologies. We have used a lightweight drone to acquire digital aerial photographs of an open mine pit for an ultimate purpose of modelling the terrain using SfM-MVS procedure. We have been able to derive a high resolution (0.3 m/pixel) DEM and a very high resolution (0.04 m/pixel) orthorectified aerial image. Both datasets are representing the topography with high sample point densities. Elevation model dataset has been compared with the regular topographic point measurements of the mine pit and the accuracy of the aerially derived model have been investigated. Sources of modelling errors, the effect of temporal physical changes in the terrain, effect and importance of geo-referencing have been discussed in detail. SfM-MVS is a cost-effective, rapid and promising technique for digital mapping, modelling and monitoring in various spatial scales of Geology.