UAV Application for Process Control of the Reclamation Project

It is essential to acquire an accurate topographic information to efficiently operate a reclamation project. However, the measurement of large-size reclaimed land using terrestrial survey methods, such as total station and GPS requires huge number of efforts in terms of time and labor spending. Moreover, the coastal surveying that should be remote and hard to reach is extremely dangerous and sometime impossible. Therefore, in this investigation, UAV (Unammaned Aerail Vehicle) which has been actively considering in the field of spatial information currently, was applied for the construction management of reclamation project. In this paper, the feature matching and SfM (Structure from Motion) algorithm were used as image correction and matching technology. The UAV images were used to create three dimensional point clouds. The points clouds are transformed and aligned to global coordinate by using 21 GCPs (Ground Control Points) which are previously measured by terrestrial surveying. The aligned point clouds were eventually used to generate a DEM (Digital Elevation Model) and ortho-imagery. This study also assessed the positioning accuracy of the results by comparing with terrestrial surveying results using total stations at 426 check points on the study area. The RMSE (Root Mean Square Error) of positioning differences between the coordinates of UAV photogrammetry and terrestrial surveying was within tolerance, 4.8 cm, except for the results at non-ground points. This paper, consequently, presented an availability of the UAV for the photogrammetry, so that it can be fully expected the UAV photogrammetry could be applied in many fields included construction application.