Continuous coastal monitoring using UAV photogrammetry

摘要

The purpose of this study is to collect ortho-images and point clouds acquired from UAVs in February and May to comprehensively assess whether they are suitable for time series offshore monitoring, such as volume change calculation and shoreline extraction. In February and May, UAV photogrammetry was performed at an altitude of 100 m using Zenmuse7 of Inspire-2 for the research area, and 245 chapters and 240 chapters were collected in ground sample resistance (GSD) 1.59 cm and 1.62 cm respectively. We obtained 40 and 21 ground control points (GCPs) that will be used for UAV photogrammetry and TLS surveying by using RTK-GNSS. The collected UAV images were treated as Pix4D mapper software. As a result, we deployed each point cloud and ortho-images in February and May. Image processing showed that the root mean square error (RMSE) in February was 0.015, 0.017, 0.040 m (x, y, z), and in May was 0.018, 0.015, and 0.035 (x, y, z). To verify accuracy, point clouds data collected with TLS surveying were collected. Using TLS point clouds and UAV point clouds (Feb, May), each DEM was deployed and the volume was calculated. In addition, a physical crosssection analysis was performed using 2 lines at the deployed TLS DEM, UAV DEM (2, 5 month). Finally, the coastline for the Imlang beach was extracted by applying the object based image segmentation technique obtained from UAV.