UAV 편광 이미지를 이용한 SfM 기반 하천 DTM 생성 방법 개발

Abstract

Creating an accurate 3D DTM (Digital Terrain Model) of a stream area is crucial for better understanding the stream hydrodynamic phenomena. The objective of this study was to develop an SfM-based method for generating a DTM of small streams using polarized imagery acquired by UAVs (Unmanned Aerial Vehicles). The target area was a 300 m reach of the Yangjae stream near the Seonbawi Station in Gwacheon, where strong water surface reflection posed challenges to accurate terrain modeling. Polarized images were captured at multiple angles and processed through SfM (Structure from Motion) to create point clouds. Elevation benchmarks measured by EDM (Electronic Distance Measurement) were used to assess the vertical accuracy of the resulting DTMs. Polarized filter and water refraction calibration improved the water depth accuracy of DTM, achieving MAE of 0.242 m and RMSE of 0.276 m, while challenges still remain in addressing randomly occurring underwater conditions and streamside vegetations. The outcome of the study can be used to improve the accuracy of shallow w ater DTM construction