TY - JOUR A1 - Kögel, Michael A1 - Carstensen, Dirk T1 - Near real-time change detection tool for photogrammetric flood preparedness JF - Environmental Monitoring and Assessment N2 - Through the mobilization of movable objects due to the extreme hydraulic conditions during a flood event, blockages, damage to infrastructure, and endangerment of human lives can occur. To identify potential hazards from aerial imagery and take appropriate precautions, a change detection tool (CDT) was developed and tested using a study area along the Aisch River in Germany. The focus of the CDT development was on near real-time analysis of point cloud data generated by structure from motion from aerial images of temporally separated surveys, enabling rapid and targeted implementation of measures. The differences identified in the study area using distance comparison (M3C2) were segmented into individual components and categorized. Subsequently, the data was compared to existing two-dimensional hydrodynamic numerical calculation results (HQ100). The implementation of the CDT is feasible for a variety of RGB camera-equipped aerial vehicles due to the point cloud-based analysis and postprocessing. By overlaying and visualizing the detected changes with numerical simulation results, a quick assessment of the hazard potential in the event of a possible flood can be made. In the case of the study area along the Aisch River, the localization of construction materials, a steel container with debris pile, and a motor vehicle in the flood hazard zone of a potential HQ100 event could be confirmed, although no mobilization of the materials was to be expected due to the expected hydraulic conditions of a flood event. T2 - Nach-Echtzeit Analysewerkzeug zur photogrammetrischen Veränderungsanalyse im Zusammenhang mit Hochwaservorsorgemaßnahmen KW - Change detection KW - Near real-time KW - Photogrammetry KW - Flood event KW - 2d-hn KW - M3C2 Y1 - 2025 U6 - https://doi.org/10.1007/s10661-024-13597-9 SN - 1573-2959 VL - 197 IS - 2 PB - Springer Science and Business Media LLC ER - TY - JOUR A1 - Kögel, Michael A1 - Carstensen, Dirk T1 - Using structure from motion for analyzing change detection and flood events in the context of flood preparedness: a case study for the Laufer Muehle area at the Aisch river in Germany for conducting near real-time analyses JF - Applied Geomatics N2 - Recent flood events (FE) in Germany have shown that the extent and impact of extreme flood events cannot be estimated solely based on numerical models. For analyzing the development of such an event and to develop and implement safety measures more efficiently, additional data must be collected during the event. Within the scope of this research, the possibilities of near real-time recording using an unmanned aerial vehicle (UAV) and data processing with the Structure from Motion (SfM) method were tested in a case study. Different recording parameter combinations were tested in the Laufer Muehle area on the Aisch river in Germany. The focus of the investigations was the identification of a parameter combination that allows a short recording interval for aerial imagery. Based on these findings, the identification of changes in the study area by comparing multitemporal photography (flood prevention), as well as the recording of flooded areas during a FE should be possible. The accuracy analysis of the different parameter combinations between two point clouds as well as the process of change detection was done by a Multiscale Model to Model Cloud Comparison (M3C2) and including ground control points. As a result, a parameter combination was identified which led to the desired results in the study area. The processes were transformed into fully automated and scripted workflows. The results serve as a basis for establishing a workflow for near real-time analyses in future studies. KW - Structure from motion KW - Flood event KW - Change detection KW - M3C2 KW - Real-time Y1 - 2024 U6 - https://doi.org/10.1007/s12518-024-00561-y SN - 1866-9298 VL - 16 IS - 2 SP - 409 EP - 427 PB - Springer Science and Business Media LLC ER -