New Supplementary Photography Methods after the Anomalous of Ground Control Points in UAV Structure-from-Motion Photogrammetry

Recently, multirotor UAVs have been widely used in high-precision terrain mapping, cadastral surveys and other fields due to their low cost, flexibility, high efficiency. Indirect georeferencing of ground control points (GCPs) is often required obtain highly accurate topographic products such as orthoimages digital surface models. However, practical projects, GCPs are susceptible anomalies caused by external factors (GCPs covered foreign objects crops cars, vandalism, etc.), resulting a reduced availability UAV images. The errors associated with the loss apparent. solution using natural feature fails meet accuracy requirements. For problem point anomalies, this paper innovatively presents two new methods completing data fusion supplementing photos via at later stage. In study, 72 sets experiments were set up, including three for analysis. Two parameters assessment: Root Mean Square Error (RMSE) Multiscale Model Cloud Comparison (M3C2). study shows that can reference requirements horizontal direction elevation (RMSEX = 70.40 mm, RMSEY 53.90 RMSEZ 87.70 mm). contrast, showed poor accuracy, RMSEX 94.80 68.80 104.40 mm checkpoints. This research considers solves problems anomalous photogrammetry project from unique perspective supplementary photography, proposes greatly expand means solving problem. they be an effective ensure when GCP anomalous, which has significant potential application promotion. Compared previous methods, applied more scenarios higher compatibility operability. These surveys, geomorphological heritage conservation, fields.