Enhancing EOM with density-adaptive downsampling for individual tree segmentation in density-heterogeneous forest point clouds

Abstract Addressing the insufficient segmentation accuracy caused by forest point cloud heterogeneity in existing extreme offset networks for individual tree segmentation, this study proposes a density-adaptive downsampling model with adaptive point cloud density sampling, multi-scale dynamic feature fusion, sample relationship enhancement. First, to resolve key feature points omission from uneven density distribution, the adaptive point cloud density sampling method enhances sparse region sampling probability through local density-weighted scoring. Second, multi-scale dynamic feature fusion module adaptively adjusts neighborhood scales based on local density and integrates cross-scale features. Finally, to clarify tree boundaries, sample relationship enhancement module with external learnable memory units captures global contextual information. For evaluating the method’s accuracy and generalizability across varying forest structures and point cloud densities, experiments are conducted on two low-density coniferous forest plots (U1, U2) in Washington’s Blue Ridge area (USA) and two high-density mixed forest plots (G1, G2) in Bretten (Germany). Results demonstrate average precision, recall, and F1-score of 0.92, 0.92, and 0.92, respectively, outperforming the baseline EOM ( p = 0.91, r = 0.88, F-score = 0.90) with improvements of 1%, 4%, and 2% in precision, recall, and F-score.