A Dual-Branch Deep Learning Framework at the Grid Scale for Individual Tree Segmentation

Individual tree segmentation from point clouds is essential for diverse forest applications. A dual-branch segmentation deep learning network operating at the grid scale was proposed, which includes the semantic segmentation branch for partitioning point clouds of tree trunks and the instance segmentation branch for individual trunk extraction. Meanwhile, the network analyzes input forest points at the grid scale instead of pointwise processing to preserve local geometric information of the forest points while reducing computational load. After extraction of each tree trunk in the understory layer using our network, a hierarchical k-nearest neighbors algorithm based on the extracted trunk parts was employed to accomplish individual tree segmentation. For the forest plots, our proposed approach achieves precision, recall, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${F}1$ </tex-math></inline-formula>-score, and mean intersection over union (MIoU) of 89.66%, 89.13%, 89.40%, and 90.84%, respectively. These results represent a significant improvement in accuracy and rapid execution capability compared to prior methods.