LWSNet: A Point-Based Segmentation Network for Leaf-Wood Separation of Individual Trees

Abstract

The accurate leaf-wood separation of individual trees from point clouds is an important yet challenging task. Many existing methods rely on manual features that are time-consuming and labor-intensive to distinguish between leaf and wood points. However, due to the complex interlocking structure of leaves and wood in the canopy, these methods have not yielded satisfactory results. Therefore, this paper proposes an end-to-end LWSNet to separate leaf and wood points within the canopy. First, we consider the linear and scattering distribution characteristics of leaf and wood points and calculate local geometric features with distinguishing properties to enrich the original point cloud information. Then, we fuse the local contextual information for feature enhancement and select more representative features through a rearrangement attention mechanism. Finally, we use a residual connection during the decoding stage to improve the robustness of the model and achieve efficient leaf-wood separation. The proposed LWSNet is tested on eight species of trees with different characteristics and sizes. The average F1 score for leaf-wood separation is as high as 97.29%. The results show that this method outperforms the state-of-the-art leaf-wood separation methods in previous studies, and can accurately and robustly separate leaves and wood in trees of different species, sizes, and structures. This study extends the leaf-wood separation of tree point clouds in an end-to-end manner and demonstrates that the deep-learning segmentation algorithm has a great potential for processing tree and plant point clouds with complex morphological traits.