基于曲率法线流的树点云骨架提取方法

Skeleton extraction of tree point cloud based on curvature normal operator

针对树木点云拓扑结构复杂、特征细节繁多等问题,提出一种基于点云收缩提取曲线骨架的算法。首先,为了在点云表面直接应用网格收缩算法,对点云进行局部主成分分析和Delaunay三角剖分;其次,针对树木点云拓扑结构复杂和末枝细节繁多等问题,用曲率法线流算子对点云进行收缩,针对树木枝条细长且弯曲幅度平缓等特点,利用改进后的QEM网格简化方法将三角网格折叠成一维曲线骨架;最后,将得到的曲线骨架进行连通和居中处理。该算法直接在点云上进行操作,不需要额外的信息和预处理操作,对噪声和残缺点云有良好的鲁棒性。实验证明,该算法提取的树木点云骨架充分表达了树木在自然环境下的生物性结构和特征,相对于Rosa、L1-中轴等经典算法,在树木点云的骨架提取速度上提高3倍以上,枝条重建度提高25%。

Aiming at that complex topological structure and various feature details of tree point cloud,this paper proposed an algorithm for extract the curve skeleton based on point cloud contraction.Firstly,in order to directly apply the mesh shrinkage algorithm on the surface of the point cloud,it performed local cloud principal component analysis and Delaunay triangulation on the point cloud.Secondly,for the problem that the tree point cloud’s complex topology and the details of the last branch,it used the curvature normal operator to shrink the point cloud.In view of the slenderness of the branches of the trees and the gentle curvature,it used the modified QEM mesh simplification method to fold the triangular mesh into a one-dimensional curve skeleton.Finally,it connected and centered the resulting curve skeleton.The algorithm operated directly on the point cloud and did not require additional information and pre-processing operations.It had good robustness to noise and residual fault clouds.Experiments show that compared with other classical algorithms such as L1-medial and Rosa,the tree point cloud skeleton extracted by the algorithm has a good topological structure,which fully expresses the biological structure and characteristics of trees in the natural environment.The skeleton extraction speed of the tree point cloud is increased by more than 3 times,and the branch reconstruction degree is increased by 25%.