基于α-shape的树冠LOD建模

Tree Crown LOD Modeling Based on α-Shape

以点云形式的树模型为输入,以3D Delaunay三角化为基础,选取最优α值并生成点云的最小连通α-shape;然后计算其距离场并进行滤波处理,以提取α-shape的光滑等距面;进一步采用Laplacian骨架提取的分割方法从等距面中分割出树干和树冠点云的包围体。最后以树冠包围体内点云的多分辨率α-shape为细节层次(LOD)模型用于非真实感VR场景。

Based on3D Delaunay theory,an optimalαis selected to construct the minimal connectedα-shape from the input point cloud of a tree model.After the calculation and filtering of its distance field,a smooth distance surface is extracted,from which the bounding volumes of tree trunk and crown are segmented respectively based on the Laplacian skeleton-based segmentation approach.Finally,the point cloud within the crown volume is utilized to generate multi-resolutionα-shapes,which can be used as levels of detail(LOD)models in non-photorealistic VR environment.