Delineating tree crowns from airborne laser scanning point cloud data using Delaunay triangulation

Most algorithms for delineating trees from laser scanning data are pixel-based region growing methods. The algorithm presented in this letter makes use of the original laser points to avoid errors introduced by interpolation. Three different scales are used to identify the seed points or the local maxima at that scale. The seed points are considered to be the estimated tree tops, and are used for growing regions or tree crowns around the seed points. For a test dataset from a Finnish mixed forest and point density of approximately 2 points m(-2), up to 75% of the reference trees could be identified. At the coarser scales, fewer trees were identified, but the crowns were less fragmented. Further work is required to determine how far the method is applicable in other forest conditions and data with other point densities.