A DSM of plot 4 shows (figure 3) that the modeling of single trees from a tree crown segmentation is very difficult. The tree crowns of trees with heights of 15 meters can have a diameter of only 1 meter. Since the Toposys scan pattern shows profile lines with a distance of about 1.8 meters across flight direction tree crowns can not be modeled in a sufficient way.
Therefore only tree tops were detected within the 3D point cloud of the DSM subtracted by the DTM. To enable the usage of fast neighbourhood operations the raw data were rastered at a resolution of 0.2 meters.