Automatic tree stem delineation supporting forest inventory

The aim of this study was to develop an automatic procedure to detect tree stems in cell phone images. If the stems can be detected, the central projection geometry of the images makes it possible to apply the so called relascope principle to predict the basal area of stems per hectare. The basal area is closely correlated with tree biomass. Images were acquired in an area where detailed tree-wise information is available. The tree stem delineation methods were based on color and edge information to tackle the challenges of occlusions and varying illumination conditions. Geolocalised images can be used as in-situ reference data for remote sensing data analysis to provide wall-to-wall estimates.