Digital-image-based tree measurement for forest inventory

摘要

Abstract: In this paper we propose a digital camera based method for estimating the stem diameters of growing trees for forest inventory purposes. The imaging system consists of a single camera, a laser distance measurement device and a calibration stick placed beside the tree to be measured. To carry out the task camera geometry parameters are first determined using linear pinhole camera and nonlinear lens distortion models. In addition of the accurate camera calibration, the viewing geometry has to be determined for 3D measurement purpose with the help of the calibration stick. The estimation of the stem diameters is carried out by combining the stem curve information from the image with a priori stem form model. Experimental results reported with Scots pines indicate that this approach provides feasible solutions for the measurement task.!7