Estimation of Tree Diameter at Breast Height using Stereo Camera by Drone Surveying and Mobile Scanning Methods

In this paper, we propose two different scanning methods, drone scanning method, and mobile scanning method, using a stereo camera for estimation of the tree's diameter at breast height (DBH). The mobile scanning method is widely used in mapping forest environments and for forest inventory due to its cost-effectiveness and accessibility. Drone scanning has gained wide attention in recent years because of the development of unmanned aerial technology. This study evaluates two existing fitting algorithms to determine the most suitable method for DBH extraction, namely, the least-squares ellipse fitting algorithm and the random Hough transform (RHT) circle fitting algorithm. A stereo camera is used to generate 3D point cloud maps of the pine forest area. The trees in the study area are segmented using clustering algorithms before performing DBH extraction. A three-dimensional point cloud map of pine trees in the study area is generated, and DBH of each individual tree is estimated. From the experimental results, the drone scanning method was found to be more appropriate than the mobile scanning method for the application of forest mapping. From our experimental results, the drone scanning method with the RHT circle fitting algorithm achieved an average precision accuracy of 92.67%.