Under-Canopy UAV Laser Scanning Providing Canopy Height and Stem Volume Accurately

• DOI: 10.20944/preprints202104.0003.v1
• Publication Date: 2021-04-02T07:09:10Z
• Authors: Juha Hyyppä; Xiaowei Yu; Teemu Hakala; Harri Kaartinen; Antero Kukko; Heikki Hyyti; Jesse Muhojoki; Eric Hyyppä
• Keywords: Laser Scanning; Tree canopy; Tree (set theory)

Automation of forest field reference data collection has been an intensive research objective for laser scanning scientists ever since the invention terrestrial more than two decades ago. Recently, it proposed that such automated providing both tree heights and stem curves would require a combination above-canopy UAV point clouds clouds. In this study, we demonstrate under-canopy system utilizing rotating scanner can alone provide accurate estimates canopy height volume majority trees in boreal forest. To end, mounted based on Velodyne VLP-16 sensor onboard manually piloted UAV. The was commanded with help live video feed from camera Since varying view angles, all important elements as treetops, branches, trunks, ground could be recorded hits. experiment including different structures, namely sparse obstructed canopy, showed our measure individual bias -20 cm standard error 40 -65 1 m accuracy obtained equivalent to airborne surveys conducted similar conditions. higher underestimation inaccuracy site attributed three exceeding 25 applied had limited measurement capacity when comes taller m. Additionally, used estimate volumes at level 10%. This is merging cloud data. Future needed testing new sensors, implementing autonomous operation inside canopies through collision avoidance navigation canopies, developing robust methods work also complex structure. results show do not necessarily need collected using systems order accurately trees.