AUTHOR=Puttonen Eetu , Lehtomäki Matti , Litkey Paula , Näsi Roope , Feng Ziyi , Liang Xinlian , Wittke Samantha , Pandžić Miloš , Hakala Teemu , Karjalainen Mika , Pfeifer Norbert 

TITLE=A Clustering Framework for Monitoring Circadian Rhythm in Structural Dynamics in Plants From Terrestrial Laser Scanning Time Series

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 10 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2019.00486

DOI=10.3389/fpls.2019.00486

ISSN=1664-462X

ABSTRACT=Terrestrial Laser Scanning (TLS) can be used to monitor plant dynamics with a frequency of several times per hour and with sub-centimetre accuracy, regardless of the external lighting conditions. TLS point cloud time series measured with short intervals produce large quantities of data that require fast processing techniques that have to be robust to noise inherent in the point clouds. This study presents a general framework to monitor diurnal plant movements from TLS time series. The framework performance was evaluated using TLS time series collected from two Norway maples (Acer platanoides) and a control target, lamp post. The results showed that the presented processing framework can capture diurnal movements of a plant with down to one centimetre spatial resolution. The largest movements in both Norway maples were observed before sunrise and at the outer edges of its crown. The individual cluster movements were up to 0.17 m (99th percentile) for the taller Norway maple and up to 0.11 m (99th percentile) for the smaller Norway maple from their initial positions before sunset.