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Research article - Peer-reviewed, 2016

Estimation of Tree Stem Attributes Using Terrestrial Photogrammetry with a Camera Rig

Forsman, Mona; Börlin, Niclas; Holmgren, Johan

Abstract

We propose a novel photogrammetric method for field plot inventory, designed for simplicity and time efficiency on-site. A prototype multi-camera rig was used to acquire images from field plot centers in multiple directions. The acquisition time on-site was less than two minutes. From each view, a point cloud was generated using a novel, rig-based matching of detected SIFT keypoints. Stems were detected in the merged point cloud, and their positions and diameters were estimated. The method was evaluated on 25 hemi-boreal forest plots of a 10-m radius. Due to difficult lighting conditions and faulty hardware, imagery from only six field plots was processed. The method performed best on three plots with clearly visible stems with a 76% detection rate and 0% commission. Diameters could be estimated for 40% of the stems with an RMSE of 2.8-9.5 cm. The results are comparable to other camera-based methods evaluated in a similar manner. The results are inferior to TLS-based methods. However, our method is easily extended to multiple station image schemas, something that could significantly improve the results while retaining low commission errors and time on-site. Furthermore, with smaller hardware, we believe this could be a useful technique for measuring stem attributes in the forest.

Keywords

mobile mapping; stem diameter; circle estimation; forest inventory; point cloud

Published in

Forests
2016, volume: 7, number: 3, article number: 61

Authors' information

Forsman, Mona
Swedish University of Agricultural Sciences, Department of Forest Resource Management
Börlin, Niclas
Umeå University
Swedish University of Agricultural Sciences, Department of Forest Resource Management

Associated SLU-program

Remningstorp

UKÄ Subject classification

Remote Sensing
Forest Science
Computer Vision and Robotics (Autonomous Systems)

Publication Identifiers

DOI: https://doi.org/10.3390/f7030061

URI (permanent link to this page)

https://res.slu.se/id/publ/73783