Estimation of Tree Stem Attributes Using Terrestrial Photogrammetry with a Camera Rig
AbstractWe 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. View Full-Text
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Forsman, M.; Börlin, N.; Holmgren, J. Estimation of Tree Stem Attributes Using Terrestrial Photogrammetry with a Camera Rig. Forests 2016, 7, 61.
Forsman M, Börlin N, Holmgren J. Estimation of Tree Stem Attributes Using Terrestrial Photogrammetry with a Camera Rig. Forests. 2016; 7(3):61.Chicago/Turabian Style
Forsman, Mona; Börlin, Niclas; Holmgren, Johan. 2016. "Estimation of Tree Stem Attributes Using Terrestrial Photogrammetry with a Camera Rig." Forests 7, no. 3: 61.
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