Next Article in Journal
Acknowledgement to Reviewers of Forests in 2019
Next Article in Special Issue
Estimating Coarse Woody Debris Volume Using Image Analysis and Multispectral LiDAR
Previous Article in Journal
Strategies for Modeling Regeneration Density in Relation to Distance from Adult Trees
Previous Article in Special Issue
Mapping the Spatial Distribution of Tea Plantations Using High-Spatiotemporal-Resolution Imagery in Northern Zhejiang, China
Open AccessArticle

Image Data Acquisition for Estimating Individual Trees Metrics: Closer Is Better

1
Laboratoire d’études et de Recherche en Statistiques et Biométrie Appliquée, Université d’Abomey-Calavi, FSA 01 BP 526 Cotonou, Benin
2
Ecology Unity, Department of Botany, University of Ibadan, 20084 Ibadan, Nigeria
3
Forest is Life, TERRA Teaching and Research Centre, Gembloux Agro-Bio Tech, University of Liège, 2 Passages des Déportés, 5030 Gembloux, Belgium
*
Author to whom correspondence should be addressed.
Forests 2020, 11(1), 121; https://doi.org/10.3390/f11010121
Received: 25 November 2019 / Revised: 9 January 2020 / Accepted: 11 January 2020 / Published: 19 January 2020
(This article belongs to the Special Issue Forest Resources Assessments: Mensuration, Inventory and Planning)
Background and Objectives: The recent use of Structure-from-Motion with Multi-View Stereo photogrammetry (SfM-MVS) in forestry has underscored its robustness in tree mensuration. This study evaluated the differences in tree metrics resulting from various related SfM-MVS photogrammetric image acquisition scenarios. Materials and Methods: Scaled tri-dimensional models of 30 savanna trees belonging to five species were built from photographs acquired in a factorial design with shooting distance (d = 1, 2, 3, 4 and 5 m away from tree) and angular shift (α = 15°, 30°, 45° and 60°; nested in d). Tree stem circumference at 1.3 m and bole volume were estimated using models resulting from each of the 20 scenarios/tree. Mean absolute percent error (MAPE) was computed for both metrics in order to compare the performance of each scenario in relation to reference data collected using a measuring tape. Results: An assessment of the effect of species identity (s), shooting distance and angular shift showed that photographic point cloud density was dependent on α and s, and optimal for 15° and 30°. MAPEs calculated on stem circumferences and volumes significantly differed with d and α, respectively. There was a significant interaction between α and s for both circumference and volume MAPEs, which varied widely (1.6 ± 0.4%–20.8 ± 23.7% and 2.0 ± 0.6%–36.5 ± 48.7% respectively), and were consistently lower for smaller values of d and α. Conclusion: The accuracy of photogrammetric estimation of individual tree attributes depended on image-capture approach. Acquiring images 2 m away and with 30° intervals around trees produced reliable estimates of stem circumference and bole volume. Research Highlights: This study indicates that the accuracy of photogrammetric estimations of individual tree attributes is species-dependent. Camera positions in relation to the subject substantially influence the level of uncertainty in measurements. View Full-Text
Keywords: Photogrammetry; SfM-MVS; Image acquisition scenario; Mean absolute percent error; Tree stem circumference; bole volume; Benin Photogrammetry; SfM-MVS; Image acquisition scenario; Mean absolute percent error; Tree stem circumference; bole volume; Benin
Show Figures

Figure 1

MDPI and ACS Style

Akpo, H.A.; Atindogbé, G.; Obiakara, M.C.; Adjinanoukon, A.B.; Gbedolo, M.; Lejeune, P.; Fonton, N.H. Image Data Acquisition for Estimating Individual Trees Metrics: Closer Is Better. Forests 2020, 11, 121. https://doi.org/10.3390/f11010121

AMA Style

Akpo HA, Atindogbé G, Obiakara MC, Adjinanoukon AB, Gbedolo M, Lejeune P, Fonton NH. Image Data Acquisition for Estimating Individual Trees Metrics: Closer Is Better. Forests. 2020; 11(1):121. https://doi.org/10.3390/f11010121

Chicago/Turabian Style

Akpo, Hospice A.; Atindogbé, Gilbert; Obiakara, Maxwell C.; Adjinanoukon, Arios B.; Gbedolo, Madaï; Lejeune, Philippe; Fonton, Noël H. 2020. "Image Data Acquisition for Estimating Individual Trees Metrics: Closer Is Better" Forests 11, no. 1: 121. https://doi.org/10.3390/f11010121

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop