Orbit

Year 2018
Authors Perng B-H, Lam TY, Lu M-K
Author Type Corresponding Author,2
Paper Title Stereoscopic imaging with spherical panoramas for measuring tree diameter and distance under forest canopies
Journal Title Forestry
Vol.No 91
Issue.No 5
From 662
To 673
Level Type SCI
Total Pages 12
Date of Publication 2018-12-01
Abstract This study is the first to adapt stereoscopic imaging to measure tree distance and diameter under forest canopy with spherical panoramas. The proposed stereoscopy method requires two spherical panoramas taken at a known distance directly on top of each other. The geometry was comprehensively laid out. Twenty-three plots were randomly established in planted forests. Sample trees were selected with a small basal area factor (BAF) for diameter at breast height and horizontal distance measurement. A larger BAF was used to subsample trees for upper stem diameters. Only fully visible trees were used in the analysis. Results showed that precision decreased with increasing distance from a plot center. Tree distance could be accurately and precisely estimated within 10 m from a plot center. For tree diameters, better accuracy and precision was achieved either a tree was within 5 m away or its diameters were less than 20 cm. Maintaining the required vertical displacement between panoramas was challenging in the field due to difficult terrain and heavy equipment, which is a likely source of error. With continued advancement in photography equipment, shooting spherical panorama becomes easier. Our proposed method could potentially lead to a citizen science based forest resources and monitoring program.
Language English
Reference URL https://academic.oup.com/forestry/article/91/5/662/5076211