Orbit

年度 2019
全部作者 Lu M-K, Lam TY, Perng B-H, Lin H-T
作者類別 Corresponding Author,2
論文名稱 Close-range Photogrammetry with Spherical Panoramas for Mapping Spatial Location and Measuring Diameters of Trees under Forest Canopies
期刊名稱 Canadian Journal of Forest Research
卷數 (In Review)
期刊等級 SCI
摘要 Measurement of tree attributes is important to derive information for forest management. While aerial photography has a long history in forestry, close-range photogrammetry with spherical panoramas has seen very little development. This study is one of the very few that explore applications of spherical panoramas in forestry. Three methods to extract tree azimuth, horizontal distance, diameter at breast height, and upper stem diameters from spherical panoramas are developed based on: (1) trigonometry principle (TRIGO), (2) trigonometry principle adjusted for slope (TRIGOSLP), and (3) attaching targets of known dimension on trees (TARGET). Twenty-three horizontal point sample plots were randomly established in planted forests in Taiwan. A total of 486 trees were analyzed. Results showed that tree azimuth was accurately and precisely estimated. TRIGO performed the worst in accuracy and precision for all other tree attributes. TRIGOSLP improved the results by correcting for tree slope but suffered from large estimation errors. TARGET achieved the best overall precision for all other tree attributes. Horizontal distance was increasingly underestimated by TARGET for trees further from plot center, and estimated diameters of larger trees was less accurate and precise than those of smaller trees. Despite the need to attach a reference target to a tree, close-range photogrammetry with spherical panoramas combined with TARGET has the greatest value in estimating upper stem diameters, which have been difficult to precisely obtain.
語言 英文
所屬計畫案 MOST 105-2628-B-002-010-MY3