{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T06:03:24Z","timestamp":1783490604068,"version":"3.55.0"},"reference-count":50,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2020,1,1]],"date-time":"2020-01-01T00:00:00Z","timestamp":1577836800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["41771370"],"award-info":[{"award-number":["41771370"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>The extraction of information about individual trees is essential to supporting the growing of fruit in orchard management. Data acquired from spectral sensors mounted on unmanned aerial vehicles (UAVs) have very high spatial and temporal resolution. However, an efficient and reliable method for extracting information about individual trees with irregular tree-crown shapes and a complicated background is lacking. In this study, we developed and tested the performance of an approach, based on UAV imagery, to extracting information about individual trees in an orchard with a complicated background that includes apple trees (Plot 1) and pear trees (Plot 2). The workflow involves the construction of a digital orthophoto map (DOM), digital surface models (DSMs), and digital terrain models (DTMs) using the Structure from Motion (SfM) and Multi-View Stereo (MVS) approaches, as well as the calculation of the Excess Green minus Excess Red Index (ExGR) and the selection of various thresholds. Furthermore, a local-maxima filter method and marker-controlled watershed segmentation were used for the detection and delineation, respectively, of individual trees. The accuracy of the proposed method was evaluated by comparing its results with manual estimates of the numbers of trees and the areas and diameters of tree-crowns, all three of which parameters were obtained from the DOM. The results of the proposed method are in good agreement with these manual estimates: The F-scores for the estimated numbers of individual trees were 99.0% and 99.3% in Plot 1 and Plot 2, respectively, while the Producer\u2019s Accuracy (PA) and User\u2019s Accuracy (UA) for the delineation of individual tree-crowns were above 95% for both of the plots. For the area of individual tree-crowns, root-mean-square error (RMSE) values of 0.72 m2 and 0.48 m2 were obtained for Plot 1 and Plot 2, respectively, while for the diameter of individual tree-crowns, RMSE values of 0.39 m and 0.26 m were obtained for Plot 1 (339 trees correctly identified) and Plot 2 (203 trees correctly identified), respectively. Both the areas and diameters of individual tree-crowns were overestimated to varying degrees.<\/jats:p>","DOI":"10.3390\/rs12010133","type":"journal-article","created":{"date-parts":[[2020,1,3]],"date-time":"2020-01-03T04:43:03Z","timestamp":1578026583000},"page":"133","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":76,"title":["Extraction of Information about Individual Trees from High-Spatial-Resolution UAV-Acquired Images of an Orchard"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7606-4826","authenticated-orcid":false,"given":"Xinyu","family":"Dong","sequence":"first","affiliation":[{"name":"International Institute for Earth System Science, Nanjing University, Nanjing 210023, China"},{"name":"Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Nanjing University, Nanjing 210023, China"},{"name":"Collaborative Innovation Center for the South Sea Studies, Nanjing University, Nanjing 210093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhichao","family":"Zhang","sequence":"additional","affiliation":[{"name":"International Institute for Earth System Science, Nanjing University, Nanjing 210023, China"},{"name":"Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Nanjing University, Nanjing 210023, China"},{"name":"Collaborative Innovation Center for the South Sea Studies, Nanjing University, Nanjing 210093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ruiyang","family":"Yu","sequence":"additional","affiliation":[{"name":"College of Resources and Environment, Shandong Agricultural University, Tai\u2019an 271018, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qingjiu","family":"Tian","sequence":"additional","affiliation":[{"name":"International Institute for Earth System Science, Nanjing University, Nanjing 210023, China"},{"name":"Jiangsu Provincial Key Laboratory of Geographic Information Science and Technology, Nanjing University, Nanjing 210023, China"},{"name":"Collaborative Innovation Center for the South Sea Studies, Nanjing University, Nanjing 210093, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xicun","family":"Zhu","sequence":"additional","affiliation":[{"name":"College of Resources and Environment, Shandong Agricultural University, Tai\u2019an 271018, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,1,1]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1973","DOI":"10.3390\/rs2081973","article-title":"Remote sensing and geospatial technological applications for site-specific management of fruit and nut crops: A review","volume":"2","author":"Panda","year":"2010","journal-title":"Remote Sens."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1596","DOI":"10.18782\/2320-7051.3088","article-title":"Precision Farming a Promising Technology in Horticulture: A Review","volume":"6","author":"Das","year":"2018","journal-title":"Int. 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