{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,30]],"date-time":"2026-01-30T06:26:45Z","timestamp":1769754405720,"version":"3.49.0"},"reference-count":45,"publisher":"MDPI AG","issue":"11","license":[{"start":{"date-parts":[[2022,5,26]],"date-time":"2022-05-26T00:00:00Z","timestamp":1653523200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"the Fundamental Research Funds for the Central Universities","award":["No. 2021ZY92"],"award-info":[{"award-number":["No. 2021ZY92"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Tree skeletons play an important role in tree structure analysis and 3D model reconstruction. However, it is a challenge to extract a skeleton from a tree point cloud with complex branches. In this paper, an automatic and fast tree skeleton extraction method (FTSEM) based on voxel thinning is proposed. In this method, a wood\u2013leaf classification algorithm was introduced to filter leaf points for the reduction of the leaf interference on tree skeleton generation, tree voxel thinning was adopted to extract a raw tree skeleton quickly, and a breakpoint connection algorithm was used to improve the skeleton connectivity and completeness. Experiments were carried out in Haidian Park, Beijing, in which 24 trees were scanned and processed to obtain tree skeletons. The graph search algorithm (GSA) was used to extract tree skeletons based on the same datasets. Compared with the GSA method, the FTSEM method obtained more complete tree skeletons. The time cost of the FTSEM method was evaluated using the runtime and time per million points (TPMP). The runtime of FTSEM was from 1.0 s to 13.0 s, and the runtime of GSA was from 6.4 s to 309.3 s. The average value of TPMP was 1.8 s for FTSEM and 22.3 s for GSA, respectively. The experimental results demonstrate that the proposed method is feasible, robust, and fast with good potential for tree skeleton extraction.<\/jats:p>","DOI":"10.3390\/rs14112558","type":"journal-article","created":{"date-parts":[[2022,5,31]],"date-time":"2022-05-31T00:25:12Z","timestamp":1653956712000},"page":"2558","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":15,"title":["Fast Tree Skeleton Extraction Using Voxel Thinning Based on Tree Point Cloud"],"prefix":"10.3390","volume":"14","author":[{"given":"Jingqian","family":"Sun","sequence":"first","affiliation":[{"name":"School of Science, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing 100083, China"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0229-4909","authenticated-orcid":false,"given":"Pei","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Science, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing 100083, China"}]},{"given":"Ronghao","family":"Li","sequence":"additional","affiliation":[{"name":"School of Science, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing 100083, China"}]},{"given":"Mei","family":"Zhou","sequence":"additional","affiliation":[{"name":"Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China"}]},{"given":"Yuhan","family":"Wu","sequence":"additional","affiliation":[{"name":"School of Science, Beijing Forestry University, No. 35 Qinghua East Road, Haidian District, Beijing 100083, China"}]}],"member":"1968","published-online":{"date-parts":[[2022,5,26]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"86","DOI":"10.1016\/j.isprsjprs.2018.02.008","article-title":"Large-Scale Urban Point Cloud Labeling and Reconstruction","volume":"138","author":"Zhang","year":"2018","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1111\/cgf.12802","article-title":"A Survey of Surface Reconstruction from Point Clouds","volume":"36","author":"Berger","year":"2017","journal-title":"Comput. Graph. Forum"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Lamb, S., MacLean, D., Hennigar, C., and Pitt, D. (2018). Forecasting Forest Inventory Using Imputed Tree Lists for LiDAR Grid Cells and a Tree-List Growth Model. Forests, 9.","DOI":"10.3390\/f9040167"},{"key":"ref_4","first-page":"72","article-title":"Individual Tree Crown Approach for Predicting Site Index in Boreal Forests Using Airborne Laser Scanning and Hyperspectral Data","volume":"60","author":"Kandare","year":"2017","journal-title":"Int. J. Appl. Earth Obs. Geoinf."},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Palace, M., Sullivan, F.B., Ducey, M., and Herrick, C. (2016). Estimating Tropical Forest Structure Using a Terrestrial Lidar. PLoS ONE, 11.","DOI":"10.1371\/journal.pone.0154115"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"1475","DOI":"10.1109\/TGRS.2015.2481492","article-title":"Assessing the Contribution of Woody Materials to Forest Angular Gap Fraction and Effective Leaf Area Index Using Terrestrial Laser Scanning Data","volume":"54","author":"Zheng","year":"2016","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"815","DOI":"10.1016\/j.ecolind.2015.10.034","article-title":"Estimation of Big Sagebrush Leaf Area Index with Terrestrial Laser Scanning","volume":"61","author":"Olsoy","year":"2016","journal-title":"Ecol. Indic."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"22","DOI":"10.1016\/j.agrformet.2015.11.005","article-title":"Retrieval of Three-Dimensional Tree Canopy and Shade Using Terrestrial Laser Scanning (TLS) Data to Analyze the Cooling Effect of Vegetation","volume":"217","author":"Kong","year":"2016","journal-title":"Agric. For. Meteorol."},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Oveland, I., Hauglin, M., Gobakken, T., N\u00e6sset, E., and Maalen-Johansen, I. (2017). Automatic Estimation of Tree Position and Stem Diameter Using a Moving Terrestrial Laser Scanner. Remote Sens., 9.","DOI":"10.3390\/rs9040350"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"456","DOI":"10.1080\/02827581.2013.777772","article-title":"Estimating Single-Tree Branch Biomass of Norway Spruce with Terrestrial Laser Scanning Using Voxel-Based and Crown Dimension Features","volume":"28","author":"Hauglin","year":"2013","journal-title":"Scand. J. For. Res."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"5408503","DOI":"10.1155\/2017\/5408503","article-title":"An Automatic Tree Skeleton Extracting Method Based on Point Cloud of Terrestrial Laser Scanner","volume":"2017","author":"Li","year":"2017","journal-title":"Int. J. Opt."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"2805","DOI":"10.1109\/TVCG.2019.2903805","article-title":"Mass-Driven Topology-Aware Curve Skeleton Extraction from Incomplete Point Clouds","volume":"26","author":"Qin","year":"2020","journal-title":"IEEE Trans. Visual. Comput. Graph."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"763","DOI":"10.1007\/s00371-014-0977-7","article-title":"Hybrid Tree Reconstruction from Inhomogeneous Point Clouds","volume":"30","author":"Aiteanu","year":"2014","journal-title":"Vis. Comput."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"113","DOI":"10.5194\/isprs-archives-XLII-2-W3-113-2017","article-title":"From TLS Point Clouds to 3d Models of Trees: A Comparison of Existing Algorithms for 3d Tree Reconstruction","volume":"XLII-2\/W3","author":"Bournez","year":"2017","journal-title":"Int. Arch. Photogramm. Remote Sens. Spat. Inf. Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1016\/j.biosystemseng.2016.04.013","article-title":"Multi-Tree Woody Structure Reconstruction from Mobile Terrestrial Laser Scanner Point Clouds Based on a Dual Neighbourhood Connectivity Graph Algorithm","volume":"148","author":"Pascual","year":"2016","journal-title":"Biosyst. Eng."},{"key":"ref_16","doi-asserted-by":"crossref","unstructured":"Zhang, C., Yang, G., Jiang, Y., Xu, B., Li, X., Zhu, Y., Lei, L., Chen, R., Dong, Z., and Yang, H. (2020). Apple Tree Branch Information Extraction from Terrestrial Laser Scanning and Backpack-LiDAR. Remote Sens., 12.","DOI":"10.3390\/rs12213592"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1111\/2041-210X.12301","article-title":"Nondestructive Estimates of Above-ground Biomass Using Terrestrial Laser Scanning","volume":"6","author":"Calders","year":"2015","journal-title":"Methods Ecol. Evol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"19","DOI":"10.1145\/1289603.1289610","article-title":"Knowledge and Heuristic-Based Modeling of Laser-Scanned Trees","volume":"26","author":"Xu","year":"2007","journal-title":"ACM Trans. Graph."},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Yan, D.-M., Wintz, J., Mourrain, B., Wang, W., Boudon, F., and Godin, C. (2009, January 19\u201321). Efficient and Robust Reconstruction of Botanical Branching Structure from Laser Scanned Points. Proceedings of the 2009 11th IEEE International Conference on Computer-Aided Design and Computer Graphics, Huangshan, China.","DOI":"10.1109\/CADCG.2009.5246837"},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Livny, Y., Yan, F., Olson, M., Chen, B., Zhang, H., and El-Sana, J. (2010). Automatic Reconstruction of Tree Skeletal Structures from Point Clouds. ACM SIGGRAPH Asia 2010 Papers, Proceedings of the SIGGRAPH ASIA 2010, Seoul, South Korea, 15\u201318 December 2010, ACM Press.","DOI":"10.1145\/1866158.1866177"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1115","DOI":"10.1016\/j.mcm.2010.11.043","article-title":"Skeleton Extraction for Tree Models","volume":"54","author":"Su","year":"2011","journal-title":"Math. Comput. Model."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"4271","DOI":"10.3390\/s140304271","article-title":"PypeTree: A Tool for Reconstructing Tree Perennial Tissues from Point Clouds","volume":"14","author":"Delagrange","year":"2014","journal-title":"Sensors"},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Verroust, A., and Lazarus, F. (1999, January 1\u20134). Extracting Skeletal Curves from 3D Scattered Data. Proceedings of the Proceedings Shape Modeling International \u201899. International Conference on Shape Modeling and Applications, Aizu-Wakamatsu, Japan.","DOI":"10.1109\/SMA.1999.749340"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"4749","DOI":"10.1109\/TGRS.2016.2551286","article-title":"A Local Structure and Direction-Aware Optimization Approach for Three-Dimensional Tree Modeling","volume":"54","author":"Wang","year":"2016","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"5653","DOI":"10.1109\/TGRS.2013.2291815","article-title":"A Structure-Aware Global Optimization Method for Reconstructing 3-D Tree Models from Terrestrial Laser Scanning Data","volume":"52","author":"Wang","year":"2014","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"4245","DOI":"10.3390\/f6114245","article-title":"SimpleTree\u2014An Efficient Open Source Tool to Build Tree Models from TLS Clouds","volume":"6","author":"Hackenberg","year":"2015","journal-title":"Forests"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"999","DOI":"10.1080\/13658816.2016.1264075","article-title":"3D Tree Modeling from Incomplete Point Clouds via Optimization and L1-MST","volume":"31","author":"Mei","year":"2017","journal-title":"Int. J. Geogr. Inf. Sci."},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Huang, Z., Huang, X., Fan, J., Eichhorn, M., An, F., Chen, B., Cao, L., Zhu, Z., and Yun, T. (2020). Retrieval of Aerodynamic Parameters in Rubber Tree Forests Based on the Computer Simulation Technique and Terrestrial Laser Scanning Data. Remote Sens., 12.","DOI":"10.3390\/rs12081318"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"2235","DOI":"10.1007\/s00371-020-01983-6","article-title":"Skeleton Extraction from Point Clouds of Trees with Complex Branches via Graph Contraction","volume":"37","author":"Jiang","year":"2020","journal-title":"Vis. Comput."},{"key":"ref_30","first-page":"929","article-title":"Structuring Laser-scanned Trees Using 3D Mathematical Morphology","volume":"35","author":"Gorte","year":"2004","journal-title":"Int. Arch. Photogramm. Remote Sens."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"115","DOI":"10.1016\/j.isprsjprs.2007.10.004","article-title":"CAMPINO\u2014A Skeletonization Method for Point Cloud Processing","volume":"63","author":"Bucksch","year":"2008","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1283","DOI":"10.1007\/s00371-010-0520-4","article-title":"SkelTre: Robust Skeleton Extraction from Imperfect Point Clouds","volume":"26","author":"Bucksch","year":"2010","journal-title":"Vis. Comput."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"27327","DOI":"10.1109\/ACCESS.2020.2971549","article-title":"Tree Skeletonization for Raw Point Cloud Exploiting Cylindrical Shape Prior","volume":"8","author":"Fu","year":"2020","journal-title":"IEEE Access"},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1016\/j.isprsjprs.2013.03.003","article-title":"Derivation of Tree Skeletons and Error Assessment Using LiDAR Point Cloud Data of Varying Quality","volume":"80","author":"Bremer","year":"2013","journal-title":"ISPRS J. Photogramm. Remote Sens."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"903","DOI":"10.1007\/s00779-018-1153-2","article-title":"Research on Geometric Features and Point Cloud Properties for Tree Skeleton Extraction","volume":"22","author":"He","year":"2018","journal-title":"Pers. Ubiquit. Comput."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"161","DOI":"10.1007\/s12145-018-0365-3","article-title":"Force Field Driven Skeleton Extraction Method for Point Cloud Trees","volume":"12","author":"Gao","year":"2019","journal-title":"Earth Sci. Inf."},{"key":"ref_37","doi-asserted-by":"crossref","unstructured":"Ai, M., Yao, Y., Hu, Q., Wang, Y., and Wang, W. (2020). An Automatic Tree Skeleton Extraction Approach Based on Multi-View Slicing Using Terrestrial LiDAR Scans Data. Remote Sens., 12.","DOI":"10.3390\/rs12223824"},{"key":"ref_38","first-page":"1","article-title":"L1-Medial Skeleton of Point Cloud","volume":"32","author":"Huang","year":"2013","journal-title":"ACM Trans. Graph."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"123","DOI":"10.34768\/amcs-2020-0010","article-title":"Curve Skeleton Extraction via K-Nearest-Neighbors Based Contraction","volume":"30","author":"Zhou","year":"2020","journal-title":"Int. J. Appl. Math. Comput. Sci."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"248","DOI":"10.3389\/fpls.2019.00248","article-title":"An Accurate Skeleton Extraction Approach From 3D Point Clouds of Maize Plants","volume":"10","author":"Wu","year":"2019","journal-title":"Front. Plant Sci."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"951","DOI":"10.1016\/j.compag.2019.05.043","article-title":"Automated Morphological Traits Extraction for Sorghum Plants via 3D Point Cloud Data Analysis","volume":"162","author":"Xiang","year":"2019","journal-title":"Comput. Electron. Agric."},{"key":"ref_42","doi-asserted-by":"crossref","unstructured":"Sun, J., Wang, P., Gao, Z., Liu, Z., Li, Y., Gan, X., and Liu, Z. (2021). Wood-Leaf Classification of Tree Point Cloud Based on Intensity and Geometric Information. Remote Sens., 13.","DOI":"10.3390\/rs13204050"},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"613","DOI":"10.1016\/S0167-8655(98)00031-2","article-title":"A 3D 6-Subiteration Thinning Algorithm for Extracting Medial Lines","volume":"19","author":"Kuba","year":"1998","journal-title":"Pattern Recognit. Lett."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"79","DOI":"10.5755\/j01.eee.18.9.2813","article-title":"A New Method of Breakpoint Connection Using Curve Features for Contour Vectorization","volume":"18","author":"Zhao","year":"2012","journal-title":"ElAEE"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"026040","DOI":"10.1117\/1.JRS.10.026040","article-title":"Adaptive Circle-Ellipse Fitting Method for Estimating Tree Diameter Based on Single Terrestrial Laser Scanning","volume":"10","author":"Bu","year":"2016","journal-title":"J. Appl. Remote Sens."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/11\/2558\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T23:19:23Z","timestamp":1760138363000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/14\/11\/2558"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,5,26]]},"references-count":45,"journal-issue":{"issue":"11","published-online":{"date-parts":[[2022,6]]}},"alternative-id":["rs14112558"],"URL":"https:\/\/doi.org\/10.3390\/rs14112558","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,5,26]]}}}