A method for identifying and segmenting branches of Scots pine (Pinus sylvestris L.) trees using terrestrial laser scanning

IF 3 2区农林科学 Q1 FORESTRY

Forestry Pub Date : 2023-12-05 DOI:10.1093/forestry/cpad062

Tuomas Yrttimaa, Ville Kankare, Ville Luoma, Samuli Junttila, Ninni Saarinen, Kim Calders, Markus Holopainen, Juha Hyyppä, Mikko Vastaranta

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引用次数: 0

Abstract

Terrestrial laser scanning (TLS) has been adopted as a feasible technique to characterize tree stems while the characterization of trees’ branching architecture has remained less explored. In general, branching architecture refers to the spatial arrangement of branches and their characteristics that are important when exploring the eco-physiological functioning of trees or assessing tree biomass and wood quality. Our aim was to develop a point cloud processing method for identifying and segmenting individual branches from TLS point clouds. We applied a Cartesian-to-cylinder coordinate transformation and a simple morphological filtering for stem surface reconstruction and stem-branch separation. Then branch origins were identified as their intersections with the stem surface, and individual branches were segmented based on their connectivity with the branch origins. The method, implemented in MATLAB and openly available, was validated on a 0.4-ha mature and managed southern boreal forest stand. The branch identification performance was assessed based on visual interpretation of 364 randomly sampled stem sections from 100 Scots pine (Pinus sylvestris (L.)) trees that were inspected for branch identification accuracy. The results showed that the branches could only be identified up to the height where the stem could be reconstructed. For 90% of the trees, this threshold ranged between 59.3% and 81.2% relative tree heights. Branches located below this threshold were identified with a recall of 75%, a precision of 92%, and an F1-score of 0.82. Based on our study, it appears that in a managed Scots pine stand, most of the branches can be identified with the developed method for the most valuable stem part eligible for logwood. The findings obtained in this study promote the feasibility of using TLS in applications requiring detailed characterization of trees. The developed method can be further used in quantifying the characteristics of individual branches, which could be useful for biomass and wood quality assessment, for example.

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利用地面激光扫描技术对苏格兰松(Pinus sylvestris L.)树枝进行识别和分割

地面激光扫描(TLS)是一种可行的树干表征技术，但对树木分枝结构的表征研究较少。通常，分枝建筑学是指树枝的空间排列及其特征，在探索树木的生态生理功能或评估树木生物量和木材质量时具有重要意义。我们的目标是开发一种点云处理方法，用于从TLS点云中识别和分割单个分支。我们应用了笛卡尔到圆柱的坐标变换和简单的形态学滤波来进行茎表面重建和茎枝分离。然后根据分支原点与茎表面的交点来识别分支原点，并根据分支原点与分支原点的连通性对单个分支进行分割。该方法在MATLAB中实现，并在一个0.4 ha的成熟管理的南方北方森林林分上进行了验证。通过对100棵苏格兰松(Pinus sylvestris (L.))的364个随机取样的茎段进行视觉判读，评估了树枝识别的准确性。结果表明，树枝只能被识别到可以重建茎的高度。对于90%的树木，该阈值范围在相对树高59.3%至81.2%之间。低于这个阈值的分支被识别出来，召回率为75%，准确率为92%，f1得分为0.82。根据我们的研究，在管理的苏格兰松林中，大多数分支可以用所开发的方法识别出最具价值的符合原木条件的茎部分。本研究的结果促进了在需要详细表征树木的应用中使用TLS的可行性。所开发的方法可进一步用于量化单个树枝的特征，例如，这可能对生物量和木材质量评价有用。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Forestry 农林科学-林学

CiteScore

6.70

自引率

7.10%

发文量

审稿时长

12-24 weeks

期刊介绍： The journal is inclusive of all subjects, geographical zones and study locations, including trees in urban environments, plantations and natural forests. We welcome papers that consider economic, environmental and social factors and, in particular, studies that take an integrated approach to sustainable management. In considering suitability for publication, attention is given to the originality of contributions and their likely impact on policy and practice, as well as their contribution to the development of knowledge. Special Issues - each year one edition of Forestry will be a Special Issue and will focus on one subject in detail; this will usually be by publication of the proceedings of an international meeting.