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以白皮松(Pinus bungeana Zucc)为研究对象,针对地基激光雷达TLS扫描的3维点云数据在单株木垂直方向的分布特征,提出了一种基于体元化方法的树干覆盖度变化检测方法,获取单木枝下高;然后根据获取的枝下高引入2维凸包算法获取垂直方向分层树冠轮廓,并计算树冠体积和冠幅;同时获取的单木参数还有胸径与树高。结果表明:单木枝下高的估测精度较高,R2与RMSE分别为0.97 m和0.21 m;胸径估测结果的R2与RMSE分别为0.79 cm和1.07 cm;采用逐步线性回归方法建立单木树冠体积与其他单木参数的相关关系,模型变量包括冠幅、叶子填充树冠长度和胸径,样本数为20,模型的R2与RMSE分别是0.967 m3和2.64 m3。本文方法能较准确地估测枝下高,TLS数据具有对树冠结构3维建模的潜力。
Taking Pinus bungeana Zucc as the research object, aiming at the vertical distribution of 3-D point cloud data of ground-based Lidar by LLS, a method based on voxelization was proposed to detect the change of trunk coverage. The height of single branch was obtained. Then the 2-D convex hull algorithm was introduced to obtain the vertical crown delineation and to calculate the crown volume and crown width. The results showed that the estimation precision of height under single branch was higher with R2 and RMSE of 0.97 m and 0.21 m, respectively. The R2 and RMSE of DBH were 0.79 cm and 1.07 cm respectively. The linear regression method was used to establish single tree The canopy volume was correlated with other single wood parameters. The model variables included crown width, canopy length and DBH, with a sample size of 20 and model R2 and RMSE of 0.967 m3 and 2.64 m3, respectively. The proposed method can accurately estimate the height of branches and the potential of TLS data to model three-dimensional canopy structures.