基于地面Lidar的树冠体积和表面积测量方法研究

Measurement and calculation methods of volume and surface area of tree crown based on terrestrial 3D laser scanning system

树冠体积和表面积是树木生物量计算中非常重要的参数。本研究的目的在于找出一套基于地面三维激光扫描系统的树木树冠体积和表面积的高精度测量和计算方法。研究方法如下:首先,介绍了该方法的外业作业流程,主要有控制点布设、控制靶标布设、控制点和靶标的坐标测量、设站、扫描等。其次,描述了内业数据处理流程,包括点云数据的配准、以1 cm为间隔分割点云、点云层表面点的筛选、内部点的剔除、分层构面等。然后,基于点云分层所构多边形,求算树冠体积和表面积。最后,以广州大学校园内的8颗样本树为例,将计算结果与前人的研究结果进行了比较分析。研究结果表明,使用本研究方法所测得的树冠体积和表面积计算结果更为合理、精度也更高。因此,本方法实现了高效、无损、精确的获取树冠的体积和表面积,具有较强的实践意义和应用价值。

Volume and surface area of tree crown are very important parameters in estimation of tree biomass. A new high-precision measurement and calculation method to survey and measure volume and surface area of tree crown on basis of terrestrial LiDAR were introduced. The field working processes include： control point layout, laser target sign point layout, point coordination survey, setting station and scan tree etc.. The procedure of was described. The indoor data processing procedure include： point cloud data registration, divided point cloud in 1cm interval, selected surface point of point cloud layer, delete internal point of point cloud slice, constructed polygon according to surface point etc. And then, volume and surface area were calculated based on constructed polygons of every point cloud slice. By taking eight trees in Guangzhou university campus as the examples, the calculated results were compared and analyzed with the previous people’s studying results. The results show that the calculated results are more reasonable and precise than the previous researches. It is concluded that this method can measure and calculate volume and surface area of tree crown effectively, and is harmless and precise and have strong practical significance and application value.