一种高郁闭度林分树高的估测方法

A tree height estimation method with high canopy density

针对单一无人机影像无法有效地提取高郁闭度林分树高的问题,该文提出一种结合无人机影像数据和全站仪测量的地形数据获取高郁闭度林分树高的方法。①利用搭载数码相机的小型无人机平台,以50m航高获取实验区局部高精度林分影像,利用全站仪获取实验区的地形数据;②利用无人机影像处理软件对影像进行处理,通过初步的几何校正以及空三加密过程得到整个实验区的高分辨率DEM和DOM模型;③采用局部最大值算法探测单株林木的树冠中心点坐标,利用自然生长算法和高程差值公式得到树冠中心对应的树根高程;④以树冠中心点高程以及树根高程的差值作为单木树高的估计值。通过实验得出:结合无人机影像与全站仪数据能够准确快速地获取高郁闭度林分树高,本文提出的方法可以为森林可持续经营提供数据基础。

Aiming at the problem that a single UAV image can not effectively extract the tree height for stands with high canopy closure,a method of obtaining the tree height based on the UAV image data and the terrain data from total station measurement was proposed.Firstly,a small UAV platform equipped digital camera was used to acquire the high-precision images of the stands in the experimental area with a flight altitude of 50 m,and the topographic data of the experimental area was obtained by using the Total Station.Then,the UAV images of the local stands were processed by the UAV image processing software Agisoft Photoscan to obtain the high-resolution DEM and DOM through initial geometric correction and aerial triangulation.And then the local maximum algorithm was used to detect the coordinates of the center of the canopy,the height of the tree bottom corresponding to the center of the canopy can be obtained by using the natural growth algorithm and the height difference formula.Finally,the estimated single tree height was obtained by taking the height difference between the center of the canopy and the tree bottom.The combination of UAV images and total station data can accurately and quickly obtain the tree height for stands with high canopy closure.The proposed method can provide basic data for the sustainable forest management.