一种基于单CCD与经纬仪的树木胸径测量方法

DBH measurement method based on tree images taken by single-CCD camera mounted on theodolite

提出一种基于单CCD相机与经纬仪的树木图像的胸径测量方法,利用单CCD相机采集的树木图像信息,经过阈值分割、开运算、边缘提取等步骤提取树木胸径二维坐标;利用经纬仪采集的角度信息转换经纬仪旋转坐标系、相机光心坐标系和图像坐标系,得出胸径的三维坐标,最终计算出胸径尺寸。采集了八组树木胸径,平均绝对误差为7.36 mm,平均相对误差率为2.46%,完全满足精度要求,验证了将单CCD相机与经纬仪应用于树木胸径测量的方法是可行的。

This paper presented a kind of measurement method based on the tree images taken by a single CCD camera mounted on a theodolite. Based on the tree images, it employed some approaches,including threshold segmentation, open computing, and edge detection, to extract the two-dimensional coordinates of the DBH; using the theodolite gathered space angle information, coordinate transformation among the theodolite rotating coordinate system, the camera optical center coordinate system and the im- age coordinate system, was made tO get the three-dimensional coordinates of the DBH, with which the diameter at the breast- height size could be figured out. It took the breast-height diameters of 8 trees in the experiment, and the mean absolute error was 7.36 ram, while the mean relative error was 2. 46%, which could completely meet the accuracy requirements. The results of the experiments show that the single CCD camera and the theodolite use in DBH measurement method is feasible.