基于低空高分辨影像的三维绿量计算方法——以南京林业大学校园为例

On the Method of Three-Dimensional Green Volume Calculation Based on Low-altitude High-Definition Images——Case Study of the Nanjing Forestry University Campus

三维绿量是指树木树冠所占空间体积,对于森林来说,它可以比较简易地反映绿化实体的生态环境效益。以南京林业大学校园内乔、灌木为研究对象,使用小型固定翼无人机获取了校园高重叠度、高空间分辨率影像,利用差分GPS获取了厘米级精度的像控点,再借助于Pix4D无人机测绘图像处理软件,得到了研究区高精度正射影像。在此基础上,基于数字图像分割技术,提取了树木的位置和冠径,并且利用三维树形树冠体积公式,计算了不同树木的三维绿量,实现了校园范围内三维绿量的定量分析。

Three-dimensional green biomass refers to all the stems and leaves of plants growing volume of space occupied, and it can truly reflect the relative environmental benefits of green ecological entity. In this paper, with the Nanjing Forestry University campus trees, shrubs as the research object, this study used a small fixed-wing UAV and acquired campus images of high overlap degree and high spatial resolution using differential GPS centimeter-level accuracy of control points. Aided with Pix4 D UAV mapping image processing software, the study area was present as the high accuracy orthophoto. On this basis, based on digital image segmentation technique, this study extracted the location of trees and crown diameter, and used three-dimensional tree crown volume formula to calculate the threedimensional green biomass of different trees. A quantitative analysis of campus-wide three-dimensional green biomass is achieved.