基于物体表面正射投影的悬崖点云植被过滤方法

The Filtration Method of Cliff Point Cloud Vegetation Based on the Surface Orthographic Projection

悬崖陡坡是地形图重要的地貌要素,该要素在生态环境工程建设和地质灾害的防治等方面具有非常重要的作用,而悬崖植被的遮挡不利于悬崖观测和数据处理.提出一种悬崖植被过滤方法,该方法主要基于物体表面正射投影原理,首先将原始采集的悬崖三维点云转换到以悬崖表面为xy平面、垂直于悬崖面的方向作为z轴的空间直角坐标系中;然后在xy平面上划分格网,分格网拟合曲面建立局部数字地面模型(DTM),通过设置合理的距离阈值剔除植被点;最后将过滤保留下来的悬崖岩石点经过投影反变换,映射到原始空间坐标系中.对实际悬崖点云数据进行实验分析,结果表明,基于物体表面正射投影的悬崖点云植被过滤方法是可行的、有效的.

Cliff and steep slope are important landscape elements of topographic map, and these elements play a very important role in the construction of the ecological environment and prevention of geological disasters, etc. However, it is unfavorable to observe and process data because of vegetation occlusion on cliff. In this paper, we present a cliff vegetation filtration method based on the principle of surface orthographic projection. Firstly, transform the original three dimensional point cloud of cliff to the spatial cartesian coordinate system, whose xy plane is the cliff face and z-axis is perpendicular to the direction of the cliff surface. Then the grid on the xy plane is divided to establish local grid Digital Terrain Model （DTM） by fitting surface, and the vegeta- tion points can be extracted through setting a reasonable distance threshold. Finally, after inverse projection transformation, cliff rocky points preserved are mapped to the original spatial coordinate system. The experi- mental analysis using actual cliff point cloud data shows that the cliff point cloud vegetation filtering method based on the surface orthographic projection is feasible and effective.