台阶线数据是露天矿开采过程中的重要基础资料,也是确保露天矿高效、智能开采的重要前提.针对现有的基于点云的露天矿台阶线提取方法存在局部特征丢失、台阶线不连续等问题,将识别台阶线特征点转为识别几何特征面,从特征面轮廓中提取出台阶线特征点,由此提出了一种顾及邻域几何特性的露天矿台阶线自动提取方法.该方法首先对露天矿点云进行规则重采样,依据露天矿台阶平盘、坡面点云法向量与竖直平面夹角具有明显差异这一几何特性提取坡面的特征点云;在此基础上,采用区域生长算法分割坡面点云,通过凹包算法提取分割后的坡面点云轮廓边界获得台阶线特征点;最后利用三阶贝塞尔曲线拟合特征点以生成露天矿台阶线.为验证算法的提取精度,将台阶线与露天矿数字高程模型(Digital Elevation Model,DEM)叠加,并计算该方法提取的台阶线与实际台阶线的位置偏差.结果表明:该方法提取的台阶线完整且连续性好,与手工绘制的台阶线基本重合,能够满足比例尺为1∶2 000 的制图精度要求;运行效率高,对于面积为 3 km2 的露天矿,提取时间在 4 min以内.证明所提方法能够准确、高效地提取露天矿台阶线,为实现露天矿山台阶线自动绘制提供重要的技术支持.
Extraction Method of Open-pit Mine Step Line Considering Geometric Characteristics of Point Cloud Neighborhood
Step line data is an important basic data in the process of open-pit mining,and is also an important premise to ensure efficient and intelligent mining of open-pit mine.Efficient and accurate extraction of step line is of great significance to the construction of intelligent open-pit mine.In view of the problems of local feature loss and discontinuity of the existing point cloud-based extraction methods of the open-pit step line,an automatic extraction method of the open-pit step line considering the geometric characteristics of the neighborhood was proposed.Firstly,regular resampling is carried out for open-pit point clouds,and the feature point clouds of open-pit slope are extracted according to the geometric property that the angle between the normal vector of point clouds and the vertical plane is obviously different.On this basis,the region growth algorithm is used to segment the slope point cloud,and the concave hull algorithm is used to extract the contour boundary of the slope point cloud after segmentation to obtain the feature points of the step line.Finally,the three-order Bessel curve is used to fit the feature points to generate the open-pit step line.In order to verify the extraction accuracy of the algorithm,the step line was superim-posed with the open-pit Digital Elevation Model(DEM),and the position deviation between the step line extracted by the method in this paper and the actual step line was calculated.The results show that the step lines extracted by this method are complete and have good continuity,and basically coincide with the step lines drawn by hand,which can meet the drawing accu-racy requirements of 1∶2 000 scale.Besides that,the the operation efficiency of this method is high,for an open-pit mine with an area of 3 km2,the extraction time is less than 4 min.It is proved that the proposed method can extract the open-pit step line accurately and efficiently,and provides important technical support for realizing the automatic drawing of the open-pit step line.
open-pit minepoint cloud datanormal vectorconcave hull algorithmstep line
NETL
NSTL
万方数据
