基于激光点云的输电线路杆塔倾斜检测算法

Transmission line tower tilt detection algorithm based on laser point cloud

为了解决基于激光雷达(LiDAR)点云杆塔倾斜检测方法鲁棒性低、自动化程度差等问题,利用杆塔塔身结构呈标准四棱台的特点,提出一种基于杆塔塔身分层投影提取中轴点的激光点云杆塔倾斜检测算法。首先将杆塔点云沿高程方向进行分层,求取分层点云的最小外接矩形,确定外接矩形中心为杆塔中轴点;其次利用外接矩形的面积、比例变化过滤塔头、高低腿等非对称杆塔结构,以及外接矩形四边内切点高程值进行缺点、噪点检验,在杆塔中轴线拟合之前剔除可检测的偏移点;最后在空间直线拟合中引入抗差估计,通过选权迭代的方式抑制其余偏移点对空间直线拟合的影响。结果表明,该方法在不同塔型、不同点云密度下均有较好的适应性,在缺点、噪点情况下抗粗差能力强,与实测值对比偏差小于0.90‰。该算法具有较强的工程实用价值。

In order to solve the problems of low robustness and poor automation of current tower tilt detection methods based on light detection and ranging(LiDAR)point cloud transmission line,a tower tilt detection method based on layered minimum external rectangle and robust estimation was proposed by using the structural characteristics of tower body which was projected into standard rectangle on the level plane.Firstly,the area and proportion changes of the minimum circumscribed rectangle of each layer of point cloud were used to filter the deviation between the middle point of the rectangle and the axis point of the actual tower caused by the tower head and the high and low legs,and the center point of the minimum circumscribed rectangle of each layer of the tower body was determined as the axis point;Secondly,the elevation difference between the four sides of the minimum circumscribed rectangle and the elevation value of the point set was used to fit the axis of the tower;Finally,robust estimation was introduced into spatial line fitting to restrain the influence of other offset points on spatial line fitting by weight iteration.The experimental results show that the method has good adaptability in different tower types and different point cloud densities,and has strong ability to resist gross errors in the case of shortcomings and noise,and the deviation from the measured value is less than 0.90‰,which has strong practical application value.