An axis extract method for rotational parts based on point cloud normal lines

Based on that the normal lines of points on the same latitude of a surface of revolution point to the same point on the axis, a strategy is proposed to find the axis of the surface of revolution by fitting the intersections of normal lines. The k-d tree is used in this paper to address the computational challenges. The shortest distance between the normal lines of two points in the neighborhood of a certain point is calculated to determine whether the intersection of normal lines needs to be calculated. The RANSAC algorithm is used to fit the line to the normal lines intersections to obtain the axis. The axis extraction method is tested on cone, cylinder, spindle, and incomplete shapes of them. the error of extracted axis is small, indicating the feasibility of this method.