Method for extracting robot processing boundary of thin-walled part with small curvature based on three-dimensional point cloud

A method for extracting a boundary of a thin-walled part with small curvature based on three-dimensional point cloud, characterized in that the method includes the following steps:

• (a) obtaining point cloud data of a part to be processed, including:
• (a1) collecting the point cloud data of the part to be processed, obtaining initial point cloud data, comprising noise, of the part to be processed, performing an preprocessing for the initial point cloud data to reduce density of the point cloud data to obtain low-density point cloud data, performing Euclidean cluster on points in the low-density point cloud data, so that the low-density point cloud data is divided into a plurality of point cloud pieces, and connecting points in each of the point cloud pieces to form a triangle to implement triangulation of each of the point cloud pieces, so as to obtain a plurality of triangular mesh surfaces;
• and
• (a2) extracting a boundary vertex of each of the triangular mesh surfaces to obtain contours of the triangular mesh surfaces, so as to obtain contours of all triangular mesh surfaces, setting a selection criteria for a contour of the part to be processed, and selecting the contour of the part to be processed among the contours of all the triangular mesh surfaces, wherein points comprised in the contour are the point cloud data corresponding to the part to be processed;
• and
• (b) extracting an ordered boundary, including:
• (b1) using each point on the contour of the part to be processed as a seed point, and searching according to a preset radius with each seed point as a center to obtain a point cloud block of each seed point, wherein point cloud blocks of all seed points form a three-dimensional boundary point cloud band;
• and
• (b2) fitting all points in the three-dimensional boundary point cloud band to form a plane, then projecting all the points on the three-dimensional boundary point cloud band into the plane to obtain a plane boundary point cloud band, extracting points in the plane boundary point cloud band according to set rules to obtain ordered boundary points within the plane, arranging corresponding points in the three-dimensional boundary point cloud band according to an order of the ordered boundary points within the plane to obtain ordered boundary points in a three-dimensional boundary point cloud band, and obtaining a boundary contour of the part to be processed after the ordered boundary points in the three-dimensional boundary point cloud band are sequentially connected, that is, implementing orderly extraction of the boundary of the part to be processed of the three-dimensional point cloud.