DETECTING AND LOCATING BURRS OF INDUSTRIAL PARTS

Burrs (excess material) are usually squeezed out around the periphery of the mould, and are irregular and vary considerably between parts. T his paper aims at the development of a machine vision system for autom atic detection of burrs and peripheral defects of casting parts. This non-contact detection result can be applied to automatic deburring sys tems and used for automatic inspection of peripheral breakdown. This r esearch concentrates on flat casting parts comprising piecewise smooth curves on the boundaries. The detection procedure is based on the fac t that the irregular burrs show high curvature changes in a small segm ent of the boundary, whereas a smooth segment without burrs presents a succession of low curvature points. Given a casting part with burrs, we arbitrarily select a few boundary points from the smooth segments a nd connect these points to form a polygon. The matching process then f inds a corresponding polygon from the model part. The transformation p arameters of rotational angle and translation between the part in the image and the model part are evaluated from these two equivalent polyg ons. The proposed matching algorithm is computationally fast and the t ime complexity is bounded by O(m), where m is the number of points on the digital boundary of the model part.