Detecting and locating burrs of industrial parts
Du‐Ming Tsai, W.-J. Lu · International Journal of Production Research · 1996
Burrs (excess material) are usually squeezed out around the periphery of the mould, and are irregular and vary considerably between parts. This paper aims at the development of a machine vision system for automatic detection of burrs and peripheral defects of casting parts. This non-contact detection result can be applied to automatic deburring systems and used for automatic inspection of peripheral breakdown. This research concentrates on flat casting parts comprising piecewise smooth curves on the boundaries. The detection procedure is based on the fact that the irregular burrs show high curvature changes in a small segment 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 and connect these points to form a polygon. The matching process then finds a corresponding polygon from the model part. The transformation parameters of rotational angle and translation between the part in the image and the model part are evaluated from these two equivalent polygons. The proposed matching algorithm is computationally fast and the time complexity is bounded by O(m), where m is the number of points on the digital boundary of the model part.