A machine vision system for measuring the eccentricity of bearings

In this paper, we describe a machine vision system for inspecting bearings, which are an important part of electro-mechanical kWh meters. The system consists of a personal computer with a frame grabber, a black and white progressive scan CCD camera, and a mechanical device with a stepper motor controlled by a special controller. The quality of a bearing depends on the eccentricity of the needle and the length of the needle that extends out of the cylinder. These two features are robustly and accurately determined by the successive application of the Hough transform (HT) and linear regression. The proposed machine vision system allows fast, accurate, reproducible, and robust 100% inspection of bearings of electro-mechanical kWh meters and as such may be a valuable tool for ensuring high-end-product quality. (C) 2002 Elsevier Science B.V. All rights reserved.