Development of Measuring Instrument for Inner and Outer Diameters of Bearing Seal Rings Based on Machine Vision

Abstract

In order to accurately and efficiently measure the inner and outer diameters of bearing seal rings, a monocular measurement instrument was developed. The mathematical principles of camera calibration and distortion correction were studied. After the figures of rings were distortion corrected and preprocessed, we calculate the inner and outer diameters based on Otsu threshold segmentation and RANSAC algorithm. Operating the monocular measuring instrument to measure eight different types of sealing rings. According to the measurement results, it is found that the average time to measure the two diameters of a sealing ring is 0.79 seconds and the relative error of the measurement is 0.12%, which proves that the monocular measuring instrument can meet actual needs for sampling measurement of rings in the factory laboratory.