Classification of defects on the surface of black ceramics

Methods of visual detection and measurement of certain surface defects of blackceramics – magnets and ferrite cores – are presented. Difficulties such as darkcolour of ferrite and variability of appearance of defects under different light con-ditions have been overcome. The monochromatic images of the product surface,taken under a highly specialised lighting system with a standard monochroma-tic digital camera, are processed with a hierarchical morphological irregularitydetector, classified with a feature-based k nearest neighbours classifier, and post-processed. The same methodology can be applied to other materials having similarappearance.Key words: quality inspection, surface defects, machine vision, pattern recognition,magnets, ferrite cores.