DESIGN AND IMPLEMENTATION OF FLEXIBLE MANUFACTURING CELL FOR THE INSPECTION OF CERAMIC WALL PLATES

Abstract

The research effort expended upon the problem of objectively inspecting, analysing and characterizing garnished ceramic tiles is easily justified by the commercial and safety benefits to the industry such as automating obsolete manual inspection procedure, providing higher homogeneity within sorted grades which consequently would improve the processing stability of the overall inspection procedure.

Tiredness and lack of concentration are common problems, leading to errors in grading tiles. Gradual changes are difficult for human inspectors to detect and it is possible that slight and progressive changes will not be noticed at an early stage. Additionally, it is particularly difficult for the human eye to accurately sort tiles into shades, with changing light conditions in a factory. Human judgment is, as usual, influenced by expectations and prior knowledge.

Since early 90s, several published papers were concerned with finding new approaches to detect cracks and colour spots in ceramic tiles. However, most of them were targeting the inspection algorithm and neglected the other aspects of machine vision system (variability in illumination and surface reflectivity, image acquisition, mechanical handling system and electrical interfacing circuit). Meanwhile, measuring drawn objects geometry and colour quality has never been discussed prior to the conducted research which is demanded when inspecting garnished wall plates.