Automated Quality Control in Ceramic Industry

This work has the goal to design an automatic system to detect flaws and edge irregularities on ceramic plates. Edge irregularities are detected as well as black spots on both sides of the plates. The detection of defects using photography and image processing techniques allows image interpretation leading to a decision to accept or reject the plates. A special system of lightning was designed. This lightning does not focus directly on the plates, therefore avoiding undesirable reflects. To analyse the data, three algorithms were developed, the first to detect the black dots on the upper side of the plate, the second with identical role for the lower side of the plate and the third to analyse the edge and the geometry. Binarization and techniques of morphology were used to detect flaws on the plates. The tests performed, with the developed prototype, concluded that the system has a reliability of 100%. Tests were performed using 643 photographs of plates without flaws and with the most common flaws. The plates were carefully rotated, to place the flaws in different positions towards the camera. The detection time varied, for the 3 algorithms, between 2,95 and 3,46 seconds for each operation. To conclude, it is possible to say that a simple and functional system was projected. This system has low construction costs and an elevated reliability, which can contribute to enhance the quality of the plates and lower its costs, increasing, therefore, national competitively. Index terms Quality control of ceramic plates, CAD, Automation Visual Inspection, Image Acquision System, Ceramic Defects, Binary Image, Hough Transform