Corner defect detection based on dot product in ceramic tile images

One of the important problems in ceramic tile industry is tiles´ quality classification with automatic systems by applying machine instead of human. Tiles´ quality can be divided into color analysis, dimension verification, and surface defect detection. It´s very difficult for human to control all of them, because of harsh industrial environment with noise, extreme temperature and humidity. In this paper, we present a method for visual inspection of ceramic tile corners. We use a method based on image processing techniques and dot product vectors if angle was more than 92 degree or less than 89 degree. Our ceramic is a defective tile. Our algorithm is evaluated on a set of images which has been taken of a Flaw master system in a tile factory and has 12.5% error in both normal and defective tile. The obtained results show efficiency our approach in corner defect detection.