Calibration of an Inspection System for Online Quality Control of Satin Glass

In this paper, a prototype system that is able to reproduce all the functionalities of an automatic glass inspection system is presented. The proposed quality inspection system assures several advantages with respect to the human-made inspection, such as objectivity and accuracy, and it is attractive for small enterprises with respect to commercial vision systems because it guarantees good results and considerable reliability with low incidence on manufacturing costs. In particular, it was proposed in this paper a method, based on morphological operations, for registering the acquisition system, which is composed of several cameras that acquire different partial images of the entire glass sheet moving on a conveyor. A method for digitally correcting the nonuniformities of the lighting system is also discussed; it is based on a least squares spline approximation of the intensity profile. The presented methods are rather general and can be applied to the calibration of image acquisition systems in other application fields.