Machine Vision System for Flatness Control Feedback

Quality control is very important in the iron and steel industry to ensure that products meet customer requirements. Flatness is one of the most important features of rolled products, and it is used to estimate the final quality of the resulting product. Therefore, flatness control, which requires precise flatness measurements, is of vital importance during rolling. This work proposes a machine vision system for flatness measurement based on the projection of a laser stripe over the surface of the steel strip. The flatness measured cannot be used as easily as the feedback of the flatness control system due to the huge amount of information it contains. In order to solve this problem, a feature extraction method based on Legendre polynomial fit is also proposed.