Method for inspecting the surface of a moving strip by prior classification of the detected surface irregularity

Abstract

A method for inspecting a surface of a moving strip to detect surface defects, which includes forming at least one digital picture of at least one face of the strip, in which the digital picture is made up of a set of successive rows of picture elements, each of which is assigned a digital value. The method also includes filtering the at least one digital picture to detect surface irregularities by detecting relative variations in the digital values, and processing the at least one filtered digital picture to identity a type of surface defect corresponding to each detected irregularity. Further, prior to the processing step, an overall characterization of each of the irregularities is performed by determining, a value of predetermined parameters characteristic of surface defects, and a prior classification of the irregularities is performed based on the determined values of the parameters, according to a set of predefined classes. The processing step is performed on each class, and the predetermined parameters characteristic of the surface irregularities is less than a total number of parameters used to identify the defect.