Planarity detection method for a moving rolled strip employing side edge detection with respect to a reference surface

摘要

A method wherein the levels of a plurality of points on the surface of a moving rolled strip are determined in relation to a horizontal reference plane by optical triangulation and planarity, or flatness, indices of the strip are deduced therefrom. The position of at least one of the side edges of the strip is detected with respect to a predetermined fixed reference in a cross-section of the strip containing at least plurality of points. The real, or true, position of the point with respect to the fixed reference is deduced and the orientation of the emitted beam and of the re-transmitted, or reflected, beam used in the triangulation is modified to compensate for the real, or true, position of the point.