MEASURING METHOD FOR BEND OF LONGER MATERIAL

PROBLEM TO BE SOLVED: To provide a measuring method for the bend of a longer material in which only a vibration component can be detected and removed even when the longer material itself is vibrated in a measurement, and in which the intrinsic shape of the longer material can be measured with high accuracy and with satisfactory efficiency. SOLUTION: First, a first distance meter 12 and a second distance meter 14 are installed at a prescribed distance-meter pitch (D), they are moved to the longitudinal direction of the longer material 10 at a prescribed movement speed (V), and a first distance (Fa) up to the longer material 10 from the distance meter 12 and a second distance (Fb) up to the longer material 10 from the distance meter 14 are measured respectively at a prescribed measuring pitch (p) (Distance measuring process). The difference between the Fa and the Fb in an identical measuring point is calculated, and the vibration component (S) of the longer material 10 is calculated (Vibration-component calculation process). The S is subtracted from the Fa or the Fb, and the shape component (L) of the longer material 10 is calculated (Shape calculation process).