METHOD FOR MEASURING THICKNESS BY LASER RANGE FINDER

PROBLEM TO BE SOLVED: To correct the difference from a micrometer-measurement value caused the ruggedness of the surface of an object material to be measured, of an automatic thickness measurement value of a steel plate, etc., which uses a laser range finder. SOLUTION: Related to a method wherein, laser range finders provided on both sides of an object to be measured, distances L1 and L2 between each laser range finder and the object material is measured, and a thickness t of the object material is obtained from a distance D between both laser range finders and the measurement values L1 and L2 through calculation, a measured value is corrected according to surface roughness of the object material. At the correction, with an interval between the average line and the ridge line of a roughness curve of the object material surface being d while a factor set according to a surface condition of the object material is α, the thickness t measured by the laser range finder is desired to be added with αd. So, the thickness control with the same standard as with conventional micrometer measurement is carried out with online automatic measurement.