OPTICAL DISPLACEMENT MEASURING INSTRUMENT

PURPOSE:To reduce errors against the shape of an object and, at the same time, to improve the reproducibility of measured values and easily select the processing procedure corresponding to the surface shape or positions on the surface of the object. CONSTITUTION:The displacement sensor 11 finds the distance to an object at each position on a cutting-plane line on the surface of an object by scanning and projecting a light beam upon the surface of the object so that the projected light spot can be moved. A changing point recognizing section 12 finds the difference increasing or decreasing tendency of the displacement between adjacent measuring points based on numerous measuring points on the cutting line at which the scanning position and displacement of the light beam are measured. A calculating point recognizing section 13 finds representative calculating points for finding the shape or dimension of the object based on the relation among changing points. An arithmetic processing section 14 finds the feature and dimension of the surface shape of the object based on the positions of found representative calculation points. A processing and setting section 2 gives instruction on the procedure to be used for finding the calculation points from the changing points in accordance with the position and shape of the object.