Shape measurement of columnar objects with specular surfaces by slit ray projection method

In this paper, a method for measuring the shape of a columnar object with specular surfaces by a slit ray projection method is proposed. Although the slit ray projection method is effective for measuring the shape of an object having diffuse reflective characteristics, applying the method to an object with specular surfaces has hitherto been difficult. In this paper, a triangulation equation for a columnar object with specular surfaces is derived and used as the basis of a method for measuring the shape of an object having specular surfaces using applicable slit rays. The basic principle is that the angle of incidence of a slit ray reflected from the measured object into an image sensor is restricted specifically by the special design of the optical system. In addition to the theoretical study of the proposed principle, a system for measuring the shape of a columnar specular object and a diffuse object was created and its effectiveness was verified.