Inspection method and inspection apparatus engraved characters

摘要

PROBLEM TO BE SOLVED: To provide an inspection method of a carved letter capable of certainly detecting a carved letter regardless of its region in a case that the carved letter is inspected by detecting the light reflected from an inspection target, and also to provide an inspection device.;SOLUTION: Circular polarized light rotated in its azimuth with the advance of the light emitted from a floodlight projection means 6 is thrown on a frame, in which the letter of a car body number is carved, to be reflected from the frame 1 and the circular polarized light, which is regularly reflected from a part including no letters carved and held to a polarized state, in the reflected light is cut off by a polarizing plate 15. The greater part of the light, which is reflected from a part of which the surface is modified by carving the letter to be brought to a partially polarized state, is transmitted through the polarizing plate 15 and the intensity of the transmitted light is measured to recognize the carved letter based on the measured intensity of the transmitted light. The recognized letter is compared with the letter set to a control unit 9 to inspect that the set letter is accurately carved in the frame 1.;COPYRIGHT: (C)2007,JPO&INPIT