SURFACE SHAPE MEASURING INSTRUMENT

摘要

PROBLEM TO BE SOLVED: To accurately measure the surface shape of a mirror body. SOLUTION: A grating 3 is arranged opposite a measured surface of a measured body 11. A light source 1 irradiates the grating 3 with illumination light. A camera 6 picks up an image of moire fringes formed on the grating 3 with the light which passes through the grating 3 and is reflected by the measured surface. A moving means 9 varies the distance H between the grating 3 and measured surface. An analyzing means 8 analysis processing for finding three- dimensional shape information on the measured surface from the image picked up by the camera 6 for at least two cases wherein the distance H is different and finds real three-dimensional shape information from which a measurement error due to the slanting of the measured surface is removed according to pieces of three-dimensional shape information and distances H of the two cases.