Patent ID: 6867871
Filing Date: 2005-03-15
Classification: G01B

Abstract:
1. In a grating irradiation type moiré fringe measuring and analyzing method in which a moiré grating disposed between a light source and a surface to be inspected is irradiated with light from said light source, so as to project a shadow of said moiré grating onto said surface, and moiré fringes formed by said shadow and said moiré grating are captured by imaging means so as to analyze a shape of said surface; a moiré grating noise eliminating method comprising: a first step of moving said moiré grating within a grating plane formed by grating lines of said moiré grating in y direction orthogonal to said grating lines by increments of a distance L where n 1 , n 2 , and n 3 are natural numbers; a second step of averaging thus obtained M y-direction positional moiré fringe images so as to attain an average moiré fringe image; and a third step of determining shape information of said surface according to thus attained average moiré fringe image.