Patent ID: 6621579
Filing Date: 2003-09-16
Classification: G01J

Abstract:
A fringe analysis method using Fourier transform, in which fringe image data carrying wavefront information of an object is obtained according to a relative wavefront profile of said object with respect to a reference, said fringe image data being in a state where a wavefront from said object and a wavefront from said reference are relatively inclined by a minute amount with respect to each other and a carrier fringe occurring due to said inclination is superposed on a fringe occurring due to said wavefront information of said object;said fringe analysis method comprising a step of subjecting said fringe image data to Fourier transform method so as to determine a wavefront profile of the object; wherein said inclination is set such that a carrier frequency occurring due to said inclination is a substantially integral multiple of a basic frequency determined by said wavefront information of said object and observing means.