METHOD AND APPARATUS FOR MEASUREMENT OF SURFACE SHAPE

PROBLEM TO BE SOLVED: To provide a method and an apparatus wherein a phase shift method can be applied to a stereolattice-type moire method simply and without any trouble, without a need of the movement operation of a lattice pattern in order to change the phase of moire fringes. SOLUTION: In a stereolattice-type moire optical system, a lattice pattern structure 11 in which lattice patterns 15, 16, 17 formed by filters 12, 13, 14 used to absorb beams of light in at least three kinds of different wavelength bands is used, a plurality of moire fringe images formed in the beams of light at a plurality of wavelengths absorbed by the respective filters 12, 13, 14 are imaged, the phase shift method is applied, and the movement mechanism of the lattice patterns required for performing a phase shift in conventional cases is not required. As a result, the waiting time for a movement in order to acquire a plurality of phase-shited moire images can be eliminated, the measuring time can be shortened, and a measurement error due to the movement accuracy of the movement mechanism can be reduced.