Patent ID: 6885460

Claim:
An apparatus for measuring surface shape of an object, comprising: a light source configured to emit light to illuminate said object; an interference optical system configured to generate interference fringes between a reference fraction of said light and a reflective fraction of said light reflected by said object; an imaging capturing unit configured to capture said interference fringes and output interference fringe data; and a computer unit configured to obtain phase data indicating the phase of said reflective fraction of said light and amplitude data indicating the amplitude of said reflective fraction of said light at a plurality of positions in the directions of the optical axis of said reflective fraction of said light using said interference fringe data, obtain first surface shape data indicating the surface shape of said object using said amplitude data by calculating an in-focus distance at each micro region of a plurality of micro regions and determining an in-focus position in the directions of the optical axis of said reflective fraction of said light, at which said reflective fraction of said light comes into focus, obtain second surface shape data indicating the surface shape of said object using said phase data by assigning the in-focus distance of each micro region of the plurality of micro regions and calculating a complex amplitude of each micro region, and obtain third surface shape data indicating the surface shape of said object by combining or comparing said first surface shape data with said second surface shape data.