Scanning wide-area surface shape analyzer

A scanning wide-area surface shape analyzer comprising:

• an optical table having a flat surface for placing an object to be inspected thereon;
• measuring means having a light source, a reference surface, and an interferometer which projects a beam emitted from the light source onto the reference surface and a surface to be inspected of the object placed on the flat surface, thereby generating an optical interference fringe image formed by interference between reflected light from the reference surface and reflected light from the surface to be inspected, said measuring means acquiring the optical interference fringe image generated by the interferometer as measured image data;
• scanning means having a scanning reference position thereof set to a point of intersection between an optical axis of the beam and the reference surface in said measuring means, for moving said measuring means in parallel with the flat surface such that the scanning reference position sequentially reaches each acquisition position used for said measuring means to acquire the measured image data;
• attitude varying means for varying an acquisition attitude of said measuring means for acquiring the measured image data, such that a direction of inclination of a reference axis being a direction vector extending along the optical axis from the scanning reference position is changed relative to the surface to be inspected;
• surface shape analyzing and calculating means for analyzing and calculating, based on the measured image data acquired at the acquisition position and in the acquisition attitude, a surface shape of an acquisition area corresponding to the acquisition position and the acquisition attitude, in the surface to be inspected;
• and
• control means for controlling driving of said scanning means and said attitude-varying means;
• wherein said control means calculates a next acquisition position by using measured image data acquired at a present acquisition position and in a present acquisition attitude, and calculates an acquisition attitude to be taken at the calculated next acquisition position.