Phase retrieval algorithm for form testing metrology in production environment

Form testing interferometry permits a fast, non-tactile and full- field quantitative phase imaging of components in ultra precise manufacturing. To reduce the influence of vibrations under manufacturing conditions, it is most common to use the FT- based spatial carrier phase measurement technique (SCPM) which requires only a single interferogram recording. The utilization of a generalized, relatively new spatial phase-shifting method operating in the position space opens up prospects for reduced phase noise and less reconstruction errors of the calculated phase-map under production conditions. Therefore this phase-shifting technique is investigated for applicability in machine integrated interferometric form testing of optical lenses. A characterization of the algorithm and a comparison with the commonly used FT-based algorithm is performed. As a reference, measurements are carried out with a coordinate measuring machine with nanometre accuracy.