Phase-shifting is a well-known technique for phase retrieval that requires a series of intensity measurements with certain phase-steps. Harmonics and linear phase-shift errors are the main source of errors in interferometry. In this work we present a systematic algebraic approach for the generation of phase-shifting algorithms(for interferograms with arbitrarily phase-steps) insensitive to harmonics and linear phase-shift errors.
Gastón A. Ayubi, Gastón A. Ayubi,
"Generalized phase-shifting algorithms: error analysis", Proc. SPIE 9525, Optical Measurement Systems for Industrial Inspection IX, 952538 (22 June 2015); doi: 10.1117/12.2184594; https://doi.org/10.1117/12.2184594