"In this dissertation, we present a procedure to measure the phase from non-uniform phase-shifting interferograms in order to estimate the surface topography of an aluminum thin film. Interferograms are acquired from a Michelson interferential microscope, and phase shifts among interferograms are non-uniform because a piezoelectric transducer (PZT), working in open-loop mode, is used as phase shifter. Non-uniform phase shifts generate two types of errors in phase measurements: the double-frequency ripple distortion and the spurious piston. Thus, in order to overcome the aforementioned errors, we design error-correcting and non-iterative phase shifting algorithms (PSAs)."