We compare quantitative phase-measuring techniques in ESPI, using temporal and spatial phase shifting (TPS and SPS). The latter is less susceptible to time-dependent disturbances but inherently yields higher noise in the results due to the spatial intensity and phase variations of the object speckle field. Moreover, the necessity of larger speckles limits the light efficiency in SPS. Based on an evaluation of phase errors in sawtooth images, we compare both of the methods quantitatively in various ESPI configurations. By varying quantities like speckle size and shape and sawtooth fringe density, we find out characteristic behaviors of the methods. Some strategies to optimize the accuracy of the SPS method are explored to estimate how competitive SPS can be in ESPI systems.

Date Published: 13 August 1999
PDF: 12 pages
Proc. SPIE 3744, Interferometry '99: Techniques and Technologies, (13 August 1999); doi: 10.1117/12.357712

Published in SPIE Proceedings Vol. 3744:
Interferometry '99: Techniques and Technologies
Malgorzata Kujawinska; Mitsuo Takeda, Editor(s)