Two-step self-tuning phase-shifting interferometry.
A two-step self-tuning phase-shifting method is presented. The phase-step between the two interferograms is not known when the experiment is performed. Our demodulating method finds, in a robust way, this unknown phase-step. Once the phase-step is estimated we proceed to phase demodulate the interferograms. Moreover our method only requires the fringe patterns to have a constant unknown phase-shift between them. As a consequence, this technique can be used to demodulate open and closed-fringed patterns without phase-sign ambiguity. The method may be regarded as a self-tuning quadrature filter, which determines the phase-shift between the two fringe patterns and finally estimates the demodulated phase map. The proposed technique has been tested with simulated and real interferograms obtaining satisfactory results.
Laboratorio de Instrumentación Espacial, Instituto Nacional de Técnica Aeroespacial, Madrid, Spain. jvargas@fis.ucm.es
J
J
Vargas
J Antonio
JA
Quiroga
T
T
Belenguer
M
M
Servín
J C
JC
Estrada
D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005374:Filtration / Q000295:instrumentation*; D007368:Interferometry / Q000295:instrumentation*; D055096:Optical Devices