title: Steerable spatial phase shifting applied to single-image closed-fringe interferograms.
abstract: It is well known that spatial phase shifting interferometry (SPSI) may be used to demodulate two-dimensional (2D) spatial-carrier interferograms. In these cases the application of SPSI is straightforward because the modulating phase is a monotonic increasing function of space. However, this is not true when we apply SPSI to demodulate a single-image interferogram containing closed fringes. This is because using these algorithms, one would obtain a wrongly demodulated monotonic phase all over the 2D space. We present a technique to overcome this drawback and to allow any SPSI algorithm to be used as a single-image fringe pattern demodulator containing closed fringes. We make use of the 2D spatial orientation direction of the fringes to steer (orient) the one-dimensional SPSI algorithm in order to correctly demodulate the nonmonotonic 2D phase all over the interferogram.
authors.affiliation: Departamento de Optica, Universidad Complutense de Madrid, Ciudad Universitaria S/N, Madrid 28040, Spain. aq@fis.ucm.es
authors.forename: Juan Antonio
authors.initials: JA
authors.lastname: Quiroga
authors.forename: Manuel
authors.initials: M
authors.lastname: Servin
authors.forename: Julio Cesar
authors.initials: JC
authors.lastname: Estrada
authors.forename: Jose Antonio
authors.initials: JA
authors.lastname: Gomez-Pedrero