A carrier removal method in Fourier transform profilometry with Zernike polynomials

In Fourier transform profilometry, an object shape is evaluated through phase distribution extracted from an angled projected fringe pattern which is regarded as the carrier, so the existence of the carrier phase is unavoidable. Ideally, the carrier phase is linear, whereas in an actual measurement system the linearity of the carrier phase will be destructed by the imaging aberration and the divergent projection. In this paper Zernike polynomials, due to their orthogonality and the correspondence with Seidel aberrations, are used to approximate the nonlinear carrier phase and then remove the influence of carrier phase accurately. Both the theoretical analysis and the experiment results are presented. By comparison with existing carrier removal methods, this proposed method has the advantage of single-frame acquisition and less error, and is applicable for both nonlinear carrier and dynamic measurement.

► Retrieve accurately the carrier frequency form single-frame deformed fringe pattern.
► Retrieve accurately the carrier frequency by Zernike polynomials fitting.
► A low error and low time consuming method for nonlinear carrier removal.