Analytic Color Imbalance Normalization for Digital Color Fringe Profilometry on Deforming Membrane Surface

Digital Color Fringe Profilometry (DCFP) is a modification of conventional fringe pattern profilometry (FPP). Three different phase fringe patterns are encoded into a single frame colored fringe to overcome the multi-frame issue of phase shifting interferometry. Even so, non-linear intensity and color imbalance are still major problems in the application of color fringe profilometry. Due this problem, modulated sinusoidal fringe pattern is distorted due to undesired harmonic component. This paper proposes an analytic color imbalance normalization based on heuristic interpolation of distorted fringe which performed through line-by-line processing. Phase maps is extracted using Hilbert transform followed by a simple phase unwrapping and an offset removal based on the absolute phase map of the reference plane. The final step is averaging of the surface profiles from all color channels. The proposed scheme contributes to a better consistency and higher quality of deforming surface reconstruction.