Pixelated phase-mask (PPM) interferometers have become an industry standard for instantaneous
phase-shifting interferometry. In commercially available PPM interferometers, an array with 2x2
unit-cells is used, which codify up-to 4 phase-steps within a single PPM interferogram. Recently we
have shown that such 2x2 unit-cell arrays allows a harmonic rejection as good as the 4-step leastsquares
phase-shifting algorithm (LS-PSA); this harmonics rejection is relatively-low and may not
be enough to correctly demodulate some severely intensity distorted fringe patterns. In previous
works we have proposed a new PPM with a 3x3 unit-cell to improve the harmonics rejection of the
2x2 array. With this new 3x3 unit-cell one is able to reject as many harmonics as with a 9-step LS-PSA10.
In this paper we are extending the analysis of MxN unit-cell synchronous demodulation of
PPM. The new results allow us to answer some important open questions about the method: for a
given configuration, which harmonics cannot be rejected and why? Why, prior to low-pass filtering,
we observe multiple copies of the interferogram’s spectrum and what does this imply? We believe
these preliminary results are important contributions towards a formulation of a general theory MxN
unit-cell pixelated carrier interferometry.
Two projection systems that use an LCoS phase modulator are proposed for 3D shape reconstruction. The
LCoS is used as an holographic system or as a weak phase projector, both configurations project a set of fringe
patterns that are processed by the technique known as temporal phase unwrapping. To minimize the influence of
camera sampling, and the speckle noise in the projected fringes, an speckle noise reduction technique is applied
to the speckle patterns generated by the holographic optical system. Experiments with 3D shape reconstruction
of ophthalmic mold and other testing specimens show the viability of the proposed techniques.