ABSTRACT
This chapter analyzes interferometric techniques to demodulate a single fringe pattern containing closed fringes. A very simple useful way to demodulate closed fringe interferograms is a system we refer to as the regularized phase tracker. The fringe orientation modulo πmust be unwrapped along the fringe direction to obtain the desired fringe orientation modulo 2π to move from the image. The optimum phase plane is built using the optimum phase and optimum spatial frequencies. The phase-locked loop has been generalized by Servín to two dimensions, a procedure we refer to as the regularized quadrature and phase tracker (RPT), or simply the phase tracker, which involves interferogram demodulation by sequentially tracking the local phase of the interferogram. The algorithm that best fits these requirements is the unwrapping algorithm based on the RPT. Another way to improve the RPT is by using a scanning strategy.
