**Comments: **Phase unwrapping is not an
easy task, and not completely solved until now. Here a very basic
algorithm should be presented in order to give an idea.

The derivation of a fringe pattern shows absolute values bigger than pi only at the jumps of the phase cycles. If the derivation is limited (wrapped) to values between plus and minus pi, a continuous function can be derived. Integrating this function yields directly to the unwrapped phase.