A parametric method applied to phase recovery from a fringe pattern based on a genetic algorithm

A parametric method to carry out fringe pattern demodulation by means of a genetic algorithm is presented. The phase is approximated by the parametric estimation of an nth-grade polynomial so that no further unwrapping is required. On the other hand, a different parametric function can be chosen according to the prior knowledge of the phase behavior. A population of chromosomes is codified with the parameters of the function that estimates the phase. A fitness function is established to evaluate the chromosomes, which considers: (a) the closeness between the observed fringes and the recovered fringes, (b) the phase smoothness, (c) the prior knowledge of the object as its shape and size. The population of chromosomes evolves until a fitness average threshold is obtained. The method can demodulate noisy fringe patterns and even a one-image closed-fringe pattern successfully. (C) 2002 Published by Elsevier Science B.V.