Algorithm for fringe pattern normalization

In this work we present a new algorithm for fringe pattern normalization, that is. background suppression and modulation normalization. Normalization is necessary for several fringe pattern processing techniques. For example, this is the case of the regularization and phase sampling methods. In general, background suppression can be accomplished by high-pass filtering, however if modulation is not constant or almost constant over the field of view, normalization is a difficult task. The solution proposed is based in the use of two orthogonal bandpass filters, from which a normalized irradiance distribution is obtained. We have applied the method to simulated as well as experimental data with good results. (C) 2001 Published by Elsevier Science B.V.