Automated interferogram analysis based on an integrated expert system

Interferometric data, either from single-frame fringe-tracking and Fourier-transform techniques or from multiframe phase-shifting techniques, pose a problem of 2π ambiguity, that is, wrapped-phase information. As the degree of noise level increases, especially in high-speed aerodynamics, these techniques encounter difficulties in phase extraction to provide continuous unwrapped-phase information. Here, a new hybrid approach, called the integrated expert system, which is developed primarily for aerodynamic interferogram evaluation, is presented. The integrated expert system utilizes interferometric-specific knowledge rules to compensate for the limitations associated with conventional techniques. It integrates in a single structure an expert system and algorithmic programming to provide, as much as possible, a unified approach for all the interferogram evaluation techniques. This initial attempt may provide a useful groundwork for future development in intelligent interferogram processing.