Strategies for unwrapping noisy interferograms in phase-sampling interferometry

In recent years, various methods for computer-aided phase reconstruction from phase-shifted interferograms have been developed. The acceptance of these techniques for practical utilization mainly depends on their degree of automation, reliability, and robustness. The main problems to be solved occur in the inverse-modulo process (phase unwrapping). There are already many solutions differing in robustness and complexity. This paper deals with the description and classification of the processing difficulties and some strategies to avoid them or to diminish their influences. First results of a new procedure considering the phase discontinuity field in a global way are presented. This topology-based approach opens the possibility of model- and knowledge-based processing of phase-shifted interferograms.