Theory and applications of random phase shifting technique

Abstract

The conventional phase shifting technique requires a specific number of phase shifting steps (e.g., 3, 4, or 5) with known phase shifting intervals (e.g., π/2 or 2π/3). However, the error of phase shifting amounts in real applications is common due to various reasons, and such error can cause substantial error in the determination of phase distributions. This practical and important problem can be well coped with by the random phase shifting technique. Unlike the conventional techniques, the random phase shifting technique is capable of accurately extracting phase distributions from any arbitrarily phase-shifted interferograms or fringe patterns. With the advanced technique, not only the number of phase shifting steps but also the phase shifting intervals/amounts can be completely random as long as at least three frames have different phase shifts. In this paper, the theory of the random phase shifting technique is reviewed and selected applications are demonstrated.