Two Dimensional Moving Average Filter for Performance Enhancement of Noisy Phase Shifted Interferograms

Abstract

In optical metrology, phase shifting is one of the most prominent strategies to retrieve the parameters (like object shape, deformations, thickness, refractive index, focal length, etc.) from acquired interferograms. However, traditional phase shifting techniques is overly sensitive towards noise (both internal and external), which limits their applicability in accurate interferometric applications. To circumvent this drawback, in this paper, a two dimensional moving average filter is combined with phase shifting technique to analyze and extract the phase information from noisy interferograms. This novel algorithm acquires the advantages of two existing strategies in terms of accuracy and speed. Proposed technique has a remarkable ability to accurately and automatically extract full-field phase distribution from four phase shifted interferograms even in the presence of high-density additive and multiplicative noise. The performance estimation and comparison of the technique is demonstrated using controlled computer simulation. © 2020 IEEE.