Advanced method of global phase shift estimation from two linear carrier interferograms

Wenqing Sun,Yun Zhao,Quanying Wu,Ting Wang,Jun Wang

doi:10.1186/s41476-018-0076-x

Abstract

BackgroundPhase-shifting interferometry is a kind of important technique used in optical interference metrology. This technique has high precision and good stability, which has been widely used in scientific research and industrial production.MethodsThis paper proposes a new method to estimate global phase shift from two interferograms. This method performs algebraic calculation of two interferograms with the assistance of Hilbert transform. An iterative approach is used for the attempted phase to ensure that the minimum of assessment function is obtained.ResultsThe simulated result indicate that the maximum calculation error of the global phase-shifting is 1.5%. And then we use experimental data to verify the performance of this method.ConclusionsThe method proposed in this article is simple but precise, and can cope with interferograms with uneven background and modulation, non-periodic apodization, and random noises. It does not require any specific carrier frequency of the measured interferogram or any adjustment of range of integration in accordance with the carrier frequency.

Highlights

Phase-shifting interferometry is a kind of important technique used in optical interference metrology
Phase-shifting interferometry (PSI) is a technique used in optical interference metrology
In which α(x) is the background, b(x) is amplitude modulation, kx is the carrier frequency, both of which are functions of x. φ(x) represents phase distribution, δm represents the global phase shift at the mth measurement, which is the value to be estimated in this article

Summary

Introduction

Phase-shifting interferometry is a kind of important technique used in optical interference metrology. This technique has high precision and good stability, which has been widely used in scientific research and industrial production. Phase-shifting interferometry (PSI) is a technique used in optical interference metrology. This technique has high precision and good stability, can be implemented through a variety of hardware, and has been consistently observed by researchers. Classical phase-shifting algorithms include fixed steps, variable steps, or random phase-shifting [1]. The estimated value can be provided through existing information from

Methods

Results

Conclusion