Robust weighted principal components analysis demodulation algorithm for phase-shifting interferometry

Area of Science:

• Optical Metrology
• Interferometry
• Signal Processing

Background:

• Phase-shifting interferometry is sensitive to environmental disturbances.
• Existing asynchronous methods have limitations in robustness and accuracy.
• Turbulence, vibrations, and temporal instabilities degrade interferogram quality.

Purpose of the Study:

• To develop a novel asynchronous phase-shifting demodulation technique.
• To enhance robustness against optical setup instabilities.
• To combine the strengths of two-step and principal component analysis methods.

Main Methods:

• A two-step approach estimates the modulating phase.
• Phase-shifted patterns are weighted based on the estimated phase.
• A weighted principal component analysis demodulation is applied.

Main Results:

• The method demonstrates high robustness against turbulence and vibrations.
• Satisfactory results were achieved with simulated and real interferograms.
• The technique effectively mitigates limitations of prior methods.

Conclusions:

• The proposed asynchronous demodulation approach is highly effective.
• It offers a robust solution for phase retrieval in challenging environments.
• This method advances optical metrology applications requiring high precision.