Phase recovery from interferograms under high amplitude vibrations.

Area of Science:

• Optical Metrology
• Interferometry
• Signal Processing

Background:

• Phase recovery in interferometry is often challenged by environmental noise, particularly vibrations.
• Vibrations introduce tilt-shift and nonlinearity errors, disrupting equidistant phase shifts crucial for standard algorithms.
• Existing algorithms struggle with large tilt-shift errors (> π radians) that cause sign changes in phase estimation.

Purpose of the Study:

• To develop a robust phase recovery procedure for interferograms acquired under severe vibration.
• To address limitations of existing methods in handling significant tilt-shift and nonlinearity errors.
• To accurately determine phase encoded in interferograms despite dominant tilt-shift errors.

Main Methods:

• A Fourier technique is employed for processing interferograms.
• The method focuses on recovering the cosine of phase differences.
• Phase differences are subsequently used to determine the encoded phase.

Main Results:

• The proposed algorithm successfully processes interferograms acquired in highly noisy, vibrating environments.
• It effectively handles significant tilt-shift errors, including those exceeding π radians.
• Experimental validation on an optical component yielded an RMS error of 0.1388 radians in phase reconstruction.

Conclusions:

• The developed Fourier-based phase recovery technique offers a robust solution for interferometry under harsh conditions.
• It overcomes the limitations of traditional methods when dealing with substantial tilt-shift errors.
• The procedure enables accurate phase determination, crucial for optical component analysis.