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Phase unwrapping through demodulation by use of the regularized phase-tracking technique.

M Servin¹, F J Cuevas, D Malacara

¹Centro de Investigaciones en Optica A C, Apartado Postal 1-948, 37150 Leon, Gto, Mexico.

|March 6, 2008

Summary

This study introduces a novel phase-unwrapping technique using a regularized phase-tracking (RPT) system. The RPT method simultaneously unwraps and demodulates phase data, offering superior noise robustness compared to traditional methods.

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Area of Science:

Optical Metrology
Signal Processing

Background:

Interferogram demodulation often results in wrapped phase due to arctangent functions.
Phase unwrapping is essential for obtaining continuous phase data from wrapped interferograms.

Purpose of the Study:

To introduce a novel phase-unwrapping technique based on a regularized phase-tracking (RPT) system.
To demonstrate the simultaneous unwrapping and demodulation of phase data.
To evaluate the noise robustness of the RPT technique.

Main Methods:

The proposed method utilizes two phase-shifted fringe patterns (sine and cosine) derived from the demodulated wrapped phase.
Phase unwrapping is achieved concurrently with demodulation using the RPT technique.
The RPT method is compared against least-squares integration of wrapped phase differences.

Main Results:

The RPT technique effectively performs phase unwrapping simultaneously with demodulation.
The RPT method exhibits substantial noise robustness.
Comparison with least-squares integration highlights the advantages of RPT in noisy conditions.

Conclusions:

The regularized phase-tracking (RPT) system provides an effective solution for phase unwrapping in interferometry.
The RPT technique offers improved performance, particularly in the presence of noise.
Simultaneous demodulation and unwrapping simplify the phase retrieval process.