Synchronous phase-demodulation and harmonic rejection of 9-step pixelated dynamic interferograms

Area of Science:

• Optical interferometry
• Image processing

Background:

• Pixelated interferograms require robust phase-demodulation techniques.
• Standard 2x2 unit-cells offer limited harmonic rejection for intensity-distorted fringe patterns.

Purpose of the Study:

• To propose a novel synchronous phase-demodulation method using 3x3 phase-shifted unit-cells.
• To enhance harmonic robustness and spectral space efficiency in interferogram analysis.

Main Methods:

• Developing a 2D pixelated carrier by tiling 3x3 unit-cells over a CCD sensor.
• Implementing synchronous phase-demodulation utilizing the 2D carrier.
• Comparing the harmonic rejection robustness with standard 2x2 unit-cells and temporal least-squares 9-step phase-shifting algorithms (PSA).

Main Results:

• The 3x3 pixelated carrier achieves higher harmonic robustness compared to 2x2 unit-cells.
• The harmonic rejection robustness of the 3x3 spatial configuration is equivalent to the temporal least-squares 9-step PSA.
• The proposed 9-step, 3x3 pixelated carrier demonstrates more efficient use of 2D spectral space than linear configurations.

Conclusions:

• The 3x3 pixelated carrier offers improved phase-demodulation for interferograms, particularly those with intensity distortions.
• This method enhances harmonic rejection and spectral efficiency in optical interferometry.
• The novel approach provides a more robust alternative to existing phase-shifting algorithms.