Temporal phase-unwrapping of static surfaces with 2-sensitivity fringe-patterns

Area of Science:

• Optics and Photonics
• Metrology
• Remote Sensing

Background:

• Measuring static surfaces often involves fringe pattern analysis.
• Existing methods frequently combine dual-sensitivity measurements, often using triangulation.
• Temporal phase unwrapping is a suitable strategy for static and discontinuous surfaces.

Purpose of the Study:

• To introduce a novel 2-step temporal phase unwrapping formula.
• To utilize two-sensitivity demodulated phases for static surface measurement.
• To provide an effective algorithm for profilometry and SAR interferometry.

Main Methods:

• A two-step phase unwrapping approach is described.
• The method employs two demodulated phases with differing sensitivities.
• The second phase demodulation exhibits significantly higher sensitivity (G-times, G>>1.0).

Main Results:

• The formula enables accurate measurement of static surfaces.
• The algorithm effectively handles highly discontinuous surfaces.
• Demonstrated applicability in profilometry and synthetic aperture radar (SAR) interferometry.

Conclusions:

• The proposed 2-step temporal phase unwrapping formula offers a robust solution for static surface metrology.
• The method's mathematical model is compatible with phase demodulation in profilometry and SAR interferometry.
• This technique advances surface measurement capabilities in key scientific and engineering fields.