Moire profilometry through simultaneous dual fringe projection for accurate phase demodulation: a comparative study

Area of Science:

• Optical metrology
• 3D surface measurement
• Metrology

Background:

• Fringe projection and moire techniques are established methods for object topography measurement.
• Combining these techniques offers potential advantages in optical metrology.
• Simultaneous dual projection generates a superimposed fringe pattern with a phase-modulated moire pattern.

Purpose of the Study:

• To present an analytic and comparative study of phase demodulation methods for a superimposed fringe pattern.
• To evaluate spatial, spatial-temporal, and temporal demodulation techniques.
• To assess the phase sensitivity and feasibility of the combined technique.

Main Methods:

• Developing a simultaneous dual projection configuration in fringe projection.
• Extracting the moire pattern from the superimposed fringe pattern.
• Demodulating the moire pattern phase using spatial, spatial-temporal, and temporal methods.

Main Results:

• Analytical results indicate double phase sensitivity compared to classical fringe projection.
• The study provides a comparative analysis of three distinct phase demodulation methods.
• Experimental and numeric results validate the technique's feasibility.

Conclusions:

• The combined fringe projection and moire technique offers enhanced phase sensitivity for topography measurement.
• The evaluated demodulation methods are effective for extracting topographic information.
• This technique presents a viable advancement in optical metrology for 3D surface analysis.