Surface recovery algorithm in white light interferometry based on combined white light phase shifting and fast...

Area of Science:

• Metrology and Surface Science
• Optical Measurement Techniques

Background:

• Accurate 3D surface profiling is critical for micro-nano structures and freeform optics.
• White light scanning interferometry (WLSI) offers fast, noncontact surface measurement but struggles with vibrations and reflective surfaces.
• Existing algorithms face challenges with environmental noise and reflective phase shifts.

Purpose of the Study:

• To develop a novel peak detection algorithm for enhanced WLSI.
• To improve the precision and anti-interference capabilities of WLSI measurements.
• To address limitations in existing 3D surface reconstruction algorithms for challenging surfaces.

Main Methods:

• Combines white light phase-shifting interferometry (WLPSI) with a fast Fourier transform (FFT) coherence-peak-sensing technique.
• Introduces a novel peak detecting algorithm for accurate local fringe peak determination.
• Evaluates the method using simulated data and experimental measurements on a microcomponent and spherical surface.

Main Results:

• The proposed algorithm significantly improves the precision and anti-interference ability of WLPSI and FFT methods.
• Effectively reduces batwing effects at surface edges.
• Solves the positioning error problem associated with maximum modulation detection.

Conclusions:

• The novel algorithm enhances WLSI for accurate 3D surface metrology, especially for rough and reflective surfaces.
• Offers improved vertical resolution and robustness against environmental disturbances.
• Provides a more reliable method for quality control in micro-nano and freeform surface characterization.