Empirical mode decomposition profilometry: small-scale capabilities and comparison to Fourier transform profilometry

Area of Science:

• Optical Metrology
• Surface Analysis
• Signal Processing

Background:

• Fringe Projection Profilometry (FPP) is a standard technique for 3D surface reconstruction.
• Existing methods like Fourier Transform Profilometry (FTP) have limitations in analyzing surfaces with broadband deformation spectra.

Purpose of the Study:

• To introduce Empirical Mode Decomposition Profilometry (EMDP) as an advanced method for FPP image analysis.
• To evaluate EMDP's performance against established techniques, particularly for small-scale surface features.

Main Methods:

• Developed an iterative filter based on Empirical Mode Decomposition (EMD).
• EMDP is designed to be free of spatial filtering and suitable for complex surfaces.
• Compared EMDP's performance numerically and experimentally against Fourier Transform Profilometry (FTP).

Main Results:

• EMDP significantly enhances the small-scale measurement capabilities of FPP.
• Achieved substantially lower height reconstruction distortion with EMDP.
• The reconstructed height field using EMDP is both spectrally and statistically accurate.

Conclusions:

• EMDP offers superior performance for FPP, especially for analyzing surfaces with broadband deformation.
• The method provides accurate and reliable height reconstruction, making it ideal for quantitative scientific experiments.
• EMDP represents a significant advancement in profilometry techniques.