Dynamic phase measurement in shearography by clustering method and Fourier filtering.

Area of Science:

• Optical Measurement
• Metrology
• Image Processing

Background:

• Phase shifting techniques are standard for static measurements but unsuitable for dynamic scenarios.
• Fourier transform methods require high-frequency carriers, which are difficult to generate.
• Existing single-image methods struggle with high fringe densities, leading to phase residues.

Purpose of the Study:

• To develop an ideal solution for dynamic phase measurement.
• To enable accurate phase extraction from single images during continuous deformation.
• To address limitations of current methods in high-fringe-density situations like shearography.

Main Methods:

• Initial phase analysis using four phase-shifted images at a reference stage.
• Clustering phase extraction for deformation phase from single images.
• Fourier transform-based phase filtering for fringe frequency analysis and residue removal.

Main Results:

• The proposed method successfully extracts phase information from single images during dynamic deformation.
• Clustering phase extraction is effective for low to medium fringe densities.
• Fourier transform-based filtering significantly improves wrapped phase map quality by removing residues in high-density fringe cases.

Conclusions:

• The integrated dynamic phase extraction method offers an effective solution for optical measurements of deforming objects.
• The combination of clustering and Fourier transform filtering enhances accuracy and robustness.
• This approach is particularly beneficial for dynamic shearography applications.