General filtering method for electronic speckle pattern interferometry fringe images with various densities based on...

Area of Science:

• Optical Engineering
• Image Processing
• Metrology

Background:

• Speckle noise significantly degrades the quality of fringe images in Electronic Speckle Pattern Interferometry (ESPI).
• Existing filtering methods struggle with the diverse densities found in ESPI fringe images (low, high, and variable).

Purpose of the Study:

• To develop a general and effective filtering method for speckle noise in ESPI fringe images of all densities.
• To introduce a variational image decomposition approach for noise reduction in ESPI.

Main Methods:

• A variational image decomposition technique is proposed to separate ESPI fringe images into fringe components and noise.
• Suitable function spaces are defined for low-density fringes, high-density fringes, and noise.
• Models and numerical algorithms are constructed and experimentally validated.

Main Results:

• The proposed method successfully filters speckle noise across low, high, and variable-density ESPI fringe images.
• Experimental results demonstrate superior performance compared to the windowed Fourier transform and coherence-enhancing diffusion methods.
• The method effectively processed experimentally obtained, poor-quality ESPI fringe images.

Conclusions:

• The variational image decomposition method offers a robust solution for speckle noise reduction in ESPI.
• This approach enhances the quality and interpretability of ESPI fringe patterns.
• The developed technique shows significant potential for practical applications in interferometry.