Two-dimensional digital processing of speckle photography fringes. 3: Accuracy in angular determination

Area of Science:

• Optics and Photonics
• Digital Image Processing
• Metrology

Background:

• Speckle photography is a technique used for measuring surface deformation and displacement.
• Accurate determination of fringe direction is crucial for quantitative analysis in speckle interferometry.
• Existing algorithms may face challenges with low-quality fringe patterns.

Purpose of the Study:

• To evaluate the performance of a previously published algorithm for determining speckle photography fringe direction.
• To assess the algorithm's robustness under challenging conditions, including low fringe density and high noise.
• To quantify the accuracy of fringe direction determination via computer simulation.

Main Methods:

• Computer simulation of speckle photography fringe patterns.
• Generation of patterns with varying fringe densities and visibility.
• Introduction of controlled noise levels to simulate realistic experimental conditions.
• Application of the previously published fringe direction determination algorithm.

Main Results:

• The algorithm successfully determined fringe direction across a range of simulated conditions.
• Accuracy remained fair even with very low fringe densities and high noise levels.
• The determined fringe direction showed a maximum error of 0.5 degrees in extreme cases.

Conclusions:

• The evaluated algorithm demonstrates robust performance for speckle photography fringe direction determination.
• The algorithm is reliable even for low-visibility and high-noise fringe patterns.
• Computer simulation confirms the algorithm's practical utility in metrology applications.