Optimized digital speckle patterns for digital image correlation by consideration of both accuracy and efficiency

Area of Science:

• Mechanical Engineering
• Materials Science
• Optical Measurement Techniques

Background:

• Digital image correlation (DIC) is a key noncontact technique for measuring deformation in scientific and engineering fields.
• The performance of DIC is significantly dependent on the quality of the digital speckle pattern (DSP).
• Existing DSPs may not offer optimal accuracy and efficiency for all DIC applications.

Purpose of the Study:

• To optimize the digital speckle pattern (DSP) for digital image correlation (DIC).
• To enhance both the accuracy and efficiency of DIC measurements.
• To identify and recommend an optimized DSP for practical use.

Main Methods:

• Evaluation of DSP quality using root-mean-square error (inverse compositional Gauss-Newton algorithm) and average iterations.
• Analysis of the influence of subset sizes and image noise levels on DIC performance.
• Comparison of simulated binary and Gaussian speckle patterns with captured DSPs; optimization of single-radius and multi-radius DSPs.

Main Results:

• Optimized single-radius and multi-radius DSPs were developed.
• The study identified key parameters influencing DSP quality for DIC.
• Experimental validation confirmed the performance of the optimized DSP.

Conclusions:

• The optimized digital speckle pattern significantly improves the accuracy and efficiency of digital image correlation.
• The recommended DSP provides a reliable solution for noncontact deformation measurements.
• This work offers a valuable reference for researchers and engineers utilizing DIC techniques.