Digital Image Correlation with a Prism Camera and Its Application in Complex Deformation Measurement.

Area of Science:

• Optical Measurement
• Mechanical Engineering
• Image Processing

Background:

• Traditional digital image correlation (DIC) methods exhibit limitations in accurately measuring complex deformations.
• Bayer cameras capture color images with limited independent channel information, impacting measurement precision.

Purpose of the Study:

• To propose and validate a novel color DIC method using a prism camera for enhanced deformation measurement.
• To improve the accuracy of DIC in scenarios involving complex and nonlinear deformations.

Main Methods:

• Utilizing a prism camera to acquire high-fidelity color images with three independent information channels.
• Adapting and enhancing classic grayscale image matching algorithms for color speckle patterns.
• Developing a merged subset matching algorithm accounting for light intensity variations across color channels, including integer-pixel and sub-pixel matching.

Main Results:

• Numerical simulations confirmed the method's effectiveness in measuring nonlinear deformations.
• Experimental validation was performed using a cylinder compression test, demonstrating practical applicability.
• The color DIC method showed superior accuracy compared to traditional grayscale DIC for complex deformation analysis.

Conclusions:

• The proposed color DIC method significantly enhances measurement accuracy, particularly for complex deformations.
• The technique's ability to utilize rich color information offers a robust solution for advanced optical metrology.
• Integration with stereo vision and projected color speckle patterns broadens its application to complex geometries.