Blue Light for Improved Digital Image Correlation

Abstract

Background: Digital image correlation (DIC) of highly curved, complex surfaces often suffers from specular reflection, even when cross polarization is applied. Cross-polarized white light introduces blur and apparent image displacement due to chromatic aberration and wavelength-dependent focal shifts. Objective: This study aims to demonstrate how cross-polarized blue light illumination mitigates optical distortion and improves imaging quality for DIC measurements on curved or reflective surfaces. Methods: A comparative evaluation was performed between traditional cross-polarized white light and cross-polarized blue light during room-temperature tensile tests of specimens with standard acrylic painted speckle patterns. The image quality was compared using grey value counts and confidence parameters from the correlation software. The cross-polarized blue light approach was applied to a complex rubber lattice that was submerged in mineral oil to demonstrate the improvements in image quality for stereo DIC. Results: Blue light illumination produced better speckle contrast, reduced blooming around speckles, and minimized apparent displacement errors compared to white light. Quantitative improvements were observed in the correlation quality metrics. Under cross-polarized white light, the oil-bathed lattice surface was unable to be rendered using commercial DIC software but was fully rendered using cross-polarized blue light. Conclusions: Cross-polarized blue light improves DIC imaging performance on curved, complex, reflective materials by reducing chromatic aberrations and specular glare; a simple modification with monochromatic light for conventional DIC.

BibTeX

@article{2026_schell_blue_light_dic,
  title     = {Blue Light for Improved Digital Image Correlation},
  author    = {Schell C and Lester M and LePage W and Keller MW},
  journal   = {Experimental Mechanics},
  year      = {2026},
  doi       = {10.1007/s11340-026-01358-3},
}

Vancouver

Schell C, Lester M, LePage W, Keller MW. Blue Light for Improved Digital Image Correlation. Exp Mech. 2026. doi:10.1007/s11340-026-01358-3

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This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature's AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s11340-026-01358-3