A case study comparison of strain measurements in micromechanical testing using optical flow and DIC

Published

September 16, 2026

Author(s)

Damian Lauria, Li-Anne Liew

Abstract

We describe a case study on the application of an Optical Flow algorithm, using predictive velocity and pyramidal search, to the measurement of displacements in two 200 μm thick metal test specimens, compared with a traditional digital image correlation (DIC) implementation. One mesoscale tensile specimen and one mesoscale shear specimen of commercially fabricated electrodeposited nickel alloys, used in Micro Electro Mechanical Systems applications, were tested to fracture. The specimens were 200 μm thick and had gauge widths of 200 and 600 μm. Optical micrographs were taken during the tests. Displacements, strains, and mechanical properties were measured from the same sets of images using Optical Flow versus traditional DIC. The engineering stress–strain curves and shear stress vs shear strain curves from both techniques were similar (to within 1% for the engineering strains and 4%–9% for the shear strains) from the start of the tests to failure. This case study thus suggests Optical Flow shows promise as a measurement tool to complement DIC for mesoscale testing and warrants further investigation with more specimens. Potential advantages provided by Optical Flow in general include increased robustness and the potential for lower image segment search time, which could be especially beneficial for micro- and mesoscale test specimens.

Citation

Materials Research Express

Volume

13

Pub Type

Journals

Download Paper

https://doi.org/10.1088/2053-1591/ae9e0f

Local Download

Keywords

Micromechanical Testing, Strain Measurement, meso scale, micro scale, Optical Flow, DIC, Digital Image Correlation

Citation

Lauria, D. and Liew, L. (2026), A case study comparison of strain measurements in micromechanical testing using optical flow and DIC, Materials Research Express, [online], https://doi.org/10.1088/2053-1591/ae9e0f, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=935632 (Accessed September 24, 2026)

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