The grid method is an alternative to Digital Image Correlation (DIC) that uses a regular marking (a grid) as opposed to a random pattern. This enables the use of spatial phase-shifting algorithms to extract displacement fields. As a consequence, the spatial resolution is superior to DIC (typically, one independent displacement data point for a 5×5 pixel subset) for roughly the same displacement resolution.
Example of a grid
- A recent and valuable review paper on the grid method:
Grédiac M., Sur F., Blaysat B., The Grid Method for in-plane displacement and strain measurement: a review and analysis, Strain, vol. 52, n° 3, pp. 205-243, 2016.
- A GUI to process grid images can be found here.
- Matlab grid processing tools can be found here.
- Paper on the transfer of printed grid – Piro J.L., Grédiac M., Producing and transferring low-spatial-frequency grids for measuring displacement fields with moiré and grid methods, Experimental Techniques, vol. 4, pp. 23-26, 2004.
- How to print grids directly on specimens using a flatbed printer (courtesy of Dr Yves Surrel). Part I, Part II