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.

grid

Example of a grid

Some resources

  • 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.
    http://dx.doi.org/10.1111/str.12182
  • A GUI to process grid images can be found here.
  • Matlab grid processing tools can be found here.