gridmarking

Gridmarking is the practice of creating, applying, or utilizing a regular grid of marks to provide a spatial reference for measurement, alignment, or registration tasks. The term encompasses techniques across disciplines and is not tied to a single standard process. Gridmarks may be physical features on a substrate, digital overlays, or patterns detected by imaging or sensing systems.

In microfabrication and microscopy, gridmarks (fiducial grids) are placed on wafers or samples so instruments can locate regions of interest, align multiple imaging passes, or correct for stage drift. In lithography, they support wafer alignment and overlay accuracy during successive patterning steps. In computer graphics and CAD, grid marking refers to overlay grids used to position and scale objects with snapping to grid lines.

Methods used for gridmarking include etching, depositing, or printing fiducial marks in a regular grid; creating contrast through materials or coatings; and software-based grid overlays, where recognition algorithms identify grid lines in an image to compute coordinate transformations. Physical gridmarks are chosen for durability, high-contrast visibility, and minimal distortion.

Challenges in gridmarking involve grid density trade-offs, distortion due to optics or mechanical flex, alignment tolerance, and legibility under varying illumination or imaging modalities. Calibration workflows often involve measuring gridmarks, computing affine or non-linear transformations, and applying corrections to subsequent data or fabrication steps.

Related concepts include fiducial markers, image registration, calibration, and grid overlays.