aerial images

Geometric pre-processing for aerial images typically involves identifying the location of 4-8 “fiducial” markers (fixed points whose location is known) in each image.

For a general workflow of identifying the location of fiducial markers, see this page.

For example camera models and fiducial marker patterns, see this page. Note that this page is not (yet) exhaustive, and it is possible that there are other fiducial marker patterns for the camera model you are working with.