"Design of an Inexpensive Very High Resolution Scan Camera System".
500 megapixels for $1600 versus scanning-back cameras that cost tens of thousands. Make the error correction a little bit simpler by rotating the scanning back ninety degrees for four 4-color shots (16 exposures), overlaying them, and taking the median pixel values, at the expense of some resolution.
There are four considerable challenges here, though, not just one, and this project could stall on any of them:
Projection determination & georeferencing
Digitizing features & establishing topology