Help? Idea for how to test a hypothesis?

[Botis]

Far as I can tell those normalizers just straighten the text and maybe make the pages a consistent size, but don't do anything about the big issue of the images being derived from not-flat paper.

Those two issues are the very issues resulting from the images being derived from non-flat paper, aren't they?

Anyway, I have no experience with such tools, so can give no further comments.

No. The big issue is with the paper being arched in various places so that it's not flat -- think three dimensions and forced perspective. The text, on a single page, curves and shrinks/grows because it's nearer or closer to the camera depending on the arch. The programs fix only tilted text or page-to-page size problems, not curved/warped text and size problems on a single page.

For example, You are not allowed to view links. Register or Login to view., making any writing in that area useless for comparison to a page You are not allowed to view links. Register or Login to view. where the right hand side is more flat -- through an overlay method, anyway, they're useless.