How to flatten a curved paper photo?

[rich2005]

It is going to depend on how many of these you have to process. No real automatic way that I know of, maybe someone will come up with something.

This using (1) Adjust the whole page with a trapezium deform then (2) the table with the gmic plugin - http://www.gmic.eu - interactive warp filter.  Never going to be wonderful and very user intensive.

   

and a 5 minute video how I got there: https://youtu.be/xRR0RbizQJA