[Gimp-user] How to flatten images of book page

[Mario Valle <mvalle cscs ch>]

The new cage tool is fantastic to solve the following problem, but I 
need suggestions how to be more effective.

I take a photo with the smartphone of a book page. I need two hands for 
this. The page does not lies flat (see 
https://dl.dropbox.com/u/2571325/before.jpg) because no more hands 
available to keep the page flat (and no glass sheet at hand...). Using 
the cage tool with 3 nodes above and 3 below the text produces an 
acceptable result (see https://dl.dropbox.com/u/2571325/after.jpg).

Question: Is there any better method? Any GIMP plugin or even Android 
app to solve this problem?

I can trace the deformed rectangle that enclose the page text, but then 
I don't know how to pass this info to the cage tool and ask to make it a 
real rectangle.

Thanks for your help!
                                mario

--
Ing. Mario Valle
Swiss National Supercomputing Centre (CSCS) | http://mariovalle.name/
v. Trevano 131, 6900 Lugano, Switzerland    | Tel: +41 (91) 610.82.60