Flattening a scanned book

[Krikor]

(12-18-2023, 07:08 PM)denzjos Wrote: @Krikor, after using your update information the workflow is working fine. Thanks. A quick example using the workflow on a free photo from the internet (not 100% level, but it was a quick try):


I'm not a gimp programmer but it must be possible to make a script from this workflow.

denzjos,

Good to know you made it. Thanks for the feedback. 

Ofnuts, in post #22, showed some skepticism in this task, and appropriately explained why.

But I'm still optimistic and believe he could translate this workflow into a plugin, even with one hand behind his back. 

[Krikor]

I tried Tin's Double Curve Bend plugin for this type of editing.

The alignment of the text was somewhat achieved, which was the initial objective here.
But the final quality greatly compromises the reading. Even using Perspective Tool as an alignment option, the quality is not affected that much.

However, perhaps with better path tracing I could have obtained a better result. I only made one attempt and just started exploring the plugin.

   

[Ofnuts]

(12-18-2023, 08:08 PM)Krikor Wrote: Ofnuts, in post #22, showed some skepticism in this task, and appropriately explained why.
But I'm still optimistic and believe he could translate this workflow into a plugin, even with one hand behind his back. 

Looking at it one more time. You have two corrections to make, but they are related. The vertical distortion (bulges at top and bottom) are cause by the change in distance between the camera and the sheet? This part is closer, and so larger. The horizontal distortion (uneven line interval) is a mix between the same distance-induced distortion and the slope of the paper. This whole thing could be deduced by a good mathematician from the shape of the top and bottom edges of the page. But I'm not that guy.

But as usual a bit of care when taking the picture goes a long way to reduce post-processing. The shape of the page is cause by the book being open flat. If you keep the book open at 90°, the pages remain nearly flat and you don' t need any correction.

[denzjos]

(01-04-2024, 04:06 PM)Ofnuts Wrote:

(12-18-2023, 08:08 PM)Krikor Wrote: Ofnuts, in post #22, showed some skepticism in this task, and appropriately explained why.
But I'm still optimistic and believe he could translate this workflow into a plugin, even with one hand behind his back. 

Looking at it one more time. You have two corrections to make, but they are related. The vertical distortion (bulges at top and bottom) are cause by the change in distance between the camera and the sheet? This part is closer, and so larger. The horizontal distortion (uneven line interval) is a mix between the same distance-induced distortion and the slope of the paper. This whole thing could be deduced by a good mathematician from the shape of the top and bottom edges of the page. But I'm not that guy.

But as usual a bit of care when taking the picture goes a long way to reduce post-processing. The shape of the page is cause by the book being open flat.  If you keep the book open at 90°, the pages remain nearly flat and you don' t need any correction.

Quote : "they are related". That's why Altostorm Panorama Corrector does vertical and horizontal corrections the same time. There are also different modes of correction tools : number of curves and different types of curves one can use. Second quote : "a good mathematician" : I also think it's not a piece of cake to make such a program.