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+--- Thread: Dewarping photographs of documents (/Thread-Dewarping-photographs-of-documents)
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Dewarping photographs of documents - The ancient one - 07-18-2024
Good day all.
In my spare time I convert photos or scans of rare technical documents to readable PDF files. Many of the photographs originate with unknown persons and I receive them third or later hand and the quality is what is politely called poor - see a typical example below where I have roughly edited out fingers at the top.
For some time I have been addressing warped pages photographed by persons unknown by using PerspectiveCropper to basically get all the corners about where they belong and then using ScanTailor to convert the images into clean PDF documents.
Because my eyesight is failing I can no longer do this as the handles for both programs are too small for me to see.
Today I tried GIMP to do my editing for the first time and the basic GIMP workflow I found to manipulate the images is fantastic. ➤ Filters, Distort, Curve bend.
That said I immediately ran into two major problems in that:
1. I am having to work with what I would call a thumbnail of the image I need to manipulate and with my eyesight that is just not practical - especially as the images tend to be dark with little contrast so I cannot see what is happening. I could not find a way to make the Curve bend control panel/palette full screen.
2. I did not manage to make the distorted "diamond" shaped page square
Obviously my most important question is - How to make the Curve bend control panel/palette full screen?
That may well solve problem two but if it does not then how do I drag the outside corners to square up the page?
I am using GIMP 2.10.38 on Win7 Enterprise
Thank you
RE: Dewarping photographs of documents - Tas_mania - 07-18-2024
Quote:Because my eyesight is failing I can no longer do this as the handles for both programs are too small for me to see.
That's not good. I had cataract surgery on both eyes 10 years ago and haven't looked back
It's one of the most common operations in the world. Maybe you have one of the other 2 common eye problems - macular degeneration and glaucoma?
RE: Dewarping photographs of documents - The ancient one - 07-19-2024
Mother nature was generous and gave me both glaucoma and cataracts and my eye surgeon has done the best that science can do at this time.
I went for a second opinion and was told by the second surgeon that he wished he could do trabeculectomy's half as well as the first did.
RE: Dewarping photographs of documents - Krikor - 07-19-2024
Perhaps you might find this post useful:
Flattening a scanned book - https://www.gimp-forum.net/Thread-Flattening-a-scanned-book
RE: Dewarping photographs of documents - PixLab - 07-19-2024
(07-19-2024, 02:14 AM)Krikor Wrote: Perhaps you might find this post useful:
Flattening a scanned book - https://www.gimp-forum.net/Thread-Flattening-a-scanned-book
+1000
I was searching for it to give the link to the OP, one of the best thread about this kind of deformation
RE: Dewarping photographs of documents - The ancient one - 07-19-2024
Thanks Krikor.
I will need several days to check all the options you suggested for me
RE: Dewarping photographs of documents - The ancient one - 07-23-2024
Thanks Krikor.
my apologies for the slow reply. The nightmare bloody network was undergoing unscheduled maintenance so I needed several days to check all the options you suggested for me and was about to give up when I found this video which was the first of the very many I watched that actually covered every transform tool in simple language suitable for beginners and old fogies like me.
https://www.youtube.com/watch?v=YiUmZMA2Vuo
I did a couple of runs today using the control P and then control W options and got reasonable results
RE: Dewarping photographs of documents - Krikor - 07-23-2024
(07-23-2024, 08:41 AM)The ancient one Wrote: Thanks Krikor.
my apologies for the slow reply. The nightmare bloody network was undergoing unscheduled maintenance so I needed several days to check all the options you suggested for me and was about to give up when I found this video which was the first of the very many I watched that actually covered every transform tool in simple language suitable for beginners and old fogies like me.
https://www.youtube.com/watch?v=YiUmZMA2Vuo
I did a couple of runs today using the control P and then control W options and got reasonable results
Hello The ancient one,
For a beginner to absorb a certain type of information, it is not enough for that information to be available. It takes time for there to be proper understanding and understanding. The curve for new learning is personal, so don't worry about the interaction time with this forum.
One step after another and slowly you go far.
I would like to highlight post #7 https://www.gimp-forum.net/Thread-Flattening-a-scanned-book?pid=37075#pid37075
"There is an old script by RobA that uses two paths and the Gimp curve-bend plugin.
The RobA site is gone, you can find via the Internet Archive. To save the hassle the script ra_curve-bend-between-paths.scm is attached.
Unzip and put in your Gimp users scripts folder C:\Users\"yourname"\AppData\Roaming\GIMP\2.10\scripts
Needs a top and a bottom path following the curve. There is a maximum of 17 path nodes. Never going to be great with the example." - rich2005
In this same post you will find a link to a video of just about 3 minutes:
https://youtu.be/fOX5p5tMt6c
Also available in the attachment is the plugin that was used in the video (ra_curve-bend-betweeen-paths.zip)
The Transform tool is a good tool, but in this case you would have better results trying to apply the technique shown in the video.
Good luck!
RE: Dewarping photographs of documents - rich2005 - 07-23-2024
About that old RobA script.
Unfortunately it no longer works, especially when using Windows Gimp 2.10.x Looks like some changes to the curve -bend plugin causes the script to crash.
Using linux you can use the curve-bend executable from Gimp 2.8 but I tried all ways with Wim10 / Gimp 2.10 without success.
RE: Dewarping photographs of documents - denzjos - 07-23-2024
Found this : https://mzucker.github.io/2016/08/15/page-dewarping.html. I don't know how to use it or is it still an attempt by the author?