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Keystone distortion

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Hi there, what a nice product!


I've been through the tutuorials and FAQs but can't find an answer, please help.


Is there a way of distorting a selection to remove the 'keystone' effect which has made a rectangular page into a trapezium.  (Photograped at a slight angle, I want it square for OCR.)



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There are quite a few ways - each has it's merits and devotees :) Which is best really depends on the source image.

Feel free to upload the image and post the link here so we can give you some idea of what will work best.

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Thanks for getting back to me.  Some background:  I'm one of the volunteers at Distributed Proofreaders (http://www.pgdp.net/c/default.php)


We take old books and convert them into e-books, plain-text, epub, mobi, html, etc.  But we always start with images of the pages.  I've deleted the one that was giving me trouble but this is the sort of image that causes a lot of grief.


Nope, not allowed to add an image either!  Here's the PhotoBucket link: http://smg.photobucket.com/user/Mebyon/media/Ebooks/015_before.jpg.html?sort=4&o=13


That's a bit exaggerated but you can see what I'd like to do; return the page to a rectangular form by dragging top left and right corners out.  It's not so very important for the OCR as Abbyy FineReader would cope quite well with that text but illustrations need 'squaring up' all the time.


Paint.net looks like a perfect solution for us, (well, at least us who use Windows), as we're all doing this work for nothing and paying for PhotoPaint or PaintShop isn't really called for!


I just hope that there's a plugin for the sort of distortion repair that I'm looking for.


Thanks for your time.



Edited by Mebyon
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No, the rotate/zoom is probably what you want.  Make sure you're on the right layer, and it should work.


Also try searching the plugin index for the Skew plugin.  If Rotate/Zoom isn't your style, give that a shot.


Either way, you won't be able to just make a selection and drag the handles.  Paint.NET doesn't offer that functionality.


The Doctor: There was a goblin, or a trickster, or a warrior... A nameless, terrible thing, soaked in the blood of a billion galaxies. The most feared being in all the cosmos. And nothing could stop it, or hold it, or reason with it. One day it would just drop out of the sky and tear down your world.
Amy: But how did it end up in there?
The Doctor: You know fairy tales. A good wizard tricked it.
River Song: I hate good wizards in fairy tales; they always turn out to be him.

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  • 1 year later...

I have to agree with David and Sozo on this...


The first tool I would go to, before a plugin, would be to try

Layers  -->  "Rotate/Zoom"


Frankly  I think it shouldn't be under "Layer", but under "Adjustments"


and I also think  maybe it's not the best name for a complicated tool...

maybe it should be called "Rotate/Zoom/Roll"  or "Rotate/Zoom/Skew"



what you're looking for are THE SECOND TWO SLIDERS FROM THE TOP,

under Roll/Rotate.



The 2nd sets the angle or direction of the skew, the 3rd sets the severity.

On the angle, 0 degrees is right or 3 o'clock.
90 is down, or 6 o'clock. etc.

When I'm shooting pics of pages with my cell phone and correcting these, this is what I use the most.


If you adjust the 2nd slider, without adjusting the 3rd, you will not see any difference,
Or you can just start with the 3rd.

And if you really want to get complicated, you can actually use the sphere on the left by clicking and dragging.


For those of you who are like me and think this should be built in and not have to delve into the world of add-ons... it is...


I hope this helps.


Edited by AriDiz
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Last post in this thread was was December 2013 AriDiz. That means the conversation is over.

If you wish to restart discussion on an old subject please just start a new thread. Thanks and welcome to the forum :D

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