Re: [Gimp-user] Unskewing images of flat rectangular objects in Gimp

[Øyvind Kolås <pippin gimp org>]

On Mon, Feb 4, 2013 at 4:11 PM, Elmer Wix
<elmer cabekaziruronometu wix gmail com> wrote:
> I often use my digital camera to take pictures of flat, rectangular
> objects, like framed paintings on a wall, book or album covers, or
> pages of documents.  Of course, I can't take these pictures straight
> on and perfectly level, but that's OK.  I know what the dimensions of
> the objects are, so I can just correct the perspective in software.
>
> Does Gimp have any function like this?  I found the perspective tool,
> but that requires me to manually shift the perspective and eyeball
> when I think a rectangular image is produced.  That's not nearly as
> convenient.

The perspective tool has an inverse mode, if you align the grid lines
from the wireframe preview with the lines desired to become
horizontal/vertical and then do the transform you should end up with a
rectified version of the quadliteral.

/pippin
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