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 Deskew Trapezoid Area

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Oribi Posted - Mar 21 2016 : 09:24:00
I'm currently working on a service that has to automatically process images of businesscards. These images are created using the camera from a mobile phone.

The problem is that these images are rotated, skewed and some are even deformed in a trapezoid way.

So far I have been able to autorate the cards, so that the text is placed horizontally and I have managed to autocrop and deskew the images so that only that card is visible.

However, I haven't been able to find a way to deskew trapezoid deformed images (=when the image is taken not straight from above, but at an angle).

Is this possible using the ImageEn components? Is it possible to use Edge detection to find the edges of the card and to scale the selection to a regular rectangle?

--
Peter.
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Oribi Posted - Mar 22 2016 : 09:23:14
Thank you.
I can indeed use the PerspectiveDraw to correct the Trapezoid deformed images. Now I just have to find a good way to find the four courners.
xequte Posted - Mar 21 2016 : 20:52:55
Hi Peter

ImageEn does not yet provide user controlled deskewing. It is on the to-do list.

You might want to take a look at:

http://www.imageen.com/ieforum/topic.asp?whichpage=3.8&TOPIC_ID=1446#9013

If you mean, automatic, programmatic deskewing then that is a much more difficult beast. If your image is well defined then it is possible that an edge detection algorithm may give you a reasonable approximation of the card. From that trapezoid, the mathematics to revert it to a rectangle would be relatively simple. You could then convert your image using:

http://www.imageen.com/help/TImageEnProc.PerspectiveDraw.html


Nigel
Xequte Software
www.xequte.com
nigel@xequte.com