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remove barrel distortion

asked 2013-07-16 22:15:32 -0500

I.Zaytsev gravatar image

Hello! I have several of the following images:




I have a task to recognize the text on the labels. I will recognize the text using the FineReader Engine (special SDK for recognize images). However, I need to do preprocessing of images for better recognition. What do I need to do to remove barrel distortion and other distortions?

For example, FineReader bad recognizes the "BordeauX" word in the first image(image1), it instead of the "BordeauX" word sees "ordeauX", may be because there is a flare? How can this be fixed?

Have any idea how to do the preprocessing of the images?

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answered 2013-07-16 22:48:16 -0500

simon111 gravatar image

updated 2013-07-17 07:21:57 -0500

calibrating and undistoring with opencv in c This is a great tutorial.

Use chessboard to get the camera initric matrix, and correct the image using the result matrix

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answered 2013-07-17 08:39:42 -0500

Ben gravatar image

I think the main problem with not recognizing the B in Bordeaux is, that you have a strong highlight in your image at the B's position. So you might want to do some preprocessing regarding the image's contrast.

And probably, the barrel distortion caused by your camera's lense is neglectible compared to the label's distortion caused by the bottle shape. Fixing that is rather complicated.

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I think @Ben could be right. Have a look at histogram equalization of your image before processing.

StevenPuttemans gravatar imageStevenPuttemans ( 2013-07-17 08:52:22 -0500 )edit
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Asked: 2013-07-16 22:15:32 -0500

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Last updated: Jul 17 '13