Image analysis – Image transformation or preprocessing – Changing the image coordinates
Patent
1992-04-06
1995-09-19
Couso, Yon J.
Image analysis
Image transformation or preprocessing
Changing the image coordinates
382293, G06K 932
Patent
active
054523745
ABSTRACT:
In a character recognition system, a method and apparatus for correcting the skew of a document image. Skew correction is typically performed during segmentation of the document image into text and non-text parts. Skew correction generally involves skew angle determination and correction of the document image based on the skew angle. A skew angle is determined through the steps of: providing a set of associated rectangles representing the document image, identifying a column edge associated with the set of associated rectangles, comparing rectangles from the set of associated rectangles to identify those that are in the same column and suitably far apart, calculating a tangential angle between the rectangles identified and identifying the most common tangential angle as the skew angle. Once the skew angle is determined, correction of the document image is made by constructing real skewed rectangles from corresponding extracted rectangles and rotating each of the real skewed rectangles around an origin coordinate for a distance based on the skew angle.
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Cullen John F.
Ejiri Koichi
Couso Yon J.
Ricoh & Company, Ltd.
Ricoh Corporation
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