Skew detection and correction of a document image representation

Details Skew detection and correction of a document image representation Skew detection and correction of a document image representation

1997-09-24

1998-12-29

Boudreau, Leo H.

Image analysis

Image segmentation

Distinguishing text from other regions

382296, G06K 900

Patent

active

058548548

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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