Techniques in optical character recognition

An image deskew system and techniques are used in the context of optical character recognition. An image is obtained of an original set of characters in an original linear (horizontal) orientation. An acquired set of characters, which is skewed relative to the original linear orientation by a rotati...

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Bibliographic Details
Main Authors Nijemcevic, Djordje, Galic, Sasa
Format Patent
LanguageEnglish
Published 29.05.2012
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Summary:An image deskew system and techniques are used in the context of optical character recognition. An image is obtained of an original set of characters in an original linear (horizontal) orientation. An acquired set of characters, which is skewed relative to the original linear orientation by a rotation angle, is represented by pixels of the image. The rotation angle is estimated, and a confidence value may be associated with the estimation, to determine whether to deskew the image. In connection with rotation angle estimation, an edge detection filter is applied to the acquired set of characters to produce an edge map, which is input to a linear hough transform filter to produce a set of output lines in parametric form. The output lines are assigned scores, and based on the scores, at least one output line is determined to be a dominant line with a slope approximating the rotation angle.