An improved document skew angle estimation technique

When a document is fed to a scanner either mechanically or by a human operator for digitization, it suffers from some degrees of skew or tilt. Skew angle detection is an important component of any Optical Character Recognition (OCR) and document analysis system. Tn this letter we consider skew estimation of Roman script. The method considers the lowermost and uppermost pixels of some selected characters of the text which may be subject to Hough transform for skew angle detection. A fast approach is also proposed which works almost as accurately as Hough transform. Experimental results are presented and compared with results on several other skew detection methods.