Automatic optimized document skew pre-processor for character segmentation algorithm

In this paper, as a part of character segmentation algorithm, an automatic optimized document skew correction approach based on Hough transform is presented. The importance of skew correction in document image analysis lies in the fact that further processing is impossible if the document image is skewed. The proposed approach is based on fast implementation of the standard Hough transform which is followed by highly optimized low-level machine code implementation of the image rotation. In order to achieve high computational results, linear image representation is used. The proposed approach results from the aspect of time complexity and skew estimation accuracy which are analyzed and compared with the already existing skew correction approaches. The proposed approach gives better results compared with analogous approach used in related work, but it gives worse results compared with optimized version which exploits a BAG algorithm. Provided results show significant improvement of the standard Hough transform implementation.