Threshold Correction of Document Image Binarization for Ruled-line Extraction

In this paper, a new threshold correction method for document image binarization that is forcused on ruled-line extraction is presented. This method enhances the binary image of a ruled line, which is often adversely influenced by adjacent text pixels or background noise. The threshold correction method consists of two submethods. One is a noise reduction method that is based on background determination, and the other is a threshold surface conversion method. Both these methods use the aspect of local straightness feature to distinguish ruled-line pixels from background pixels.