Detection and removal of hand-drawn underlines in a document image using approximate digital straightness

Abstract

A novel algorithm for detection and removal of underlines present in a scanned document page is proposed. The underlines treated here are hand-drawn and of various patterns. One of the important features of these underlines is that they are drawn by hand in almost a horizontal fashion. To locate these underlines, we detect the edges of their covers as a sequence of approximately straight segments, which are grown horizontally. The novelty of the algorithm lies in the detection of almost straight segments from the boundary edge map of the underline parts. After getting the exact cover of the underlines, an effective strategy is taken for underline removal. Experimental results are given to show the efficiency and robustness of the method.