HORIZONTAL AND VERTICAL LINE DETECTION AND REMOVAL FOR DOCUMENT IMAGES

摘要

PROBLEM TO BE SOLVED: To remove vertical and horizontal lines from a document image.SOLUTION: The horizontal line removal method includes: for a column of black pixels at each horizontal position along the line, removing the black pixels if their maximum stroke width is less than an average value of maximum stroke widths in a small window centered at that horizontal position; removing connected components that remain in the horizontal line bounding box and do not extend significantly above or below the bounding box boundaries; and performing closing operation to join broken pieces of character strokes caused by underline removal. This method preserves character strokes while removing underlines. The vertical line removal method includes: for vertical lines that have a large height to width ratio, removing parts of vertical lines that are not at intersection with horizontal or near-horizontal lines; and removing all remaining connected components that touch neither left nor right boundary of the bounding box.SELECTED DRAWING: Figure 1