1. A method of processing an image of a scanned document, said document image having been previously scanned and segmented into image units, said method comprising the steps of: (a) determining a length and height of each image unit; (b) defining short image units as image units having a length no greater than a predetermined length; (c) deleting image units from the image that are not said short image units, using the results of step (b); (d) blurring the image in a horizontal direction to form a blurred image; (e) eroding the blurred image using a set of ascender matching structuring elements and a set of descender matching structuring elements to form two eroded images; (f) taking a UNION of the two eroded images; (g) performing a seed filling operation using the image resulting from step (f) to provide 1) short image unit masks filled for short image units with at least one ascender, and 2) short image unit masks filled for short image units with at least one descender; and (h) identifying image units corresponding to said filled short image unit masks.