1. A method for deleting a ruled line from an image of a ruled form which includes a plurality of ruled lines for defining at least one character area, comprising the steps of: defining a scanning area on the image of the ruled form which encompasses the ruled lines and a portion of a character area which is within a predetermined distance from the ruled lines which define a border of said character area; extracting from said ruled line to be deleted black runs having a length greater than a predetermined length from said scanning area; and changing black pixels corresponding to the extracted black runs to white pixels in the image of said ruled line to be deleted.