11. A hand-held scanner for reading characters from a string of characters on a substrate comprising: a housing adapted to be held and moved by a hand; optical means, located within said housing, for viewing an image of an area on the substrate; an image splitter for receiving the image of the area from said optical means and producing two images of the area wherein one of the two images of the area is rotated with respect to the other of the two images of the area; optical detector means, located within said housing for detecting the relative intensity of light at a plurality of points in each of the two images and generating an electrical signal representative of the relative intensity of light in the plurality of points in each of the two images.
11. A hand-held scanner for reading characters from a string of characters on a substrate comprising: a housing adapted to be held and moved by a hand; optical means, located within said housing, for viewing an image of an area on the substrate; an image splitter for receiving the image of the area from said optical means and producing two images of the area wherein one of the two images of the area is rotated with respect to the other of the two images of the area; optical detector means, located within said housing for detecting the relative intensity of light at a plurality of points in each of the two images and generating an electrical signal representative of the relative intensity of light in the plurality of points in each of the two images. 12. The hand-held scanner of claim 11 wherein said image splitter produces two images that are rotated 90 degrees with respect to each other.