| 摘要 |
<p>A hand held scanner includes a lens (28) which focuses an image of a character on a photodiode array (30). Clock signals applied to the photodiode array (30) cause successive sets of row signals to be provided, including representations of black, gray and white data. A logic circuit (104, 108, 110, 112) provides a control signal if a set of row signals represents white data at both ends of the row and at least one item of gray data intermediate the white data. The control signal, which indicates correct positioning of a character image portion on the photodiode array (30), causes the provision of black and gray data to a recognition device (52) which may include a processing unit. A further logic circuit (132, 134) provides a signal indicative of the direction of scan.</p> |
