| 摘要 |
<p>In a document scanning system, a column of document sensors (16) is scanned to provide digital signals representing pixel gray levels which are applied sequentially to a latch (55) coupled to the first of a sequentially coupled group of RAM's (40-43) addressed by a common address circuit (44) and having further latches (56-59) for input-output operations. This arrangement effects a one scan line delay. Outputs of the latches (55-59) are applied to combining means (204, 206, 208) including sequences of adders (e.g. 214), element delays (e.g. 216) and multipliers (e.g.. 212) whereby for each sensed pixel the values of the pixels in a window are multiplied by predetermined constants and summed to provide a total representing an enhanced value for the sensed pixel. The window is shifted by one row for each sensed pixel. Thus, character enhancement is effected by a digital filter of simple construction.</p> |
