| 摘要 |
In optical character recognition systems scanning may be accomplished by a multi element scanning matrix, in which each element detects a portion of the reading field and an output voltage is generated for each element depending upon whether the element is looking at the dark character or a portion of the background which usually is of a lighter shade. The instantaneous output of each element is digitized with a value dependent upon the amount of light detected by the cell and may have a value from 0 to fifteen. This digitized quantized information is then used to make a black/white decision for each cell, for example, if the information is background or is representative of a character being read. Improper referencing of the background due to reflective variation caused by multi colored backgrounds or different paper textures may cause an incorrect reading and make a black/white decision which is in error. This invention describes a technique for determining an improper reference background and subsequently altering the parameters to restore satisfactory performance.
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