| 摘要 |
A method and apparatus for generating and applying quality factors (QFs) to an optical reader. After an optical reader is calibrated, a mid-range gray scale level is selected and scanned. The reader outputs digital numbers (DNs) that are generated for all the pixels that will be responding to the reading of a document. A histogram of the DNs is generated and characteristics of the histogram distribution are calculated and used as QFs. For example, the standard deviation of the histogram may serve as a QF, where a lower standard deviation is preferred. Thresholds and standards may be developed from experience that indicate the operating condition of the reader. The QFs, thus, may be used during manufacturing and for field servicing of the reader. |
