The Free On-line Dictionary of Computing (30 December 2018):

Optical Character Recognition
OCR

    (OCR, sometimes /oh'k*/) Recognition of printed or
   written characters by computer.  Each page of text is
   converted to a digital using a scanner and OCR is then
   applied to this image to produce a text file.  This involves
   complex image processing algorithms and rarely achieves
   100% accuracy so manual proof reading is recommended.

   (1999-08-26)