I.R.I.S. Readiris Corporate 12 for Windows User Guide - Manual (Page 72)

Chapter 10 – Recognizing documents
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If the results are correct:
o Click the Learn button to save the result as sure.
The learning results are temporarily stored in the computer memory,
for the duration of the recognition. Readiris will no longer display
the learned characters when OCRing the rest of the document.
When a new document is OCRed, the learning results are erased.
To save learning results permanently, use a font dictionary. For
more information, see the section Using font dictionaries.
o Click Finish to save all solutions the software offers.
If the results are incorrect:
o Type in the correct characters and click the Learn button.
or
o Click Don't learn to save the result as unsure.
Use this command for damaged characters which could be confused
with other characters if learned. E.g. the number 1 and the letter I,
which have an identical form in many fonts.
o Click Delete to delete characters from the output.