I.R.I.S. Readiris 14 for Windows User Guide - Manual (Page 45)

Section 4: Selecting the Configuration Options
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Note: make sure your documents are facing the right direction -
meaning the text is facing the scanning surface. Otherwise Readiris
will not be able to rotate them.
Page Deskewing
Select this option when you need to straighten documents that were
scanned crookedly.
Page Analysis
This option is activated by default. It splits up each page in
recognition zones. Readiris analyzes the entire page and indicates
which zones contain text, images and tables.
These recognition zones are required in order to process your
documents. If your documents do not contain any recognition
zones, Readiris will not be able to process them.
See the section Editing the Recognition Zones for detailed
information on the recognition zones, and on how to change them if
necessary.