I.R.I.S. Readiris 14 for Mac User Guide - Manual (Page 49)

Section 4: Scanning and Opening Documents
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Deskewing Digital Camera Images
When photographing documents with a digital camera, it may
happen that the documents are shot from an angle, which gives
them a 3D effect and renders the recognition impossible.
To solve this issue, you can deskew your digital camera images:
 Open your digital camera image.
 On the Layout and Editing toolbar, click the Deskew icon.
 Drag the corners one by one in the direction of your text.