docs: explain --rotate-pages-threshold

2020-06-08 07:46:55 -07:00
parent c6c70c2171
commit fd1cd8e50a
1 changed files with 5 additions and 1 deletions
@@ -56,7 +56,11 @@ portrait pages.
    ocrmypdf --rotate-pages myfile.pdf myfile.pdf

 You can increase (decrease) the parameter ``--rotate-pages-threshold``
-to make page rotation more (less) aggressive.
+to make page rotation more (less) aggressive. The threshold number is the ratio
+of how confidence the OCR engine is that the document image should be changed,
+compared to kept the same. A value of ``15.0`` is the default, and is fairly
+conservative. A value of ``2.0`` will produce more rotations, and more false
+positives.

 If the page is "just a little off horizontal", like a crooked picture,
 then you want ``--deskew``. ``--rotate-pages`` is for when the cardinal