Whether to detect and remove page headers.
Most accessibility standards regard repeated text as chrome
rather than content. For this reason they often mandate that
headers and footers are removed from the semantic structure of the
If this property is set to true, the AccessibilityOperation will
attempt to detect repeated headers and mark them as artifacts.
If your documents are complicated and you require complete
control over the detection process, you can do this using the
techniques detailed in the AccessiblePDF example project which
comes with ABCpdf.