I'm new to openCv, so apologies if I have overlooked an obvious method (that I obviously haven't found yet).
My goal is to 'clean' an image of scanned text in preparation for an OCR-esque process: already I have found a method of eliminating page shadow and texture (I can share it, if this is not already common knowledge), but I am stuck at the 'cleaning' of the text itself: an overall satisfactory result results in detail loss, and maintained details results in 'plugged' letters ('R's looking like 'B's in serifed, bold fonts, for example), and the process takes a long time on larger images.
original
Shadow removed, histogram normalised
Page cleaned