Graphics or any kind of symbols. I tried this with an out of print edition of an economics textbook from the 70s: the scans were fine but I never found any OCR that could even semi-faithfully reproduce the equations, nor anything in a table.
It occurs to me that a place where scans and first-pass OCRs of this stuff are shared with the intention of version controlling the resultant epub would be handy, such that small PRs could be applied cumulatively and the result be versioned (and therefore referenced). That's considerable work and legal risk, though.
It occurs to me that a place where scans and first-pass OCRs of this stuff are shared with the intention of version controlling the resultant epub would be handy, such that small PRs could be applied cumulatively and the result be versioned (and therefore referenced). That's considerable work and legal risk, though.