I’m becoming increasingly impressed by Plustek’s specialised book-scanner, the OpticBook 3600. I bought one ages ago, and was unimpressed to discover that the built-in TWAIN driver only supported 300 dpi, since scanning and converting to text is best done at 400 dpi. Later I found that, when using Abbyy Finereader 8 OCR software, the Abbyy driver did allow access to a 400 dpi mode, but by then I’d sort of lost interest.
However this weekend I got hold of vol. 1 of Graf’s Geschichte der christlichen arabischen Litteratur from the library. Since you can’t buy this book, I thought that I would pull out the Opticbook. It is amazingly fast — zoom! zoom!, in fact! The scan goes up to the edge of the machine, meaning that you can hang the book over the edge rather than flatten the spine. It takes barely longer to scan than to turn a page and reposition the book. The quality is at least as good as my main scanner, which cost three times more. (Trimming the images to a common size is handled excellently by Abbyy Finereader’s crop tool).
I also used it a while back on vol. 1 of Michael the Syrian, and indeed on a large 19th century edition of Eusebius’ Chronicle. In each case it produced an excellent PDF, and the results OCR’d very well.
The price is very modest. If you do any book scanning, consider it seriously.