Never built one, but I know about the basics of book scanning. The bottom bit basically just holds the book open, while the cameras take pictures of their respe

Never built one, but I know about the basics of book scanning. The bottom bit basically just holds the book open, while the cameras take pictures of their respective pages. Two glass panes hold the pages flat while the cameras do their thing. The rest is taken care of on the software side, with algorithms to clean up the image and then perform OCR. Previously, cutting the spine off the book and using a high-speed document scanner was the norm. This newer method, which is possible because of good, cheap digital cameras, doesn't involve destroying the book to get it into digital format. The operator has to turn the pages manually, but that's a small price to pay for getting to keep the original book.