Scanning a whole book with a normal flatbed scanner is a very tedious task. A better way is to just take photos of the pages with macro mode activated which gives at least very human-readable results. Automatic text conversion software (OCR) is having a hard time however reading the lines correctly, thus a lot of extra manual work is necessary to prepare scanned book for re-publishing. The biggest problem are the non-flat pages and my first solution was to push the pages down with a piece of glass and shoot photos from a tripod. In the do-it-yourself bookscanner forum they came up with a more sophisticated solution called “the standard model” which usually looks something like this:
The images are taken from two opposite sides. The glass “box” pushes the book very evenly and produces perfect images. One point to keep in mind when building a book scanner though is that the middle of the book is moving along as more pages are flipped. A colleague and I built the following prototype which is a very simple and cheap build we came up with (10€ for wood+screws+20€ for plastic glass):
It has movable parts to hold the book but can be fixated with little wing-screws. The arms for the digicam just use friction for fixation. After doing some test shots I noticed that all that was needed are flat images, so if I shoot the book from the middle with only camera I still get flat images which are just uniformly distorted to the back. Thus finally I came up with…
* from german “Rammbock” (battering ram)… in case you didn’t get the pun
You actually move the whole scanner and “ram” the book into a corner. The pages are shot with one camera only which snaps both sides. The little carton shield in the middle is just to avoid specular highlights. The quality is actually pretty good with fulltext pages (10 Megapixel). Finereader 10 gets confused with dewarping though if there is very few text on the page (like the TOC page) so I have to remove the distortion first. I’m very proud of this model as it is very very cheap and only uses one camera. You may also find a thread of my build in the forum.
Lessons learned for next build:
- Avoid scratches in glass!
- Use a real camera mount! 1. Camera really gets fixated; 2. Metal screws won’t destroy mount hole :/
- Use a thinner bottom => Text at bottom won’t get covered
- Use a spotlight shield (and use thin wood instead of carton if possible, because it’s more stable)
- Use black or white wood => no paper needed to cover the ram to avoid blotches
- Buy power supply and >512 MB card for camera