3D infra-red cameras

The secret behind Google's book scanning project

Google created some seriously nifty infrared camera technology that detects the three-dimensional shape and angle of book pages when the book is placed in the scanner. This information is transmitted to the OCR software, which adjusts for the distortions and allows the OCR software to read text more accurately. No more broken bindings, no more inefficient glass plates.

http://www.guardian.co.uk/technology/blog/2009/may/04/google-gadgets

http://www.theregister.co.uk/2009/05/04/google_book_scanning_patent/