How can I scan a chessboard and obtain its FEN? I am planning to create a chess puzzle book for beginners. Diagrams need to be published in the book. Right now I have all the materials in PDF. But I need a software to create diagrams for a particular chess position. Is there any way to scan chess diagrams from a PDF?
I wrote a program that can recognize positions from books and magazines and give you the FEN. Here is the web interface for 
Chessputzer  

You can upload the image or paste directly from the clipboard. 

Note: it is designed for the the most common fonts used in print. It won't work for images from Chessbase etc. For that, use Fenbot. 

My aim was to make it good enough to read blurry images from old chess books so it should be pretty tolerant of artifacts and such.