How to create QR code recognition in Processing

For a start you need a library that can be used in Processing.
There is a library implemented in Java at http://qrcode.sourceforge.jp/.
But for our purpose we use library from http://www.shiffman.net/p5/pqrcode/ in processing.
Why use QR Code that is widely used in Japan? The advantage is larger data capacity can be stored and have error correction than well-known barcode.
You can generate an QR code image online at http://qrcode.kaywa.com