A physical medium is encoded with machine readable information that provides a human interface to a computer system. The information encoded into the medium indicates a computer implemented process, and is encoded according to a spectral encoding scheme, such as encoding by modifying color values of...http://www.google.com.tw/patents/US20030031341?utm_source=gb-gplus-share專利 US20030031341 - Printable interfaces and digital linking with embedded codes
