The present invention relates to various digital watermarking methods and systems. In one embodiment, a handheld device displays a digitally watermarked ticket image at an event center. At the event center, a watermark decoder extracts the watermark to determine authorized entry. In another embodiment,...http://www.google.fr/patents/US7024016?utm_source=gb-gplus-shareBrevet US7024016 - Digital watermarking apparatus and methods
