Patent ID: 7826636

Claim:
A non-transitory computer readable memory medium comprising: a data area for storing data in the form of marks, in which the data is encoded by means of a channel code, wherein a parameter of the channel code is controlled so as to introduce a predetermined run length distribution in the marks on the computer readable memory medium, thereby introducing first information relating to a visually discernable watermark, wherein at least a portion of the first information is visually discernable on the computer readable memory medium in the data area without a device to discern the first information, and a non-data area comprising second information relating to the visually discernable watermark, wherein at least a portion of the second information is visually discernable on the computer readable memory medium in the non-data area without a device to discern the second information, the first and the second information together forming the visually discernable watermark, wherein the visually discernable watermark is visually discernable on the computer readable memory medium without a device discerning the visually discernable watermark.