| abstract |
Plastic items, such as beverage bottles, convey two different digital watermarks encoded using two different signaling protocols. The first printed label watermark conveys the retail payload, including the Global Trade Item Number (GTIN) used by point-of-sale scanners in retail stores to identify and price items at checkout. The second plastic texture watermark may convey the recycling payload, including data identifying the plastic content. The use of two different signaling protocols ensures that point-of-sale scanners do not spend their limited time and computing resources decoding the recycling watermark, which may lack the data required for retail checkout. In some embodiments, recycling facilities advantageously use both types of watermarks to identify the plastic content of items (eg, using an associated database to associate GTINs with plastic types), thereby increasing the proportion of items correctly identified for sorting and recycling. In other embodiments, the plastic item (or the label thereon) bears only a single watermark. Numerous other features and arrangements are also detailed. |