Dual Watermark Signaling for Plastic Sorting
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Solution Overview
Problem
Current plastic recycling systems face challenges in reliably reading and distinguishing between retail and recycling watermarks on plastic items, particularly due to limited processing time and differences in signaling protocols, which can lead to confusion and inefficient sorting.
Innovation Solution
The implementation of distinct signaling protocols for retail and recycling watermarks, using different reference signals and encoding algorithms, allows for quick and accurate identification by point-of-sale scanners and recycling systems, ensuring reliable sorting and recycling of plastic items.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same watermark pattern is used for both retail and recycling identification, then the system structure is simplified, but the reliability of identification deteriorates due to confusion between retail and recycling watermarks
Solution Approach 1:
The patent divides the watermark identification system into two separate segments: a retail watermark pattern and a recycling watermark pattern. Each pattern has distinct characteristics (different reference signals, encoding algorithms, and visual appearances) that allow scanners to reliably distinguish between retail and recycling identification purposes, eliminating confusion while maintaining system manageability.
Solution Approach 2:
The patent applies different local qualities to different parts of the packaging system. The retail watermark uses one set of characteristics optimized for point-of-sale scanning, while the recycling watermark uses different characteristics optimized for recycling facility reading. This differentiation ensures that each scanning context receives the appropriate watermark type without interference.
2Reliability
If distinct watermark patterns are used for retail and recycling, then the reliability of identification is improved, but the complexity of the marking system increases
Solution Approach 1:
The patent creates a multi-functional packaging system where the same physical container can carry both retail and recycling watermarks. The packaging system is designed to accommodate both identification purposes simultaneously, with the retail watermark providing product information for checkout and the recycling watermark providing material identification for recycling sorting.
3Loss of time
If a single scanning system reads both retail and recycling watermarks, then the processing time is reduced, but the measurement precision deteriorates due to interference between different signaling protocols
Solution Approach 1:
The patent segments the watermark decoding process into separate processing paths. The scanning system identifies which watermark type is present (retail or recycling) and routes the decoding process to the appropriate decoder with the correct reference signal and algorithm. This segmentation allows fast processing by avoiding unnecessary decoding attempts and preventing interference between different signaling protocols.
Data Source
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AI summary
A plastic item, such as a beverage bottle, can convey two distinct digital watermarks, encoded using two distinct signaling protocols. A first, printed label watermark conveys a retailing payload, including a Global Trade Item Number (GTIN) used by a point-of-sale scanner in a retail store to identify and price the item when presented for checkout. A second, plastic texture watermark may convey a recycling payload, including data identifying the composition of the plastic. The use of two different signaling protocols assures that a point-of-sale scanner will not spend its limited time and computational resources working to decode the recycling watermark, which may lack data needed for retail checkout. In some embodiments, a recycling apparatus makes advantageous use of both types of watermarks to identify the plastic composition of the item (e.g., relating GTIN to plastic type using an associated database), thereby increasing the fraction of items that are correctly identified for sorting and recycling. In other embodiments the plastic item (or a label thereon) bears only a single watermark. A great number of other features and arrangements are also detailed.