Serialized digital watermarking for variable data printing

In a method of compiling multiple 2D code patterns for labeling multiple respective items, each 2D code pattern comprising plural marks, each mark occupying a corresponding location in its respective 2D code pattern, each of said multiple 2D code patterns being different, each 2D code pattern expressing a payload signal component and a reference signal component, the reference signal component enabling a compliant decoder to determine scale and rotation of a 2D code pattern depicted within a camera-captured image of a labeled item, an improvement comprising the acts:

• identifying a first set of locations that are consistently occupied by marks in said multiple 2D code patterns;
• storing first data identifying said first set of locations in a first data structure;
• for each of said multiple 2D code patterns, identifying a second set of locations occupied by marks, excluding locations included in the first set of locations;
• and
• for each of said multiple 2D code patterns, storing second data identifying said second set of locations in a second data structure;
• wherein said second data structure expresses each mark location by a single datum rather than two or more data, said single datum being a single binary number, thereby effecting a reduction in storage medium capacity required for data structure storage.

In a method of printing multiple 2D code patterns for labeling multiple respective items, each 2D code pattern comprising plural marks, each mark occupying a corresponding location in its respective 2D code pattern, each of said multiple 2D code patterns being different, each 2D code pattern expressing a payload signal component and a reference signal component, the reference signal component enabling a compliant decoder to determine scale and rotation of a 2D code pattern depicted within a camera-captured image of a labeled item, an improvement comprising the acts:

• (a) reading first data from a first data structure, the first data indicating a first set of mark locations;
• (b) reading second data from a second data structure, the second data indicating a second set of mark locations, the second data expressing each mark location by a single datum rather than two or more data, said single datum being a single binary number;
• (c) printing a composite 2D code pattern having marks placed at mark locations indicated by the first data and the second data;
• and
• (d) repeating at least acts (b) and (c) multiple times, each with a different second set of mark locations, yielding different composite 2D code patterns.