Data hiding through optimization of color error and modulation error
AssigneeDigimarc Corporation
InventorsAlastair M. Reed, Tomas Filler, Kristyn R. Falkenstern, Yang Bai
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Abstract
The present disclosure relates generally to data hiding for retail product packaging and other printed objects such as substrates. One embodiment embeds an information signal in a spot color for printing on various substrates. The spot color is screened, and overprinted with process color tint. The tint is modulated prior to overprinting with optimized signal tweaks. The optimization can include consideration of a detector spectral dependency (e.g., red and/or green illumination). Many other embodiments and combinations are described in the subject patent document.
Claims19
A printed label or packaging comprising:
- a first printed area, the first printed area comprising a combination of i) a first color (S1), and ii) a second color (S2), in which encoded information is provided on said printed label or packaging through modulation of data representing the second color (S2) with max (positive) and min (negative) tweaks;
- in which the combination has been optimized by:
- determining a color error between data representing third color data (S3) and a combination of S1 and S2,
- determining an information modulating error associated with the max and min tweaks;
- and
- minimizing the color error and minimizing the information modulating error in the combination of S1 and S2;
- a second printed area including a 1-dimensional or 2-dimensional barcode;
- and
- a third printed area including text information printed thereon.
An image processing system for generating a design for a printed label or packaging comprising:
- memory storing data representing a first color (Si);
- means for minimizing i) a color match error between (S1) and a combination of data representing second color data (S2) and data representing third color data (S3), the combination including auxiliary encoded information in (S3), and ii) an information modulating error associated with modulations of (S3) that carry the auxiliary encoded information,
- said means for minimizing being constrained by a spectral component associated with an anticipated information detector,
- means for obtaining color percentage values associated with at least (S3) and a signal strength value for regulating the modulations;
- means for outputting the color percentage values and signal strength value;
- means for encoding a signal in the design using the color percentage values and signal strength value, said means for encoding signal encoder generating an encoded design;
- and
- means for determining signal robustness associated with the encoded design.
An image processing method comprising:
- obtaining color data representing a spot color ink;
- obtaining data representing a process color ink tint, the process color ink tint including at least a Cyan (C) component, a Magenta (M) component and a Yellow component (Y);
- determining an overprinting of the process color ink tint with the color data;
- decomposing the process color ink tint into a maximum signal tweak and a minimum signal tweak, each of the maximum signal tweak and the minimum signal tweak having a Cyan (C) component, a Magenta (M) component and a Yellow component (Y);
- minimizing a color error metric of the overprinting relative to the data representing the spot color ink;
- optimizing the maximum signal tweak and the minimum signal tweak according to at least a spectral dependency;
- transforming the process color ink tint with the maximum signal tweak and the minimum signal tweak to represent an information signal, said transforming yielding a transformed process color ink tint;
- and
- outputting the transformed process color ink tint for overprinting with the color data.
Dependencies are inferred from the claim text.