Embedding digital watermarks in spot colors
First Claim
1. A method of digital watermarking a spot color comprising:
- providing a first multicolor approximation of the spot color;
based at least in part on the first multicolor approximation, providing multicolor components including a digital watermark signal; and
combining a percentage of the spot color with the multicolor components.
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Accused Products
Abstract
The present invention relates to digitally watermarking spot color images. In one embodiment, an original spot color is replaced with a combination of cyan (C), magenta (M) and yellow (Y) components and the original spot color. The CMY components convey a digital watermark. Preferably, a large percentage halftone process screens the spot color. This screened spot color is combined with the CMY components. Combining the CMY components with a large percentage halftone screening results in a watermarked image color that closely approximates to the original spot color. In another embodiment, a spot color is halftone-screened to a percentage of its original intensity. The screened-back spot color is modulated to accommodate a watermark signal.
162 Citations
28 Claims
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1. A method of digital watermarking a spot color comprising:
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providing a first multicolor approximation of the spot color; based at least in part on the first multicolor approximation, providing multicolor components including a digital watermark signal; and combining a percentage of the spot color with the multicolor components. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A digital watermarking method comprising:
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screening a spot color; and combining the screened spot color with multicolor components, wherein the multicolor components comprise at least cyan, magenta, and yellow, and wherein the multicolor components include hidden data. - View Dependent Claims (13, 14, 15, 16, 17)
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18. A paper product comprising an image printed thereon, the printed image including a combination comprising a halftone-screening of a spot color ink, and at least cyan, magenta and yellow inks, wherein the cyan, magenta and yellow inks include a digital watermark signal.
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19. A method of digital watermarking an image including a spot color comprising:
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approximating the spot color with cyan, magenta and yellow components; changing the cyan, magenta and yellow components to include a digital watermark; combining the changed cyan, magenta and yellow components with a scaled spot color component; and applying the combined components to a medium. - View Dependent Claims (20, 21)
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22. A method of embedding a spot color area comprising:
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screening the spot color area to a percentage of its original intensity; and modulating of a set of pixels within the spot color area to comprise a watermark signal, wherein the screened spot color area varies in intensity or luminance, and said modulating adapts modulation of the watermark signal according to localized areas of intensity or luminance resulting in the watermark signal varying across the spot color area; and applying the spot color area to a medium. - View Dependent Claims (23, 24, 25, 26, 27, 28)
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Specification