SPECTRAL EDGE MARKING FOR STEGANOGRAPHY OR WATERMARKING
First Claim
1. A system for detecting visibly hidden content on a print media, comprising:
- a print media printed with image content comprising one or more normal printing process colorants;
printing of at least one spectral edge marker material onto at least one image region of the print media to provide visually hidden data, wherein the spectral edge marker material has a substantial spectral absorption just outside the human visible spectrum;
an image capture device having a visible spectral response which includes both red, green, and blue spectrally distinct imaging channels and an overall spectral response including a spectral region just outside the visible spectrum;
wherein the at least one normal printing process colorant is printed on the print media in regions that are both overlapping with and adjacent to the image regions having the at least one selectively printed spectral edge marker material, such that image regions having only the at least one normal process colorant and the image regions having the at least one selectively printed spectral edge marker material and the at least one normal printing process colorant are color matched; and
wherein the image capture device detects the at least one spectral edge marker material ink using at least one spectrally distinct color imaging channel having a spectral response inclusive of at least a portion of the spectral absorption of the at least one spectral edge marker material.
13 Assignments
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Accused Products
Abstract
A system for detecting visibly hidden content on a print media (200) in which image content is printed with one or more normal printing process visible colorants (340), and which further includes embedded hidden data (220) printed with spectral edge markers (320). These spectral edge marker materials (320) have a substantial spectral absorption just outside the human visible spectrum, either at the UV edge or IR edge, but only slight visible absorption which is masked by the visible colorants (340). Although the hidden data is nominally visually imperceptible, an image capture device (250) having a visible spectral response from at least one spectrally distinct color imaging channel that extends into a spectral region just outside the visible spectrum where the spectral edge marker absorption occurs, can then detect the hidden data.
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Citations
25 Claims
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1. A system for detecting visibly hidden content on a print media, comprising:
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a print media printed with image content comprising one or more normal printing process colorants; printing of at least one spectral edge marker material onto at least one image region of the print media to provide visually hidden data, wherein the spectral edge marker material has a substantial spectral absorption just outside the human visible spectrum; an image capture device having a visible spectral response which includes both red, green, and blue spectrally distinct imaging channels and an overall spectral response including a spectral region just outside the visible spectrum; wherein the at least one normal printing process colorant is printed on the print media in regions that are both overlapping with and adjacent to the image regions having the at least one selectively printed spectral edge marker material, such that image regions having only the at least one normal process colorant and the image regions having the at least one selectively printed spectral edge marker material and the at least one normal printing process colorant are color matched; and wherein the image capture device detects the at least one spectral edge marker material ink using at least one spectrally distinct color imaging channel having a spectral response inclusive of at least a portion of the spectral absorption of the at least one spectral edge marker material. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification