Automated methods for distinguishing copies from original printed objects
First Claim
1. A method for analyzing an image of a printed object to determine whether the printed image is a copy or an original, the method comprising:
- determining whether a machine readable auxiliary signal is embedded in the image, wherein the auxiliary signal is embedded at embedding locations using a set of two or more print structures that change in response to a copy operation, the change causing a divergence or convergence of a characteristic of the print structures such that the machine readable signal becomes more or less detectable; and
based on evaluating the machine readable auxiliary signal, determining whether the printed object is a copy or an original.
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Accused Products
Abstract
This disclosure describes methods for using embedded auxiliary signals in documents for copy detection and other applications. In on application, the auxiliary signal is formed as an array of elements selected from a set of print structures with properties that change differently in response to copy operations. These changes in properties of the print structures that carry the embedded auxiliary signal are automatically detectable. For example, the changes make the embedded auxiliary signal more or less detectable. The extent to which the auxiliary data is detected forms a detection metric used in combination with one or more other metrics to differentiate copies from originals. Examples of sets of properties of the print structures that change differently in response to copy operations include sets of colors (including different types of inks), sets of screens or dot structures that have varying dot gain, sets of structures with different aliasing effects, etc. Robust and fragile watermarks are used in Image Replacement Documents for a variety of applications. Digital watermarks act as on-board mediators in authentication of a variety of printed documents. Finally, digital watermarks are used to help manage quality of the scanners used in imaging systems.
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Citations
21 Claims
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1. A method for analyzing an image of a printed object to determine whether the printed image is a copy or an original, the method comprising:
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determining whether a machine readable auxiliary signal is embedded in the image, wherein the auxiliary signal is embedded at embedding locations using a set of two or more print structures that change in response to a copy operation, the change causing a divergence or convergence of a characteristic of the print structures such that the machine readable signal becomes more or less detectable; and
based on evaluating the machine readable auxiliary signal, determining whether the printed object is a copy or an original. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for creating an image to be printed on a printed object, the image being used to determine whether the printed image is a copy or an original, the method comprising:
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embedding a machine readable auxiliary signal in the image, wherein the auxiliary signal is embedded at embedding locations using a set of two or more print structures that change in response to a copy operation, the change causing a divergence or convergence of a characteristic of the print structures such that the machine readable signal becomes more or less detectable; and
creating a metric to detect the convergence or divergence from an image scanned of a suspect printed object to determine whether the suspect printed object is a copy or an original. - View Dependent Claims (16)
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17. A method for analyzing an image of a printed object to determine whether the printed image is a copy or an original, the method comprising:
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determining whether a machine readable auxiliary signal is embedded in the image, wherein the auxiliary signal is embedded at embedding locations using a print structure that changes in response to a copy operation, the change causing a divergence or convergence of a characteristic of the print structure such that the machine readable signal becomes more or less detectable, the print structure comprising a color that changes in response to a copy operation; and
based on evaluating the machine readable auxiliary signal, determining whether the printed object is a copy or an original. - View Dependent Claims (18, 19)
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20. A method for creating an image to be printed on a printed object, the image being used to determine whether the printed image is a copy or an original, the method comprising:
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embedding a machine readable auxiliary signal in the image, wherein the auxiliary signal is embedded at embedding locations using a print structure that changes in response to a copy operation, the change causing a divergence or convergence of a characteristic of the print structures such that the machine readable signal becomes more or less detectable; and
creating a metric to detect the convergence or divergence from an image scanned of a suspect printed object to determine whether the suspect printed object is a copy or an original. - View Dependent Claims (21)
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Specification