US 7,889,390 B2 · System and method for the generation of correlation-based digital watermarks using uniform-rosette color halftoning

Abstract

Systems and method for digitally reproducing a moiré-free color halftone output image having an embedded correlation-based digital watermark are provided using an enhanced halftone screen set consisting of a halftone screen for each of N colorants forming N color separations (where N≧3). The N different uniform rosette halftone screen configurations are generated such that each meets uniform rosette halftone screen conditions. A corresponding three-dimensional threshold array is generated for each halftone screen configuration having a phase shift value as an input. The color input image is halftoned, halftoning each one of the N different color separations using a corresponding halftone screen configuration and three-dimensional threshold array to form a moiré-free color output image having the correlation-based digital watermark embedded therein. A single key can be used to produce a full color image of the output image having the watermark image visible therein.

Claims16

Dependent claims

An image forming method for digitally reproducing a moiré-free color:

halftone image having an embedded correlation-based digital watermark using an enhanced halftone screen set consisting of a halftone screen for each of N colorants forming N color separations (where N≧3), the method comprising:
providing a color input image to be watermarked;
providing a watermark image to be embedded in the N-color image;
generating N different uniform rosette halftone screen configurations each meeting uniform rosette halftone screen conditions;
generating N three-dimensional threshold arrays each having a phase shift value as an input;
and
halftoning the color input image by halftoning N different color separations using a different one of the halftone screen configurations and three-dimensional threshold arrays for each color separation to produce a moiré-free color output image having the watermark image embedded therein.

4 more elements

A system for digitally reproducing an N (where N≧3) color channel moiré-free color halftone output image having an embedded correlation-based digital watermark, comprising:

an input image source providing a color input image;
image memory for storing the input image to be watermarked;
watermark memory for storing the watermark image to be embedded in the color input image;
and
an image processor for generating N (where N≧3) different uniform rosette halftone screen configurations each meeting uniform rosette halftone screen conditions, generating N three-dimensional threshold arrays each having a phase shift value as an input, and halftoning the color input image by halftoning N different color separations using a different one of the halftone screen configurations and three-dimensional threshold arrays for each color separation to produce a moiré-free color output image having the watermark image embedded therein.

2 more elements

Dependencies are inferred from the claim text.

System and method for the generation of correlation-based digital watermarks using uniform-rosette color halftoning

Life of this patent

System and method for the generation of correlation-based digital watermarks using uniform-rosette color halftoning

Life of this patent

Abstract

Claims16