Geometric enumerated watermark embedding for spot colors
The present invention relate generally to digital watermarking spot colors. A process color approximation can be used for a spot color, and chrominance watermarking can be performed to insert a watermark. These techniques are particularly suitable for product packaging, color brochures, etc.
1. A digital watermarking method comprising:
using a programmed electronic processor, modeling a first color ink and a second color ink in terms of CIE Lab values;
transforming the values through modulating with a watermarking signal;
scaling the modulated values in a spatial frequency domain;
spatially masking the scaled, modulated values;
providing the spatially masked, scaled, modulated values, such values comprising the watermark signal.
2. A non-transitory computer readable medium comprising instructions stored thereon to cause an electronic computing device to perform the method of claim 1 .
3. An apparatus comprising:
memory for storing data representing a first color ink and a second color ink;
one or more programmed electronic processors programmed for:
modeling the data representing the first color ink and the second color ink in terms of CIE Lab values;
transforming the values by modulating with a watermarking signal;
scaling the modulated values in a spatial frequency domain;
spatially masking the scaled, modulated values;
providing the spatially masked, scaled, modulated values, such values comprising the watermark signal.
4. A non-transitory computer readable medium comprising instructions stored thereon to cause one or more processors to perform the following:
modeling a first color ink and a second color ink in terms of CIE Lab values;
modulating the values with a watermarking signal;
scaling the modulated values in a spatial frequency domain;
spatially masking the scaled, modulated values;
providing the spatially masked, scaled, modulated values, such values comprising the watermark signal.
5. An apparatus comprising:
memory for storing data representing a first color ink and a second color ink;
means for modeling the data representing the first color ink and the second color ink in terms of CIE Lab values;
means for transforming the values by modulating the values with a watermarking signal;
means for scaling the modulated values in a spatial frequency domain;
means for spatially masking the scaled, modulated values;
means for outputting the spatially masked, scaled, modulated values, such values comprising the watermark signal.