Signal encoding for difficult environments
This disclosure relates to advanced image signal processing technology including encoded signals and digital watermarking. We disclose methods, systems and apparatus for selecting which ink(s) should be selected to carry an encoded signal for a given machine-vision wavelength for a retail package or other printed design. We also disclose retail product packages and other printed objects, and methods to generate such, including a sparse mark in a first ink and an overprinted ink flood in a second ink. The first ink and the second ink are related through tack and spectral reflectance difference. Of course, other methods, packages, objects, systems and apparatus are described in this disclosure.
1. A method of providing a design for a printed object comprising:
obtaining information associated with a first substrate comprising a first area, the first area comprising a first region and a second region, the first region comprising a layer of an ink flood and a layer of a first substrate, the second region comprising a layer of the ink flood, a layer of sparse mark pattern and a layer of the first substrate, in which an encoded signal is carried by the sparse mark pattern to be printed within the second region with a first ink;
obtaining information associated with the layer of the ink flood to be printed over the sparse mark pattern and the first substrate within the second region with a second ink, in which the second ink comprises a greater tack or adhesion with the first substrate relative to a tack or adhesion with the first ink;
determining whether the first region and the second region comprise a spectral reflectance difference at a machine-vision wavelength in a range of 8%-60%;
selecting a different combination of first ink and second ink when the spectral reflectance difference at the machine-vision wavelength is not within the range of 8%-60%.
2. The method of claim 1 in which the range comprises 12%-20%.
3. The method of claim 1 in which the spectral reflectance difference comprises 12% or higher, and the range comprises 12%-60%.
4. The method of claim 1 in which the first region comprises a darker region relative to the second region.
5. The method of claim 1 in which first reflectance values from the first region at the machine-vision wavelength account for a package's fill and the ink flood.
6. The method of claim 5 in which the first substrate comprises a clear plastic substrate.
7. The method of claim 6 in which second reflectance values from the second region at the machine-vision wavelength account for the package's fill, first ink and the ink flood.
8. The method of claim 7 in which the spectral reflectance difference comprises a difference between the first reflectance values and the second reflectance values.
9. The method of claim 1 in which the printed object comprises a product hag tag.
10. The method of claim 1 in which the printed object comprises a product label.
11. A printed package for surrounding a fill comprising:
a first substrate comprising a first region and a second region, the first region comprising, from top to bottom, a layer of an ink flood and a layer of the first substrate, the second region comprising, in order from bottom to top, a layer of the first substrate, a layer of the ink flood, and a printed sparse mark pattern, in which an encoded signal is carried by the printed sparse mark pattern, and in which first reflectance values from the first region and second reflectance values from the second region comprise a spectral reflectance difference at a machine-vision wavelength in a range of 8%-60%, in which the first reflectance values at the machine-vision wavelength account for the fill, ink flood and the layer of the first substrate, and in which the second reflectance values at the machine-vision wavelength account for the fill, the layer of the first substrate, the ink flood and the printed sparse mark pattern.
12. The printed package for surrounding the fill of claim 11 in which the range comprises 12%-20%.
13. The printed package for surrounding the fill of claim 11 in which the spectral reflectance difference comprises 12% or higher for a range of 12%-60%.
14. The printed package for surrounding the fill of claim 11 in which the first region comprises a darker region relative to the second region.
15. The printed package for surrounding the fill of claim 11 in which the first substrate comprises a clear plastic substrate.
16. The printed package for surrounding the fill of claim 15 in which the fill comprises a black fill.
17. The printed package for surrounding the fill of claim 15 in which the fill comprises a white fill.