US Patent 11010857 Signal encoding based on spectral requirements

This disclosure relates to advanced image signal processing technology including encoded signals and digital watermarking. A printed object is provided including: a white substrate or printed white background comprising a first area; an ink mixture printed at a first plurality of spatial locations within the first area, the ink mixture printed such that the first area comprises a second plurality of spatial locations without the ink mixture, in which the first plurality of spatial locations is arranged in a 2-dimensional pattern conveying an encoded signal. The white substrate or white background and the ink mixture comprise a spectral reflectivity difference at or around 660 nm in a difference range of 8%-30%. Of course, other implementations, methods, packages, systems and apparatus are described in this patent document.