Digimarc Corporation
Sparse modulation for robust signaling and synchronization

Abstract:

The present disclosure relates to advanced image processing and encoded signal processing. One claim currently recites an image processing method comprising the acts: receiving a digital representation of artwork, the artwork having an area of uniform color; generating a two-dimensional data signal that redundantly encodes a plural-bit message, the data signal comprising plural elements, each of which has a single bit value; receiving a two-dimensional synchronization signal comprising plural elements, each of which has a plural-bit value, each element of said data signal having an element of the synchronization signal corresponding thereto; processing the two-dimensional data signal with the two-dimensional synchronization signal and with a gradient function to yield a two-dimensional gradient marking signal; and printing an ink counterpart of the gradient marking signal on a medium with the artwork, said printing comprising printing plural dithered two-dimensional blocks of at least four contiguous elements each, in which one or more elements of each block are printed to be dark. Of course, other claims and combinations are described as well.