Uniform rosette for moire-free color halftoning

摘要

By selecting halftone frequencies from high-order harmonics of two common rosette fundamentals for all color separations, a true moire-free color halftoning can be achieved. With such screen configurations, the interference between any two frequency components, fundamentals or high-order harmonics, of different colors will also result in a linear combination of the two rosette fundamentals. Thereby, no visible interference, or moire, at all will be shown in the output. The halftone outputs are two-dimensionally repeated patterns, as visually pleasant uniform rosettes. The uniform-rosette configurations can be implemented by single-cell non-orthogonal halftone screens for digital halftoning. Unlike "dot-on-dot" screening, or using one screen for all colors, uniform-rosette halftoning is robust to mis-registration between color separations. Several designs of uniform-rosette halftone screens have been successfully applied to Xerox iGen3 color printers for high-quality color reproduction.