ABSTRACT
In green-noise halftoning, stochastic moire has the same impact as in frequency modulated halftoning expect that the lower frequency content of green-noise halftones results in lower frequency fluctuations in texture for stochastic moire. The human visual system being more sensitive to low-frequency textures makes the stochastic moire of green-noise more noticeable and, therefore, of greater impact on the resulting print. The drawback to increasing pattern coarseness, for the purpose of minimizing stochastic moire visibility, is the increased low-frequency graininess of the component dither patterns caused by the increased visibility of the clusters. The stochastic moire surface completely characterizes the phase relationship between two overlapping dither patterns at all pixels. Periodic moire created by the superposition of amplitude modulated (AM) patterns has been studied in great detail by I. Amidror et al. who model AM screens as cosinusoidal gratings and their superposition in the spatial domain as convolution in the spectral domain.
