Green noise digital halftoning

In this paper, we introduce the concept of green-noise-the mid-frequency component of white-noise-and its advantages over blue-noise for digital halftoning. Unlike blue-noise, which creates the illusion of continuous tone by spreading the minority pixels of a binary dither pattern as homogeneously as possible, green-noise forms minority pixel clusters which are themselves distributed as homogeneously as possible. By clustering pixels, green-noise patterns are less susceptible to image degradation from printer distortions such as dot-overlap (the overlapping of a printed dot with its nearest neighbors), and by adjusting the average number of pixels per cluster, green-noise patterns are tunable to specific printer characteristics. Using both spectral and spatial statistics, we establish models for ideal green-noise patterns.