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, are establish models for ideal green noise patterns.
['Daniel L. Lau', 'Gonzalo R. Arce', 'Neal C. Gallagher']
Green noise digital halftoning