ABSTRACT
Digital halftoning refers to algorithms that convert continuous-tone images to binary, for display in bilevel devices such as ink jet and electro-photographic printers. Halftoning’s contribution to computer industry has been essential to its success. A surprising development in the field of halftoning has been the recent discovery that the original relationship in the spacing between printed dots and the corresponding gray-levels, as proposed by R. Ulichney in his blue-noise model, was wrong. Multitoning presents inherent advantages with respect to halftoning in that the use of multiple inks reduces contouring and the overall visual error of the image. The process of direct binary search is an algorithm that has largely succeeded, assuming that an appropriate seed pattern and visual model are selected. Green-noise results in a stochastic pattern of dots that is pleasant when compared with white-noise or ordered-dithering, but since green-noise creates clusters of dots, its dot pattern is more obvious to the human visual system than blue-noise.
