Adaptive cluster dot dithering

Cluster dot dithering is one of the most common halftoning techniques. It i s fast, low in complexity and allows for variability and inconsistencies in point spreads in printer outputs. Determination of the basic dither cell s ize is critical for the quality of the halftoning. There is a basic tradeof f between large and small cell sizes: spatial resolution versus gray tone r esolution. Large dither cell sizes produce good tone resolution but poorly reproduce spatial details in the image. Small dither cells, on the other ha nd, produce fine spatial resolution but lack the tone resolution which prod uces smooth gray tone gradients in halftone images. Typically, cluster dot dithering assumes a predefined dither cell size that compromises between fi ne detail reproduction and good gray tone reproduction. It is clearly advan tageous to allow variability in the dither cell size using small cell sizes in image regions of fine details and using large cell sizes in image regio ns where gray tones are to be accurately reproduced in this paper, we intro duce and discuss several adaptive dithering techniques based on cluster dot dithering. (C) 1999 SPIE and IS&T. [S1017-9909(99)00402-X].