Abstract: Halftoning to two or more levels by means of ordered dither has always been attractive because of its speed and simplicity. However, the so-called recursive tessellation arrays in wide use suffer from strong periodic structure that imparts an unnatural appearance to resulting images. A new method for generating homogeneous ordered dither arrays is presented. A dither array is built by looking for voids and clusters in the intermediate patterns and relaxing them to optimize isotropy. While the method can be used for strikingly high quality artifact-free dithering with relatively small arrays, it is quite general; with different initial conditions the familiar recursive tessellation arrays can be built. This paper presents the algorithm for generating such arrays. Example images are compared with other ordered dither and error diffusion-based techniques. !12
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