On Filter Techniques for Generating

We use the term \Blue Noise Mask" to mean a halftone threshold array that has been constructed to produce pleasing, unstructured (but not white noise) binary patterns. An eecient way to produce a Blue Noise Mask is to construct a set of binary patterns that are constrained by neighboring levels. These binary patterns are appropriate for diierent grey levels, and can be summed to form a single threshold array. The key to production of these binary patterns is ltering operations, which have received appropriate attention as an important element in the-nal quality of the halftone patterns. In this paper, we survey the peer reviewed, scientiic literature concerning lter design, emphasizing both the frequency domain and the corresponding image domain operations. Some limitations of ltering are examined, along with some novel lter types. Finally, the role of post-ltering, or adjunct, criteria are examined for special eeects.