Jon S. McElvain

Holladay halftoning using super resolution encoded templates

A new method for halftoning using high resolution pattern templates is described, that expands the low level rendering capabilities for engines that support this feature. This approach, denoted super resolution encoded halftoning (SREH) is an extension of the Holladay concept, and provides a compact way to specify high resolution dot growth patterns using a lower resolution Holladay brick. Fundamentally, this new halftoning method involves using the SRE patterns as building blocks for constructing clustered dot growth assemblies. Like the traditional Holladay dot description, the SRE halftone is characterized by a size, height, and shift, all of which are specified at the lower resolution. Each low resolution pixel position in the SRE halftone brick contains a pair of lists. The first of these is a list of digital thresholds at which a transition in SRE patterns occurs for that pixel position, and the second is the corresponding list of SRE codes. For normal cluster dot growth sequences, this provides a simple and compact mechanism for specifying higher resolution halftones. Techniques for emulating traditional high resolution Holladay dots using SREH are discussed, including mechanisms for choosing substitutions for patterns that do not exist among the available SRE patterns.