Digital halftoning using pre-computed maps

Digital halftoning techniques using threshold matrices have clear advantage s in their speed of operation together with the possibility of controlling the produced dot patterns. However, due to an inherent restriction discusse d in this article, the quality of dispersed dots halftones produced with th is technique is not always satisfactory. In this article we describe a tech nique that overcomes this restriction, thereby allowing for an individual d esign of each tint value without any loss of speed. We also propose a desig n strategy for obtaining near optimal tints without losing the necessary co rrelation between tints. High quality reproduction of both tints and transi tions between different intensity levels is thus possible. This technique a lso allows for new types of dispersed dot halftones with predefined micro s tructures. Halftones with micro structures are less sensitive to both mecha nical and optical dot gain and can advantageously be used in processes with severe dot gain or low printing precision. In this article we present two types of micro structures together with several image examples.