Frequency Domain Design of Cluster Dot Screens

摘要

Clustered dots screens are widely used in digital printing. Our research focuses on irregular cluster-dot screens. Irregular screens are appealing since there are many more irregular screens than regular ones. As a result, they provide a larger set of multi-separation screen combinations for avoiding interaction between screening frequencies of concurrent screens. Their down side is that they often have harmonic artifacts. Our design challenge is to reduce these artifacts' visual impact. We present frequency-domain based methods to reduce these artifacts' visual impact. State-of-the-art screens incorporate many, predominantly spatial domain, design considerations which we cannot ignore. Accordingly, the proposed methods are designed to introduce minimal modifications to given screens. The proposed methods eliminate, or reduce the few artifacts visible in a set of irregular screens. This work can be generalized to other printing technologies, and to screen design.