Halftone Screen Offset Cluster Patterns for Moiré Reduction
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Solution Overview
Problem
Existing printing technologies face issues with moiré patterns and periodic artefacts in two-dimensional and three-dimensional printing, which detract from image quality due to the interaction of print agents and halftone screens, particularly in multi-color and high-resolution prints.
Innovation Solution
The method involves designing halftone screens with offset cluster patterns and varying screen angles and resolutions to combat moiré effects, and using replicated tiles to reduce computational resources, while applying a Gaussian distribution to determine centre position offsets to minimize periodic artefacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If halftone screens with regular cluster patterns are used, then printing process is simple, but moiré patterns and periodic artefacts appear reducing image quality
Solution Approach 1:
The patent applies asymmetry by introducing offset cluster patterns where the center position of clusters varies across different cells of the halftone screen. This breaks the regular periodic symmetry that causes moiré patterns, while maintaining computational efficiency through replicated tile structures.
Solution Approach 2:
The patent implements local quality by applying different offset values to different regions or cells of the halftone screen. Each cell can have its cluster center positioned differently according to a Gaussian distribution, creating local variations that eliminate periodic artefacts while preserving overall image quality.
2Manufacturing precision
If high-resolution printing is performed, then print quality improves, but periodic artefacts and graininess become more noticeable
Solution Approach 1:
At high resolutions, the patent uses asymmetric offset cluster patterns to prevent the formation of visible periodic artefacts and graininess. By varying cluster center positions across cells, the regular patterns that become noticeable at high resolution are disrupted, maintaining image quality.
3Object-affected harmful factors
If cluster pattern centre positions are varied to reduce artefacts, then image quality improves, but computational complexity increases
Solution Approach 1:
The patent changes the parameter of cluster center position by introducing offsets based on a Gaussian distribution. This parameter variation reduces periodic artefacts while maintaining a systematic approach that can be implemented through replicated tiles, balancing complexity reduction.
Solution Approach 2:
The patent uses copying by creating replicated tiles that can be reused across the halftone screen. This reduces computational complexity by avoiding the need to design unique patterns for every cell, while still achieving artefact reduction through offset variations within the replicated structure.
4Object-affected harmful factors
If offset cluster patterns with Gaussian distribution are applied, then periodic artefacts are minimized, but processing complexity increases
Solution Approach 1:
The patent applies parameter changes by using a Gaussian distribution to determine offset values for cluster centers. This statistical approach minimizes periodic artefacts through controlled randomness while providing a systematic method that can be efficiently implemented in processing algorithms.
Data Source
AI summary
In an example, a method includes determining, using a processor, a first halftone screen comprising a plurality of cells. Each of the cells may contain a predetermined pixel cluster pattern, and a centre position of a cluster pattern within a first cell may be different to a centre position of a cluster pattern within a second cell.