Halftone Screen Tile Layout for Print Authentication and Moiré Control
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Solution Overview
Problem
Existing halftone screens in printing technologies struggle to avoid moiré patterns while maintaining image quality, and there is a need for a method to authenticate the source of printed outputs.
Innovation Solution
Implementing a halftone screen encoding a unique signature arrangement of halftone screen tiles, where the relative placement of first and second halftone tiles with distinct patterns forms a discernible pattern in the printed output, allowing for authentication and validation of the print source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional halftone screen is used, then image quality is maintained, but moiré patterns appear in the printed output
Solution Approach 1:
The halftone screen is divided into multiple tiles, each with distinct patterns. These segmented tiles are arranged in a predetermined spatial configuration that encodes authentication information. The segmentation allows the screen to simultaneously maintain image quality through proper halftoning while avoiding moiré patterns through the distributed tile structure.
Solution Approach 2:
Different tiles in the halftone screen have asymmetric and distinct patterns rather than uniform repetition. This asymmetry in tile patterns helps prevent moiré interference while the overall arrangement maintains the necessary image rendering qualities.
2Reliability
If a halftone screen with unique signature arrangement is implemented, then authentication capability is enabled, but device complexity increases
Solution Approach 1:
The halftone screen serves multiple functions simultaneously: it performs standard halftoning for image quality, encodes authentication signatures through tile arrangement, and provides moiré pattern avoidance. This multi-functionality is achieved by integrating the signature encoding into the existing halftone screen structure without requiring separate authentication hardware.
3Loss of information
If distinct halftone tiles are arranged in predetermined patterns, then signature encoding is achieved, but processing complexity increases
Solution Approach 1:
The authentication signature is embedded in advance during the halftone screen generation phase through the predetermined arrangement of distinct tiles. This preliminary encoding means that no additional processing is required during the actual printing operation, as the signature is already baked into the halftone screen data that drives the print head.
Data Source
AI summary
In an example, a method includes obtaining, by at least one processor, a first halftone screen tile having a first halftone pattern. In some examples, the method further comprises obtaining a second halftone screen tile having a second halftone pattern. The method may include determining a halftone screen having a predetermined spatial arrangement of the first and second halftone screen tiles, wherein the relative placement of the first and second halftone screen tiles in the predetermined spatial arrangement provides a signature for the halftone screen which when applied to image data provides a printed output in which the signature is discernible.