Halftone-Independent Scanner Profiling via Binary Pattern Modeling
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Solution Overview
Problem
Existing color scanner characterization techniques are not halftone-independent, leading to errors when scanning images produced with different halftoning methods, as they are sensitive to the specific halftone used in the scanner profile creation, resulting in inaccurate color prediction and the need for multiple scanner profiles for various halftones.
Innovation Solution
A halftone-independent scanner characterization target based on the 2×2 binary printer model is used, which allows for the prediction of gray levels and color appearance across various halftones by modeling any binary pattern as a combination of seven fundamental patterns, eliminating the need for multiple profiles and reducing user burden.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a scanner profile is created using a specific halftoning method, then the scanner characterization is accurate for that halftone, but it produces errors when scanning images created with different halftoning methods
Solution Approach 1:
The patent applies universality by creating a single scanner profile that works across multiple halftoning methods. Instead of requiring separate profiles for each halftone type (screen halftone, stochastic, clustered), the invention develops a characterization approach using fundamental binary patterns (2×2 patterns) that can represent any halftone structure. This universal profile eliminates the need for users to match profiles to specific halftones, resolving the contradiction between accuracy for a specific halftone and compatibility across different halftones.
Solution Approach 2:
The patent employs parameter changes by transforming the scanner characterization from being dependent on specific halftone parameters (screen frequency, dot pattern) to being based on fundamental binary pattern parameters. By changing the basis of characterization from halftone-specific features to universal binary patterns, the system can accurately represent any halftone variation without requiring profile changes, thus maintaining measurement precision while improving adaptability.
2Measurement precision
If multiple scanner profiles are created for different halftones, then accuracy for each halftone is improved, but the device complexity and user burden increase
Solution Approach 1:
The invention reduces device complexity by replacing multiple halftone-specific scanner profiles with a single universal profile. The universal profile based on 2×2 binary patterns can characterize any halftoning method, eliminating the need for users to manage multiple profiles and reducing the overall system complexity while maintaining color accuracy across different halftones.
Solution Approach 2:
The patent extracts the essential characteristics of halftoning by focusing on fundamental binary patterns rather than specific halftone implementations. By taking out the common binary pattern structure that underlies all halftones and using that as the basis for profile creation, the system simplifies the characterization process from managing multiple complex halftone-specific profiles to using a single profile based on extracted fundamental patterns.
3Ease of manufacture
If a finite set of halftoning schemes is used for scanner characterization, then the characterization process becomes practical, but it cannot cover the vast variety of halftoning methods employed in practice
Solution Approach 1:
The patent resolves this contradiction by changing the parameter basis from specific halftone configurations to fundamental binary patterns. The 2×2 binary pattern system provides a practical, finite set of basis patterns that can be easily manufactured for characterization, while simultaneously providing universal coverage for any halftoning method through linear combination, thus achieving both ease of manufacture and broad adaptability.
Data Source
AI summary
A method and system is disclosed for characterizing a color scanner comprising generating a halftone-independent target of color patches, printing the target on a color hardcopy device, measuring the target to obtain device-independent color values, scanning the target to obtain scanner color values, and building a scanner profile that relates scanned color values to device-independent color values.