Halftone Independent Printer Characterization Using Binary Patches
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Solution Overview
Problem
Current color printer characterization methods are costly and inefficient due to their dependence on halftone screens, requiring large numbers of patch measurements and computations, especially when dealing with multiple media types, leading to unmanageable data sets and compromising accuracy.
Innovation Solution
A halftone-independent method using a fundamental binary pattern to characterize printers, where a target set of basic patches is printed and measured, and a halftone screen correction factor is calculated to model the printer's response, allowing for accurate characterization without repeated halftone-dependent measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If halftone-dependent patch printing and measurement is used to characterize printers, then characterization accuracy can be achieved, but the number of patches required scales proportionally with the number of halftoning methods, making the process expensive and inefficient
Solution Approach 1:
The patent extracts the halftone screen dependency from the characterization process by introducing a halftone screen correction factor that separates the fundamental binary pattern response from the halftone-specific variations. This allows characterization to be performed independently of any specific halftoning method, eliminating the need to repeat measurements for each halftone screen while maintaining accuracy through the correction factor.
Solution Approach 2:
The patent changes the fundamental parameter from halftone-dependent continuous tone patches to halftone-independent binary patches. By using binary patterns (0 or 1) instead of continuous tone values that vary with halftoning methods, the characterization becomes independent of halftone screens. The correction factor then adjusts for halftone-specific variations without requiring repeated patch measurements.
2Productivity
If the number of patches is reduced to improve characterization speed, then productivity increases, but characterization accuracy deteriorates
Solution Approach 1:
The patent uses a small set of fundamental binary patches that can represent and 'copy' the behavior of any halftone screen through mathematical transformation. Instead of measuring actual halftone patches for each screen, the system measures binary patches once and generates equivalent halftone responses through correction factors, dramatically reducing measurement requirements while maintaining accuracy.
3Adaptability or versatility
If multiple media types are incorporated into characterization, then printer performance across different media is captured, but the number of patches required scales with the number of media types, making the process unmanageable
Solution Approach 1:
The patent creates a universal binary patch characterization method that works across multiple media types and halftone screens through a single correction factor. The fundamental binary patterns serve as a universal basis that can be adapted to any media type by applying the appropriate correction factor, eliminating the need to create separate patch sets for each media-halftone combination.
4Measurement precision
If halftone screen correction factors are calculated for each halftone screen, then accurate color transformation is achieved, but the offline computation time and resources increase
Solution Approach 1:
The patent performs preliminary characterization using binary patches once, storing the results as a fundamental binary pattern response. The halftone screen correction factors are then calculated offline once per halftone screen based on this fundamental response. This preliminary action eliminates the need for repeated measurements and computations for each halftone screen, reducing both measurement time and computational burden while maintaining accuracy.
Data Source
AI summary
A model-based halftone independent method for characterizing a printer equipped with a plural of halftone screens comprises: printing a target set of basic patches comprised of a fundamental binary pattern independent of a halftone screen; measuring true color printer response from the target set; modeling a halftone independent characterization of the printer with the mathematical transformation using the measured response; modeling a first halftone dependent characterization of the printer with the mathematical transformer to generate a first predicted result using a selected halftone screen; comparing a measured response of the printer using the halftone screen with the predicted result to define a correction factor corresponding to the halftone screen; and modeling a halftone dependent characterization of the printer using a predicted response of the fundamental binary pattern and the correction factor.