Scanner Profile Selection for Accurate Color Reproduction
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Solution Overview
Problem
Existing color conversion methods in image processing systems face challenges in securing color reproducibility due to the need for extensive storage and time-consuming creation of scanner profiles for various paper types, often resulting in inappropriate profile selection and reduced color accuracy.
Innovation Solution
A method that involves obtaining paper white information, searching for registered scanner profiles with similar spectral reflectance and scanner response values, determining if a new profile is needed, and creating or selecting the optimal profile based on approximation degrees and thresholds to ensure accurate color conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If scanner profiles are prepared for all types of paper used by a user, then color reproducibility is improved, but storage device capacity requirement increases
Solution Approach 1:
The patent creates a universal scanner profile that can be applied to multiple paper types. Instead of preparing separate profiles for each paper type, the system uses a single profile that works across different paper types, reducing storage requirements while maintaining color reproducibility. The profile is created by measuring color patches on a representative paper type and using that profile for converting RGB values to XYZ values for various paper types.
Solution Approach 2:
The patent changes the approach from storing multiple complete profiles to storing a single profile with modified parameters. The system adjusts the profile creation process to account for different paper types through parameter modifications rather than creating entirely separate profiles, thereby reducing storage capacity requirements while maintaining color accuracy.
2Reliability
If a scanner profile is created for another paper type when needed, then color reproducibility for that paper type is improved, but processing time increases
Solution Approach 1:
The patent performs preliminary actions by creating a universal scanner profile in advance that can be used for multiple paper types. Instead of creating profiles on-demand for each paper type, the system prepares a versatile profile beforehand that covers various paper types, thereby reducing the processing time required when color conversion is needed for different papers.
3Measurement precision
If a spectrophotometer is used to measure paper white portion and select a printing profile, then paper type identification is improved, but color reproducibility cannot be secured due to glossiness differences
Solution Approach 1:
The patent introduces an intermediary approach by using a scanner (which captures glossiness information) in addition to or instead of relying solely on a spectrophotometer. The scanner's RGB measurements serve as an intermediary that accounts for surface properties like glossiness, allowing the system to select or create profiles that consider both paper type and surface characteristics, thereby improving color reproducibility.
Solution Approach 2:
The patent combines measurements from different devices (spectrophotometer and scanner) to create a composite assessment of paper properties. By integrating data from multiple sources, the system achieves a more comprehensive understanding of paper characteristics including glossiness, leading to better profile selection and improved color reproducibility.
4Manufacturing precision
If color patches including combinations of C, M, Y, and K are output and measured to create a scanner profile, then color conversion accuracy is improved, but the amount of paper used increases
Solution Approach 1:
The patent uses digital copying and simulation techniques to reduce physical paper consumption. Instead of creating and measuring color patches on actual paper for every profile creation, the system uses digital models and existing profile data to simulate and predict color behavior, thereby maintaining color conversion accuracy while significantly reducing the amount of physical paper required.
Data Source
AI summary
A color conversion method includes: a step (a) of obtaining paper white information including a spectral reflectance and a scanner response value of a paper white portion of a document, a step (b) of searching for a registered scanner profile corresponding to paper white information the same as or similar to the paper white information, from a plurality of registered scanner profiles for paper types, and a step (c) of determining whether a new scanner profile needs to be created corresponding to the paper white information obtained in the step (a), according to a result of searching in the step (b).