Printer Color Linearization Using Minimal Test Charts
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Solution Overview
Problem
The existing process for linearizing and characterizing image-producing devices, such as printers, is time-consuming and costly due to the need for large color test charts with hundreds of measurement fields, making it impractical for typical users.
Innovation Solution
A process using significantly smaller color test charts with 45 fields for RGB devices and 34 fields for CMYK devices, involving a predefined test chart printed and scanned to generate spectral values, analyzed for linearization curves, and then used to create a conversion table for ICC profile generation, allowing for efficient linearization and characterization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If large color test charts with hundreds of measurement fields are used for linearization and characterization, then measurement precision and device characterization accuracy are improved, but time consumption and process complexity increase significantly
Solution Approach 1:
The patent extracts only the most essential color measurement fields from the complete test chart, selecting a minimal subset that captures the critical characteristics of the imaging device. This selective extraction maintains sufficient characterization accuracy while dramatically reducing the number of measurements required
Solution Approach 2:
The patent applies partial action by performing measurements on only a portion of the full test chart rather than all fields. The selected subset of measurement fields provides adequate data for linearization and characterization without requiring exhaustive measurement of every test field
2Measurement precision
If large color test charts with hundreds of measurement fields are used for linearization and characterization, then device characterization accuracy is improved, but process complexity and user involvement increase
Solution Approach 1:
The complex process of evaluating hundreds of measurement fields is simplified by extracting and focusing only on the critical subset of fields needed for accurate characterization. This reduces the complexity of the overall process while maintaining measurement precision
Solution Approach 2:
The test chart evaluation process is segmented into essential and non-essential portions. By dividing the complete set of measurement fields into a minimal necessary subset, the patent simplifies the characterization process without sacrificing accuracy
3Measurement precision
If standard large color test charts are used for ICC profile generation, then profile accuracy is improved, but cost and time requirements make it impractical for typical users
Solution Approach 1:
The patent enables typical users to generate accurate ICC profiles by performing partial measurements on a reduced set of color test fields. This partial action approach maintains sufficient profile accuracy while making the process practical and efficient for user-level implementation
Solution Approach 2:
The patent extracts the essential measurement fields needed for accurate ICC profile generation, eliminating the need to measure all fields in standard large test charts. This extraction approach significantly reduces the time and resources required while maintaining profile quality
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables faster and less involved linearization and characterization of printers without quality loss, considering print head, ink, and paper performance, reducing the need for extensive measurement fields and simplifying the ICC profile generation process.
Implementation Method 1
the printed colour test chart is scanned according to colour (block 3) by way of a spectrophotometer or colour measurement device
Data Source
AI summary
Exemplary methods are directed to the linearization and characterization of an image producing device. In the method, a color test chart of the device is reproduced and measured based on a small number of color measurement fields with defined device color values. Associated color values are determined for each color measurement field and used to calculate linearization curves for the device. Additionally, by analysis of the device color values, the measured color values, and device behavior, an expanded color test chart with expanded device color values and associated expanded color values is calculated. The number of color measurement fields in the expanded color test chart is larger than the number of color measurement fields in the original color test chart. An ICC profile for the device is calculated from the expanded device color values and the expanded color values.