Image Processing Color Correction via Patch Data Measurement
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Solution Overview
Problem
Conventional color management systems struggle to maintain accurate color reproduction across devices with changing characteristics, leading to inconsistent output quality, especially in multifunction peripherals and electrographic printers, due to the time-consuming and computation-intensive process of creating new ICC profiles for varying device statuses.
Innovation Solution
An image processing system that outputs patch-data items of multi-order colors, measures their color values, calculates reference values using a first color conversion table, calculates distances between measured and reference values, and corrects a second color conversion table to adapt to changing device conditions, allowing for real-time color correction and reduced profile updating time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If new ICC profiles are created to reflect current device characteristics, then color reproduction accuracy is improved, but the process becomes time-consuming and computation-intensive
Solution Approach 1:
The patent segments the color correction process into two distinct parts: (1) a comprehensive ICC profile creation process for establishing the baseline color characteristics, and (2) a rapid color difference calculation process for real-time adjustments. This segmentation allows the time-consuming profile creation to be performed periodically while enabling fast real-time color corrections through simpler calculations of color differences between current and reference states.
Solution Approach 2:
The patent performs preliminary action by pre-calculating and storing reference color values for multiple patches in a reference color space before actual printing operations. These reference values are established in advance when device characteristics are stable, creating a baseline that can be quickly compared against current measurements without requiring full profile recreation.
2Measurement precision
If comprehensive color patches are measured to create accurate profiles, then color matching accuracy is improved, but the number of patches and computational complexity increase
Solution Approach 1:
The patent extracts only the essential color difference information needed for correction by comparing measured patch colors against pre-established reference values. Instead of processing all possible color combinations, the system extracts color difference data for a limited set of representative patches, significantly reducing computational complexity while maintaining color matching accuracy for the full color gamut.
Solution Approach 2:
The patent changes the approach from absolute color value matching to relative color difference calculation. By measuring the difference between current and reference color values rather than comparing against complex ICC profile transformations, the system simplifies the parameters involved in color correction while maintaining accuracy for multi-order colors.
3Stability of the object's composition
If frequent profile updates are performed to track device status changes, then color consistency over time is improved, but processing time and computational resources increase
Solution Approach 1:
The patent implements periodic action by performing full ICC profile creation periodically when device characteristics undergo significant changes, while using rapid color difference-based corrections for routine adjustments between periodic profile updates. This periodic approach maintains color consistency over time while avoiding the computational burden of frequent full profile recreations.
Solution Approach 2:
The patent introduces feedback by continuously measuring patch colors and comparing them against reference values, then using the calculated color differences to adjust the color conversion table. This feedback loop enables real-time color consistency maintenance through simple additive corrections rather than complex full profile recalculations, preserving productivity while ensuring color stability.
Data Source
AI summary
An image processing system and method include allowing an output device to output patch-data items of plural multi-order colors represented by a first color space, measuring the color values, in an absolute color space, of the output patch-data items, calculating reference values by converting the plural multi-order colors represented by the first color space based on a first color conversion table containing correspondence between the first color space and the absolute color space, calculating distances between the color values measured by the color measuring means and the reference values, which correspond thereto, and correcting, based on the calculated distances, a second color conversion table containing correspondence between the absolute color space and an output color space.