Intermediate Color Space for CMYK Conversion Ink Reduction
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Solution Overview
Problem
Conventional color conversion methods face challenges in efficiently converting between color spaces, particularly when converting from a three-color component space to a four-color component space, often resulting in redundancy and inaccuracies due to the limited gamut and ink usage, leading to issues like banding artifacts and suboptimal ink usage.
Innovation Solution
The method involves identifying preferred color values in a destination color space with more components, using an intermediate color space with the same number of components as the source space, and applying a conversion process that includes a lookup table and smoothing functions to determine optimal color values, thereby maximizing ink reduction and minimizing banding artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional color conversion methods are used to convert from three-color component space to four-color component space, then color space conversion is achieved, but ink usage is suboptimal and banding artifacts occur
Solution Approach 1:
The patent introduces an intermediate color space with three components as a dimensional bridge between the source three-color space and destination four-color space. This intermediate dimension enables optimization of the black component distribution without compromising color accuracy, achieving up to 66% ink savings while maintaining faithful color reproduction through the two-step conversion process.
Solution Approach 2:
The intermediate color space acts as a mediator that decouples the direct mapping between source and destination color spaces. By introducing this intermediate representation with optimized black component generation, the system achieves both accurate color conversion and reduced ink usage without the banding artifacts that plague conventional direct conversion methods.
2Productivity
If more color components are used in the destination color space, then color gamut and ink reduction are improved, but conversion complexity increases
Solution Approach 1:
The patent segments the color conversion process into two distinct stages: first converting from source three-color space to intermediate three-color space, then from intermediate three-color space to destination four-color space. This segmentation allows each stage to be optimized independently, with the intermediate stage handling black component generation, thereby simplifying the overall complex conversion process while improving productivity.
3Loss of substance
If black generation levels are optimized for ink reduction, then ink savings increase, but banding artifacts may occur
Solution Approach 1:
The patent applies local quality optimization by generating the black component specifically in the intermediate color space stage, rather than uniformly distributing it throughout the conversion process. This localized approach to black component generation allows for aggressive ink reduction (up to 66% savings) while maintaining smooth gradients and eliminating banding artifacts through precise control of where and how black is introduced.
Data Source
AI summary
A method includes identifying multiple preferred color values in a destination color space. Each preferred color value is one of a set of colorimetrically equivalent color values. The destination color space has color values defined by a particular number of color components. The method further includes defining intermediate color values in an intermediate color space. The intermediate color values correspond to the multiple color values and the intermediate color space has a number of color components that is less than the particular number of color components of the destination color space. The method also includes identifying a known mapping from the destination color space to a source color space and using the intermediate color values and the known mapping to determine a conversion process for converting source color values to preferred color values.