Inverse Device Model for CMYKcm Colorant Control
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Solution Overview
Problem
Current color management technologies face challenges in producing accurate color transforms for inkjet printers with multiple colorants, particularly CMYKcm systems, as they result in excessive ink usage and image artifacts like graininess, bleeding, and banding, due to the complex mathematics involved in managing six color channels, and existing methods like Under Color Removal (UCR) are not suitable for systems with extra colorants like orange and green.
Innovation Solution
A method to determine n-dimensional colorant control signals that map to a point in an m-dimensional color space by using a forward device model, simplex transformations, and sequential slicing processes, allowing for the selection of optimal colorant combinations based on cost functions that consider ink volume and noise, thereby avoiding excessive ink usage and improving image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional color transform methods are used for CMYKcm printers, then color reproduction is achieved, but excessive ink usage and image artifacts occur
Solution Approach 1:
The patent segments the colorant control signal determination into multiple discrete steps: forward device model determination, simplex determination, range space simplex mapping, and sequential slicing processes. This segmentation allows for precise control of each transformation stage, enabling optimal colorant selection that minimizes ink usage while maintaining color accuracy.
Solution Approach 2:
The patent transforms the colorimetric data from traditional 3D color space to 4D colorant control signal space, adding an extra dimension for optimization. By determining n-dimensional colorant control signals that map to m-dimensional color space points (where n>m), the system gains additional degrees of freedom to minimize ink usage while achieving the desired color reproduction.
2Manufacturing precision
If traditional color transform methods are used for CMYKcm printers, then color reproduction is achieved, but image artifacts like graininess and banding occur
Solution Approach 1:
The patent performs preliminary determination of the forward device model and colorant control signal simplexes before actual color transformation. By pre-establishing the mapping relationships and valid signal ranges through sequential slicing processes, the system proactively avoids combinations that would produce artifacts like graininess and banding, rather than correcting them after occurrence.
Solution Approach 2:
The patent introduces range space simplexes as an intermediary representation between the colorimetric data and the final colorant control signals. This intermediary layer allows for validation and optimization of the transformation process, ensuring that only artifact-free colorant combinations are selected while maintaining accurate color reproduction.
3Device complexity
If UCR or Black Generation techniques are used, then color transform is simplified, but they are not suitable for systems with extra colorants like orange and green
Solution Approach 1:
The patent develops a universal color transform method that works for any n-colorant system where n>m, including traditional CMYK (4>3) and extended CMYKcm (6>3) systems. The methodology uses general n-dimensional simplex determination and m sequential slicing processes that can be applied regardless of the specific number of colorants, making it adaptable to various printing systems without requiring technique-specific modifications.
Solution Approach 2:
The patent changes the fundamental parameters of the color transform approach by working in n-dimensional colorant control signal space rather than traditional 3D color space. By determining n-dimensional colorant control signals that map to m-dimensional color space points through systematic slicing, the method accommodates any number of colorants while maintaining mathematical rigor and computational efficiency.
4Manufacturing precision
If n-dimensional colorant control signals are determined using sequential slicing, then optimal colorant combinations are selected, but complex mathematics is involved
Solution Approach 1:
The patent segments the complex n-dimensional optimization problem into m sequential slicing steps, where each slice reduces the dimensionality by one. This segmentation transforms an intractable high-dimensional optimization problem into a series of manageable lower-dimensional operations, maintaining precision while reducing computational complexity through systematic decomposition.
Data Source
AI summary
A method for determining a set of n-dimensional colorant control signals that map to a point P in an m-dimensional color space where n>m, including determining a forward device model that maps n-dimensional colorant control signals to m-dimensional color space signals; determining a set of n-dimensional colorant control signal simplexes that span a domain of the forward device model; and determining a set of range space simplexes in the m-dimensional color space corresponding to the set of n-dimensional colorant control space signal simplexes by mapping the vertices of the n-dimensional colorant control signal simplexes into the m-dimensional color space using the forward device model. The method also includes specifying a point P in the m-dimensional color space; and determining the set of n-dimensional colorant control signals that map to the point P in the m-dimensional color space, by performing m sequential slicing processes through the set of range space simplexes.