Color Conversion Table Creation for CMYK Toner Limitation
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Solution Overview
Problem
Conventional color conversion methods using three-dimensional LUTs for CMY and one-dimensional LUTs for K in CMYK color conversion can lead to inaccuracies due to separate calculations, resulting in toner amount limitations that affect the accuracy of color conversion, causing issues like toner fusion defects and blurring in printers.
Innovation Solution
A color conversion table creating device that performs color material amount limiting, followed by separate color conversions using three-dimensional and one-dimensional tables for CMY and K components, and then combines them with inverse conversion to ensure accurate CMYK value output, considering toner amount limitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate color conversion is performed using three dimensional LUT for CMY and one dimensional LUT for K, then the device complexity is reduced and ease of manufacture is improved, but the manufacturing precision of color conversion decreases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing correction values in the three dimensional LUT that compensate for future toner amount limitations. During LUT creation, the system performs inverse conversion of expected limitation amounts, embedding these corrections in advance. This allows the separate CMY and K conversion processes to remain simple while achieving accurate final color conversion that accounts for toner constraints.
2Reliability
If toner amount limitation is applied after color conversion, then the reliability of print output is improved by preventing toner fusion defects and blurring, but the manufacturing precision of color conversion decreases due to mismatch with LUT correspondence
Solution Approach 1:
The patent applies preliminary anti-action by performing inverse conversion of toner limitation amounts during LUT creation to pre-compensate for the harmful effects of future toner limitations. The system calculates what the CMY values would be after limitation and adjusts the LUT correction values accordingly, so that when toner limitation is applied after conversion, the final colors remain accurate. This counteracts the negative impact of toner limitation before it occurs.
3Reliability
If total amount of color material is fixed to prevent printer defects, then the reliability of printing process is improved, but the manufacturing precision of color conversion decreases when LUT correspondence is disrupted
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the LUT correction values based on the total toner amount limitation parameter. The system modifies the CMY correction amounts in the three dimensional LUT according to the specific limitation level that will be applied, creating different LUT configurations for different toner constraints. This allows the system to maintain color accuracy across various fixed toner amount scenarios while ensuring reliable printing.
Data Source
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AI summary
Disclosed are a device, a method, and a storage medium to create a color conversion table. According to one implementation, a color conversion table creating device includes, a color material amount limiting processing section; a first color conversion processing section; a second color conversion processing section; a combining section; a color material amount limiting inverse conversion processing section; and an output value determining section. The color material amount limiting processing section performs color material amount limiting of an input value in the color conversion table. The color material limiting inverse conversion processing section performs inverse conversion of the color material amount limiting after color conversion and combining the CMYK components. The output value determining section sets the inverted CMYK color components as an output value in the color conversion table.