Cross-Channel Color Correction Using Sub-Sampled Data
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Solution Overview
Problem
Existing digital color printing systems face challenges in maintaining color uniformity across various print engines, particularly with electrostatic printing engines using intermediate transfer belts, due to the high cost and impracticality of real-time cross-channel color correction.
Innovation Solution
A method is introduced that combines full resolution values of a selected colorant with low resolution versions of other colorants, using sub-sampling and look-up tables to achieve cross-channel correction, requiring only a 4% increase in bandwidth and allowing for additional compression to reduce bandwidth further.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If full resolution data for all colorants is used for cross-channel color correction, then color uniformity is improved, but memory capacity and system cost become prohibitively expensive
Solution Approach 1:
The patent segments the colorant data into two groups: one colorant processed at full resolution and the other colorants processed at reduced resolution. This segmentation allows the system to maintain color uniformity for the selected colorant while reducing memory requirements by processing other colorants at lower resolution, directly resolving the contradiction between color uniformity and system cost.
Solution Approach 2:
The patent applies local quality by assigning different processing qualities to different colorants based on their importance. The selected colorant receives full resolution processing to ensure color uniformity, while other colorants receive reduced resolution processing. This differential quality approach maintains necessary color accuracy while reducing overall system complexity and cost.
2Manufacturing precision
If real-time cross-channel color correction is implemented, then color consistency is improved, but bandwidth requirements increase significantly
Solution Approach 1:
The patent segments the bandwidth allocation by transmitting full resolution data for only one colorant channel while transmitting reduced resolution data for other colorant channels. This segmentation reduces the total bandwidth required for real-time cross-channel color correction while maintaining color consistency through the full resolution processing of the selected colorant.
3Quantity of substance
If reduced resolution data is used for color correction, then bandwidth is reduced, but color accuracy deteriorates
Solution Approach 1:
The patent applies local quality by ensuring that the selected colorant, which requires high color accuracy, is processed at full resolution. Other colorants that are less critical for the specific correction task are processed at reduced resolution. This approach maintains color accuracy where needed while reducing bandwidth overall.
Data Source
AI summary
A technique for cross-channel correction in real time for digital color printing in which the full resolution value of a selected colorant is combined with low resolution versions of the remaining colorants to provide a basis for correcting the selected colorant based upon the data for the other colorants employed. The pixel values of sub-samples of the remaining colorants are derived from the cell in which the full resolution selected colorant is taken; and, the desired output value is selected from a look-up table established for the known printing process.