Image Revising Apparatus Black Text Legibility Ink Yield
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Solution Overview
Problem
Conventional image copying methods suffer from misregistration errors in the CMYK color model, leading to deteriorated legibility of black text and inefficient ink yield, as they intensify black offset without effectively addressing hardware faults and ink misregistration issues.
Innovation Solution
An image revising method and apparatus that calibrate the black value in a lookup table and adjust other color levels in a black area, using a preset reference level and Gaussian coefficients to regulate and compensate color levels, thereby improving image spreading and legibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the black offset is intensified in a 1D lookup table to raise legibility of black text, then the legibility of black text is improved, but the ink yield deteriorates and the misregistration error is not effectively addressed
Solution Approach 1:
The patent changes the parameter structure by transitioning from a 1D lookup table to a 2D lookup table that considers both black level and CMY color levels. This allows simultaneous optimization of black text legibility and ink yield by adjusting multiple parameters (black offset and CMY levels) together rather than intensifying black offset alone, thereby resolving the contradiction between improving legibility and maintaining ink yield efficiency.
2Measurement precision
If the black offset is intensified to emphasize black text, then the legibility of black text is improved, but the misregistration error of CMYK colors remains unaddressed
Solution Approach 1:
The patent merges the adjustment of black level with the adjustment of CMY color levels into a unified 2D lookup table system. This allows simultaneous correction of black text legibility and CMYK misregistration errors by coordinating the adjustment of multiple color channels together, rather than treating them as separate problems. The combined approach ensures that black intensification does not exacerbate color misregistration issues.
3Ease of manufacture
If conventional methods are used for copying documents with black text, then the copying process is simple, but the image quality deteriorates due to misregistration error and black point mismatch
Solution Approach 1:
The patent introduces a 2D lookup table as an intermediary component between the scanning and printing processes. This lookup table serves as a correction mechanism that pre-calculates and stores the optimal mapping between input black levels and output CMYK color levels. By using this intermediary table, the system automatically compensates for misregistration errors and black point mismatches without requiring complex real-time adjustments, thus maintaining process simplicity while improving image quality.
Data Source
AI summary
An image revising method, an image forming apparatus, and a method for revising image spreading are provided. The image revising method includes regulating a black color level in a black area of an input image; adjusting a color level of at least one other color excluding the black color in the black area; and revising the image by applying the regulated black color level and the adjusted color level of the at least one other color. Thus, in copying a document, the black color with the enhanced legibility can be serviced.