Selective Achromatization for Scanner Color Shift Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Color shifts in images read by scanners, particularly in the sub-scanning direction, lead to potential misapplication of achromatization, which can degrade image quality.
Innovation Solution
An image processing apparatus with an achromatization determination portion, processing portion, and line designation portion that selectively achromatizes pixels based on the presence of black pixels and attributes of background pixels within specific ranges, limiting achromatization to predetermined areas in the sub-scanning direction to prevent quality degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If achromatization is applied to all pixels in the image, then color shift is eliminated, but image quality is degraded due to misapplication of achromatization
Solution Approach 1:
The patent applies achromatization selectively only to specific regions where color shifts occur (edge portions of characters) rather than uniformly across the entire image. The achromatization determination portion identifies target pixels at character edges and applies achromatization processing only to those pixels, while preserving the original colors in other regions. This localised approach eliminates color shifts at critical areas without degrading overall image quality.
Solution Approach 2:
The patent segments the image processing into distinct functional portions: achromatization determination portion, achromatization processing portion, and line designation portion. The determination portion identifies which pixels require achromatization based on local characteristics (presence of black pixels, background pixel attributes), separating the decision-making process from the actual processing. This segmentation enables precise control over where achromatization is applied.
2Reliability
If achromatization is applied broadly to eliminate color shifts, then sub-scanning direction color shift is reduced, but non-white background colors are incorrectly processed
Solution Approach 1:
The patent examines local pixel characteristics (presence of black pixels within a predetermined range, attributes of background determination pixels) to determine whether achromatization should be applied. This local analysis enables the system to adapt to different background colors (white, colored, patterned) and apply achromatization only when appropriate, preserving background color integrity while eliminating color shifts in text regions.
3Reliability
If achromatization processing is performed on the entire image, then color consistency is improved, but processing complexity increases
Solution Approach 1:
The patent divides the image processing into distinct functional modules: line designation portion (identifying processing regions), achromatization determination portion (selecting target pixels), and achromatization processing portion (applying the transformation). This segmentation allows the system to process only necessary regions with appropriate algorithms, reducing overall processing complexity compared to uniform full-image processing.
Solution Approach 2:
The patent applies achromatization processing only to the extent necessary - specifically to edge portions of characters where color shifts occur - rather than processing the entire image. The determination portion identifies a subset of pixels (target pixels) that require processing, applying achromatization only to those pixels while leaving other pixels unchanged, thus reducing processing complexity.
Data Source
AI summary
An image processing apparatus includes an achromatization determination portion, an achromatization processing portion, and a line designation portion. If a black pixel is present within a predetermined peripheral range from a target pixel in a sub-scanning direction, the achromatization determination portion determines whether to achromatize the target pixel, on the basis of an attribute of a background determination pixel present in an opposite direction from the target pixel with respect to the black pixel and within a range of a predetermined number of pixels from the black pixel. If no black pixel is present within the predetermined peripheral range from the target pixel in the sub-scanning direction, the achromatization determination portion determines not to achromatize the target pixel. The achromatization processing portion achromatizes the target pixel determined to achromatize by the achromatization determination portion, and does not achromatize the target pixel determined not to achromatize by the achromatization determination portion.