Image Processing Device Selective Luminance Filtering for Black Characters
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Solution Overview
Problem
Conventional image processing devices apply filtering processing to all image data, including black character signals, leading to color blurring, which is wasteful and harmful.
Innovation Solution
An image processing device that acquires pixel data, converts it into luminance and color difference components, determines if it has a black character attribute, and applies filtering only to the luminance component to prevent color blurring, using specific filter coefficients to enhance differences between target and neighboring pixel data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If filtering processing is applied to all image data, then edge enhancement is achieved, but color blurring occurs and processing becomes wasteful
Solution Approach 1:
The patent applies filtering processing selectively only to pixel data determined to have black character attributes, rather than uniformly to all image data. The determination section identifies black character pixels by checking if luminance is below a threshold and color difference is within a range, then applies edge enhancement filtering only to these identified pixels. This localized application prevents color blurring in non-black regions while maintaining edge enhancement benefits where needed.
2Manufacturing precision
If filtering processing is applied to all image data, then edge enhancement is achieved, but processing efficiency decreases
Solution Approach 1:
The patent extracts and processes only the necessary portion of image data by identifying black character attributes first. The determination section separates black character pixels from other pixels based on luminance and color difference thresholds. Only the extracted black character pixel data undergoes filtering processing, eliminating wasteful computation on non-black pixels and improving overall processing efficiency.
3Object-generated harmful factors
If filtering processing is applied to black character signals, then color blurring is prevented, but processing complexity increases
Solution Approach 1:
The patent performs preliminary determination of black character attributes before applying filtering processing. The determination section evaluates luminance and color difference thresholds in advance to identify black character pixels. This preliminary classification simplifies the subsequent filtering stage by pre-marking target pixels, reducing the complexity of the overall processing system compared to attempting to prevent color blurring through complex filtering parameter adjustments.
Data Source
AI summary
An image processing device includes an acquisition section, first conversion section, determination section, filtering section, and second conversion section. The acquisition section acquires first image data defined by a plurality of color components. The first conversion section converts, for each pixel data, the plurality of color components into converted pixel data defined by a luminance and a color difference. The determination section determines whether or not each converted pixel data is target pixel data having a black character attribute. The filtering section performs a filtering process on a luminance of each target pixel data using a filter coefficient to obtain processed pixel data defined by the luminance and the color difference. The filter coefficient enhances a difference in the luminance between the each target pixel data and neighboring pixel data. The second conversion section converts each processed pixel data into updated pixel data defined by the plurality of color components.