Region-Specific Color Conversion for Tonality and Color Accuracy
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Solution Overview
Problem
Existing image processing systems face issues with color degeneration, where colors in digital documents are mapped to printer color gamuts in a way that reduces their perceived distance, leading to incorrect color representation and loss of tonality, especially in regions requiring different color conversion methods.
Innovation Solution
An image processing apparatus that applies different color conversion methods based on pixel region analysis, using a first method for maintaining tonality in photo regions and a second method for graphic regions, ensuring appropriate color conversion regardless of image area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If colorimetric mapping is performed to maintain accurate color representation, then color degeneration occurs reducing the perceived distance between colors, but if perceptual mapping is performed to maintain tonality, then color accuracy deteriorates
Solution Approach 1:
The image is divided into multiple regions (photo regions and graphic regions) based on local characteristics. Different color conversion methods are applied to different regions: perceptual mapping for photo regions to maintain tonality, and colorimetric mapping for graphic regions to maintain color accuracy. This segmentation allows both requirements to be satisfied in their respective domains.
Solution Approach 2:
The patent applies different quality requirements to different parts of the image. Photo regions require tonality preservation through perceptual mapping, while graphic regions require color accuracy through colorimetric mapping. This local differentiation resolves the contradiction by allowing each region to be processed according to its specific needs rather than applying a uniform approach.
2Ease of manufacture
If a single color conversion method is applied to the entire image, then processing simplicity is maintained, but color conversion appropriateness deteriorates for different image regions
Solution Approach 1:
The image processing is segmented into region detection and region-specific color conversion steps. The system automatically identifies photo and graphic regions, then applies appropriate conversion methods to each. This maintains reliability for different image types while keeping the overall process manageable through automated segmentation.
Solution Approach 2:
The color conversion method is made dynamic and adaptive rather than static. The system automatically determines the appropriate conversion method based on local image characteristics, allowing the processing approach to change dynamically across different regions of the same image, thereby improving appropriateness without significantly complicating the workflow.
Data Source
AI summary
An image processing apparatus includes: an input unit that inputs image data, and a color conversion unit that, on the image data input by the input unit, executes color conversion using a first color conversion method on a target pixel with a difference in pixel value between the target pixel and a surrounding pixel in a case where the target pixel satisfies a condition and execute color conversion using a second color conversion method different from the first color conversion method on the target pixel in a case where the target pixel does not satisfy the condition. A result of executing color conversion using the first color conversion method maintains tonality more than a result of color conversion using the second color conversion method.