Image Processing Gradation Conversion for High Brightness Saturation Control
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Solution Overview
Problem
Existing image processing technologies struggle to provide sufficient flexibility in color saturation compression at high brightness levels, limiting users' ability to create images with desired color and hue.
Innovation Solution
An image processing apparatus that performs gradation conversion and modulation processing based on specific features, allowing for adjustable color depth and saturation modulation, ensuring natural-looking images by altering the slope of brightness and color components above a predetermined level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If knee processing is executed to compress high brightness data, then the brightness data can be expressed within a manageable range, but the color saturation compression flexibility is reduced
Solution Approach 1:
The patent divides the brightness range into multiple segments (below and above the knee point) and applies different processing characteristics to each segment. For brightness values above the knee point, the gradation conversion features have a slope less than 1 to compress saturation, while below the knee point, the slope is 1 to preserve saturation. This segmentation allows flexible control over color saturation compression in the high brightness region while maintaining natural appearance in the low brightness region.
Solution Approach 2:
The patent applies different gradation conversion characteristics to different local regions of the brightness spectrum. Specifically, for the high brightness region (above knee point), it applies compression with slope < 1, while for the low brightness region (below knee point), it applies linear transformation with slope = 1. This local differentiation enables precise control over where saturation compression occurs, allowing users to adjust color saturation in highlights without affecting shadows.
2Quantity of substance
If color saturation is compressed at high brightness, then the dynamic range is manageable, but the initial hue is altered
Solution Approach 1:
The patent changes the slope parameter of the gradation conversion features based on the brightness level. When brightness is above the knee point, the slope is set to a value less than 1 to compress saturation. When brightness is below the knee point, the slope is set to 1 to preserve the relationship between brightness and saturation, thereby maintaining hue accuracy. This parameter change allows the system to achieve both dynamic range management and hue preservation.
3Manufacturing precision
If modulation features are set to compress color saturation, then the color depth is controlled, but the slope of the modulation function increases complexity
Solution Approach 1:
The patent makes the modulation features dynamic by setting them to depend on the brightness level. Specifically, the modulation features are defined piecewise: for brightness values above the knee point, the modulation features have a slope less than 1 to compress saturation, while for brightness values below the knee point, the modulation features have a slope of 1 to preserve saturation. This dynamic adjustment of the modulation function's slope based on input brightness enables precise color depth control without requiring a single complex modulation function for all brightness ranges.
Data Source
AI summary
An image processing apparatus includes: a gradation conversion unit that executes gradation conversion processing based upon gradation conversion features assuming a slope that changes at a predetermined brightness level, on a component representing a brightness of an image in a color space expressed with the component representing the brightness and a component representing a color depth; and a modulation unit that executes modulation processing on the component representing the color depth by multiplying the component representing the color depth by modulation features, wherein: the modulation features are set so as to assume values equal to or less than 1 over at least part of a brightness range above the predetermined brightness level.