Adaptive Color Saturation Adjustment Using Lookup Tables
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Solution Overview
Problem
Existing methods for adjusting color saturation in images are not adaptive to changing illumination conditions and uniformly adjust color saturation values for all pixels, leading to artificial results in regions with high luminance and color saturation.
Innovation Solution
A method that adjusts color saturation values for individual pixels based on both brightness and color values using look-up tables, allowing for adaptive adjustments by calculating specific scale parameters for each pixel, which enhances perceived image contrast and details.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If uniform color saturation adjustment is applied to all pixels, then the operation is simple and fast, but the result becomes artificial in regions with high luminance and color saturation
Solution Approach 1:
The patent applies different color saturation adjustment parameters to different spatial regions of the image. The image is divided into multiple regions, and each region receives customized color saturation adjustment based on its local characteristics, thereby avoiding the artificial appearance caused by uniform adjustment while maintaining operational simplicity through automated region-based processing.
Solution Approach 2:
The patent dynamically adjusts color saturation parameters based on local image characteristics such as luminance and existing color saturation levels. Rather than applying a fixed uniform parameter, the system adapts the adjustment strength for each pixel or region according to its specific properties, ensuring natural enhancement while preserving operational efficiency through algorithmic adaptation.
2Productivity
If color saturation values are adjusted uniformly for all pixels, then the processing speed is fast, but the adaptability to changing illumination conditions is poor
Solution Approach 1:
The patent pre-calculates and stores lookup tables containing color saturation adjustment parameters for various combinations of luminance and color saturation levels. During actual image processing, the system quickly retrieves the appropriate parameters from these pre-computed tables based on local image characteristics, thereby achieving both fast processing speed and high adaptability to different illumination conditions without performing complex real-time calculations.
3Device complexity
If gain values are set for representative hues only with linear interpolation, then the device complexity is reduced, but the manufacturing precision of color saturation adjustment deteriorates
Solution Approach 1:
The patent transforms the color saturation adjustment problem from setting individual gain values for multiple hues into a two-dimensional parameter space defined by luminance and color saturation levels. By pre-computing adjustment parameters across this continuous parameter space and storing them in lookup tables, the system achieves high precision color saturation adjustment for all hues and conditions while maintaining low device complexity through automated parameter generation and efficient table-based retrieval.
Data Source
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AI summary
A method and apparatus is provided for adjusting colour saturation in an input image to provide an output image. Colour values for at least some of the pixels in an input image are adjusted in dependence on both the brightness value and the colour value for said pixels in the input image to provide an output image.