Image Color Correction via Ratio-Based Interpolation
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Solution Overview
Problem
Standard color correction methods fail to provide accurate results when one or more color channels are strongly damped or selectively lighted, leading to large errors, particularly in underwater imaging where the relative strength of color components changes with depth.
Innovation Solution
An image color correction method that interpolates between a first and second corrected color component vector, using an interpolation coefficient based on the ratio of color components to adjust the correction factors, allowing for adaptable and accurate color compensation across varying depth ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If standard color correction methods (average grey correction or maximum white correction) are applied, then color correction can be performed, but large errors occur when one or more color channels are strongly damped or selectively lighted
Solution Approach 1:
The patent introduces an intermediary approach by computing correction factors based on ratios between color channels rather than absolute values. This intermediary method (using ratio-based correction factors) bridges the gap between standard correction methods and handles cases with strong damping or selective lighting more reliably
Solution Approach 2:
The patent changes the parameter basis for correction from absolute color channel values to ratios between color channels. This parameter transformation allows the correction method to adapt to varying lighting conditions and depth-related damping effects, improving both accuracy and reliability
2Measurement precision
If correction factors are computed to correct strongly damped color channels, then color balance can be restored, but the correction factors become very large and inaccurate
Solution Approach 1:
The patent transforms the correction approach by using ratios of color channel values instead of absolute values to compute correction factors. This parameter change prevents the computation of excessively large correction factors that would otherwise result from trying to correct strongly damped channels directly
3Measurement precision
If a fixed correction method is used for one depth range, then good correction results are achieved in that range, but the method does not work well in other depth ranges
Solution Approach 1:
The patent implements a dynamic correction method where correction factors are computed based on the actual color channel ratios in the image. This dynamic approach allows the correction to adapt automatically to different depth ranges and lighting conditions, unlike fixed correction methods that are optimized for specific conditions
Solution Approach 2:
The correction method uses the image's own color channel ratios to determine the appropriate correction factors. This self-service mechanism enables the algorithm to automatically adapt to different depth ranges and lighting conditions without requiring external parameters or manual adjustment
Data Source
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AI summary
Corrected color components are obtained that correspond to an interpolation between a first and second corrected color component vector, in the first vector the color component are scaled to move a characteristic color component vector towards a target and in the second set the color components are contracted towards a reference determined by part of the color components. A position of the interpolation between the first and second corrected color component vectors is controlled by an interpolation coefficient computed from a ratio of an average value of the at least one of the color component in the input image or one or more reference images with similar content and an average obtained from the other color components of the input image or the or one or more reference images with similar content. The position of the interpolation is moved increasingly toward the second corrected color component vector with decreasing values of said ratio.