Adaptive Auto White Balance Using Brightness-Weighted Gray Components
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Solution Overview
Problem
Current automatic white balance (AWB) techniques in imaging systems often misidentify light sources due to similar color signatures, leading to incorrect color shift corrections, particularly between fluorescent light and sunlight.
Innovation Solution
An imaging system generates gains for image components based on the brightness of the light source, using weight factors to determine the probability of different light sources, allowing for accurate correction of color shifts by weighting potential gray components associated with each light source.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current AWB techniques use color signature matching to identify light sources, then the process is simple and fast, but the accuracy deteriorates when different light sources have similar color signatures (e.g., fluorescent light vs. sunlight)
Solution Approach 1:
The patent introduces brightness as an additional parameter to distinguish between light sources with similar color signatures. By combining color signature analysis with brightness level detection, the system can differentiate between fluorescent light and sunlight more accurately, resolving the identification ambiguity without requiring complex additional hardware
Solution Approach 2:
The patent employs gray component analysis as an intermediary step between color signature detection and final light source identification. By examining the gray components of the image and comparing them against reference gray components for different light sources, the system creates an additional verification layer that improves identification accuracy while maintaining processing efficiency
2Adaptability or versatility
If AWB techniques assume a fixed light source type based on color signature, then the processing is straightforward, but the adaptability deteriorates when the actual brightness level differs from assumptions
Solution Approach 1:
The patent makes the white balance correction dynamic by adjusting the assumed light source type based on detected brightness levels. Instead of using a fixed assumption, the system adapts its light source model according to whether the scene is bright (suggesting sunlight) or dimmer (suggesting artificial lighting), enabling accurate color correction across varying illumination conditions
Solution Approach 2:
The system changes operational parameters (assumed light source characteristics) based on the detected brightness parameter. When brightness exceeds a threshold, the system assumes sunlight conditions; when below the threshold, it assumes artificial lighting conditions. This parameter-based adaptation maintains operational simplicity while improving versatility
Data Source
AI summary
An imaging system generates a gain for a component of an image format. The gain is at least partially dependent on the brightness of the light source illuminating a scene when an image of the scene was generated. The gain can be used to correct the component of the image format for the color shift in the image caused by the light source. In some instances, the imaging system generates a gain for a plurality of the components of the image format or for all of the components of the image format. The gains can be used to correct the components for the color shift in the image caused by the light source.