Automatic White Balance Control Using Dynamic Thresholds
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional automatic white balance systems in digital cameras are unstable and prone to misjudgment due to noise and brightness changes, especially when capturing images with weak light sources or large monochromatic blocks, leading to frequent enabling and disabling of the white balance function and decreased image brightness stability.
Innovation Solution
An automatic white balance control system that dynamically adjusts threshold values based on image sharpness and occurrence frequency, using a color space coordinate system to select appropriate image blocks for white balance computation, thereby enhancing stability and preventing the influence of monochromatic blocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the automatic white balance function is enabled to correct color errors in images, then the color accuracy of images is improved, but the system becomes unstable and frequently switches between enabling and disabling when external light intensity is weak or images contain monochromatic blocks
Solution Approach 1:
The image is divided into multiple image blocks, and the system selects specific blocks for white balance computation based on sharpness criteria. This segmentation prevents monochromatic blocks from dominating the calculation and causes unstable switching.
Solution Approach 2:
The system dynamically adjusts the threshold value for determining whether to execute white balance operations based on the occurrence frequency of determining parameters. This adaptive parameter adjustment stabilizes the system by preventing frequent switching between enabling and disabling states.
2Device complexity
If the automatic white balance function uses a fixed threshold value for determining when to execute, then the control logic is simple, but the system cannot adapt to different image conditions and becomes sensitive to noise and brightness changes
Solution Approach 1:
The threshold value is transformed from a fixed parameter to a dynamic one that adjusts based on occurrence frequency. This allows the system to adapt to different image conditions while maintaining stable operation by preventing excessive sensitivity to noise and brightness variations.
Solution Approach 2:
The system counts the occurrence frequency of determining parameters and uses this feedback to adjust the threshold value. This feedback mechanism enables the system to learn from past performance and stabilize future operations, reducing sensitivity to environmental variations.
3Measurement precision
If the system executes automatic white balance operations frequently to maintain color accuracy, then the color correction is thorough, but the image brightness becomes unstable due to alternate enabling and disabling
Solution Approach 1:
The system performs preliminary evaluation by calculating the determining parameter and comparing it with the threshold value before executing white balance operations. This preliminary action prevents unnecessary operations and ensures that white balance is only executed when truly needed, maintaining brightness stability.
Solution Approach 2:
The occurrence frequency counting mechanism provides feedback that regulates the execution of white balance operations. By adjusting the threshold based on this feedback, the system prevents over-correction and maintains stable brightness while still achieving thorough color correction when necessary.
Data Source
AI summary
The present invention discloses an automatic white balance control system, an automatic white balance module, and a method thereof. The automatic white balance (AWB) control system calculates a distance value from a coordinate related to the image to a reference point in a color space coordinate system for each image. If the median or mean of the distance values is greater than a threshold value, an automatic white balance operation will be performed. The system dynamically adjusts the threshold value to prevent a blinking caused by the automatic white balance. The white balance module selects an image block of a higher image sharpness to perform a gain adjustment to prevent a monochromatic block from misjudging a white balance gain.