Dual Camera White Balance Correction for Flicker Detection
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Solution Overview
Problem
Digital cameras are affected by their operating environment, leading to undesirable effects such as color variations due to lighting conditions and flicker from AC-powered light sources, which existing technologies have not adequately addressed.
Innovation Solution
The use of a second camera in conjunction with a first camera to automatically white balance images and detect flicker sources, where the second camera captures images under the same lighting conditions as the first camera to provide correction values and exposure settings incompatible with mains frequency to identify flicker, respectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single camera is used for image capture, then the device complexity is low, but the image quality is degraded due to environmental lighting effects and color variations
Solution Approach 1:
A second camera is introduced as an intermediary device to capture reference images under the same lighting conditions. This reference camera provides data that mediates the white balancing process for the primary camera, enabling accurate color correction without requiring complex hardware modifications to the primary camera itself.
Solution Approach 2:
The patent uses a second camera to create a copy or duplicate image capture under identical lighting conditions. This copied reference image is then analyzed to determine white balance correction values, which are applied to the primary camera's images. The copying approach allows environmental lighting effects to be measured and compensated without adding complexity to the primary imaging path.
2Measurement precision
If white balancing is performed using a single camera, then the processing is simple, but the accuracy is insufficient due to inability to detect environmental lighting variations
Solution Approach 1:
The patent merges the functionality of two cameras working in coordination - one primary camera for capturing the main image and one reference camera for measuring lighting conditions. By combining their outputs, the system achieves accurate white balance measurement that neither camera could achieve alone, particularly in detecting environmental lighting variations and flicker.
Solution Approach 2:
The system changes the operational parameters of the second camera to be incompatible with mains frequency, allowing it to detect flicker that would be missed by standard exposure settings. This parameter change enables the detection of AC-powered light source variations, providing more accurate white balance information across different lighting conditions.
3Difficulty of detecting and measuring
If standard exposure settings are used, then the camera operates normally, but flicker from AC-powered light sources is not detected
Solution Approach 1:
The patent implements periodic action by using the second camera with exposure settings specifically designed to detect the periodic flicker caused by AC-powered light sources. By capturing images at different phases of the mains frequency cycle, the system can identify and measure flicker effects that would be averaged out by standard continuous exposure settings.
Data Source
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AI summary
Methods and devices for automatically white balancing an image are described. In one embodiment, a method includes: capturing a first image using a first camera associated with an electronic device and capturing a second image using a second camera associated with the electronic device, the first image and the second image being temporally related; determining one or more white balance correction values for the first image by analyzing the first image and the second image, the white balance correction value representing the effect of lighting conditions on the first image and the second image; and correcting one or more images captured by the first camera based on the white balance correction value.