Multi-Exposure White Balance via Light Source Detection
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Solution Overview
Problem
Current image processing systems face challenges in accurately recognizing ambient light sources and achieving true color representation due to limited information in single images, requiring complex calibration and resulting in lower image quality when trying to combine images with different exposure values.
Innovation Solution
A multi-exposure imaging system captures two images with different exposure values, performs light source detection on the second image to obtain a light source color ratio, and applies a color gain process to the first image to generate an output image, effectively addressing the limitations of existing auto-white balance methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple images are captured at various angles or with different ambient light sources to recognize true colors, then white-balance accuracy is improved, but device complexity and ease of operation deteriorate due to requiring camera movement and extra light sources
Solution Approach 1:
The patent combines multiple images captured at different exposure values within the same scene into a single composite image for white-balance processing. This merging approach consolidates the information from multiple exposures without requiring physical camera movement or additional light sources, thereby maintaining high measurement precision while reducing device complexity and operational difficulty
Solution Approach 2:
The imaging system uses the same camera and light source for both capturing individual images and performing white-balance recognition. By making the system multi-functional - using standard imaging components for both primary capture and white-balance calibration - the patent avoids needing separate dedicated components, thus improving accuracy without increasing device complexity
2Measurement precision
If manual calibration is performed to obtain best white-balance effect, then white-balance accuracy is improved, but ease of operation deteriorates due to complicated calibration process
Solution Approach 1:
The system performs automatic white-balance recognition by processing the captured images through algorithms that automatically detect light sources and calculate color ratios. This self-service approach eliminates the need for manual calibration operations while maintaining high white-balance accuracy, thereby improving measurement precision without compromising operational simplicity
Solution Approach 2:
The system captures multiple images at different exposure values as preliminary data before white-balance processing. This preliminary capture of diverse exposure data enables the algorithm to automatically identify light sources and perform calibration without user intervention, achieving high accuracy while keeping the operation simple
3Loss of information
If images with different exposure values are combined for high dynamic range imaging, then information completeness is improved, but image quality deteriorates due to non-consecutive blocks from inaccurate bright/dark region determination
Solution Approach 1:
The patent extracts light source information and color ratios from the second image (captured at smaller exposure value) separately from the main image combination process. By extracting this calibration data independently and applying it uniformly to the first image, the system avoids the quality degradation caused by inaccurate region determination, while still combining information from multiple exposures for high dynamic range output
4Ease of operation
If a single image is captured for white-balance processing, then ease of operation is improved, but measurement precision deteriorates due to limited information for recognizing ambient light sources
Solution Approach 1:
The system merges information from multiple images captured at different exposure values to enhance light source recognition. By combining the data from these images, the system obtains sufficient information for accurate white-balance processing while maintaining operational simplicity, as the user still only needs to capture a single scene without manual calibration
Data Source
AI summary
A white-balance method for use in a multi-exposure imaging system having an image capturing unit is provided. The method includes the steps of: utilizing the image capturing unit to simultaneously capture a first image and a second image of a scene with a first exposure value and a second exposure value, respectively, wherein the second exposure value is smaller than the first exposure value, and the first exposure value and the second exposure value have individual exposure time and exposure gain; performing light source detection on the second image to obtain light source information and a corresponding light source color ratio of the scene; and performing a color gain process on the first image according to the light source color ratio to generate an output image.