Automatic White Balance Calibration Using Dual Image Sensors
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Solution Overview
Problem
Existing image capturing devices face challenges in effectively calibrating automatic white balance (AWB) due to insufficient information for estimating the color temperature of light sources, which degrades the performance of AWB calibration.
Innovation Solution
The method involves generating frame data using multiple image sensors, estimating color temperature based on sufficient or insufficient information from each sensor, and adjusting the frame data using calculated gains to achieve accurate AWB calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single image sensor is used for AWB calibration, then the device complexity is reduced, but the measurement precision of color temperature estimation deteriorates due to insufficient information
Solution Approach 1:
The patent combines data from multiple image sensors to estimate color temperature. When the first image sensor provides insufficient color temperature estimation information, the system merges data from the second image sensor to achieve reliable AWB calibration, thereby improving measurement precision without significantly increasing device complexity.
Solution Approach 2:
The patent makes the image capturing device multi-functional by enabling it to perform both general image capturing and specialized color temperature estimation functions. The system can switch between using single-sensor data and multi-sensor data based on whether sufficient color temperature information is available, providing universal adaptability across different lighting conditions.
2Measurement precision
If multiple image sensors are used for AWB calibration, then the measurement precision of color temperature estimation is improved, but the device complexity increases
Solution Approach 1:
The patent implements a dynamic system that adaptively selects between single-sensor and multi-sensor operation modes. The controller determines whether color temperature estimation information from the first image sensor is sufficient, and dynamically switches to the second image sensor or combines both sensors only when necessary, thereby improving measurement precision while minimizing device complexity.
Solution Approach 2:
The patent changes the operational parameters of the image sensors based on lighting conditions. The system monitors the quality of color temperature estimation information and adjusts sensor usage accordingly, activating additional sensors only when parameter thresholds indicate insufficient data quality, thus balancing precision improvement with complexity management.
3Measurement precision
If color temperature estimation information is insufficient, then the AWB calibration accuracy deteriorates, but activating additional sensors increases energy consumption
Solution Approach 1:
The patent employs dynamic sensor activation based on real-time assessment of color temperature estimation quality. The controller monitors whether the first image sensor provides sufficient information and only activates the second image sensor when necessary, thereby maintaining AWB calibration accuracy while minimizing energy consumption by keeping sensors in low-power states when not needed.
Solution Approach 2:
The system performs self-assessment of its own data quality by evaluating whether color temperature estimation information from the first image sensor is sufficient. This self-service mechanism allows the device to autonomously determine when additional sensors are needed, avoiding unnecessary energy consumption while ensuring calibration accuracy when required.
Data Source
AI summary
An image capture device and a method of calibrating automatic white balance thereof are provided. The method includes generating first and second frame data using first and second image sensors, respectively, in response to incident light; generating first and second color temperature estimation information based on the first frame data and the second frame data, respectively; determining whether an amount of the first color temperature estimation information is sufficient to estimate a color temperature of a light source; estimating the color temperature of the light source based on the first color temperature estimation information when the amount of the first color temperature estimation information is sufficient; and when the amount of the first color temperature estimation information is insufficient estimating the color temperature of the light source based on the first and second color temperature estimation information; and adjusting the first frame data based on the estimated color temperature.