Camera Exposure Control Using Weighted Photometric Averages
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Solution Overview
Problem
Conventional methods for determining exposure in backlight environments face challenges in stabilizing exposure fluctuations due to inaccurate detection of face and human body regions, leading to sudden changes in brightness.
Innovation Solution
An apparatus that includes an acquisition unit for images, detection units for face and human body regions, a measurement unit for photometric values, and a determination unit that calculates a weighted average of photometric values from previous frames to stabilize exposure adjustments, using weight parameters to prioritize accurate detection processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If face detection and human body detection are used to determine exposure in backlight environments, then exposure determination capability is improved, but exposure fluctuations occur due to inaccurate detection
Solution Approach 1:
The system performs detection and photometric measurement on previous frames before acquiring current frame data. By preparing detection results and photometric values in advance from historical data, the system reduces reliance on potentially inaccurate real-time detection alone, thereby stabilizing exposure determination while maintaining accuracy.
Solution Approach 2:
The exposure determination unit incorporates feedback from previous frame detection results and photometric measurements. By continuously referencing historical detection accuracy and adjusting current exposure based on accumulated data, the system compensates for inaccurate detection in individual frames, improving both precision and reliability.
2Speed
If detection results from current frame alone are used for exposure determination, then response speed is improved, but detection errors cause sudden brightness changes
Solution Approach 1:
The system performs detection and photometric measurement on previous frames in advance, storing these results for later reference. This preliminary preparation allows the system to quickly determine exposure by comparing current frame data with pre-processed historical data, maintaining fast response while reducing the impact of detection errors through accumulated information.
3Device complexity
If only face detection is used for exposure determination, then processing simplicity is maintained, but exposure accuracy deteriorates in backlight environments
Solution Approach 1:
The system merges face detection results with human body detection results to determine exposure. By combining multiple detection approaches, the system achieves more accurate exposure determination in backlight environments where face detection alone may fail, while the integrated processing maintains acceptable complexity levels.
4Measurement precision
If multiple detection methods are combined for exposure determination, then exposure accuracy is improved, but processing complexity increases
Solution Approach 1:
The system performs detection and photometric measurement on previous frames in advance, storing these results for efficient comparison with current frame data. This preliminary processing reduces the computational burden during real-time operation, allowing multiple detection methods to be combined accurately while maintaining acceptable processing complexity.
Data Source
AI summary
An apparatus includes an acquisition unit configured to acquire an image, a first detection unit configured to detect a first region corresponding to a first feature from the image, a second detection unit configured to detect a second region corresponding to a second feature from the image, a measurement unit configured to perform photometric measurement on the first region and the second region, a determination unit configured to determine an exposure based on a weighted average of a first photometric value of the first region that is acquired by the measurement unit and a second photometric value of the second region that is acquired by the measurement unit before the first photometric value is acquired, and an output unit configured to output information about the exposure.