Image Exposure Adjustment for Face Detection in Backlight
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Solution Overview
Problem
Facial recognition performance is compromised due to poor face imaging effects caused by environmental factors, especially in extreme backlight conditions where faces become underexposed, leading to detection failures.
Innovation Solution
An image exposure adjustment method and apparatus that performs human body detection, segments the image to determine foreground and background regions, generates a mask image, and adjusts the exposure value based on an exposure weight table derived from the mask image, thereby improving face imaging quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If automatic exposure algorithm is used to adjust exposure value based on entire image, then average exposure quality is improved, but face imaging quality deteriorates under extreme backlight conditions
Solution Approach 1:
The patent divides the image into multiple regions including foreground region, background region, and skin tone region. By segmenting the image and identifying the skin tone region specifically, the system can apply different exposure adjustments to different regions, ensuring that the face region receives appropriate exposure correction even when the overall image exposure is suboptimal due to backlight conditions.
Solution Approach 2:
The patent implements region-specific exposure adjustment by determining exposure parameters for different image regions independently. The skin tone region is identified and given priority in exposure adjustment, allowing local optimization of face imaging quality without being constrained by the overall image exposure requirements. This enables the system to maintain good face imaging quality even when the entire image would be underexposed in extreme backlight scenarios.
2Measurement precision
If exposure adjustment is made to improve face imaging, then face detection accuracy is improved, but processing complexity increases
Solution Approach 1:
The patent performs skin tone region detection and exposure parameter determination before the actual exposure adjustment is applied. By pre-identifying the skin tone region and calculating the appropriate exposure parameters in advance, the system streamlines the processing pipeline and avoids complex real-time adjustments during image capture, thereby reducing overall processing complexity while maintaining high face detection accuracy.
Solution Approach 2:
The system uses the skin tone characteristics inherent in the image itself to automatically identify the face region and determine exposure parameters without requiring external reference data or complex manual configuration. The algorithm leverages the natural properties of skin tones in the image to guide the exposure adjustment process, making the system self-sufficient and reducing the need for additional complex processing components.
Data Source
AI summary
Provided are an image exposure adjustment method and apparatus, a device, and a medium. The image exposure adjustment method includes performing human body detection on a collected image; in a case where a human body is detected, segmenting the image to determine a foreground region and a background region in the image; determining a mask image according to the foreground region and the background region; and determining an exposure weight table according to the mask image, and performing exposure value adjustment on the image according to the exposure weight table.