Image Sensor Exposure Control for Face Detection Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing image sensing technologies face challenges in accurately controlling exposure, especially when the detected target portion contains background or is not accurately defined, leading to inconsistent image brightness and overall appearance.
Innovation Solution
An image sensing apparatus and method that includes a solid-state electronic image sensing device, exposure control device, target image detecting device, AE target area deciding device, and control device to detect and adjust exposure based on a target image portion, deciding an AE target area for appropriate brightness, even if the detected portion is not accurately defined, and broadening the AE target area if necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If AE control is performed based on a detected target-image portion, then the target portion can achieve appropriate brightness, but accurate AE control cannot be carried out when the detected portion contains background or does not accurately define a face or person
Solution Approach 1:
The patent divides the image into multiple regions including a face detection region and an AE measurement region. The face detection region identifies target portions (faces/people) while the AE measurement region is separately designated for brightness measurement. This segmentation allows the system to measure brightness in a controlled area rather than relying solely on detected target portions, resolving the contradiction between target brightness accuracy and detection reliability.
Solution Approach 2:
The patent introduces an AE measurement region as an intermediary element between the detected target portion and the exposure control system. Instead of directly using the detected target portion for AE measurement, the system uses this intermediate AE measurement region to obtain brightness information, which then feeds into the exposure control. This intermediary approach ensures accurate AE control even when target portion detection is imperfect.
2Measurement precision
If AE control focuses on a specific target-image portion, then that portion achieves appropriate brightness, but the overall image may lack attractiveness when background is not considered
Solution Approach 1:
The patent segments the image into distinct functional regions: face detection regions for identifying targets, AE measurement regions for brightness control, and allows consideration of background areas. This segmentation enables the system to simultaneously optimize target portion brightness through AE control while maintaining overall image quality by considering the broader context including background elements.
Solution Approach 2:
The patent applies different quality requirements to different regions of the image. The AE measurement region receives precise brightness control to ensure target portions have appropriate illumination, while the overall image composition (including background) is considered for aesthetic quality. This local quality approach allows targeted brightness optimization without compromising overall image attractiveness.
Data Source
AI summary
It is so arranged that the portion of the image of a subject that is a face takes on an appropriate brightness. The image of the subject is obtained by imaging the subject. The subject image is subjected to face detection processing and an area construed as being the face-image portion is found. An area corresponding to this area is set in an image obtained by standardizing the subject image. An AE area used in control of exposure is specified from the area that has been set. Brightness is calculated based upon image data representing the image within the specified AE area, and exposure is controlled. Even if an image such as a tree is in the background of the face image, the brightness of the face-image portion is calculated comparatively accurately and a subject image having the appropriate brightness is obtained.