Under-display Camera Brightness Control for Image Interference
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Solution Overview
Problem
The placement of digital cameras underneath device displays in modern devices, such as smartphones, leads to interference from light emitted by the display, which corrupts captured images, especially when capturing images like selfies or face recognition.
Innovation Solution
The use of calibration and recalibration images to generate subtraction images, and controlling display brightness by adjusting the ambient light levels, such as strobing or blacking out specific regions, to mitigate interference from display light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the digital camera is positioned underneath the display to maximize screen area, then the display area is increased, but light from the display interferes with image capture quality
Solution Approach 1:
The system performs preliminary calibration by capturing calibration images of the display at different brightness levels before actual image capture. These calibration images are stored and used to generate subtraction images that compensate for display light interference during photo taking, enabling the camera to capture accurate images despite the display being positioned over the camera
Solution Approach 2:
The system changes the brightness parameter of the display dynamically - reducing display brightness during image capture moments and using strobe lighting techniques. By adjusting display brightness to match ambient light conditions and synchronizing display refresh with camera shutter timing, the system minimizes display light interference while maintaining acceptable display visibility
2Manufacturing precision
If display brightness is reduced to mitigate interference, then image capture quality improves, but display visibility and user experience deteriorate
Solution Approach 1:
The system uses periodic strobe lighting where the display flashes at specific intervals synchronized with the camera shutter speed. This periodic display activation provides sufficient light for image capture during the flash moments while keeping the display dark otherwise, maintaining both image quality and user experience
Solution Approach 2:
The system applies partial brightness reduction only to specific regions of the display (particularly areas that would directly interfere with the camera field of view) rather than reducing entire display brightness. This selective approach maintains overall display visibility while minimizing interference with image capture
3Measurement precision
If calibration images are captured at multiple brightness levels, then accuracy of interference compensation improves, but processing time and complexity increase
Solution Approach 1:
The system performs calibration image capture and processing as a preliminary setup step during device initialization or in the background, before actual photo capture by the user. This separates the time-consuming calibration process from the user's photo-taking experience, maintaining accuracy while minimizing perceived processing time
Solution Approach 2:
The system captures calibration images that represent typical display brightness conditions and stores these as reference copies. During actual photo capture, instead of performing complex real-time calculations, the system uses pre-computed subtraction images based on these calibration copies, significantly reducing processing time while maintaining compensation accuracy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly improves the accuracy of captured images by reducing display interference, enhancing user authentication and image quality by accounting for changes in display pixel alignment and ambient conditions.
Implementation Method 1
light emitted by the display can get into the digital camera, interfering with or corrupting the captured images
Data Source
AI summary
A device includes a digital camera positioned underneath a display of the device that captures images through the display. The brightness of the display is controlled when capturing images using the digital camera to reduce interference from light emitted by the display with the captured images. The brightness can be controlled in various manners, such as reducing the brightness of only a camera region of the display that is within the field of view of the camera, reducing the brightness of only an expanded region of the display that includes a camera region of the display and an area surrounding the camera region but less than the entire display, reducing the brightness of the entire display or the brightness of only particular colors of the display, blacking out the camera region of the display, blacking out the expanded region of the display, strobing the display, and so forth.