Mobile Terminal Screen Fill Light for Luminance Uniformity
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Solution Overview
Problem
Existing mobile terminal technologies suffer from defects in photo luminance, where the center exhibits high luminance and edges low luminance, and vice versa, leading to uneven luminance in screen displays and photos, and introduce noise through digital gains in image processing.
Innovation Solution
A method for a mobile terminal that detects environmental luminance, adjusts screen fill light mode based on thresholds, and performs specific image processing procedures to achieve luminance uniformity without using dark corner modules, employing an optical filter to ensure uniform light source luminance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If digital gains are added around original photos through image processing chips to equalize luminance, then luminance uniformity is improved, but noise level increases
Solution Approach 1:
The patent inverts the conventional approach by projecting fill light patterns through the display screen rather than using external flash or ambient light. The screen itself becomes the light source, projecting complementary luminance patterns that directly counteract the lens-induced non-uniformity without requiring post-processing digital gains, thereby avoiding noise amplification
Solution Approach 2:
The patent replaces the mechanical/image processing system (dark corner modules and digital gain adjustment) with an optical system (screen fill light projection). By using the display screen to project pre-calculated luminance compensation patterns during the exposure period, the system achieves luminance uniformity through optical means rather than digital post-processing, eliminating the noise problem associated with digital gains
2Illumination intensity
If screen fill light is used to compensate luminance, then luminance uniformity is improved, but reverse complementary imaging produces high luminance on center and low luminance on edges
Solution Approach 1:
The patent performs preliminary calculation of the fill light pattern based on the specific lens characteristics and desired output luminance distribution. Before actual photography, the system pre-calculates and stores the complementary luminance pattern that, when projected through the screen, will result in uniform luminance after accounting for the lens's inherent non-uniformity. This preliminary action ensures accurate luminance distribution without requiring real-time adjustment
Solution Approach 2:
The patent incorporates feedback mechanisms where the system measures the actual luminance distribution produced by the lens and screen combination, then adjusts the fill light pattern accordingly. By iteratively optimizing the fill light projection based on measured results, the system achieves precise luminance uniformity while compensating for variations in lens characteristics and display screen properties
Data Source
AI summary
A screen fill light photographing method and system for a mobile terminal includes detecting a first luminance information of a current environment, comparing the same with a luminance threshold, controlling, according to the comparison result, a powered-on or powered-off state of a screen fill light mode; and according to the state of the screen fill light mode, performing corresponding image processing of a photo.