Optical Sensor Ambient Light Compensation for Display Brightness
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Solution Overview
Problem
Existing technologies face challenges in accurately determining ambient light in a display environment due to the contribution of display screen light, which affects the measurement precision and requires precise timing alignment with display refresh cycles.
Innovation Solution
The method involves using an optical sensor to receive environment light measurements, identifying screen on and screen off illumination measurements, and applying a polynomial approximation to determine the screen brightness amplitude. This amplitude is then correlated with the screen brightness contribution using a screen contribution correlation coefficient, allowing for the accurate subtraction of screen brightness from environment light to determine ambient light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the optical sensor measures ambient light directly without compensation, then the measurement process is simple, but the measurement precision deteriorates due to screen brightness contamination
Solution Approach 1:
The system performs preliminary characterization of screen brightness by capturing images at multiple known brightness levels and establishing a correlation model before actual ambient light measurement. This pre-established model is then used to compensate for screen brightness during normal operation, resolving the contradiction by preparing the compensation mechanism in advance rather than implementing complex real-time separation.
Solution Approach 2:
The system uses the captured display screen images as feedback to determine the actual screen brightness contribution to the ambient light measurement. By continuously monitoring the screen output and comparing it with the optical sensor readings, the system dynamically compensates for screen brightness, improving measurement precision while maintaining manageable complexity through closed-loop control.
2Measurement precision
If the system captures images at multiple brightness levels for calibration, then the measurement precision improves, but the time required for calibration increases
Solution Approach 1:
The system performs the multi-level brightness calibration periodically or at scheduled intervals rather than continuously or on-demand. This periodic calibration approach allows the system to gather necessary data at multiple brightness levels while minimizing the time impact on normal operation, as the calibration process is confined to specific time windows rather than interrupting continuous measurement.
3Volume of moving object
If the optical sensor is positioned close to the display screen for compact design, then the device compactness improves, but the screen brightness contribution to measurement increases
Solution Approach 1:
The system extracts and separates the screen brightness component from the total light measurement by capturing images at different brightness levels and establishing a correlation model. This extracted screen brightness information is then subtracted from the total measurement, effectively removing the harmful interference while maintaining the compact sensor positioning close to the display screen.
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 ambient light measurements by accounting for screen brightness contributions, leading to better battery life and display performance in electronic devices.
Implementation Method 1
receiving a plurality of illumination measurements corresponding to the environment light comprising the screen brightness contribution received at an optical sensor
Data Source
AI summary
An example method, electronic device, and computer program product for determining a screen brightness contribution to environment light, are provided. The method includes receiving illumination measurements representing the environment light received at an optical sensor positioned near a display screen. Display screen on illumination measurements, corresponding to illumination measurements captured in an instance in which the display pixels proximate the optical sensor are illuminated are identified. Display screen off illumination measurements, corresponding to illumination measurements captured in an instance in which the display pixels proximate the optical sensor are not illuminated are identified. A screen brightness amplitude corresponding to a comparison between the display screen on illumination measurements and the display screen off illumination measurements is determined. The screen brightness contribution is determined based on the screen brightness amplitude and a screen contribution correlation coefficient corresponding to a relationship between the screen brightness amplitude and the screen brightness contribution.