Ambient Light Sensor Interference Compensation Using Fourier Transform
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Solution Overview
Problem
Existing ambient light detection methods in terminal devices face interference from screen luminance, leading to inaccurate ambient light intensity measurements, especially when the screen luminance is high, which affects the adjustment of display luminance and power consumption.
Innovation Solution
A method that involves acquiring a detection signal from an ambient light sensor and determining the luminance level of the screen region, using Fourier transforms to identify and subtract interference signals, and calculating the ambient light intensity based on the corrected signal, with a threshold set by multiplying non-charging time luminance by the number of sub-pixels, to mitigate interference and improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the ambient light sensor is placed under the screen to improve screen-to-body ratio, then the screen-to-body ratio is improved, but the detection accuracy of ambient light is reduced due to screen light interference
Solution Approach 1:
The patent segments the detection signal into different frequency components using Fourier transform, separating the ambient light signal from the screen light interference signal based on their different frequency characteristics. This allows independent processing and compensation of each component.
Solution Approach 2:
The patent implements a feedback mechanism where the detected screen luminance value is used to calculate the interference amount, which is then subtracted from the raw detection signal to compensate for the interference. This closed-loop approach continuously adjusts the compensation based on actual screen luminance conditions.
2Measurement precision
If Fourier transform is used to separate interference signal, then the ambient light detection accuracy is improved, but the processing complexity increases
Solution Approach 1:
The patent performs preliminary calibration to establish the relationship between screen luminance and interference signal characteristics before actual ambient light detection. This pre-established relationship model simplifies the real-time processing by providing a reference for interference compensation.
Solution Approach 2:
The patent transforms the detection signal from the time domain to the frequency domain using Fourier transform, changing the parameter representation to enable easier separation and identification of different signal components based on their frequency characteristics.
3Illumination intensity
If the screen luminance is high, then the display brightness is improved, but the interference to ambient light sensor increases leading to reduced detection accuracy
Solution Approach 1:
The system continuously monitors the screen luminance value and uses it as feedback to dynamically adjust the interference compensation amount. When screen luminance is high, the compensation amount increases proportionally, maintaining detection accuracy across different display brightness conditions.
Solution Approach 2:
The patent changes the detection approach by transitioning to frequency domain analysis when screen luminance exceeds a threshold, enabling effective separation of interference signals that become more prominent at higher luminance levels.
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 reduces the impact of interference light, resulting in more accurate ambient light intensity determination and improved adjustment of screen luminance, thereby enhancing user experience and battery life.
Implementation Method 1
The ambient light sensor is capable of sensing or perceiving an intensity of light in an environment where the terminal device is placed
Implementation Method 2
performing Fourier transform for the sampling signal to obtain a first transformation value
Data Source
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Figure 3~4
AI summary
A method for detecting ambient light, includes: acquiring (11) a detection signal of an ambient light sensor; acquiring (12) a luminance level of a screen region corresponding to the ambient light sensor; and determining (13) an intensity of the ambient light based on the detection signal of the ambient light sensor and the luminance level of the screen region corresponding to the ambient light sensor.