Time-of-Flight Sensor Background Light Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Time-of-flight sensors face accuracy and reliability issues due to the presence of ambient or background light, which can interfere with their measurements by detecting spurious non-modulated or off-modulation light, leading to inaccurate distance determination.
Innovation Solution
A time-of-flight sensor module that obtains a background signal measurement of ambient light and a sample signal containing both emitted and reflected modulated light, then performs a background correction by subtracting the background signal from the sample signal to determine the distance between the sensor and the object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the sensor detects light in the presence of background light, then the sensor can operate in various lighting conditions, but the measurement accuracy deteriorates due to spurious light contributions
Solution Approach 1:
The patent segments the light detection process into two distinct measurements: a first light measurement taken without modulated light emission to capture background light, and a second light measurement taken with modulated light emission to capture both background and reflected modulated light. This segmentation allows separate characterization and subtraction of background light contributions, thereby maintaining measurement accuracy in varying lighting conditions
Solution Approach 2:
The patent performs an additional background light measurement beyond the standard reflected light measurement. This excessive action (taking a first measurement without modulated light) enables the system to capture and subtract background light contributions, thereby maintaining accuracy even when operating in environments with significant ambient light
2Measurement precision
If background correction is performed by subtracting background signal from sample signal, then measurement accuracy is improved, but device complexity increases due to additional measurement steps
Solution Approach 1:
The system performs self-correction by using its own photodetector to automatically measure and subtract background light contributions. The sensor module independently executes both the background light measurement and the reflected light measurement, then processes these measurements to eliminate background effects, thereby improving accuracy without requiring external correction devices or complex additional hardware
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 enhances the accuracy and reliability of distance measurements, allowing the sensor to operate effectively across a wider range of conditions and applications, including varying light intensities and environments.
Implementation Method 1
obtaining a first light measurement using a photodetector of a sensor module... obtaining a second light measurement using the photodetector
Implementation Method 2
generating modulated light using a light source of the sensor module
Data Source
AI summary
In an example implementation, a first light measurement is obtained using a photodetector of a sensor module. The first light measurement corresponds, at least in part, to ambient light in an environment of the sensor module. Modulated light is generated using a light source of the sensor module, and a second light measurement is obtained using the photodetector of the sensor module. The second light measurement corresponds, at least in part, to modulated light reflected from an object toward the photodetector. A distance between the sensor module and the object is estimated, using an electronic control device, based on the first measurement, the second light measurement, and the modulated light.