Time-of-Flight Sensor Ambient Light Correction
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Solution Overview
Problem
Time-of-flight (TOF) systems face challenges in accurately determining ambient lighting conditions and distance/proximity measurements due to spurious reflections from smudges or optical components, which can compromise data accuracy and require complex correction processes.
Innovation Solution
The implementation of a TOF-based system with active demodulation detection pixels and spurious reflection detection pixels, operating at different wavelengths, generates amplitude data that is processed by a computational device to determine ambient lighting conditions and correct for spurious reflections, allowing for accurate distance or proximity measurements and adaptive adjustments to display settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spurious reflection detection pixels are added to detect and correct reflections from smudges or optical components, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The sensor array is segmented into different functional regions: active demodulation detection pixels for primary distance measurement and spurious reflection detection pixels for detecting reflections from smudges or optical components. This segmentation allows each pixel type to be optimized for its specific function while working together to improve overall measurement accuracy.
Solution Approach 2:
The spurious reflection detection pixels act as intermediary sensors that detect unwanted reflections before they interfere with the primary measurement. By detecting these spurious reflections separately, the system can compensate for their effect on the ambient light measurement and distance measurement, improving precision without requiring complete system redesign.
2Adaptability or versatility
If multiple wavelengths are detected for ambient light measurement, then adaptability to different ambient light source types is improved, but device complexity increases
Solution Approach 1:
The sensor system is designed to detect multiple wavelengths of light simultaneously using the same sensor array infrastructure. By detecting both the first particular wavelength (for primary distance measurement) and the second particular wavelength (for spurious reflection detection), the system achieves multi-functionality in a single device, enabling adaptation to different ambient light source types without requiring separate detection systems for each wavelength.
Solution Approach 2:
The system changes the wavelength parameter of detected light to differentiate between various ambient light sources. By analyzing the amplitude data at different wavelengths and comparing it against stored spectrum data for different light source types, the system can identify and adapt to the specific ambient lighting conditions, improving versatility while using efficient computational methods.
3Measurement precision
If computational processing of amplitude data from multiple wavelengths is performed, then measurement precision is improved, but use of energy increases
Solution Approach 1:
Spectrum data corresponding to different ambient light source types is pre-stored in the computational device. This preliminary preparation of reference data allows the system to quickly compare and identify ambient light conditions without performing complex real-time spectral analysis, thereby reducing energy consumption during operation while maintaining measurement precision.
Solution Approach 2:
The system uses efficient computational algorithms that process amplitude data in a lightweight manner, comparable to using simplified processing methods rather than exhaustive analysis. By implementing energy-efficient comparison techniques against pre-stored spectrum data, the system achieves accurate ambient lighting condition determination with minimal energy expenditure.
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 of ambient light and distance/proximity measurements by effectively compensating for spurious reflections and enables dynamic adjustments to display settings based on ambient conditions, improving user experience in handheld devices.
Implementation Method 1
detecting, in at least one active demodulation detection pixel, a first particular wavelength and generating amplitude data of the first particular wavelength
Implementation Method 2
detecting, in at least one spurious reflection detection pixel, a second particular wavelength and generating amplitude data of the second particular wavelength
Implementation Method 3
TOF systems are based on the phase-measurement technique of emitted intensity-modulated light, which is reflected by a scene
Implementation Method 4
the phase-measurement technique of emitted intensity-modulated light
Data Source
AI summary
A time of flight-based system is operable for ambient light measurements. A method of operation includes detecting, in at least one active demodulation detection pixel, a first particular wavelength and generating amplitude data of the first particular wavelength; and detecting, in at least one spurious reflection detection pixel, a second particular wavelength and generating amplitude data of the second particular wavelength. In a computational device that stores spectrum data corresponding respectively to a plurality of different ambient light source types, an ambient lighting condition is determined based on the amplitude data of the first particular wavelength, the amplitude data of the second particular wavelength and the spectrum data of a particular one of the ambient light source types associated with the amplitude data of the first particular wavelength and the amplitude data of the second particular wavelength.