Variable Frequency 3D Imaging for Electromagnetic Interference Reduction
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Solution Overview
Problem
Conventional 3D imaging systems face challenges with electromagnetic interference between electronic car components, which affects the accuracy and robustness of depth information generation, especially in automotive applications.
Innovation Solution
A 3D imaging method that varies the modulation frequency of intensity-modulated light over an integration time interval, allowing for spatially resolved phase detection and distance calculation, while reducing electromagnetic interference by spreading energy content over a broader spectral range, using a system with signal generation means, an illumination unit, an imaging sensor, and an evaluation unit to calculate distance information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed modulation frequency is used for 3D imaging, then the distance measurement precision is improved, but electromagnetic interference with other electronic components increases
Solution Approach 1:
The patent applies dynamics by making the modulation frequency variable rather than fixed. The frequency is modulated according to a predetermined pattern during the integration time interval, transforming the static frequency parameter into a dynamic one. This resolves the contradiction by spreading the energy content over a broader spectral range, reducing peak interference while maintaining measurement capability through frequency analysis.
Solution Approach 2:
The patent changes the frequency parameter from a constant value to a time-varying parameter. By modulating the frequency according to a predetermined pattern (e.g., linear sweep, sinusoidal variation), the system spreads the modulation energy across multiple frequencies, reducing electromagnetic interference with other components operating at fixed frequencies while enabling distance measurement through spectral analysis of the returned signal.
2Reliability
If the modulation frequency is varied over a broader range, then electromagnetic compatibility is improved, but distance determination precision deteriorates
Solution Approach 1:
The system uses dynamic frequency modulation with a predetermined pattern that balances spectral spreading for EMC with sufficient frequency stability for measurement. The frequency varies over time but follows a controlled pattern that allows correlation-based or spectral-analysis-based distance determination, achieving a compromise between electromagnetic compatibility and measurement precision.
Solution Approach 2:
The modulation frequency varies periodically or in a predetermined pattern over the integration time interval. This periodic variation spreads energy across frequencies for better EMC while maintaining a structured pattern that enables distance determination through frequency analysis or correlation techniques, resolving the contradiction between reliability and precision.
3Device complexity
If a fixed modulation frequency of 20 MHz is used, then distance measurement is simplified, but interference with other illumination devices increases
Solution Approach 1:
Instead of using a fixed 20 MHz modulation frequency, the system dynamically varies the frequency over time according to a predetermined pattern. This dynamic approach reduces interference with other illumination devices operating at fixed frequencies while maintaining manageable complexity through the use of standard frequency modulation techniques and spectral analysis methods.
Solution Approach 2:
The modulation frequency parameter is changed from a fixed 20 MHz value to a time-varying parameter. This parameter change reduces spectral interference with other devices while the predetermined variation pattern maintains measurement simplicity through established frequency analysis techniques, balancing complexity reduction with interference mitigation.
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
The method enhances electromagnetic compatibility and robustness of phase detection, achieving accurate distance determination while minimizing interference from other illumination devices, with a compromise between frequency range width and precision.
Implementation Method 1
A scattered and/or reflected fraction of the light is detected during an integration time interval by phase-sensitive integration in each pixel of an imaging sensor
Implementation Method 2
From this phase, the time lapsed between transmission and echo-return of the transmitted light and hence the distance the light has travelled can be determined for each pixel
Data Source
AI summary
A method for 3D imaging of an actively illuminated target region includes emitting intensity-modulated light at a variable modulation frequency into the target region, the emitted light is scattered/reflected in the target region depending on the optical properties of the objects or beings present therein, a scattered and/or reflected fraction of the light is detected during an integration time interval by phase-sensitive integration in each pixel of an imaging sensor, the modulation phase between the emitted and the detected light is determined and spatially resolved, and distance information is calculated based on the spatially resolved modulation phase and an average frequency of the modulation frequency.