LiDAR LED Emitter Intensity Compensation via Narrow Band Filtering
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Solution Overview
Problem
LiDAR devices face ambiguity and increased errors due to variations in emission characteristics of LEDs caused by manufacturing processes and operating conditions, affecting their reliability in autonomous vehicle navigation and other applications.
Innovation Solution
A measurement device and method that utilize a light source with multiple emitters and a controller to set and adjust operative parameters based on intensity measurements, employing narrow band filters to mitigate these variations and achieve consistent light pulses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple LEDs are used as light emitters in LiDAR devices, then the light beam generation capability is improved, but the variation in emission characteristics due to manufacturing processes and operating conditions causes ambiguity and increased errors
Solution Approach 1:
The system performs preliminary characterization of each LED emitter during manufacturing or initial operation to determine its specific emission characteristics. This preliminary data is stored and used during actual LiDAR operation to compensate for individual LED variations, allowing the system to account for manufacturing tolerances and operating condition effects before they cause measurement errors
Solution Approach 2:
The system dynamically adjusts operational parameters such as drive current and pulse width for each LED emitter based on its measured characteristics and current operating conditions (temperature, age). By changing these parameters in real-time, the system compensates for drift in emission characteristics and maintains consistent light output despite variations in manufacturing or environmental conditions
2Adaptability or versatility
If LEDs operate under varying operating conditions (temperature, current), then adaptability is improved, but the emission characteristics (central wavelength, spectral bandwidth, emitted power) vary causing ambiguity in return signal processing
Solution Approach 1:
The system incorporates feedback mechanisms that continuously monitor LED operating conditions (temperature sensors, current measurements) and emission characteristics. This feedback information is used to dynamically adjust drive parameters and compensate for drift, allowing the system to adapt to changing conditions while maintaining signal integrity and preventing information loss
Solution Approach 2:
The system uses a multi-functional approach where the same LED emitters serve both as light sources for distance measurement and as subjects for self-characterization. The measurement system itself is used to characterize the emitters, eliminating the need for separate calibration equipment and enabling the system to handle multiple functions (measurement, calibration, compensation) with a unified device
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 solution significantly reduces ambiguity in LiDAR systems, enhancing their reliability and performance in autonomous driving and other applications by compensating for LED variations, thereby improving real-time decision-making and reducing accidents.
Implementation Method 1
a light intensity measurement unit; configure the light intensity measurement unit to measure a first light intensity value of the first light beam; configure the light intensity measurement unit to measure a second light intensity value of the second light beam
Implementation Method 2
wherein a first narrow band filter is arranged to filter the light beams received by the light intensity measurement unit and a second narrow band filter is arranged to filter the light beams emitted by the light source
Implementation Method 3
LiDAR devices, generally, employs light emitting diodes (LEDs) as light emitters for generation of light beams. The LEDs are made of direct energy gap semiconductors. On forward biasing the LED, excess electron hole pairs are stored in the diode. These excess electron hole pairs recombine with each other producing photons of light which are emitted as light beams
Implementation Method 4
excess electron hole pairs recombine with each other producing photons of light which are emitted as light beams
Data Source
AI summary
A measurement device including a light source with a first emitter and a second emitter, and a light intensity measurement unit. A controller configures the first emitter to emit a first light beam using a first operative parameter and the second emitter to emit a second light beam using a second operative parameter. The controller configures the light intensity measurement unit to measure a first light intensity value of the first light beam and a second light intensity value of the second light beam. The controller compares the measured first and second light intensity values with a target intensity value; and adjust the first operative parameter and the second operative parameter based on the comparison to derive a first adjusted operative parameter and a second adjusted operative parameter. The controller configures the emitters to use the adjusted operative parameters during a measurement and a first narrow band filter is arranged to filter the light beams received by the light intensity measurement unit and a second narrow band filter is arranged to filter the light beams emitted by the light source.