3D LiDAR Calibration System Using Structured Light Patterns
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Solution Overview
Problem
Current calibration methods for 3D time-of-flight LiDAR sensors are time-consuming, costly, and inefficient, particularly when dealing with linear-mode avalanche photodiode and PIN diode imagers, which suffer from electronic crosstalk and require lengthy lab-based characterization, limiting their deployment in applications like autonomous vehicles.
Innovation Solution
A system utilizing a spatial light modulator to structure light patterns that mitigate electronic crosstalk, combined with a timing synchronization system and variable attenuation, enables rapid characterization of response-specific parameters such as range walk error and gain-error non-uniformity, allowing for simultaneous calibration of multiple sensors in a compact and automated process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional lab-based characterization methods are used to calibrate 3D LiDAR sensors, then measurement precision can be achieved, but the calibration process becomes extremely time-consuming and costly
Solution Approach 1:
The patent replaces traditional mechanical/lab-based characterization systems with a light-based calibration system using structured light patterns. A light source projects specific patterns through optical elements (lenses, diffusers) directly onto the sensor, eliminating the need for complex physical measurement apparatus and lengthy lab procedures. This substitution of mechanical measurement systems with optical projection systems achieves rapid calibration while maintaining precision.
Solution Approach 2:
The patent changes the calibration approach by varying light intensity parameters through variable attenuators and adjusting optical configuration parameters (focal lengths, distances) to characterize sensor response. By changing these controllable parameters systematically, the system rapidly maps sensor behavior across different operating conditions without requiring time-consuming physical measurements for each condition.
2Manufacturing precision
If detailed characterization of response-specific parameters is performed to improve image quality, then manufacturing precision improves, but the process becomes complex and time-consuming
Solution Approach 1:
The patent segments the calibration process into distinct functional modules: light source, optical path elements (lenses, diffusers), variable attenuators for intensity control, and independent adjustment mechanisms for each optical element. This segmentation allows each component to be independently optimized and adjusted, simplifying the overall system while achieving detailed sensor characterization through systematic control of individual parameters.
3Productivity
If rapid calibration is implemented to reduce production time, then productivity increases, but calibration accuracy may be compromised
Solution Approach 1:
The patent implements preliminary action by pre-configuring the optical system with fixed optical elements (lenses, diffusers) positioned at predetermined locations and orientations. The variable attenuators and adjustment mechanisms are pre-positioned to systematically cover the required parameter range. This preliminary setup eliminates the need for time-consuming adjustments during actual calibration, enabling rapid repeated calibrations while maintaining consistent accuracy through the pre-optimized optical configuration.
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 significantly reduces the time and cost of calibrating 3D LiDAR sensors, enabling their deployment in large volumes by characterizing sensors in minutes rather than weeks, improving image quality and reducing production costs while addressing electronic crosstalk issues.
Implementation Method 1
Light from the optical transmission source passes through the coarse adjustment, the optical device, the fine adjustment, and the lens to illuminate a LiDAR sensor under test
Implementation Method 2
the LiDAR system measures the time for the reflected light to return to a receiver to determine a distance of the object of interest from the LiDAR system
Data Source
AI summary
A system for calibrating a light detection and ranging (LiDAR) sensor comprises an optical transmission source, a coarse adjustment optically coupled to the optical transmission source, an optical device optically coupled to the coarse adjustment, a fine adjustment optically coupled to the optical device, and a lens optically coupled to the fine adjustment. Light from the optical transmission source passes through the coarse adjustment, the optical device, the fine adjustment, and the lens to illuminate a LiDAR sensor under test. Further, a single optical transmission source, coarse adjustment, and optical device may be coupled to a splitter to test multiple LiDAR sensors at once, where each LiDAR sensor is associated with an individually controlled fine attenuator and an individually controlled variable lens.