Multi-Eye Lidar System Cross-Talk Reduction
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Solution Overview
Problem
Lidar systems face challenges in effectively scanning multiple fields of regard simultaneously due to cross-talk events and solar background noise, which can lead to false-positive detections and reduced signal-to-noise ratio, especially when using sensitive detectors like SPADs.
Innovation Solution
A lidar system with multiple 'eyes' configured to scan respective fields of regard independently or with overlap, using separate or shared scanners, and employing different wavelengths to reduce cross-talk, and incorporating a controller to dynamically adjust scan patterns and overlap areas for improved data density and noise reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple fields of regard are scanned simultaneously using a single lidar system, then the coverage area and detection capability are improved, but cross-talk events and solar background noise increase leading to false-positive detections
Solution Approach 1:
The patent divides the lidar system into multiple independent sub-systems or 'eyes,' each with its own light source, scanner, and detector. Each eye scans a specific field of regard independently, preventing cross-talk between channels while maintaining comprehensive coverage. This segmentation resolves the contradiction by allowing expanded coverage without compromising detection accuracy.
Solution Approach 2:
The patent introduces wavelength division as an intermediary mechanism to separate signals from different fields of regard. By assigning different wavelengths to different eyes or scan regions, the system can distinguish between genuine targets and cross-talk or solar noise, thereby maintaining high detection accuracy while scanning multiple fields simultaneously.
2Measurement precision
If sensitive detectors like SPADs are used to improve detection capability, then the signal-to-noise ratio deteriorates due to solar background noise and cross-talk
Solution Approach 1:
The patent applies local quality by making each detector tuned to a specific wavelength range corresponding to its associated light source. This wavelength-specific detection allows each sensitive detector to operate at peak sensitivity while being immune to solar background noise and cross-talk from other channels, resolving the contradiction between detection sensitivity and noise susceptibility.
Solution Approach 2:
The patent changes the wavelength parameter of the light sources and corresponding detectors to create distinct spectral channels. By operating at different wavelengths, the system maintains high detection sensitivity while avoiding solar background noise (which is concentrated in the visible range) and cross-talk between adjacent fields of regard.
3Area of stationary object
If multiple independent scanners are used to scan respective fields of regard, then the scanning coverage is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple lidar sub-systems into a single integrated unit with shared mechanical housing, power supply, and control electronics. While each eye has its own scanner for independent field scanning, the overall system architecture is consolidated, reducing device complexity compared to completely separate lidar units while maintaining expanded field of regard coverage.
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
Enhances scanning efficiency and accuracy by reducing cross-talk and solar noise interference, allowing for higher data density in critical areas and improved detection capabilities in lidar systems, particularly in autonomous vehicle applications.
Implementation Method 1
a first optical element configured to output a first beam of light, a first scan mirror configured to scan the first beam of light
Implementation Method 2
The light source emits light toward a target which then scatters the light. Some of the scattered light is received back at the receiver.
Implementation Method 3
The system determines the distance to the target based on one or more characteristics associated with the returned light. For example, the system may determine the distance to the target based on the time of flight of a returned light pulse.
Data Source
AI summary
A lidar system operating in a vehicle comprising a first eye configured to scan a first field of regard and a second eye configured to scan a second field of regard. Each of the first eye and the second eye includes a respective optical element configured to output a beam of light, a respective scan mirror configured to scan the beam of light along a vertical dimension of the respective field of regard, and a respective receiver configured to detect scattered light from the beam of light. The field of regard of the lidar system includes the first field of regard and the second field of regard, combined along a horizontal dimension of the first field of regard and the second field of regard.