Far-Field Overlapping LIDAR Beams for Eye Safety and Precision
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Solution Overview
Problem
Existing LIDAR systems face limitations in achieving a broad field of view and high point cloud density due to the inherent limitations of single laser emitters, which also lead to issues with measurement noise and cross-talk among multiple pulses, restricting their ability to extend measurement ranges while ensuring human eye safety.
Innovation Solution
A 3-D LIDAR system that simultaneously emits multiple beams of light from different locations, with the beams diverging to minimize eye damage at short distances and overlapping at longer distances, allowing for enhanced signal strength and noise rejection by overlapping in the far field, thereby improving measurement range and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple laser emitters are used to achieve broad field of view and high point cloud density, then measurement range and accuracy are improved, but device complexity increases
Solution Approach 1:
Multiple laser emitters and detectors are integrated into a single LIDAR system that operates simultaneously, combining their measurement capabilities to achieve broad field of view and high point cloud density without requiring sequential scanning mechanisms
Solution Approach 2:
The system divides the measurement space into multiple regions, with each laser emitter/detector pair responsible for a specific angular sector, allowing parallel measurement across different spatial zones to improve both coverage and density
2Measurement precision
If beam overlap is increased at far-field distances to enhance signal strength, then measurement accuracy is improved, but eye safety is compromised at close ranges
Solution Approach 1:
The beam configuration provides different overlap characteristics at different distances: minimal overlap at near-field distances to ensure eye safety, and increasing overlap at far-field distances to enhance signal strength for distant object detection
Solution Approach 2:
The system changes the effective beam parameters (overlap degree) as a function of distance, transitioning from non-overlapping beams at close ranges to overlapping beams at far ranges, optimizing both safety and measurement performance across different operational zones
3Productivity
If pulse repetition rate is increased to improve point cloud density, then measurement speed is improved, but cross-talk among multiple pulses increases
Solution Approach 1:
Each laser emitter operates with its own pulse sequence and timing, segmenting the overall measurement process into independent parallel channels that can be synchronized to avoid cross-talk while maintaining high pulse repetition rates for dense point cloud generation
Solution Approach 2:
The system uses timing feedback and range gating to distinguish between return signals from different pulse sequences, allowing high pulse repetition rates without cross-contamination of measurements by identifying which pulse each return signal corresponds to
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 system achieves a broader field of view with increased point cloud density and reduced measurement noise, while ensuring human eye safety by minimizing beam overlap at close ranges and maximizing it at safe distances, thus enhancing the overall performance of the LIDAR system.
Implementation Method 1
LIDAR systems employ pulses of light to measure distance to an object based on the time of flight (TOF) of each pulse of light
Implementation Method 2
In some examples, pulses of light are generated by a laser emitter. The light pulses are focused through a lens or lens assembly
Data Source
AI summary
Methods and systems for performing 3-D LIDAR measurements of objects simultaneously illuminated by two or more beams of light in the far field are described herein. A 3-D LIDAR based measurement device simultaneously emits at least two beams of light into a three dimensional environment from different locations. A portion of the three dimensional environment is simultaneously illuminated by the two or more light beams at a distance of at least five meters from the LIDAR device. However, the two or more light beams do not overlap at a distance less than five meters from the LIDAR device. The beams of light are slightly divergent, having highest intensity at the device and steadily lower intensity further away. By overlapping illumination beams in the far field, but not near the LIDAR device, overall intensity is maintained at moderate levels throughout the field of view of the LIDAR device.