Multi-Facet Mirror LiDAR Scanning for Point Density
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Solution Overview
Problem
Current LiDAR systems face challenges in increasing point density while maintaining detection range due to the complexity of mechanical steering systems and ambiguity in returned signals, which limits their ability to efficiently scan and map the environment.
Innovation Solution
The use of a rotating polygon in conjunction with a multi-facet mirror and multiple light sources of different wavelengths, along with dispersion elements, allows for more efficient scanning by directing light pulses in different angles and paths, enabling overlapping scan areas and higher resolution without the need for complex mechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional mechanical steering systems are used to scan the environment, then the system can achieve coverage of the field of view, but the complexity of the mechanical system increases and reliability decreases
Solution Approach 1:
The patent replaces traditional mechanical steering systems with a multi-facet mirror system that uses optical reflection principles. The mirror assembly with multiple facets reflects laser beams in different directions to scan the field of view, eliminating complex mechanical steering components while maintaining scanning functionality and improving system reliability.
Solution Approach 2:
The mirror is divided into multiple facets (typically 3-6 facets) that are arranged to reflect laser beams in different directions. Each facet handles a specific portion of the scanning field, allowing the system to cover the entire field of view without requiring a single complex mechanical steering mechanism.
2Measurement precision
If single light source is used, then the system is simpler, but the point density and resolution of the generated point map are insufficient
Solution Approach 1:
The patent employs multiple light sources (typically 2-4 sources) that emit laser beams at different wavelengths or characteristics. Each light source contributes to illuminating specific regions or providing different measurement capabilities, thereby increasing point density and resolution without requiring a single overly complex light source system.
Solution Approach 2:
The multi-facet mirror system is designed to work with multiple light sources simultaneously, allowing the same optical infrastructure to handle different wavelengths and measurement requirements. This multi-functional approach enables enhanced measurement precision while avoiding the need for separate dedicated systems for each light source.
3Loss of information
If mechanical steering components are used to direct light pulses, then the system can scan the environment, but the ambiguity in returned signals increases
Solution Approach 1:
The patent replaces mechanical steering with a static multi-facet mirror arrangement that uses optical reflection to direct laser beams. This substitution eliminates mechanical ambiguities in signal return paths and improves signal clarity, as the optical paths are precisely defined by the mirror geometry rather than mechanical positioning.
Solution Approach 2:
The mirror facets are pre-configured at specific angles and positions to define precise optical paths for the laser beams before the scanning operation begins. This preliminary geometric arrangement ensures unambiguous signal returns by establishing fixed reflection paths, avoiding the ambiguities that arise from dynamic mechanical steering.
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 results in a simpler, more reliable LiDAR system that can maintain detection range while increasing point density and resolution, allowing for more precise mapping of the environment without the limitations of traditional mechanical systems.
Implementation Method 1
a multi-facet mirror operative to rotate about a second rotational axis, wherein a planar face of at least one facet of the multi-facet mirror is aligned at a non zero skew angle with respect to the second rotational axis
Implementation Method 2
a beam steering system including a polygon having a plurality of facets and operative to rotate around a first rotational axis
Implementation Method 3
Using the time it took for the returned pulse to be detected after the light pulse was transmitted and the speed of light, the LiDAR system can determine the distance to the object along the path of the transmitted light pulse
Implementation Method 4
When a transmitted light pulse is scattered by an object, some of the scattered light is returned to the LiDAR system as a returned pulse
Data Source
AI summary
Embodiments discussed herein refer to using LiDAR systems that uses a rotating polygon with a multi-facet mirror. Such multi-facet galvanometer mirror arrangements generate a point map that has reduced curvature.