LIDAR Optical Filtering and Shutter Control Against External Light

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Solution Overview

Problem

Autonomous vehicles equipped with LIDAR devices face issues due to external light sources, which can damage the devices or cause false object detection, leading to potential safety hazards and operational disruptions.

Innovation Solution

The implementation of a mitigation system within the LIDAR device, including filters such as spatial, interference, absorptive, and adaptive filters, along with a control system that can proactively or reactively adjust optical characteristics and activate shutters to block external light, ensuring the device operates effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If LIDAR emits high-power laser pulses to achieve long-range detection, then detection range is improved, but risk of damage to human eyes and skin increases

Engineering Contradiction:
Improvedetection rangeVSAvoidrisk of damage to human eyes and skin
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary safety checks by detecting the presence of humans in the LIDAR scan path before emitting high-power laser pulses. The controller monitors for human detection continuously and prevents high-power emission until the area is confirmed safe, thereby eliminating the harmful effect before it can occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A human detection system acts as an intermediary between the LIDAR system and the environment. This intermediary detects human presence and communicates safety status to the controller, which then decides whether to permit high-power laser emission, thereby mediating between the need for long-range detection and the risk of human exposure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If LIDAR uses high-power laser pulses for long-range detection, then detection capability is improved, but safety compliance with ANSI standards becomes difficult to maintain

Engineering Contradiction:
Improvedetection capabilityVSAvoidsafety compliance
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The system implements a feedback loop where the human detection system continuously monitors the environment and provides real-time safety status to the controller. Based on this feedback, the controller dynamically adjusts or prevents high-power laser emission to maintain compliance with ANSI safety standards while preserving detection capability when safe.

Inventive Principle:
Principle #23Feedback

3Reliability

If LIDAR system implements comprehensive human detection and safety control, then safety is improved, but system complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The human detection system serves multiple functions: it detects human presence, determines safety status, and provides feedback for control decisions. By making this single subsystem multi-functional, the patent reduces the need for separate dedicated components for each safety function, thereby improving safety while limiting the increase in overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 mitigation system effectively protects the LIDAR device from external light interference, preventing damage and false data generation, thereby enhancing the reliability and safety of autonomous vehicle operations.

Implementation Method 1

the LIDAR device includes a spatial filter

Methodology Applied
Scientific EffectSpatial filtering: Spatial Filter

Implementation Method 2

the LIDAR device may also include an interference filter

Methodology Applied
Scientific EffectOptical interference: Interference

Implementation Method 3

the LIDAR device may include an absorptive filter

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentEP3510418B1Methods and systems for protecting a light detection and ranging (LIDAR) device
Publication Date: 2024.03.06 WAYMO LLC
  • EP3510418B1 patent drawingFigure 1
  • EP3510418B1 patent drawingFigure 2A
  • EP3510418B1 patent drawingFigure 2B

AI summary

Described herein are methods and systems for protecting a light detection and ranging (LIDAR) device against external light that is originated at a light source other than a light source of the LIDAR device and that is being emitted towards the LIDAR device. In particular, the LIDAR device may be equipped with a mitigation system that includes an interference filter, an absorptive filter, an adaptive filter, and/or a spatial filter. Additionally or alternatively, the LIDAR device may be operated to carry out reactive and/or proactive mitigation operations. For example, the LIDAR device may be operated to vary over time characteristics with which light is being emitted and to only detect light having characteristics that match the characteristics with which light is being emitted. In another example, the LIDAR device may be operated to activate a shutter to block the external light from being detected by the LIDAR device.