Tunable Filter Wavelength Drift Compensation in LiDAR

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Solution Overview

Problem

LiDAR systems face operational performance issues due to background interference from sunlight and other radiation sources, which conventional methods fail to adequately mitigate, leading to reduced accuracy and efficiency.

Innovation Solution

The implementation of a LiDAR system with tunable filters that adjust their characteristics based on monitored wavelength to reject background noise, using wavelength monitoring circuitry and filter tuning circuitry to maintain a narrow bandpass filter, ensuring only targeted wavelengths pass through, thereby enhancing interference rejection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a narrow bandpass filter is used to reject background interference, then the rejection of background noise is improved, but the filter becomes sensitive to laser wavelength drift causing loss of signal

Engineering Contradiction:

Improvebackground interference rejectionVSAvoidsignal detection reliability

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent implements a tunable filter whose center wavelength can be dynamically adjusted to track the laser wavelength. The filter tuning circuitry receives wavelength information from the light source and adjusts the filter's center wavelength accordingly, transforming a static filter into a dynamic system that adapts to laser drift while maintaining narrow bandwidth for background rejection.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system establishes a feedback loop where the wavelength monitoring circuitry continuously monitors the light source wavelength and feeds this information to the filter tuning circuitry, which then adjusts the tunable filter's center wavelength to maintain alignment with the laser wavelength, ensuring reliable signal detection despite drift.

Inventive Principle:

Principle #23Feedback

2Reliability

If a wide bandpass filter is used to accommodate laser wavelength drift, then the reliability of signal detection is improved, but the rejection of background interference deteriorates

Engineering Contradiction:

Improvesignal detection reliabilityVSAvoidbackground interference rejection

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The tunable filter dynamically adjusts its center wavelength to track the laser wavelength through feedback from the wavelength monitoring circuitry. This dynamic tracking allows the system to use a narrow bandwidth filter without sacrificing reliability, as the filter moves with the laser wavelength rather than requiring a wide static bandwidth.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If the filter center wavelength is fixed, then the device complexity is reduced, but the adaptability to wavelength drift is worsened

Engineering Contradiction:

Improvefilter configuration simplicityVSAvoidwavelength drift compensation

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The system transforms a static fixed-wavelength filter into a dynamic tunable filter controlled by circuitry. The filter tuning circuitry adjusts the filter's center wavelength based on feedback from the wavelength monitoring circuitry, providing adaptability to wavelength drift while adding controlled complexity through electronic adjustment mechanisms.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system implements self-adjustment where the wavelength monitoring circuitry automatically detects laser wavelength changes and the filter tuning circuitry autonomously adjusts the tunable filter's center wavelength to maintain alignment, eliminating the need for manual recalibration and providing automatic adaptation to drift conditions.

Inventive Principle:

Principle #25Self-service

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 improves the rejection of background interference, maintaining system accuracy and efficiency by dynamically adjusting the filter characteristics to match the wavelength of the light source, thereby improving the operational performance of LiDAR systems.

Implementation Method 1

The one or more filters can be tuned to compensate for laser drift such that the narrowest possible bandpass filter can be used, thereby increasing the rejection of background interference

Methodology Applied

Scientific EffectOptical filtering: Filter (optical)

Implementation Method 2

wavelength monitoring circuitry operative to monitor a wavelength of the light pulses originating from the light source

Methodology Applied

Scientific EffectWavelength detection:

Implementation Method 3

filter tuning circuitry. The receiving system can include a first optic, tunable filter, second optic, and detector. The filter tuning circuitry can be operative to adjust a filter characteristic of the tunable filter based on the monitored wavelength

Methodology Applied

Scientific EffectFilter tuning:

Data Source

PatentUS11796645B1Systems and methods for tuning filters for use in lidar systems

Publication Date: 2023.10.24 SEYOND INC

AI summary

Embodiments discussed herein refer to LiDAR systems and methods that tune one or more filters to mitigate background interference. The one or more filters can be tuned to compensate for laser drift such that the narrowest possible bandpass filter can be used, thereby increasing the rejection of background interference.