FMCW LiDAR Segmentation Using Velocity and Polarization Cues

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Solution Overview

Problem

Existing object detection systems using LiDAR sensors face limitations in spatial resolution and immunity to extraneous light, and camera systems have issues with coherent measurement principles, leading to suboptimal performance in industrial and surveillance applications.

Innovation Solution

A device employing a frequency-modulated continuous wave (FMCW) LiDAR sensor that uses coherent light measurement, polarization-dependent intensity analysis, and spatially resolved radial velocity to enhance object segmentation and classification, offering improved immunity to extraneous light and higher spatial resolution compared to traditional LiDAR and radar systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If incoherent LiDAR measurement is used, then maximum range can be extended, but spatial resolution and immunity to extraneous light deteriorate

Engineering Contradiction:
Improvemaximum rangeVSAvoidspatial resolution
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The patent changes the fundamental measurement parameter from incoherent time-of-flight to coherent frequency-modulated continuous wave (FMCW) measurement. This parameter change enables simultaneous achievement of high spatial resolution through frequency encoding and extended range through the continuous wave approach, while the coherent measurement provides inherent immunity to extraneous light

Inventive Principle:
Principle #35Parameter changes

2Length of stationary object

If incoherent LiDAR measurement is used, then measurement range can be increased, but immunity to extraneous light deteriorates

Engineering Contradiction:
Improvemeasurement rangeVSAvoidimmunity to extraneous light
Core Design Contradiction:
Length of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potential harm of extraneous light into a benefit by using coherent FMCW measurement. The frequency-modulated continuous wave approach allows the system to distinguish desired signals from extraneous light through frequency encoding, transforming the challenging ambient light environment into a manageable condition that does not interfere with measurement accuracy

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Productivity

If traditional LiDAR segmentation is used, then computational effort is reduced, but segmentation accuracy deteriorates

Engineering Contradiction:
Improvecomputational efficiencyVSAvoidsegmentation accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent performs preliminary action by encoding spatial and velocity information into the frequency domain during the measurement process itself. The FMCW measurement inherently provides range and velocity data through frequency encoding, allowing segmentation to be performed more efficiently using pre-encoded information rather than requiring computationally intensive post-processing of raw time-of-flight data

Inventive Principle:
Principle #10Preliminary action

4Object-affected harmful factors

If radar systems are used, then immunity to extraneous light is improved, but spatial resolution deteriorates

Engineering Contradiction:
Improveimmunity to extraneous lightVSAvoidspatial resolution
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent substitutes the mechanical/radar-based detection system with an optical FMCW LiDAR system. By using frequency-modulated continuous wave optical measurement, the system achieves radar-like immunity to extraneous light interference while simultaneously obtaining superior spatial resolution through the optical wavelength, effectively replacing the radar approach with an enhanced optical alternative

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 FMCW LiDAR sensor enables more accurate and efficient segmentation and classification of objects by utilizing coherent light measurement and polarization-dependent intensities, reducing computational effort and improving spatial resolution, thus enhancing object detection in surveillance and industrial environments.

Implementation Method 1

the measured radial velocity, vr, of the transmitted light reflected or remitted by the measuring points

Methodology Applied
Scientific EffectDoppler effect: Doppler Effect

Implementation Method 2

A light pulse is emitted by the sensor, reflected by an object, and then detected again by the sensor. The time-of-flight of the light pulse is determined by the sensor, and the distance between the sensor and the object is estimated using the speed of light

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Implementation Method 3

A device employing a frequency-modulated continuous wave (FMCW) LiDAR sensor that uses coherent light measurement

Methodology Applied
Scientific EffectCoherent light: Coherent Light

Data Source

PatentEP4310541A1Device and method for detecting objects in a surveillance area
Publication Date: 2024.01.24 SICK AG
  • EP4310541A1 patent drawingFigure 1~2
  • EP4310541A1 patent drawingFigure 3
  • EP4310541A1 patent drawingFigure 4

AI summary

A device and a method for securing a surveillance area are described, comprising at least one FMCW LiDAR sensor for emitting light beams into the surveillance area. The FMCW LiDAR sensor scans a plurality of measurement points within the surveillance area and generates measurement data from the transmitted light emitted or reflected by the measurement points. A control and evaluation unit evaluates the measurement data and generates a safety-related signal based on the evaluation. The measurement data includes the radial velocities of the measurement points and the polarization-dependent intensities of the transmitted light emitted or reflected by the measurement points. The control and evaluation unit is configured to segment the measurement points using the radial velocities and polarization-dependent intensities and to group them into objects and/or object segments.