LiDAR Pulse Width Saturation Control

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Solution Overview

Problem

LiDAR devices face challenges in accurately measuring distances to objects at short distances due to signal saturation, which occurs when the laser reflection light intensity exceeds the dynamic range of the detector, leading to inaccurate distance calculations and increased signal-to-noise ratio errors.

Innovation Solution

The LiDAR device adjusts the laser light intensity and amplifier gain based on the measured pulse width of the saturated signal, using a lookup table or an equation (LD Power=0.0002*Width^2−0.025*Width+1.2179) to prevent saturation, allowing for accurate distance measurement by irradiating adjusted laser light with changed intensity or gain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If high laser light intensity is used to improve signal detection capability, then the signal-to-noise ratio improves, but signal saturation occurs leading to measurement inaccuracies

Engineering Contradiction:

Improvesignal detection capabilityVSAvoiddistance measurement accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies dynamics by making the laser light intensity adjustable rather than fixed. The controller dynamically changes the laser light intensity based on the measured distance to the object, using higher intensity for distant objects and lower intensity for nearby objects, thereby preventing saturation while maintaining detection capability across varying ranges

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of laser light intensity based on distance measurements. By adjusting this critical parameter according to the object's distance, the system optimizes signal quality without causing saturation, directly resolving the contradiction between detection capability and measurement precision

Inventive Principle:

Principle #35Parameter changes

2Reliability

If high amplifier gain is used to enhance weak signal detection, then the signal-to-noise ratio improves, but saturated signals are further distorted

Engineering Contradiction:

Improvesignal detection capabilityVSAvoidsignal saturation distortion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by measuring the distance to the object before amplifying the reflected light signal. Based on this preliminary distance information, the controller pre-adjusts the amplifier gain to an appropriate level, preventing saturation distortion before it occurs while still enhancing weak signals from distant objects

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback by continuously monitoring distance measurements and adjusting amplifier gain accordingly. The controller receives distance information and feeds it back to optimize the amplifier gain setting, creating a closed-loop system that prevents saturation while maximizing signal detection

Inventive Principle:

Principle #23Feedback

3Device complexity

If fixed laser light intensity is used to simplify the system, then device complexity is reduced, but accurate measurement at varying distances cannot be achieved

Engineering Contradiction:

Improvesystem structureVSAvoiddistance measurement accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the laser light intensity parameter based on measured distance, allowing the system to adapt to varying ranges. This dynamic parameter adjustment enables accurate measurements at both short and long distances without requiring complex hardware modifications

Inventive Principle:

Principle #35Parameter changes

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 adjustment technique enables accurate distance measurement to objects at short distances by preventing signal saturation, thereby improving the signal-to-noise ratio and ensuring precise distance calculations.

Implementation Method 1

a laser light irradiator configured to irradiate a laser light toward an object

Methodology Applied

Scientific EffectLaser: Laser

Implementation Method 2

a laser light receiver configured to output a laser reflection light signal by detecting the laser light reflected from the object

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Implementation Method 3

a time-to-digital converter (TDC) configured to measure the pulse width by counting a time of a period in which the laser reflection light signal exceeds the reference level

Methodology Applied

Scientific EffectTime of Flight: Time of Flight

Data Source

PatentUS20230213652A1LiDAR DEVICE AND OPERATING METHOD THEREOF

Publication Date: 2023.07.06 SAMSUNG ELECTRONICS CO LTD

AI summary

A light detection and ranging (LiDAR) device and an operating method thereof include irradiating a laser light toward an object; outputting a laser reflection light signal by detecting the laser light reflected from the object; measuring a pulse width corresponding to a period in which the laser reflection light signal is saturated from the laser reflection light signal and changing at least one of a laser light intensity to be irradiated by the laser light irradiator or a gain of an amplifier according to the analyzed pulse width; and controlling the laser light irradiator to irradiate an adjusted laser light corresponding to the changing.