Laser Scan Sensor Interpolation for Weather Detection

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Solution Overview

Problem

Conventional laser area sensors face challenges in accurately detecting intruders in thick fog, heavy rain, and heavy snow due to complete reflection of laser beams by small droplets in the air, leading to incomplete distance information and reduced recognition accuracy.

Innovation Solution

A laser scanning sensor with a distance information interpolation unit that substitutes missing distance data with interpolated values from adjacent measurement directions or previous cycles, enhancing detection accuracy by correcting for unintended objects at shorter distances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a laser beam is used for detection, then detection precision is improved, but reliability deteriorates in bad weather due to complete reflection by small droplets

Engineering Contradiction:
Improvedetection precisionVSAvoidreliability in bad weather
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary processing system (the control unit with interpolation algorithm) that mediates between the raw laser measurement data and the final detection result. When complete reflection occurs in certain directions, the system uses interpolation to estimate the missing distance information based on data from adjacent measurement directions, thereby maintaining reliable detection despite adverse weather conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transitions from single-direction distance measurement to multi-dimensional scanning measurement. By performing measurements in multiple directions and using spatial interpolation across these dimensions, the system can reconstruct missing information from directions affected by complete reflection, thus improving reliability while maintaining precision

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Area of stationary object

If laser beam measurement is performed in all directions, then detection coverage is improved, but loss of information increases due to complete reflection in certain directions

Engineering Contradiction:
Improvedetection coverageVSAvoidmissing distance information
Core Design Contradiction:
Area of stationary objectVSLoss of information

Solution Approach 1:

The patent performs preliminary measurements in multiple directions before final analysis. By collecting distance information from all available directions first, the system creates a complete data set that can later be processed through interpolation to recover any missing information, thus minimizing information loss while maintaining comprehensive coverage

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from adjacent measurement directions to compensate for information loss in affected directions. The interpolation process continuously refines the distance information by incorporating feedback from neighboring measurements, ensuring that complete reflection in certain directions does not result in permanent information loss

Inventive Principle:
Principle #23Feedback

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 sensor effectively restores missing distance information and improves detection accuracy in adverse weather conditions, ensuring reliable intruder detection by minimizing the impact of laser beam interference from fog, rain, and snow.

Implementation Method 1

a laser distance meter that emits a laser beam and measures a distance to at least one object present in a direction of the laser beam, based on a time until the laser beam reflects off the at least one object

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

measures a distance to at least one object present in a direction of the laser beam, based on a time until the laser beam reflects off the at least one object

Methodology Applied
Scientific EffectTime of flight: Time of Flight

Data Source

PatentEP2899705B1Laser scan sensor
Publication Date: 2017.12.06 OPTEX CO LTD
  • EP2899705B1 patent drawingFigure 1
  • EP2899705B1 patent drawingFigure 2
  • EP2899705B1 patent drawingFigure 3

AI summary

The laser scanning sensor includes a laser distance meter (110), a scanning mechanism (120), a distance data acquisition unit (130), a distance data complementation unit (135), a human body judgment unit (140), an alarm output control unit (150), and a memory (160). For each measurement direction when a piece of distance information is judged to correspond to an unintended object that exists at a shorter distance than an object to be originally detected and when complementation of the piece of distance information corresponding to the unintended object is judged to be possible based on a piece of distance information in an adjacent measurement direction or a piece of distance information at a previous measurement cycle, the distance data complementation unit (135) replaces the piece of distance information in the measurement direction corresponding to the unintended object with an interpolated value based on the piece of distance information acquired in the adjacent measurement direction or with an interpolated value based on the piece of distance information acquired in the measurement direction at a previous measurement cycle.