Railway Signal Detection via 3D Point Cloud Slicing

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Solution Overview

Problem

Existing systems for automatically detecting and reading railway track signals require precise mapping of sign locations and accurate train positioning, which is costly and prone to errors, especially in non-ETCS compatible tracks.

Innovation Solution

A method and system using a 3D sensor and optical sensor to acquire and process environmental data, partitioning 3D point clouds into 2D slices, comparing shapes to predetermined signs, and analyzing light information without requiring artificial intelligence or external mapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If precise mapping of sign locations and accurate train positioning are used, then detection reliability is improved, but system complexity and cost increase

Engineering Contradiction:
Improvedetection reliabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system uses the train's own motion and onboard sensors to detect signals, eliminating the need for external mapping infrastructure. The 3D sensor continuously scans the environment and automatically identifies signal panels through shape recognition, making the system self-sufficient without requiring external server assistance or pre-existing maps.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical/geomatics approach (precise GPS positioning and mapped coordinate systems) with a sensory-perceptual approach. Instead of calculating positions based on pre-stored maps, the system uses 3D point cloud acquisition and 2D shape recognition to directly detect and identify signal panels in real-time.

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

2Measurement precision

If precise mapping and accurate positioning are implemented, then signal detection accuracy is improved, but implementation cost increases

Engineering Contradiction:
Improvesignal detection accuracyVSAvoidimplementation cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The system replaces expensive, permanent infrastructure (precise mapping databases, external positioning servers) with relatively simple, self-contained onboard equipment. The 3D sensor and shape recognition algorithm provide a cost-effective alternative to deploying and maintaining complex geomatics infrastructure across the railway network.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The train equips itself with detection capabilities using standard onboard sensors rather than relying on external positioning services. This eliminates the need for costly external server infrastructure and reduces dependence on expensive, precision-mapped databases, making the system more economically viable for deployment.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If 3D point cloud processing and shape recognition are used, then prior mapping knowledge is eliminated, but processing complexity increases

Engineering Contradiction:
Improveadaptability to various sign configurationsVSAvoidprocessing complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system divides the complex 3D point cloud data into manageable 2D cross-sectional slices perpendicular to the track direction. Each slice is independently processed and compared against predetermined signal panel shapes, breaking down the complex recognition task into simpler, repetitive operations that can be efficiently executed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transforms the 3D point cloud problem into a 2D recognition problem by creating cross-sectional slices. This dimensionality reduction simplifies the pattern recognition task, allowing standard 2D shape matching algorithms to effectively identify signal panels without requiring complex 3D object recognition.

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

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

Enables real-time detection and reading of track signals without prior mapping or precise train location, suitable for autonomous trains, and adaptable to various sign configurations, with robustness against atmospheric conditions.

Implementation Method 1

acquiring a 3D point cloud of an environment of a track from a 3D sensor mounted on a railway vehicle

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

acquiring an image of said environment of said railway track from an optical sensor on board said railway vehicle

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP4574624A1System and method for automatically detecting and reading railway signals
Publication Date: 2025.06.25 SN SNCF
  • EP4574624A1 patent drawingFigure 1
  • EP4574624A1 patent drawingFigure 2
  • EP4574624A1 patent drawingFigure 3

AI summary

The invention relates to a system and method for automatically detecting and reading railway track signs, comprising: a step (E1) of acquiring a 3D point cloud of the track environment; a concomitant step (E2) of acquiring an image of the environment of said track; a step (E3) of partitioning said acquired 3D point cloud into a plurality of slices; a step (E4) of orthogonal projection of the points of each slice; a step (E6) of comparing said projected 2D point cloud with a plurality of predetermined panel shapes; a step (E7) of selecting a panel, called a recognized panel, chosen from said plurality of predetermined panels; a step (E8) of detecting, on said acquired image corresponding to said 3D point cloud from which the 2D point cloud corresponding to said recognized panel is derived, the light information provided by said recognized panel.