Traffic Sign Classification via Geometric Dimension Analysis

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Solution Overview

Problem

Existing traffic sign recognition systems for motor vehicles struggle to accurately and reliably distinguish between stationary traffic signs and traffic sign stickers on commercial vehicles, leading to potential misinformation for drivers and inefficient assistance functions.

Innovation Solution

A method that involves analyzing images captured by a vehicle's camera to determine the geometric dimensions and movement patterns of traffic signs, classifying them as stationary or dynamic by comparing their movement patterns in image coordinates, and using reference dimensions to differentiate between stationary signs and stickers, thereby providing relevant assistance only for signs pertinent to the motor vehicle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traffic sign recognition systems monitor all detected traffic signs, then comprehensive information is provided to drivers, but irrelevant information from traffic sign stickers on commercial vehicles is also included, reducing reliability

Engineering Contradiction:
Improvereliability of traffic sign informationVSAvoidloss of relevant traffic sign information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The system dynamically adapts its behavior based on the detected object type. When a stationary traffic sign is detected, the system activates assistance functions. When a traffic sign sticker on a moving commercial vehicle is detected, the system deactivates these functions. This dynamic adaptation based on object classification resolves the contradiction by ensuring reliability is maintained through selective information processing.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent introduces an intermediary classification mechanism that determines whether a detected traffic sign is stationary or attached to a commercial vehicle. This intermediary step (object type classification) acts as a mediator between raw traffic sign detection and the final assistance function activation, filtering out irrelevant information while preserving relevant traffic sign data.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the system recognizes commercial vehicles to identify traffic sign stickers, then irrelevant information is filtered out, but the system complexity increases and recognition delays may occur

Engineering Contradiction:
Improveaccuracy of traffic sign classificationVSAvoidcomplexity of recognition system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The recognition system is segmented into distinct functional modules: a traffic sign detection module that identifies potential traffic signs, and a separate object type classification module that determines whether the sign is stationary or on a commercial vehicle. This segmentation allows each module to specialize in its specific task, improving overall accuracy while managing system complexity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary classification of the object type (stationary vs. commercial vehicle) before processing the traffic sign information. This preliminary action allows the system to quickly determine relevance and avoid unnecessary processing of traffic sign stickers, reducing overall system complexity by filtering early in the processing chain.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If traffic sign stickers on commercial vehicles are treated as valid traffic signs, then more information is available to drivers, but misinformation is provided that can lead to incorrect driver assistance

Engineering Contradiction:
Improveefficiency of driver assistance systemVSAvoidmisinformation from traffic sign stickers
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

Instead of assuming all detected traffic signs are valid and then trying to filter out stickers, the system inverts the approach by first classifying the object type and only then considering the traffic sign information. This inversion ensures that traffic sign stickers on commercial vehicles are automatically excluded from triggering driver assistance functions, eliminating misinformation while maintaining system efficiency.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP3520020B1Road sign classification in a surrounding area of a motor vehicle
Publication Date: 2021.12.08 VALEO SCHALTER & SENSOREN GMBH
  • EP3520020B1 patent drawingFigure 1
  • EP3520020B1 patent drawingFigure 2~3
  • EP3520020B1 patent drawingFigure 4~5

AI summary

The invention relates to a method for classifying a road sign (7) in a surrounding area (4) of a motor vehicle (1) as a road sign sticker (9) arranged on a commercial vehicle (10) or as a static road sign (8), wherein the method involves at least one first image (11, 12), captured by a camera (3) of the motor vehicle (1), of the surrounding area (4) being received and the road sign (7) being detected in the at least one first image (11, 12), wherein the first image (11, 12) is used to determine a geometric dimension (D1', D2') of the road sign (7) in the first image (11, 12), a first reference dimension (Dmin, Dmax) that is characteristic of a static road sign (8) is prescribed for the captured road sign (7), the geometric dimension (D1', D2') of the road sign (7) in the first image (11, 12) and the first reference dimension (Dmin, Dmax) are used to estimate a first position (Pmin, Pmax) of the road sign (7) in the surrounding area (4) and the estimated first position (Pmin, Pmax) is used to classify the road sign (7) as the road sign sticker (9) or the static road sign (8). The invention also relates to a computation apparatus (6), a driver assistance system (2) and a motor vehicle (1).