Event-Based Traffic Speed Sensing With Simplified Optical Alignment

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Solution Overview

Problem

Existing traffic monitoring devices based on optical sensors require significant space, are costly, and suffer from alignment errors leading to inaccurate speed measurements due to the need for precise alignment of multiple sensors and limited spacing between components.

Innovation Solution

A traffic monitoring device utilizing an event-based image sensor with a pixel matrix that independently detects relative changes in light intensity, allowing for compact design, reduced components, and precise speed measurement with simplified alignment, enabling simultaneous detection of multiple vehicles and flexible deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If multiple spaced-apart sensors (active light sources or passive contrast diodes) are used to detect vehicle speed, then speed measurement capability is achieved, but device space requirement and cost increase significantly

Engineering Contradiction:
Improvevehicle speed measurementVSAvoiddevice space requirement
Core Design Contradiction:
Measurement precisionVSArea of stationary object

Solution Approach 1:

The patent merges multiple sensor functions into a single image sensor. Instead of using multiple spaced-apart active light sources or passive contrast diodes, the invention uses one image sensor with multiple pixels that collectively perform the speed detection function, significantly reducing the device space requirement while maintaining measurement capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The image sensor serves multiple functions simultaneously: it detects light intensity changes, determines vehicle presence, calculates speed through temporal analysis of pixel events, and provides spatial information. This multi-functionality eliminates the need for separate components for each measurement task

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Measurement precision

If multiple spaced-apart sensors are used for speed detection, then measurement capability is provided, but manufacturing cost increases due to more components

Engineering Contradiction:
Improvevehicle speed measurementVSAvoidmanufacturing cost
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent combines multiple sensor elements into a single integrated image sensor component. This merging reduces the total number of discrete parts that need to be manufactured, assembled, and calibrated, thereby lowering manufacturing costs while preserving the ability to measure vehicle speed accurately

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention uses the natural array structure of image sensor pixels as a cost-effective alternative to expensive specialized sensors. The pixel matrix provides multiple detection points without requiring multiple separate sensor components, achieving measurement capability through a standardized, mass-producible component

Inventive Principle:
Principle #26Copying

3Illumination intensity

If active light sources are used for detection, then sufficient light intensity for detection is achieved, but energy consumption increases

Engineering Contradiction:
Improvelight intensity for detectionVSAvoidenergy consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The system uses passive detection by capturing light reflected from vehicles and the environment rather than actively emitting light. The image sensor serves itself by detecting existing light intensity changes caused by vehicle movement, eliminating the need for active light sources and their associated energy consumption

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The detection works by sampling light intensity at discrete time intervals through the image sensor's frame rate. This periodic sampling captures sufficient information about vehicle movement without requiring continuous active illumination, reducing energy requirements while maintaining detection effectiveness

Inventive Principle:
Principle #19Periodic action

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 solution provides a compact, cost-effective, and energy-efficient traffic monitoring system with improved accuracy and reduced measurement errors, capable of simultaneous multi-vehicle speed detection and flexible deployment across various road conditions.

Implementation Method 1

at least one event-based image sensor comprising a pixel matrix with a plurality of pixels, each pixel being configured to detect relative changes in light intensity independently and asynchronously as events

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP4668245A1Traffic monitoring device, traffic monitoring system and method
Publication Date: 2025.12.24 KISTLER HLDG AG
  • EP4668245A1 patent drawingFigure 1~2
  • EP4668245A1 patent drawingFigure 3~4
  • EP4668245A1 patent drawingFigure 5~6

AI summary

The invention relates to a traffic monitoring device (10) with at least one detection unit (12) for detecting the speed of at least one vehicle (14, 16) on a roadway (18) based on relative changes in light intensity generated by the vehicle (14, 16). To provide a generic device with improved efficiency, it is proposed that the detection unit (12) comprise at least one event-based image sensor (20) comprising a pixel matrix (22) with a plurality of pixels (24, 26), wherein the pixels (24, 26) are each configured to detect relative changes in light intensity independently and asynchronously as events (28, 30).