License Plate Light Photometric Measurement Using Composite Imaging

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Solution Overview

Problem

Existing methods for photometric measurement of vehicle license plates are time-consuming and require point-by-point scanning, making it difficult to efficiently test various geometric arrangements of license plate lights for compliance with regulatory standards.

Innovation Solution

A method and device that utilize a camera and a positioning system to capture a luminance image of a reflection standard, allowing for the determination of photometric parameters by moving a license plate light to multiple positions relative to the standard, and combining images to form an overall image, which can be corrected for geometric and photometric variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If point-by-point scanning measurement is used, then measurement precision is maintained, but measurement time increases significantly

Engineering Contradiction:
Improvephotometric measurement precisionVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent transitions from one-dimensional point-by-point scanning to two-dimensional area imaging measurement. By using a camera to capture the entire reflection standard at once, the measurement process moves from sequential point detection to simultaneous area detection, dramatically reducing measurement time while maintaining precision through image processing and photometric calculations.

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

Solution Approach 2:

The patent creates a digital luminance image copy of the reflection standard that can be processed and analyzed without requiring physical repositioning or repeated measurements. This digital copy allows for efficient computation of photometric parameters and facilitates multiple analysis approaches from a single captured image.

Inventive Principle:
Principle #26Copying

2Measurement precision

If physical repositioning of license plate lights is required for each geometric arrangement, then measurement accuracy is ensured, but device complexity and operation time increase

Engineering Contradiction:
Improvecompliance testing accuracyVSAvoidoperation simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical repositioning system with a computational approach. Instead of physically moving license plate lights to different geometric arrangements, the system uses image processing and photometric calculations to simulate and analyze multiple geometric configurations from a single captured image, eliminating complex mechanical repositioning operations.

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

Solution Approach 2:

The patent performs preliminary capture of the entire reflection standard in a single image, which then allows for post-processing analysis of multiple geometric arrangements. This preliminary action of capturing comprehensive spatial information enables subsequent virtual repositioning and analysis without requiring actual physical repositioning during the measurement process.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If multiple license plate lights are measured simultaneously, then productivity improves, but device complexity increases

Engineering Contradiction:
Improvemeasurement throughputVSAvoidmeasurement setup complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent merges the measurement of multiple license plate lights into a single integrated imaging process. By capturing all illuminated areas of the reflection standard in one photograph, the system simultaneously measures multiple light sources without requiring separate measurement setups, thereby improving productivity while keeping the device configuration relatively simple.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal measurement system that can handle various geometric arrangements and multiple license plate lights using the same basic setup. The single camera and reflection standard configuration serves multiple measurement functions, allowing the system to adapt to different testing scenarios without requiring specialized equipment for each case.

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

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 rapid and efficient measurement of photometric parameters across various geometric arrangements of license plate lights without physical repositioning, simplifying compliance testing with regulatory standards.

Implementation Method 1

a reflection standard that is geometrically designed and arranged in the same way as the license plate... a camera (4) arranged and aligned relative to a holding device (3) configured to receive a reflection standard (Z)... a luminance image recorded by the camera covers at least the reflective surface of a reflection standard (Z)

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3913337B1Method and device for the photometric measurement of an identifier for a vehicle
Publication Date: 2025.10.15 TECHNOTEAM HLDG GMBH
  • EP3913337B1 patent drawingFigure 1~2
  • EP3913337B1 patent drawingFigure 3A~3B
  • EP3913337B1 patent drawingFigure 4A~5

AI summary

The invention relates to a method for the photometric measurement of a reflectance standard (Z) illuminated by at least one license plate light (1). A camera (4), which can be triggered by a control unit (5), is arranged and aligned relative to a holding device (3) designed for receiving a reflectance standard (Z) such that a luminance image (B1, B2) received by the camera (4) covers at least the reflective surface (Z.1) of a reflectance standard (Z) received by the holding device (3). A license plate light (1) is arranged in a positioning device (2) that can be moved by means of the control unit (5).The control unit (5) controls the positioning device (2) such that the license plate light (1) arranged therein is moved to at least one position (P1, P2), optionally successively to several positions (P1, P2), relative to the reflection normal (Z) arranged in the holding device (3), and held there. In each position (P1, P2), the recording of a luminance image (B1, B2) is triggered. A composite image (B) is formed from the luminance images (B1, B2) recorded by the camera (4). The invention relates to a device for carrying out this method.