Magnetic Sensor Compensation for Valuables

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Solution Overview

Problem

Magnetic measurements on documents of value, such as banknotes, are susceptible to interference from electromagnetic sources, leading to inaccurate readings due to the small amounts of magnetic or magnetizable materials used in security elements.

Innovation Solution

A method employing multiple measurement tracks to generate data sets, where the magnitude of disturbances is determined from non-covered tracks, allowing for compensation of interference by adjusting measurement signals to account for existing deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If magnetic measurements are performed on documents of value using sensors, then the magnetic properties of security elements can be detected, but the measurements are highly susceptible to electromagnetic interference and disturbances

Engineering Contradiction:
Improvemeasurement precisionVSAvoidelectromagnetic interference
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The sensor system is divided into multiple independent measurement tracks (at least three tracks). Each track independently measures magnetic properties, and at least one track is positioned to remain uncovered by the document during measurement. This segmentation allows the system to separate useful measurement signals from interference signals, as the uncovered tracks only detect environmental disturbances without document-related signals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The uncovered measurement track acts as an intermediary that measures only the environmental interference without being affected by the document's magnetic properties. This intermediary measurement is then used to compensate for disturbances in the covered tracks, effectively filtering out electromagnetic interference from the final measurement result.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If only small amounts of magnetic or magnetizable materials are used in security elements, then the security features remain subtle and hard to detect, but the magnetic fields emanating from these elements are low and measurements become particularly susceptible to disruption

Engineering Contradiction:
Improveamount of magnetic materialVSAvoidmeasurement reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The system uses feedback from the uncovered measurement tracks to adjust and compensate for interference in the covered tracks. The measured disturbance values from uncovered tracks are fed back into the evaluation process to correct the measurement signals from tracks that detect the document, thereby maintaining reliable measurements even with minimal magnetic material.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system changes the operational parameters by using multiple measurement tracks with different coverage configurations. By varying which tracks are covered and which remain uncovered, the system can differentiate between document-related magnetic signals and environmental interference, enabling reliable detection of small amounts of magnetic material.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multiple measurement tracks are used to compensate for disturbances, then measurement reliability improves, but the device complexity increases

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoidsensor complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Each measurement track serves multiple functions: covered tracks detect both document magnetic properties and environmental interference, while uncovered tracks detect only environmental interference. This multi-functionality allows the system to use the same sensor structure for both measurement and interference detection, reducing overall system complexity while maintaining high reliability.

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 reliable and accurate magnetic property measurements even in the presence of strong interference, such as near electrical machines, by precisely compensating for disturbances using determined interference values.

Implementation Method 1

Magnetic measurements are usually carried out on the documents of value by means of sensors

Methodology Applied
Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

a sensor with a plurality of measurement tracks is used to generate measurement signals

Methodology Applied
Scientific EffectMagnetic measurement: Magnetometer

Data Source

PatentEP2608160B1Method for the compensation of disturbances in magnetic measurements on vakuable documents
Publication Date: 2019.03.20 GIESECKE & DEVRIENT CURRENCY TECHNOLOGY GMBH
  • EP2608160B1 patent drawingFigure 1~3
  • EP2608160B1 patent drawingFigure 4~6

AI summary

The present invention relates to a method for compensating for disturbances in magnetic measurements of valuables. The invention is based on a method for compensating for disturbances in magnetic measurements of valuables, in which a sensor with multiple measurement tracks is used to generate measurement signals, in which a predetermined number of data records are generated for each valuables document, wherein the valuables document is not detected by at least one of the measurement tracks during the measurement, wherein a value for the magnitude of a disturbance present in the area of ​​the sensor during the measurement is determined from the measurement signal of the at least one measurement track, and a compensation of the deviations of the measurement signals of the measurement tracks detecting the valuables document caused by the disturbance present during the measurement is carried out using the determined value for the magnitude of the existing disturbance.