Banknote Classification via Luminescence Decay Integration
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Solution Overview
Problem
Existing banknote processing machines struggle to quickly and reliably classify banknotes with luminescent features due to noise sensitivity and speed limitations, which affect the accuracy of decay behavior determination.
Innovation Solution
A method and device that classify banknotes by exciting the luminescent feature, recording intensity values at specific times, determining the decay time through numerical approximate integration, and comparing it to a reference decay time for classification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If banknotes are moved quickly past a fixed sensor during checking, then productivity is improved, but the signal-to-noise ratio of the measured decay curve deteriorates
Solution Approach 1:
The system performs preliminary actions by recording multiple intensity values at different times before final classification. The decay curve is captured in advance with multiple sampling points, allowing subsequent processing to determine decay time through numerical integration of the recorded data, thus maintaining accuracy despite fast movement
Solution Approach 2:
The patent replaces mechanical/physical measurement limitations with numerical computational methods. Instead of relying on high signal-to-noise ratios from slow movement, the system uses numerical integration algorithms to extract decay time information from the decay curve data, substituting physical measurement quality with computational processing capability
2Speed
If decay time is determined using the first derivative of the intensity value curve, then speed is improved, but sensitivity to noise deteriorates
Solution Approach 1:
The patent substitutes the first-derivative method with numerical integration of the intensity values. This replacement maintains computational speed while improving noise resistance, as integration accumulates signal information over time rather than amplifying noise through differentiation
Solution Approach 2:
The system changes the mathematical parameter used for decay time determination from derivative-based to integration-based. By integrating the intensity values over time and using the relationship between integrated area and decay time, the system achieves both speed and noise immunity
3Reliability
If decay time is determined using a nonlinear fit, then reliability is improved, but speed deteriorates
Solution Approach 1:
The patent applies partial action by using numerical integration over selected time intervals rather than complete nonlinear fitting of the entire decay curve. This partial approach maintains sufficient reliability for noise-resistant measurement while significantly reducing computational time required for analysis
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
This approach allows for quick and reliable classification of banknotes by accurately determining the decay time despite noise, thereby enhancing counterfeit security.
Implementation Method 1
the banknote is normally illuminated with an illuminating flash and, in this way, the luminescent feature is excited. Subsequently, the intensity of the resulting luminescence is recorded
Data Source
AI summary
A method for classifying a banknote has at least one luminescent feature, in which the following steps are carried out: a) exciting the luminescent feature; b) recording at least a first intensity value of the excited luminescent feature at a first time and a second intensity value at a second time that is different from the first time; c) determining a decay time of the luminescent feature by approximate integration over the intensity values between the first time and the second time; d) comparing the determined decay time with a reference decay time of the luminescent feature; and e) classifying the banknote based on the comparison.