Spectral Sensor Device for Document Authentication
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Solution Overview
Problem
Existing sensor devices for detecting the authenticity of documents of value, such as banknotes, face challenges due to changes in detection properties over time, which can lead to inaccurate differentiation between real and counterfeit documents, as spectral shifts occur and may not be recognized promptly.
Innovation Solution
A sensor device that detects spectrally resolved optical properties of documents as they move through a detection area, using reference radiation to compensate for changes in detection properties and ensure accurate authentication by coupling reference radiation into the detection beam path, allowing for real-time adjustment and evaluation of detection signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If machine testing is used to check document authenticity, then detection speed and productivity are improved, but detection precision deteriorates due to spectral shifts in sensor properties over time
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the sensor's spectral response using reference substances with known spectra. The system compares detected spectra against reference spectra, identifies deviations caused by sensor drift, and automatically compensates for these changes, thereby maintaining measurement precision during high-speed operation
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting detection parameters based on monitored sensor drift. The system modifies spectral calibration parameters in real-time to compensate for sensor property changes, allowing the maintenance of accurate spectral differentiation between genuine and counterfeit documents during continuous high-speed detection
2Measurement precision
If spectral calibration is performed frequently to maintain detection accuracy, then measurement precision is improved, but loss of time increases due to calibration interruptions
Solution Approach 1:
The patent ensures continuity of useful action by performing spectral calibration continuously in the background during normal detection operations. Reference substances are constantly present in the detection area, enabling uninterrupted monitoring and compensation of sensor drift without requiring separate calibration cycles that would interrupt document verification
Solution Approach 2:
The patent applies preliminary action by pre-positioning reference substances with known spectra in the detection area before actual document verification begins. This allows the system to establish baseline spectral characteristics and proactively compensate for sensor drift before it affects authentication accuracy, eliminating the need for time-consuming mid-operation calibration interruptions
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 enables precise and reliable detection of document authenticity by compensating for changes in sensor properties, ensuring consistent and accurate differentiation between genuine and counterfeit documents, thereby enhancing the reliability of the authentication process.
Implementation Method 1
a detection device (40) for spectrally resolved detection of detection radiation in a predetermined spectral detection range and for generating detection signals which reflect a property of the detection radiation
Implementation Method 2
a reference radiation device (46) for emitting optical reference radiation in a narrow wavelength range with a full width at half maximum (FWHM) of 1 nm, which lies within the specified spectral detection range
Implementation Method 3
The lighting device has, as the illumination radiation source, a plurality of controlled surface-emitting laser diodes
Data Source
AI summary
The invention relates to a sensor device for the spectrally resolved capture of optical detection radiation that originates from a valuable document transported through a capture zone of the sensor device. The sensor device comprises a detection device for the spectrally resolved detection of the detection radiation and the emission of detection signals that reflect at least one property of the detection radiation, at least one reference radiation device emitting an optical reference radiation that is injected into a detection beam path of the detection device and that has a spectrum having a structure that lies within the spectral detection zone, and that has a radiation source which acts as a transmitter of a photoelectric barrier or of a light scanner by means of which a movement and/or a position of the valuable document in relation to the capture zone can be detected, and a control and evaluation device that is designed to receive detection signals of the detection device, to evaluate them and to emit evaluation signals depending on the result of evaluation and that is further designed to use detection signals that reflect the property of the reference radiation to examine and/or adjust the detection device and/or to make correction data available which can be used in the evaluation of detection signals that reflect at least one property of the detection radiation originating from the valuable document.