Optical Security Feature Verification via Multi-Wavelength Pixel Analysis
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Solution Overview
Problem
Current methods for verifying the authenticity of optical security features on value documents, such as banknotes, are inadequate in preventing counterfeiting due to advancements in counterfeiting techniques, and there is a need for more precise and efficient methods that do not require excessive equipment or processing delays.
Innovation Solution
A method using pixel data from spatially resolved images of value documents to check optical security features, specifically OVD security features, by analyzing remission and transmission properties in multiple wavelength ranges, determining if the pixel data within specified reference ranges exceed minimum hit and scatter values, and forming an authenticity signal based on these criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional verification methods are used, then equipment simplicity is maintained, but measurement precision and reliability of security feature verification deteriorate
Solution Approach 1:
The patent extends verification from single wavelength to multiple wavelength ranges (UV, visible, IR), adding spectral dimension to the analysis. This enables detection of optical properties that are invisible or indistinguishable in conventional single-wavelength inspection, thereby improving measurement precision without requiring complex mechanical or structural modifications to the verification device
Solution Approach 2:
The invention changes the verification parameter from simple visual appearance to quantitative optical properties (remission, transmission, absorption coefficients) across multiple wavelengths. By measuring and comparing these physical parameters against reference values, the system achieves higher verification accuracy while using standard optical sensors and light sources
2Reliability
If comprehensive verification methods are used, then reliability of authenticity detection is improved, but processing time increases
Solution Approach 1:
The system performs preliminary capture of pixel data across multiple wavelength ranges simultaneously using array sensors, rather than sequential scanning. This preliminary action captures all necessary optical information in a single verification pass, enabling comprehensive analysis without increasing processing time
Solution Approach 2:
The patent replaces mechanical or manual verification methods with automated optical sensing and digital image processing. The use of pixel data analysis and automated comparison algorithms enables rapid verification that is both comprehensive and time-efficient, eliminating the need for manual inspection or complex mechanical testing apparatus
3Measurement precision
If advanced verification methods are used, then measurement precision is improved, but ease of operation deteriorates
Solution Approach 1:
The verification system performs self-verification by automatically capturing pixel data, analyzing optical properties, comparing against reference values, and generating authenticity results without human intervention. The device serves itself by integrating all verification functions into a single automated process, making operation simple while maintaining high measurement precision through systematic multi-wavelength 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 method allows for precise and efficient verification of optical security features, effectively preventing counterfeiting by ensuring that only documents meeting specific optical property criteria are deemed authentic, reducing the risk of false positives and negatives.
Implementation Method 1
pixel data of pixels of a spatially resolved image of the given section... represent optical properties of the valuable document at those locations
Implementation Method 2
pixel data for each pixel or location includes components that represent remission or transmission properties in at least two, preferably at least three, different wavelength ranges
Data Source
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AI summary
Described is a method for checking a specified optical security feature in or on a specified section of a valuable document on the basis of pixel data of pixels of an image of the specified section, which are assigned in each case to locations in or on the section, and represent optical properties of the valuable document at the locations, in which method a check is carried out as to whether a first number of those pixels or a first proportion of those pixels of the pixels of the image whose pixel data are within a first reference region specified for the security feature according to a first specified criterion exceeds a first hit minimum value specified for the security feature, and whether a first scattering of the pixel data of those pixels which are within the first reference region for the pixel data according to the first criterion exceeds a first scatter minimum value specified for the security feature, and, in dependence on the result of the check, an authenticity signal is formed which represents an authenticity indication only if the first number or the first proportion exceeds the first hit minimum value and the scattering exceeds the first scatter minimum value.