Optically Variable Tag Authentication via Dual-Image Digital Imprint Comparison
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Solution Overview
Problem
Existing authentication methods for secure documents are inadequate in detecting falsifications without specialized equipment and require specific lighting conditions or multiple camera orientations, making them difficult to use for general public authentication and identification.
Innovation Solution
A method using a security label with optically variable elements that employs geometric characteristics in the visible light spectrum, allowing for authentication through photographs taken under different lighting conditions, enabling discrimination between authentic and counterfeit labels using image processing without needing specialized equipment or multiple orientations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specialized equipment or specific lighting conditions (ultraviolet, infrared) are used for authentication, then the reliability of detecting forgery is improved, but the ease of operation deteriorates due to requiring specialized equipment and specific lighting conditions
Solution Approach 1:
The patent uses a standard camera to capture optical images of the security label, creating a digital copy that can be analyzed. This replaces the need for specialized authentication equipment while maintaining the ability to detect security features through image processing of the captured optical data
Solution Approach 2:
The patent analyzes changes in optical parameters (reflectivity, brightness) of security label elements under different viewing conditions by capturing multiple images. This allows detection of genuine security features using standard equipment while maintaining high reliability in forgery detection
2Measurement precision
If multiple relative positionings or camera orientations are required for authentication, then the measurement precision of security features is improved, but the time required for authentication increases
Solution Approach 1:
The patent captures multiple images of the security label in rapid succession, exploiting the periodic or alternating reflectivity patterns of genuine security elements. This allows verification of security features through temporal analysis of optical responses without requiring physical repositioning of the camera or document
Solution Approach 2:
The system pre-processes and analyzes multiple images simultaneously, extracting security verification information from optical variations captured in a single authentication sequence. This eliminates the need for sequential positioning operations and reduces overall authentication time while maintaining precision
3Reliability
If authentication requires observations outside the visible light spectrum, then the reliability of detecting security features is improved, but the device complexity increases due to needing specialized lighting and detection equipment
Solution Approach 1:
The patent captures optical information from security label elements using a standard camera in the visible spectrum, creating digital copies that can be analyzed. This avoids the need for specialized ultraviolet or infrared equipment while maintaining effective security verification through analysis of optical reflectivity patterns
Solution Approach 2:
The system detects security features by analyzing changes in visible light optical parameters (intensity, reflectivity) of security elements. This approach maintains high detection reliability using only standard visible light cameras, eliminating the need for complex specialized equipment operating outside the visible spectrum
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 reliable, automatic authentication and identification of secure documents using standard tools, effectively detecting counterfeits by analyzing differences in images taken with and without flash, enhancing security without requiring advanced equipment or complex procedures.
Implementation Method 1
optically variable elements having different reflection properties on the surface of the label for a light source in the frequency range of visible light
Data Source
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AI summary
The invention relates to a method for automatically authenticating a document comprising a tag portion, including the following steps: a) printing an authentic tag (101) having optically variable elements; b) photographing the authentic tag (101) in order to create a first reference image; c) calculating and registering a digital reference imprint of the tag; d) photographing a tag (102) to be verified sequentially under first lighting conditions, and under second lighting conditions essentially different from those of the first lighting conditions, so as to create first and second verification images, using a imaging apparatus (107) having a communication unit (109), a memory unit (113), and a calculation unit (112); e) verifying the optically variable character on the basis of first and second verification images and calculating a digital verification imprint of the tag to be verified; and f) comparing the digital verification imprint and the corresponding digital reference imprint, calculating the distance between said two digital imprints, and comparing said distance relative to a predetermined threshold.