Invisible Authentication Mark via Pseudo-Random Micro-Dot Coating
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Solution Overview
Problem
Existing methods for applying invisible authentication marks on large production volumes face challenges due to constraints in printing speed and the difficulty of replicating subtle variations in reflectance and color, making it hard to prevent counterfeiting and unauthorized modifications.
Innovation Solution
The method involves applying pseudo-random defects on the surface of materials using a liquid substance that solidifies, modifying optical characteristics, and creating a digital two-dimensional pattern detectable by cross-correlating the signal-to-noise ratio, which is challenging for standard scanners and printers to replicate, ensuring the mark is invisible and naturally occurring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional printing methods are used to apply invisible marks, then the mark can be applied on the media, but the printing speed is limited and cannot meet very large production volumes
Solution Approach 1:
The invisible mark is segmented into a pseudo-random pattern of micro-dots distributed across the media surface. Each dot is extremely small (below human visual resolution) and their collective arrangement forms the authentication pattern. This segmentation allows the mark to be applied using high-speed printing processes without requiring precise, slow positioning of large mark elements.
Solution Approach 2:
The invention applies different properties to different locations: the media surface receives a uniform coating except at specific locations where pseudo-random micro-dots are deposited. These localized modifications create the authentication mark while the majority of the surface maintains its original properties, enabling fast processing.
2Ease of manufacture
If standard printing processes are used to create the mark, then the process is simple, but the subtle variations in reflectance and color are difficult to replicate, making counterfeiting prevention challenging
Solution Approach 1:
The authentication mark uses an asymmetric pseudo-random distribution of micro-dots that is inherently difficult to replicate. The pattern lacks symmetry and follows a deterministic yet complex sequence based on cryptographic keys, making it impossible to reproduce accurately with standard printing processes that cannot capture or replicate such fine-grained spatial variations.
Solution Approach 2:
The invention changes physical parameters at the micro-scale: the micro-dots create subtle variations in reflectance, absorption, and surface topology that are below human visual detection thresholds. These parameter changes at the micrometer scale create a fingerprint-like signature that is easy to apply but extremely difficult to counterfeit, as standard printers cannot reproduce sub-visual variations.
3Ease of operation
If the mark is made visible for authentication, then it can be easily checked by customers or authorized dealers, but it compromises the invisibility requirement
Solution Approach 1:
The invention replaces manual visual inspection with automated optical detection systems. A scanner or imaging device captures the reflectance patterns of the micro-dot distribution, and software algorithms analyze the pseudo-random pattern to verify authenticity. This substitution allows the mark to remain invisible to human eyes while enabling efficient automated authentication.
Solution Approach 2:
The invention introduces an intermediary detection system between the mark and the authentication process. Instead of direct human visual inspection, an optical scanner serves as an intermediary that translates the invisible micro-dot pattern into detectable signal variations, which are then processed by computational algorithms to determine authenticity.
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 solution effectively prevents counterfeiting and unauthorized modifications by creating a unique, invisible authentication mark that is difficult to imitate, while maintaining the appearance of the material and allowing for reliable detection through cross-correlation analysis.
Implementation Method 1
said substance modifying at least one optical characteristic of said material... the calculated mark has very specific auto-correlation properties facilitating recovery after affine transformations... These irregularities are the result of the modulation with the mark, in particular with the active dots; they correspond to small local variations of the surface's reflectance
Implementation Method 2
said mark being detected at a later time by measuring the signal to noise ratio of the two dimensional digital signal obtained by cross-correlating said pattern with a digital two-dimensional digital image of the printed material
Data Source
AI summary
The present application aims to propose a solution for embedding invisible mark suitable for very large production volumes. This is achieved by a method for applying an invisible mark on a media based on a pattern, and comprising the following steps: determining an area to apply this mark, applying a transparent or semi-transparent substance, on the media, said substance being modulated with the active dots to form the pattern by modifying the quantity of the substance at each active dot.