Sub-Pixel Matrix Registration for Security Document Deformation
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Solution Overview
Problem
Existing registration methods for sub-pixel matrices in security documents fail to accurately account for complex deformations without increasing the number of visible registration marks, leading to potential misregistration and image quality issues.
Innovation Solution
A method and system that utilize sub-pixel positions and interpolation curves to determine additional registration points between visible marks, allowing for precise alignment of sub-pixel matrices by iteratively determining intermediate positions and adjusting deformation models.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a limited number of registration marks are used, then the device complexity is reduced, but the manufacturing precision deteriorates because complex localized deformations cannot be accurately modeled
Solution Approach 1:
The patent segments the registration task by dividing the matrix into multiple zones, each with its own local deformation model. Instead of using fewer global registration marks, the system creates multiple local models that can capture localized deformations in different regions independently, thereby maintaining high precision without increasing overall system complexity
Solution Approach 2:
The patent transitions from a global 2D deformation model to a multi-dimensional approach by creating multiple local 2D models for different zones. This dimensional segmentation allows each local model to focus on specific localized deformations, improving overall registration accuracy without requiring proportionally more registration marks across the entire matrix
2Manufacturing precision
If the number of registration marks is increased to model complex deformations, then the manufacturing precision improves, but the device complexity increases
Solution Approach 1:
The patent divides the matrix into multiple zones, each with its own local deformation model. This segmentation allows accurate modeling of complex localized deformations using fewer registration marks per zone, rather than requiring a large number of global registration marks, thus improving precision without proportionally increasing device complexity
Solution Approach 2:
The patent applies local quality by creating zone-specific deformation models that are optimized for local characteristics. Each local model uses registration marks and parameters tailored to its specific zone's deformation patterns, allowing high precision in each local area without requiring uniform high-density registration marks across the entire matrix
3Manufacturing precision
If registration marks are added to improve deformation modeling, then the manufacturing precision improves, but the image quality deteriorates due to disruption of the geometric periodicity
Solution Approach 1:
The patent segments the matrix into zones with local deformation models, allowing accurate deformation compensation without adding visible registration marks to the overall pattern. The local models are calculated based on subset registration marks that do not disrupt the global geometric periodicity, thus maintaining image quality while improving deformation modeling accuracy
4Device complexity
If registration marks are used to define a global grid, then the device complexity is reduced, but the measurement precision deteriorates because localized singularities cannot be detected
Solution Approach 1:
The patent divides the registration system into multiple local models for different zones, each capable of detecting localized singularities and deformations. This segmentation maintains relative system simplicity while dramatically improving the ability to detect and model localized deformations that a single global model would miss
Solution Approach 2:
The patent applies local quality by creating zone-specific deformation models that are optimized for local characteristics. Each local model can detect and model singularities and deformations specific to its zone, providing high measurement precision for localized features without requiring a completely complex global system
Data Source
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AI summary
Method for registering a subpixel matrix arranged within a security document, the subpixels each being associated with a color and a target position, the document further comprising registration marks arranged around or within the subpixel matrix (SP), the method comprising: a - obtaining the position within the document of the registration marks (MR), b - determining an intermediate position (PI) located between at least two positions of registration marks obtained and adjacent, c - determining the position (SPI) of the subpixel associated with a color of interest that is closest to the intermediate position, d - determining a set of interpolation curve parameters passing through the positions of the registration marks and through the position of said sub-, e - registering the matrix.