Correlation Mark Pixel Filtering for Copy Protection
Solution Overview
Problem
Conventional security marks used in printing, such as correlation marks, can be easily copied or scanned, compromising their effectiveness in preventing counterfeiting and altering documents.
Innovation Solution
A method and system for rendering a security mark with a correlation effect using black and white pixels, where a filter is applied to remove specific pixels, making the mark unreadable when copied or scanned, and only visible with a decoding key, utilizing a modulation transfer function to ensure the mark is not preserved during copying or scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a correlation mark is made visible and readable, then the security mark can be detected and verified, but the mark can be copied and scanned, compromising security
Solution Approach 1:
The patent applies color changes by using a pattern color space with specialty imaging characteristics that are invisible to standard scanners and copiers but visible to human eyes with proper decoding. The correlation mark uses specific color patterns (black and white pixels in a defined pattern) that change their visibility based on the viewing conditions and decoding key, allowing the mark to be readable for verification while remaining undetectable to copying devices
Solution Approach 2:
The patent employs parameter changes by modifying the imaging parameters of the correlation mark to match the capabilities of human vision while excluding standard scanning devices. The mark uses specific spatial frequency patterns and color space parameters that are preserved in printed materials but degraded or eliminated during scanning and copying processes, thus maintaining security while enabling verification
2Object-affected harmful factors
If a security mark is made invisible to standard scanners, then copying is prevented, but the mark becomes unreadable without a decoding key
Solution Approach 1:
The patent applies segmentation by dividing the correlation mark into distinct visual elements (black pixels, white pixels, and intermediate gray levels) that can be selectively processed. The mark is segmented into a pattern that maintains coherence when viewed with a decoding key but appears as random noise or is completely invisible when scanned without the key, allowing differentiated access based on whether the decoding key is available
Solution Approach 2:
The patent uses an intermediary approach by introducing a decoding key as a mediator between the correlation mark and the viewer. The decoding key acts as an intermediary that transforms the invisible or scrambled pixel pattern into a readable and meaningful correlation mark, enabling authorized users to verify the mark's authenticity while preventing unauthorized copying
3Ease of operation
If conventional correlation marks are used, then the mark can be read with a decoding key, but the mark survives copying and scanning, undermining security
Solution Approach 1:
The patent applies preliminary anti-action by pre-configuring the correlation mark with specific imaging characteristics that are inherently resistant to copying and scanning. The mark is designed with a pattern color space and pixel distribution that anticipates and counteracts the effects of scanning and copying processes, ensuring that any attempt to copy or scan the mark results in degradation or complete loss of the correlation effect
Data Source
AI summary
A security apparatus and a method for rendering a security mark can involve creating a security mark that includes a correlation mark having a correlation effect and comprising black pixels and white pixels, and subjecting the security mark to a filter that can removes at least some of the black pixels or the white pixels so that the correlation effect no longer functions and the security mark is not visible when rendered on a recording medium.