Security Print Media Latent Image Line-Screen Frequency Segmentation
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Solution Overview
Problem
Current document security methods are ineffective against sophisticated digital reproduction technologies, as they fail to reliably distinguish unauthorized copies from originals, especially with color copiers and scanners that can reproduce documents with high accuracy.
Innovation Solution
The implementation of line-screen patterns with varying frequencies, embedded within a visually integrated setting, that exploit the limitations of digital reproduction technologies to produce altered imaging or moiré fringes, ensuring that latent images are not reproduced accurately, thereby differentiating originals from copies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional printing methods with hidden information are used, then original documents can be verified and unauthorized copies can be distinguished, but sophisticated digital reproduction technologies can still accurately reproduce documents, rendering the security features ineffective
Solution Approach 1:
The patent divides the document into multiple frequency components using line-screen patterns. The latent image is segmented into a first line-screen pattern with a first frequency, while the visually integrated setting uses a second line-screen pattern with a second frequency. This segmentation causes digital reproduction systems to reproduce frequencies differently, making the latent image discernable in copies while maintaining visual integration in the original.
Solution Approach 2:
The patent changes the frequency parameter of line-screen patterns to create security features. By using different frequencies for the latent image (first frequency) versus the background setting (second frequency), the invention exploits the fact that digital reproduction systems reproduce different frequencies with different accuracy, causing the latent image to become discernable in reproduced copies.
2Difficulty of detecting and measuring
If latent images are embedded within visually integrated settings using matching colors and densities, then the latent images remain invisible to the unaided eye in originals, but the same matching causes the latent images to be indistinguishable from the setting in copies as well
Solution Approach 1:
The patent segments the visual information into different frequency components. The latent image uses a first line-screen pattern frequency while the visually integrated setting uses a second line-screen pattern frequency. This frequency segmentation ensures that in the original document, both frequencies appear visually integrated to the unaided eye, but in reproduced copies, the reproduction system handles different frequencies differently, causing the latent image frequency to stand out.
Solution Approach 2:
The patent changes the frequency parameter between the latent image line-screen pattern and the visually integrated setting line-screen pattern. This parameter change creates a situation where color and density matching hide the latent image in originals, but frequency differentiation causes the latent image to become discernable in reproduced copies.
3Reliability
If multiple line-screen patterns with different frequencies are used for latent images, then at least one latent image becomes discernable upon reproduction, but the printing process becomes more complex
Solution Approach 1:
The patent segments the security feature into multiple line-screen patterns with different frequencies. This segmentation approach, while adding complexity, reliably produces discernable latent images in reproduced copies because digital reproduction systems handle different frequencies differently, ensuring at least one frequency component becomes visible.
Solution Approach 2:
The patent uses parameter changes in frequency to create multiple line-screen patterns. This approach systematically manages complexity by varying a single parameter (frequency) rather than introducing multiple unrelated variables, making the printing process more complex but still manageable through standardized frequency variations.
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 approach effectively thwarts undetected copying by rendering latent images discernable only upon reproduction, ensuring that the original document can be differentiated from unauthorized copies, even with advanced digital scanning and printing technologies.
Implementation Method 1
The different line-screen patterns of the latent images have a line frequency less than a line frequency of the line-screen pattern of the visually integrated setting and line frequencies differing from one another so that upon reproduction of the print medium through a sensor array, at least one of the latent images is rendered readily discernable to the unaided eye
Data Source
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AI summary
Copy protections are incorporated into print media by embedding a plurality of latent images formed by different line-screen patterns within a visually integrated setting formed by another different line-screen pattern. The different line-screen patterns of the latent images have line frequencies empirically selected so that upon reproduction at least one of the latent images is rendered more readily discernable to the unaided eye. A masking design formed by another line-screen pattern overlies both the latent images and the visually integrated setting.