Automated Pantograph Mark Generation via Frequency Analysis

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Solution Overview

Problem

The process of creating pantograph marks for security documents is labor-intensive and time-consuming, requiring subjective evaluation of numerous test patterns to determine the optimal frequency range for hiding the mark in the original while making it visible in copies.

Innovation Solution

A system that analyzes test pattern marks on a copy to determine frequency ranges, generates an array of cells with varying frequencies, and selects polygons where the foreground and background patterns are distinguishable, allowing for the creation of a pantograph mark that remains hidden in the original but visible in copies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple test patterns are printed and visually evaluated to determine optimal frequency range, then the pantograph mark can be made invisible in original and visible in copies, but the process becomes labor-intensive and time-consuming

Engineering Contradiction:

Improveeffectiveness of pantograph markVSAvoidtime to create pantograph mark

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the manual visual evaluation process with an automated computer-based system that analyzes test pattern marks printed on copies, determines frequency ranges objectively, and generates pantograph mark patterns without requiring subjective human assessment

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system performs self-evaluation by automatically analyzing the printed test patterns on copies, identifying which frequency ranges produce visible marks in copies while remaining invisible in originals, and using this analysis to generate the final pantograph mark pattern

Inventive Principle:

Principle #25Self-service

2Measurement precision

If numerous test patterns are printed to guide pattern selection, then the optimal frequency range can be determined, but the manufacturing complexity and resource usage increase

Engineering Contradiction:

Improveaccuracy of frequency range selectionVSAvoidcomplexity of pattern generation process

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent divides the frequency spectrum into multiple discrete frequency ranges and tests specific patterns within each range, allowing systematic exploration of the parameter space without requiring exhaustive testing of all possible patterns

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system varies the frequency parameter of test patterns systematically across different frequency ranges, using the analyzed results to identify the optimal frequency range for the pantograph mark without requiring complex manual adjustment of multiple parameters

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10425554B1Method for generating and printing a drift resistant pantograph mark

Publication Date: 2019.09.24 XEROX CORP

AI summary

To generate a security mark, a system prints test pattern marks of varying frequencies on a first substrate. The system copies the test pattern marks onto a second substrate. The system analyzes the copy to identify a frequency or period range for test patterns that exhibit a high level of contrast as compared to the original. It then uses the identified range to generate an array of cells having pantograph marks of various foreground/background frequencies/periods. The system prints the array and generates polygons that contain cells in which the foreground is visually distinguished from the background. The system identifies the polygon having an inner point having a largest range to edge. It identifies the frequency/period of the background pattern and of the foreground pattern of the cell that contains the inner point. It then generates a pantograph mark having a background and foreground that correspond the identified frequencies or periods.