Forged Seal Imprint Inspection via Image Processing

Solution Overview

Problem

Current methods for inspecting forged seal imprints are prone to errors due to subjective human judgment, variability in reproduction processes, and difficulties in distinguishing genuine and forged seals, especially with advanced copying techniques like computer-aided manufacturing, which produce highly accurate but potentially indistinguishable seals.

Innovation Solution

A method that generates a reference seal imprint from a genuine seal, calculates characteristic values such as packing rates and error rates by comparing it with comparative seal imprints, and uses these values to objectively determine if a compared seal imprint is forged, employing image processing and registration techniques to match and analyze seal regions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If photolithography is used to create copy seals, then the copying process becomes automated and efficient, but the accuracy and distinguishability from genuine seals deteriorates due to photographing errors

Engineering Contradiction:

Improvecopying efficiencyVSAvoidseal accuracy

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent replaces manual inspection methods with automated image processing systems. A computer captures images of both genuine and copy seals, then uses software to compare their characteristics objectively, eliminating human subjectivity while maintaining high accuracy in detecting forgery despite the automated copying process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent transforms the inspection approach by changing from visual/subjective parameters to quantitative/image-based parameters. By converting seal characteristics into digital image data and comparing pixel-level differences, the system can detect subtle variations introduced during photolithography copying that would be imperceptible to human inspectors

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If computer-aided manufacturing is used to create forged seals, then the manufacturing precision improves significantly, but the ease of detecting forgery deteriorates as the seals become indistinguishable from genuine ones

Engineering Contradiction:

Improveseal accuracyVSAvoidforgery detection difficulty

Core Design Contradiction:

Manufacturing precisionVSDifficulty of detecting and measuring

Solution Approach 1:

The patent replaces manual inspection methods with automated image processing systems. A computer captures images of both genuine and copy seals, then uses software to compare their characteristics objectively, eliminating human subjectivity while maintaining high accuracy in detecting forgery despite the automated copying process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent moves the inspection from the physical dimension to the digital image dimension. By capturing seals as digital images and performing pixel-level comparison, the system can detect subtle variations in shape, size, and pattern that are beyond human visual capability, even when the physical seals appear identical

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Device complexity

If manual tracing or contour extraction methods are used for seal inspection, then the device complexity is reduced, but the measurement precision and time consumption worsen due to subjective judgment and technical requirements

Engineering Contradiction:

Improveinspection device simplicityVSAvoidinspection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces manual inspection methods with automated image processing systems. A computer captures images of both genuine and copy seals, then uses software to compare their characteristics objectively, eliminating human subjectivity while maintaining high accuracy in detecting forgery despite the automated copying process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8577121B2Forged seal imprint inspection method and recording medium

Publication Date: 2013.11.05 REPUBLIC OF KOREA (NTL FORENSIC SERVICE DIRECTOR MINIST OF PUBLIC ADMINISTRATION & SECURITY)

AI summary

Disclosed herein is a forged seal imprint checking method which includes a step ST-101 of generating a reference seal imprint from a genuine seal (ST-110) and a step ST-121 of comparing a compared seal imprints with the reference seal imprint to calculate characteristic values of the compared seal imprint with respect to the reference seal imprint (ST-140). According to experimental results, forged seal imprints obtained by seals forged by etching a zinc plate or a resin plate can be recognized and forged seal imprints generated by seals forged through computer copy can be also recognized. Accordingly, an objective basis on which it can be determined whether seal imprints on documents are forged in civil and criminal cases can be provided to prevent errors which may be generated when seal imprints are inspected with the naked eyes or microscopes.