Document Image Authentication via Fourier Spectrum Analysis

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Solution Overview

Problem

Existing technologies face challenges in differentiating between images of original documents and images of documents that are not original scans, particularly in web services where users may or may not comply with instructions to scan original documents.

Innovation Solution

A method and system that use a resolution analysis test, specifically a Fourier-transform based spectrum analysis, to determine whether a digital image of a document was generated by scanning an original document, by analyzing the textured region of interest in the image.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If users are allowed to upload document images freely, then ease of operation is improved, but reliability deteriorates because users may not comply with instructions to scan original documents

Engineering Contradiction:

Improveease of document uploadVSAvoidreliability of document authentication

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The system performs automated authentication analysis on uploaded document images and provides feedback to users about whether the document appears to be an original scan or a copy. This feedback loop enables users to understand compliance status and re-upload if necessary, maintaining ease of operation while improving reliability through automated verification.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The authentication system operates autonomously to analyze uploaded documents without requiring manual verification. The self-service nature of the automated analysis maintains ease of operation for users while improving reliability through consistent, objective authentication decisions made by the system itself.

Inventive Principle:

Principle #25Self-service

2Reliability

If automated authentication analysis is performed on all uploaded images, then reliability is improved, but productivity deteriorates due to increased processing time

Engineering Contradiction:

Improvereliability of document authenticationVSAvoidproductivity of document processing

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The system performs automated authentication analysis selectively rather than on every single uploaded image. By applying partial action only when needed or when initial filters indicate potential issues, the system maintains high reliability for critical cases while preserving overall productivity by avoiding unnecessary processing of clearly compliant documents.

Inventive Principle:

Principle #16Partial or excessive action

3Measurement precision

If resolution analysis test is applied to textured regions, then measurement precision is improved, but device complexity worsens due to additional processing requirements

Engineering Contradiction:

Improveprecision of document scan detectionVSAvoidcomplexity of image processing system

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The image processing system divides the document image into multiple regions and applies resolution analysis specifically to textured regions rather than the entire image. This segmentation approach improves measurement precision by focusing computational resources on discriminative areas while reducing overall device complexity by avoiding unnecessary processing of uniform regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system applies different processing qualities to different regions of the image, with higher resolution analysis applied specifically to textured regions where authentication cues are most valuable. This local quality approach improves measurement precision in critical areas while reducing device complexity by using simpler processing elsewhere.

Inventive Principle:

Principle #3Local quality

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

Effectively differentiates between images of original documents and images of copied documents, improving the accuracy of document authentication processes in web services and other applications.

Implementation Method 1

The Fourier transform (FT) decomposes a function of time (signal) into the frequencies that make it up.

Methodology Applied

Scientific EffectFourier transform:

Implementation Method 2

the power spectrum of a time series describes the distribution of power into frequency components composing that signal

Methodology Applied

Scientific EffectSpectrum analysis:

Data Source

PatentUS12217405B2System, method and computer program product for differentiating images comprising original scans of documents, from images of documents that are not original scans

Publication Date: 2025.02.04 AU10TIX

AI summary

A method for processing images generated by unsupervised end-users, the method comprising determining whether or not at least one digital image of a document was generated by scanning an original document, including using a processor for applying a resolution analysis test to a textured region of interest; and sending at least one output indication of the determining operation.