Multiclass ID Category Prediction for Photo Replacement Detection

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Solution Overview

Problem

Conventional methods for detecting photograph replacement in photo identity documents are inefficient due to the time-consuming process of data labeling and the need for numerous samples to achieve high accuracy, particularly in binary classification tasks.

Innovation Solution

A multiclass classification model is trained using cropped photograph regions from various ID categories, which includes background features, and utilizes a convolutional neural network to predict the ID category, eliminating the need for extensive data labeling and fake ID samples.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a binary classification model is used to detect photograph replacement, then the detection capability is provided, but the training time and data preparation effort increase significantly

Engineering Contradiction:
Improvephotograph replacement detection capabilityVSAvoidtraining time and data preparation effort
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Instead of directly training a binary classification model to detect fake IDs, the patent inverts the approach by training a multiclass classification model to identify genuine ID categories. The detection of photograph replacement is then achieved by comparing the predicted category with the indicated category, rather than directly classifying as real or fake.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the classification parameter from binary (real/fake) to multiclass (multiple ID categories). This transformation allows the model to learn from diverse genuine ID samples without requiring fake ID samples, fundamentally changing how the detection problem is approached and reducing data preparation burden.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If thousands of fake ID samples are collected to achieve high accuracy, then the model accuracy improves, but the data collection and labeling time becomes prohibitively long

Engineering Contradiction:
Improvemodel accuracyVSAvoiddata collection and labeling time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent extracts the essential feature for detection from the complex fake ID creation process. Instead of requiring actual fake ID samples, it extracts and utilizes the characteristic that replaced photographs will be misclassified into wrong ID categories, eliminating the need for time-consuming fake ID data collection and labeling.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses copies of genuine ID photographs (with replaced photos) as training data instead of requiring actual fake IDs. By cropping photograph regions from various genuine ID cards and using them as training samples, the model learns to identify category mismatches without needing authentic fake ID samples.

Inventive Principle:
Principle #26Copying

3Productivity

If a multiclass classification model is trained with cropped photograph regions including background, then the training efficiency improves, but the complexity of data processing increases

Engineering Contradiction:
Improvetraining efficiencyVSAvoiddata processing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent segments the ID card image into a specific photograph region by cropping, including some background surrounding the photograph. This segmentation approach simplifies the training data preparation compared to using entire ID card images, while the cropping process itself handles the complexity of data processing automatically.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS11250254B2Methods and systems for detecting photograph replacement in a photo identity document
Publication Date: 2022.02.15 ZOLOZ PTE LTD
  • US11250254B2 patent drawing
  • US11250254B2 patent drawing
  • US11250254B2 patent drawing

AI summary

Disclosed are computer-implemented methods, non-transitory computer-readable media, and systems for detecting identity document photograph replacement. One computer-implemented method includes receiving image data of a cropped photograph region of an identity document (ID), where the ID comprises a photograph, and where the cropped photograph region comprises at least the photograph. Using a multiclass classification model and as a predicted ID category, an ID category is predicted based on the image data of the cropped photograph region, where the predicted ID category corresponds to a predefined class of a set of predefined classes in the multiclass classification model. The predicted ID category is compared with an indicated category of the ID. In response to a calculated mismatch between the predicted ID category and the indicated category of the ID, a determination is made that the cropped photograph region includes a replaced photograph.