Template-Based Identity Document Classification with RANSAC Filtering

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing template-based classification systems for identity documents suffer from high false detection rates, particularly in remote authentication scenarios, due to the reliance on optical checks which lack robustness in handling varied capture conditions and document orientations, leading to increased errors and resource wastage.

Innovation Solution

An iterative procedure using a RANSAC algorithm to generate hypotheses for document location and type, followed by filtering based on criteria such as well-conditionedness, geometric correctness, and area coverage, to reject poorly conditioned hypotheses, thereby reducing false detections.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If template-based classification is used for identity documents, then processing speed is improved, but false detection rate increases

Engineering Contradiction:
Improveprocessing speedVSAvoidfalse detection rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies preliminary action by performing hypothesis generation before full document analysis. The system generates multiple hypotheses about document location and type using template matching, then filters these hypotheses before proceeding to detailed analysis. This preliminary filtering step reduces false detections while maintaining processing speed by avoiding unnecessary detailed analysis of obviously incorrect hypotheses.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent segments the document classification process into distinct stages: hypothesis generation, hypothesis filtering, and detailed document analysis. By dividing the complex task into segments, the system can efficiently process documents at different levels of detail, maintaining high processing speed while improving reliability through multi-stage verification.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If optical checks are used for remote authentication, then convenience is improved, but robustness in varied capture conditions deteriorates

Engineering Contradiction:
ImproveconvenienceVSAvoidrobustness in varied capture conditions
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies parameter changes by adjusting the sensitivity and threshold parameters of the template matching algorithm based on capture conditions. The system modifies matching thresholds and hypothesis filtering criteria dynamically to accommodate varied lighting, angles, and document orientations, maintaining robustness while preserving the convenience of remote authentication.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by making the classification system adaptive to different capture conditions. The hypothesis filtering mechanism dynamically adjusts its criteria based on the quality and characteristics of the input image, allowing the system to maintain high reliability across varied conditions while keeping the user experience convenient.

Inventive Principle:
Principle #15Dynamics

3Reliability

If hypothesis filtering criteria are applied, then false detections are reduced, but computational complexity increases

Engineering Contradiction:
Improvefalse detection rateVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies partial action by implementing hypothesis filtering with selective thoroughness. The system applies simple filtering criteria initially to reject obviously incorrect hypotheses, then applies more complex analysis only to hypotheses that pass the initial filter. This approach reduces false detections while minimizing the increase in computational complexity by avoiding exhaustive analysis of all hypotheses.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentUS12387520B2Reducing false detections in template-based classification of identity documents
Publication Date: 2025.08.12 SMART ENGINES SERVICE LLC
  • US12387520B2 patent drawing
  • US12387520B2 patent drawing

AI summary

Reducing false detections in template-based classification of identity documents. In an embodiment, an iterative procedure is used to generate one or more hypotheses for the location of a document in image data and a type of document in the image data based on a plurality of predefined models representing a plurality of types of documents. The one or more hypotheses are filtered by rejecting any hypothesis that is not well-conditioned according to one or more criteria. When a best hypothesis that satisfies a threshold remains after filtering the one or more hypotheses, the document in the image data is analyzed, and, when no hypothesis that satisfies the threshold remains after filtering the one or more hypotheses, the image data is rejected.