Intelligent License Plate Recognition with Multi-Layer Verification

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Solution Overview

Problem

Existing electronic tolling systems face challenges in accurately reading license plates due to environmental conditions and human review inefficiencies, leading to incorrect identifications and increased costs.

Innovation Solution

The implementation of multiple layers of license plate recognition processes and probability evaluation circuitry, combined with behavior analysis, to improve the confidence level of license plate identification, reducing reliance on human review.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional single-layer license plate recognition is used, then device complexity is low, but measurement precision of license plate identification is insufficient leading to errors

Engineering Contradiction:
Improvelicense plate identification accuracyVSAvoidrecognition system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The license plate recognition system is divided into multiple independent analysis layers, each performing specific recognition tasks with different algorithms and confidence thresholding. The first layer performs initial recognition while the second layer performs verification, with each layer independently evaluating candidate license plates and generating confidence scores. This segmentation allows the system to achieve high accuracy through cumulative verification while maintaining modular architecture that manages complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs more recognition actions than traditionally required by implementing two complete analysis layers instead of one. Each layer independently processes candidate license plates, generates confidence levels, and contributes to the final determination. This excessive action ensures that even if one layer makes an error, the second layer can correct it, thereby achieving higher measurement precision at the cost of increased processing steps.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If multiple layers of recognition processes are implemented, then measurement precision improves, but use of energy and processing time increases

Engineering Contradiction:
Improvelicense plate identification accuracyVSAvoidprocessing resource consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The first analysis layer performs preliminary recognition and filtering of candidate license plates before the second layer conducts detailed verification. By pre-processing and identifying high-probability candidates in the first layer, the system reduces the search space for the second layer, thereby lowering the overall computational burden. This preliminary action ensures that the more energy-intensive second layer only processes a reduced set of promising candidates rather than all possible license plate patterns.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system implements feedback mechanisms where confidence levels from the first layer influence the processing depth and intensity of the second layer. High-confidence results from the first layer can trigger simplified verification in the second layer, while low-confidence results trigger more intensive analysis. This feedback-based adaptive processing optimizes energy consumption by adjusting computational effort based on intermediate results, preventing unnecessary full-processing of already confidently identified license plates.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If human review is used to verify license plate readings, then measurement precision improves, but productivity decreases due to manual intervention

Engineering Contradiction:
Improveidentification accuracyVSAvoidtoll processing throughput
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The system performs self-verification through automated dual-layer analysis, where the recognition system validates its own outputs without requiring external human intervention. The first and second analysis layers independently evaluate candidate license plates, compare results, and resolve discrepancies automatically through confidence level comparison and cross-validation. This self-service capability eliminates the need for human reviewers while maintaining high accuracy, thereby preserving toll processing throughput and productivity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system replaces the mechanical human review process with automated electronic verification using computer vision algorithms and probability-based confidence evaluation. Instead of human operators visually inspecting and verifying license plate readings, the system uses algorithmic cross-validation between two independent analysis layers, each generating confidence scores that are mathematically combined to produce final identification results. This substitution of mechanical human labor with automated computational processes maintains high measurement precision while eliminating productivity losses associated with manual intervention.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP3261022B1Intelligent automatic license plate recognition for electronic tolling environments
Publication Date: 2022.02.16 ACCENTURE GLOBAL SOLUTIONS LTD
  • EP3261022B1 patent drawingFigure 1
  • EP3261022B1 patent drawingFigure 2
  • EP3261022B1 patent drawingFigure 3

AI summary

An intelligent automatic license plate recognition (IALPR) system implements technical solutions that improve the accuracy of automatic license plate recognition. The IALPR analyzes an image of a vehicle proximate to a toll collection point using optical character recognition (OCR), and determines candidate license plate identifications based, at least in part, on the corresponding OCR confidence level. The IALPR can also perform fingerprinting for candidate license plate images and matching analysis with a knowledge base, resulting in additional confidence levels. The IALPR can also perform behavioral analysis on the candidate license plate identifications, including trip context analysis, historical behavioral analysis, or other analytics. The IALPR can generate an overall confidence level for the candidate license plate identifications responsive to the OCR and vehicle fingerprint confidence levels and the behavioral analysis. This enhanced analysis helps the IALPR reduce the number of incorrect license plate identifications and reduce the need for human review.