False Alarm Reduction in Automatic Manufacturing Quality Control

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Solution Overview

Problem

Automatic Manufacturing Quality Control (AMQC) systems face high rates of false alarms, leading to unnecessary costs and production disruptions, especially in scenarios where defective items are rare or varied, making it challenging to differentiate between true defects and false alarms without access to sufficient examples of defective items.

Innovation Solution

A false alarm reduction system utilizing a machine learning approach, including a feature extractor and classifier, to identify and eliminate false alarms by transforming image boxes into numerical features and using one-class or multi-class classifiers to distinguish between true defects and false alarms, even in situations where examples of defective items are scarce.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If automatic defect detection systems increase sensitivity to detect more defects, then defect detection capability is improved, but false alarm rate increases

Engineering Contradiction:
Improvedefect detection capabilityVSAvoidfalse alarm rate
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent introduces an intermediary classification system between the initial defect detection and the final decision-making process. This intermediary layer analyzes multiple features (texture, shape, location, size) of detected anomalies and compares them against learned patterns of true defects versus false alarms, thereby mediating between high-sensitivity detection and reliable classification to reduce false alarms while maintaining defect detection capability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system changes multiple parameters simultaneously including texture features, shape descriptors, location characteristics, and size metrics of detected anomalies. By analyzing changes across multiple parameters rather than relying on a single threshold, the system can distinguish between true defects and false alarms more effectively, resolving the contradiction between detection sensitivity and false alarm rate

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If follow-up actions are taken for all detected defects, then defect identification thoroughness is improved, but production efficiency deteriorates

Engineering Contradiction:
Improvedefect identification thoroughnessVSAvoidproduction efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent applies partial action by selectively performing follow-up actions only on detected anomalies that are classified as true defects with high confidence, rather than taking exhaustive follow-up actions on all detected anomalies. This selective approach maintains thorough defect identification for genuine defects while avoiding unnecessary follow-up actions on false alarms, thereby preserving production efficiency

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system implements feedback by using the results of follow-up actions (operator confirmations, re-inspections) to continuously refine and update the classification model. This feedback loop improves the system's ability to distinguish true defects from false alarms over time, reducing the need for exhaustive follow-up actions and thereby improving production efficiency while maintaining defect identification thoroughness

Inventive Principle:
Principle #23Feedback

3Measurement precision

If more training data with definitive defect labels is used, then classification accuracy is improved, but data availability deteriorates

Engineering Contradiction:
Improveclassification accuracyVSAvoiddata availability
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The system applies self-service by automatically generating training data from production images and initial defect detections without requiring extensive manual labeling. The classification model learns from the patterns it encounters during normal operation, using the available production data to train and refine its ability to distinguish true defects from false alarms, thereby achieving improved classification accuracy without requiring additional labeled training data

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent performs preliminary action by pre-processing and feature extraction on production images before classification, creating enriched training representations from the available data. This preliminary feature engineering maximizes the information content of limited training data, improving classification accuracy without requiring additional data collection

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS11087452B2False alarm reduction system for automatic manufacturing quality control
Publication Date: 2021.08.10 NEC CORP
  • US11087452B2 patent drawing
  • US11087452B2 patent drawing
  • US11087452B2 patent drawing

AI summary

A false alarm reduction system and method are provided for reducing false alarms in an automatic defect detection system. The false alarm reduction system includes a defect detection system, generating a list of image boxes marking detected potential defects in an input image. The false alarm reduction system further includes a feature extractor, transforming each of the image boxes in the list into a respective set of numerical features. The false alarm reduction system also includes a classifier, computing as a classification outcome for the each of the image boxes whether the detected potential defect is a true defect or a false alarm responsive to the respective set of numerical features for each of the image boxes.