Automated Surface Anomaly Detection Using Guided Wave Imaging

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Solution Overview

Problem

Existing techniques for detecting surface anomalies, such as pitting corrosion, are limited by requiring expert evaluation and are not suitable for automatic feedback control, making it difficult to accurately detect and characterize surface degradation in real-time.

Innovation Solution

A surface anomaly detection system that uses synthetic aperture focusing technique (SAFT) with guided waves and a piezoelectric transducer array to create images of surfaces, combined with noise filtering, threshold detection, contour analysis, and severity estimation to automatically identify and characterize anomalies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If expert evaluation is used to interpret surface anomaly data, then detection accuracy is improved, but automation capability deteriorates

Engineering Contradiction:
Improveanomaly detection accuracyVSAvoidautomatic detection capability
Core Design Contradiction:
Measurement precisionVSExtent of automation

Solution Approach 1:

The system performs self-evaluation through automated image processing algorithms that independently analyze surface anomaly images, extract features, and generate detection results without requiring external expert intervention. The processing unit automatically compares extracted features against reference data to determine anomaly presence and characteristics.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical expert evaluation process with automated computational image processing. The system uses digital image analysis, feature extraction algorithms, and automated comparison methods to substitute human expert interpretation, thereby achieving both high accuracy and full automation.

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

2Ease of manufacture

If traditional surface anomaly detection methods are used, then implementation simplicity is improved, but applicability to automatic feedback control deteriorates

Engineering Contradiction:
Improvesystem implementation simplicityVSAvoidfeedback control loop compatibility
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The system incorporates feedback capability by generating structured detection results that can be fed into control loops. The automated processing unit produces quantifiable anomaly data that can trigger corrective actions, enabling the system to function within automatic feedback control architectures for real-time surface quality management.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent transforms the detection output into standardized parameters and metrics that are suitable for control system integration. By converting visual anomaly detection into quantifiable data with defined thresholds and classifications, the system enables seamless integration with automatic feedback control mechanisms while maintaining implementation simplicity.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If pitting corrosion is detected with high precision, then structural integrity assessment is improved, but detection complexity increases

Engineering Contradiction:
Improvepitting corrosion detection accuracyVSAvoiddetection system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments the complex task of pitting corrosion detection into distinct processing stages: image acquisition, preprocessing, feature extraction, anomaly identification, and characterization. This segmentation allows each module to focus on a specific function, achieving high detection precision while managing overall system complexity through modular architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent enhances detection precision by transitioning from two-dimensional surface imaging to three-dimensional anomaly characterization. The system extracts depth information, volume measurements, and spatial distribution data from 2D images, enabling accurate pitting corrosion assessment without significantly increasing device complexity through advanced image processing techniques.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Enables robust, automated detection and characterization of surface anomalies, providing a metric for structural damage assessment and enabling predictive maintenance by determining the extent and impact of surface defects on devices.

Implementation Method 1

the waves are guided using a piezoelectric transducer array. In this embodiment, the guided waves are reflected back to the transducer by the physical defects in the material

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

the image data comprises data created using a synthetic aperture focusing technique (SAFT). This technique applies guided waves to the surface under evaluation

Methodology Applied
Scientific EffectSynthetic aperture focusing technique:

Implementation Method 3

The noise filter uses an estimated characterization of the background noise to remove the background noise from the image data. In one embodiment, the background noise is removed by using a stochastic model to estimate a smoothed value for the intensity at each pixel

Methodology Applied
Scientific EffectStochastic modeling:

Implementation Method 4

The smoothed pixel intensity is then compared to a threshold to identify significant departures. In one embodiment, the threshold detector uses a threshold calculated using a constant false positive rate

Methodology Applied
Scientific EffectThreshold detection:

Implementation Method 5

The detected anomalies are then passed to a contour detector, which determines the contours of anomalies in the surface to provide more precise characterization of the surface defects

Methodology Applied
Scientific EffectContour detection:

Data Source

PatentUS7653235B2Surface anomaly detection system and method
Publication Date: 2010.01.26 HONEYWELL INTERNATIONAL INC
  • US7653235B2 patent drawing
  • US7653235B2 patent drawing
  • US7653235B2 patent drawing

AI summary

A system and method is provided to detect surface anomalies. The detection system and method provides the ability to automatically detect and characterize anomalies on a surface, such as detecting and characterizing pitting corrosion on metal surfaces. The surface anomaly detection system and method uses an image of the surface under evaluation. The image data is passed to a noise filter. The noise filter uses an estimated characterization of the background noise to remove the background noise from the image data. The smoothed pixel intensity is then compared to a threshold to identify significant departures. The detected anomalies are then passed to a contour detector, which determines the contours of anomalies in the surface to provide more precise characterization of the detected anomalies. The detected closed contours of anomalies may then be passed to a defect severity estimator that provides an anomaly factor metric.