Guided Wave Mode Identification via Wavelet Cross-Correlation

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Solution Overview

Problem

Current systems for detecting leaks and characterizing defects in fluid containers and structural members are inadequate due to complexities in wave propagation, reflections, and interactions with structural features, leading to inaccurate and unreliable results.

Innovation Solution

A method and system utilizing image cross-correlation between wavelet transform images of guided waves and theoretical dispersion curves to automatically identify wave modes and locate defects without assumptions, overcoming reflection issues and providing deterministic analysis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional wave analysis methods are used to detect defects in structures, then the system can identify wave modes, but the analysis becomes unreliable due to complex wave propagation, reflections, and interactions with structural features

Engineering Contradiction:

Improvereliability of defect detectionVSAvoidcomplexity of wave propagation analysis

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces conventional mechanical wave analysis methods with a digital image processing approach. Wavelet transform images of guided waves are converted into visual representations that can be cross-correlated with theoretical dispersion curves, substituting complex mechanical analysis with optical/image processing techniques that are more reliable and less susceptible to propagation complexities

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces wavelet transform images as an intermediary between the physical wave propagation and the defect detection process. These images serve as a mediator that captures wave characteristics in a visual format that can be systematically compared with theoretical models through cross-correlation, eliminating the need to directly analyze complex wave propagation physics

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If manual evaluation of 2D waveform plots is used to identify wave modes, then the process can be performed with simple tools, but the automation and precision of defect location are insufficient

Engineering Contradiction:

Improveprecision of wave mode identificationVSAvoidautomation of defect detection

Core Design Contradiction:

Measurement precisionVSExtent of automation

Solution Approach 1:

The patent replaces manual visual evaluation of waveforms with an automated digital image cross-correlation system. The wavelet transform images are automatically compared with theoretical dispersion curves using cross-correlation algorithms, providing both high precision in wave mode identification and complete automation of the defect detection process

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates digital copies of wave characteristics through wavelet transform images, which can be repeatedly analyzed and compared with theoretical models. These image copies enable automated processing while preserving all the information needed for precise wave mode identification and defect location

Inventive Principle:

Principle #26Copying

3Measurement precision

If assumptions are made about wave propagation to simplify analysis, then the computation becomes easier, but the accuracy of defect characterization is reduced

Engineering Contradiction:

Improveaccuracy of defect characterizationVSAvoidcomplexity of analysis method

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent uses wavelet transform images as an intermediary that naturally captures the full complexity of wave propagation without requiring simplifying assumptions. The images preserve all wave characteristics including reflections and mode conversions, allowing accurate defect characterization while maintaining computational tractability through visual pattern matching

Inventive Principle:

Principle #24Intermediary (Mediator)

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 accurate and reliable detection and characterization of defects by identifying wave propagation characteristics in a deterministic manner, improving the precision of source location and severity assessment.

Implementation Method 1

comparing theoretical dispersion curves for the structure and a wavelet transform image of the guided wave

Methodology Applied

Scientific EffectWavelet transform:

Implementation Method 2

A method and system utilizing image cross-correlation between wavelet transform images of guided waves and theoretical dispersion curves to automatically identify wave modes

Methodology Applied

Scientific EffectCross-correlation:

Data Source

PatentUS20230334646A1System and Method for Mode Identification and Extraction in Guided Wave Signals and nondestructive methods for automatically sensing, locating, and/or characterizing problems in structures

Publication Date: 2023.10.19 ANTECH SYSTEMS INC

AI summary

A system and method are provided herein for determining a characteristic of a guided wave traveling in a structure. The method includes comparing theoretical dispersion curves for the structure and a wavelet transform image of the guided wave to identify a match, which in an embodiment is a cross-correlation. In an exemplary embodiment, the wavelet transform image is a three-dimensional image, and the theoretical dispersion curves are calculated using Lamb mode theory or finite element analysis.