Defect Estimation Using Coupling Matrix and DPSM

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Non-destructive testing methods face challenges in accurately estimating defects within objects due to superposition of images and secondary quantity disturbances, especially when access to both sides of the object is limited, leading to inaccurate defect reconstruction.

Innovation Solution

A method involving the use of a coupling matrix and Distributed Point Sources Method (DPSM) to establish interaction equations between waves and objects, allowing for the inversion of global equations to estimate defects by isolating the components of the induced wave field at specific depths and orientations, and applying principal component analysis for quantitative estimation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional non-destructive testing methods are used to detect defects, then defect detection is performed, but image superposition and secondary quantity disturbances cause inaccurate defect reconstruction

Engineering Contradiction:
Improvedefect reconstruction accuracyVSAvoidimage superposition and disturbance
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent segments the defect detection problem by dividing the object into multiple depth layers (voxels) and processing each layer independently through iterative inversion. This segmentation separates the superimposed defect signals from different depths, allowing accurate reconstruction of individual defect locations and characteristics without interference from other defects in the superposition.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies mathematical inversion techniques to reverse the forward modeling process. Instead of predicting sensor readings from known defects, the method inverts the relationship to estimate defect characteristics from measured sensor data. This inversion approach, combined with regularization, recovers the original defect distribution from the superimposed and disturbed sensor signals.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If sensors are used on one side of the object only, then access is simplified, but defect image reconstruction becomes inaccurate due to superposition and disturbance

Engineering Contradiction:
Improvesensor accessVSAvoiddefect image accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces depth as an explicit dimensional parameter by discretizing the inspection volume into voxels along the depth axis. This dimensional transformation allows the method to resolve defects at different depths independently, converting the superimposed 2D sensor readings into accurate 3D defect reconstruction even when sensors are placed on only one side of the object.

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

Solution Approach 2:

The patent introduces a forward model and iterative inversion algorithm as intermediaries between the sensor measurements and defect reconstruction. This intermediary computational framework processes the superimposed sensor signals, separates contributions from different depth layers, and reconstructs accurate defect images without requiring physical access to both sides of the object.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If multiple observation angles are used to obtain 3D images, then defect reconstruction improves, but device complexity and measurement time increase

Engineering Contradiction:
Improve3D defect reconstructionVSAvoidmultiple observation angles
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent makes the computational system self-service by implementing an iterative inversion algorithm that automatically extracts depth information and reconstructs 3D defect images from single-angle sensor measurements. The algorithm internally performs the mathematical operations equivalent to multiple observation angles, eliminating the need for physical repositioning of sensors while achieving 3D reconstruction.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical system of physically moving sensors to multiple observation angles with a computational system performing mathematical inversion. This substitution uses algorithms to simulate multi-angle measurements from single-angle data, reducing device complexity and measurement time while maintaining accurate 3D defect reconstruction capability.

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

4Measurement precision

If conventional imaging methods are used, then defect detection is performed, but quantitative estimation of defects is not achieved

Engineering Contradiction:
Improvedefect quantificationVSAvoiddefect characteristics
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent transforms the defect characterization from qualitative visual inspection to quantitative parameter estimation by inverting the forward model to directly calculate defect properties such as depth, size, and location. The method outputs numerical values for defect parameters rather than images, enabling precise quantification of defect characteristics from the sensor measurements.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces conventional image-based qualitative assessment with a computational inversion system that directly calculates quantitative defect parameters. This substitution transforms the measurement process from producing visual images to generating numerical estimates of defect characteristics, achieving accurate quantification without information loss.

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

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

This approach enables precise quantitative estimation and three-dimensional reconstruction of defects, improving the accuracy of defect detection by filtering noise and aligning with the excitation currents' phase and modulus, thereby overcoming the limitations of existing methods.

Implementation Method 1

a) "illumination" of a surface of the object using an inductive wave field, in particular an electromagnetic or ultrasonic field, etc ... b) raised, at the level of the surface of the object, of a induced wave field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The principle of the method according to the invention consists in establishing global equations of an interaction between a wave and an object in order to obtain a model of an image perceived by an instrumentation system

Methodology Applied
Scientific EffectDistributed Point Sources Method:

Data Source

PatentEP2529212B1Method for evaluationg defects in an object and corresponding apparatus
Publication Date: 2018.07.18 CENT NAT DE LA RECH SCI (C N R S)
  • EP2529212B1 patent drawingFigure 1~2
  • EP2529212B1 patent drawingFigure 3~4
  • EP2529212B1 patent drawingFigure 5(a)~5(d)

AI summary

The invention relates to a device and method for estimating defects potentially present in an object (10) comprising an outer surface (18), wherein the method comprises the steps of: a) illuminating the outer surface of the object with an inductive wave field (14) at a predetermined frequency; b) measuring an induced wave field (I) at the outer surface of the object; c) developing from the properties of the object's material a coupling matrix T associated with a depth Z of the object from the outer surface; d) solving the matrix system (II) in order to determine a vector (III) at depth Z; e) extracting a sub-vector (IV) from the vector (III) corresponding to a potential defect on the object at depth Z; and f) quantitatively estimating the potential defect from the sub-vector (IV) at depth Z.