Multi-Energy X-Ray Spectral Imaging for Low Absorption Material Detection

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Solution Overview

Problem

Detecting materials with low x-ray absorption characteristics within materials with high x-ray absorption characteristics is challenging, as they become 'invisible' in x-ray images, requiring costly neutron radiography for aerospace components, such as detecting residual casting core material.

Innovation Solution

A method involving creating multiple digital x-ray images of a blade using different energy spectra (60-650 keV and 300-650 keV) and subtracting these images to enhance the visibility of low absorption materials, while maintaining the blade in a fixed position, and using automated algorithms for image processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If higher x-ray energies are used to penetrate high absorption materials, then penetration capability is improved, but low absorption materials become invisible in the resulting image

Engineering Contradiction:
Improvepenetration capabilityVSAvoiddetection capability of low absorption materials
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The x-ray energy spectrum is segmented into multiple discrete energy levels (e.g., 60 keV, 120 keV, 180 keV, 240 keV, 300 keV, 360 keV, 420 keV, 480 keV, 540 keV, 600 keV, 650 keV). By capturing images at each energy level separately and then combining them through spectral unmixing algorithms, the system can simultaneously achieve deep penetration of high absorption materials and sensitive detection of low absorption materials, resolving the contradiction between penetration capability and detection precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The method transitions from conventional single-energy 2D x-ray imaging to multi-energy spectral x-ray imaging, adding the energy dimension to the detection process. This spectral dimension allows the system to differentiate between materials with different absorption characteristics at various energy levels, enabling simultaneous visualization of both high and low absorption materials that would be indistinguishable in traditional single-energy images.

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

2Measurement precision

If neutron radiography is used to detect residual core material, then detection accuracy is improved, but inspection cost and time increase significantly

Engineering Contradiction:
Improvedetection accuracyVSAvoidinspection efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The method creates multiple virtual copies of the x-ray image at different energy levels and processes them through spectral unmixing algorithms to generate a final image that replicates the detection capability of neutron radiography. This computational approach provides neutron-like detection accuracy using conventional x-ray hardware, dramatically improving inspection efficiency while maintaining high detection accuracy for residual core material.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The invention replaces the complex neutron radiography system with a conventional x-ray system enhanced by multi-energy spectral analysis and computational image processing. This substitution maintains detection accuracy for low absorption materials while eliminating the need for expensive, time-consuming neutron sources and associated safety infrastructure, thereby significantly improving productivity.

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 method allows for timely and cost-effective detection of low absorption materials within high absorption materials, integrating with existing x-ray inspection processes, thereby improving the efficiency of component inspections.

Implementation Method 1

An x-ray source is provided that creates a full energy spectrum x-ray between 60 and 650 keV

Methodology Applied
Scientific EffectX-ray emission: X-Ray

Implementation Method 2

A digital x-ray detector is provided that is capable of detecting the full energy spectrum

Methodology Applied
Scientific EffectX-ray detection: Photoelectric Effect

Data Source

PatentEP2820400B1Method of detecting material in a part
Publication Date: 2022.04.20 RTX CORP
  • EP2820400B1 patent drawingFigure 1~2C
  • EP2820400B1 patent drawingFigure 3

AI summary

A method includes the steps of producing a first digital x-ray image of a part utilizing a full energy spectrum, producing a second digital x-ray image of the part with a hardened beam correlating to a higher energy portion of the full energy spectrum, subtracting the second x-ray image from the first x-ray image, and using a remainder of the subtracting step to locate the matter.