Dual-Energy Radiography Material Recognition via Layered Decomposition

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Solution Overview

Problem

Current dual-energy radiography systems struggle to accurately recognize materials when they overlap along the X-ray transmission path, leading to false recognition and errors, particularly in security inspection and anti-smuggling applications.

Innovation Solution

A layered material-based dual-energy radiography technology that uses high-low-energy curves to coarsely divide material intervals, decompose X-ray data into sets corresponding to individual materials, and calculate their composition, allowing for stratified imaging and accurate recognition of multiple materials without significant hardware changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If dual-energy radiography is used to recognize material composition, then material recognition capability is improved, but accuracy decreases when materials overlap along the X-ray transmission path

Engineering Contradiction:
Improvematerial recognition capabilityVSAvoidrecognition accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the overlapping material region into multiple layers along the X-ray transmission path. By dividing the inspection object into front, middle, and rear layers, the system can independently analyze each layer's material composition, eliminating the interference caused by material overlap and improving recognition accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a depth dimension (transmission path position) to the traditional two-dimensional dual-energy analysis. By determining the transmission path distance of each pixel and combining it with dual-energy attenuation data, the system creates a three-dimensional material distribution map that resolves overlapping materials along the beam path.

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

2Device complexity

If mono-energy spectrum radiography is used for imaging, then system complexity is reduced, but material information recognition becomes impossible

Engineering Contradiction:
Improvesystem complexityVSAvoidmaterial information
Core Design Contradiction:
Device complexityVSLoss of information

Solution Approach 1:

The patent changes the energy parameter of the X-ray beam by implementing dual-energy spectrum imaging. By acquiring images at two different energy levels and analyzing the differential attenuation, the system extracts material composition information (such as effective atomic number) that cannot be obtained with mono-energy imaging, thus preventing information loss.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If shape information is used to determine objects in mono-energy radiography, then false positives and false negatives increase for materials without fixed shape

Engineering Contradiction:
Improveobject determination accuracyVSAvoidmaterial composition information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent introduces material composition information (effective atomic number, density) as an intermediary parameter between the X-ray image and object identification. This intermediary provides objective material characterization that is independent of shape, enabling accurate identification of materials without fixed shapes such as explosives, drugs, and liquids.

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

This approach enhances the accuracy of substance recognition, reduces false positives and negatives, and extends to multi-energy scenarios, effectively addressing the limitations of existing dual-energy systems in recognizing overlapped materials.

Implementation Method 1

The X-ray attenuated after passing through the object to be inspected is received by a detector and converted into an electronic signal to form an image. Magnitude of signal strength of each pixel in the image reflects the degree of absorption of the X-photons by the material in the direction of the X-ray transmission

Methodology Applied
Scientific EffectX-ray attenuation: Absorption (EM radiation)

Implementation Method 2

The interactions between the X-ray photons and the substance are typically divided into three categories: the photoelectric effect, the Compton scattering, and the electron pair effect, and the reaction cross-sections for the three categories of interactions are related to the X photon energy and atomic number of the substance

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 3

The interactions between the X-ray photons and the substance are typically divided into three categories: the photoelectric effect, the Compton scattering, and the electron pair effect

Methodology Applied
Scientific EffectCompton scattering: Compton Scattering

Data Source

PatentEP3242126B1Dual-energy ray imaging method and system
Publication Date: 2022.01.26 NUCTECH CO LTD
  • EP3242126B1 patent drawingFigure 1~2
  • EP3242126B1 patent drawingFigure 3
  • EP3242126B1 patent drawingFigure 4

AI summary

Disclosed is a dual-energy ray imaging method and system. The method comprises: calculating the mass thicknesses of the materials in the overlapped area of two materials by using a calibrated surface fitting method, and then decomposing a pair of original high-energy and low-energy data for this pixel into two high-low-energy data sets corresponding to the two materials, and finally calculating and acquiring the composition result of different materials for each pixel. The disclosure is especially advantageous in that the problem of error recognition of materials due to the two overlapped materials can be eliminated and the stratified imaging of multiple materials can be achieved, thereby improving the accuracy of the substance recognition and reducing the rate of false positive and false negative which is very important to the applications in the field of security check and anti-smuggling.