X-ray Tomography Beam Hardening Correction via Statistical Analysis
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Solution Overview
Problem
Conventional X-ray imaging techniques struggle to separate geometrical and compositional information from a specimen, leading to hybrid images that are difficult to interpret, and fail to effectively correct for Beam Hardening effects in tomographic imaging.
Innovation Solution
The method involves capturing multiple X-ray images of a specimen to calculate mean and variance of signal strength per pixel, allowing for the separation of X-ray photon energy and number maps, which are then used to produce a map of mean X-ray photon energy and correct for Beam Hardening by estimating energy shifts, enabling the disentanglement of compositional and topographical information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conventional X-ray imaging techniques are used to capture specimen information, then both geometrical and compositional information are obtained, but the information becomes hybrid and difficult to interpret
Solution Approach 1:
The patent segments the hybrid X-ray signal into two distinct components: geometrical information (from photon number variations) and compositional information (from photon energy variations). By calculating mean and variance of signal strength across multiple images, the method separates these intertwined information types into independent maps, making each interpretable for its specific purpose without contamination from the other.
Solution Approach 2:
The patent introduces statistical moments (mean and variance of signal strength) as intermediary quantities that mediate between the raw hybrid X-ray images and the separated information maps. These statistical parameters act as bridges that enable the decomposition of the mixed signal into pure geometrical and compositional components through mathematical relationships.
2Measurement precision
If conventional tomographic imaging is performed, then a volume image is reconstructed, but Beam Hardening artifacts remain uncorrected
Solution Approach 1:
The patent extracts the energy distribution information (compositional data) from the X-ray images using variance calculation. This extracted compositional map is then used to identify and remove Beam Hardening artifacts from the tomographic reconstruction, separating the harmful artifacts from the useful imaging information.
Solution Approach 2:
The patent implements a feedback mechanism where the compositional information derived from image variance is fed back into the tomographic reconstruction process to correct Beam Hardening artifacts. This feedback loop allows the system to use its own measured data to eliminate systematic errors, improving the accuracy of both geometrical and compositional results.
3Loss of information
If multiple X-ray images are captured and processed to separate photon energy and number, then compositional information is extracted, but processing complexity increases
Solution Approach 1:
The patent replaces complex physical spectroscopy systems with a computational approach. Instead of using physical devices to separate and measure photon energies, the method uses statistical analysis (mean and variance calculations) on standard X-ray images to extract energy information, substituting mechanical/spectral complexity with mathematical processing.
Solution Approach 2:
The patent creates statistical copies (mean and variance maps) of the original X-ray images that encode different types of information. These copied statistical representations serve as simplified surrogates that contain the essential compositional and geometrical information without requiring complex physical measurement systems.
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 allows for the accurate extraction of compositional information without X-ray spectroscopy and significantly reduces Beam Hardening artifacts in reconstructed tomograms, enhancing the resolution and clarity of X-ray tomographic imaging.
Implementation Method 1
Using a detector to detect a flux of output X-rays emanating from the specimen in response to said irradiation
Implementation Method 2
For each pixel pi in each image Ij, determining the accumulated signal strength Sij, thus producing an associated set of signal strengths {Sij}. Using the set {Sij} to calculate the following values: A mean signal strength S per pixel position i; A variance σ2S in S per pixel position i. Using these values S and ν2S to produce a map of mean X-ray photon energy E per pixel
Data Source
AI summary
A method of analyzing a specimen using X-rays, comprising the steps of:Irradiating the specimen with input X-rays;Using a detector to detect a flux of output X-rays emanating from the specimen in response to said irradiation,which method further comprises the following steps:Using the detector to intercept at least a portion of said flux so as to produce a set {Ij} of pixeled images Ij of at least part of the specimen, whereby the cardinality of the set {Ij} is M>1.For each pixel pi in each image Ij, determining the accumulated signal strength Sij, thus producing an associated set of signal strengths {Sij}.Using the set {Sij} to calculate the following values:A mean signal strength S per pixel position i;A variance σ2S in S per pixel position i.Using these values S and σ2S to produce a map of mean X-ray photon energy E per pixel.