Multi-energy X-ray Imaging Substance Identification
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Solution Overview
Problem
Current multi-energy-spectrum X-ray imaging systems face challenges in accurately identifying substances due to complex mathematical calculations and limited energy discrimination, particularly in distinguishing between narrow energy regions and materials with similar atomic numbers.
Innovation Solution
The proposed method involves acquiring a transparency related vector from multiple energy regions, using algorithms like Mahalanobis distance, Euclidean distance, or Cosine distance to determine the item's identity by comparing it to stored vectors, and employing non-linear dimension reduction techniques to map data into a two-dimensional plane for simplified classification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dual-energy X-ray imaging is used to obtain atomic number information, then substance identification capability is improved, but energy spectrum overlap limits the identification accuracy
Solution Approach 1:
The patent segments the broad X-ray energy spectrum into multiple narrow energy regions using a photon counting detector. Each detector element is assigned to a specific energy region, allowing independent measurement of photon counts in each region. This segmentation eliminates the energy spectrum overlap problem in dual-energy imaging and enables precise measurement of attenuation coefficients at different energy levels, thereby improving substance identification accuracy.
2Measurement precision
If multi-energy-spectrum imaging divides X-ray into more energy regions, then energy discrimination ability is improved, but calculation complexity increases
Solution Approach 1:
The patent transforms the complex multi-energy spectrum data into simplified parameters by calculating attenuation coefficients for each energy region using the formula μ = -ln(T)/t, where T is transparency and t is material thickness. This parameter transformation reduces the complexity of raw photon count data while preserving the essential information needed for substance identification. The calculated attenuation coefficients are then used in subsequent classification algorithms.
Solution Approach 2:
The patent replaces complex mathematical curve approximation methods with a database lookup approach. Pre-calculated attenuation coefficient data for various substances are stored in a database, and the measured attenuation coefficients are compared against this database to identify substances. This substitution of calculation methods significantly reduces computational complexity while maintaining identification accuracy.
3Measurement precision
If photon counting detector is used to achieve multi-energy-spectrum imaging, then substance identification capability is improved, but radiation dose measurement and energy calibration complexity increase
Solution Approach 1:
The patent performs energy calibration and radiation dose measurement procedures before actual substance identification. The system first determines the energy response characteristics of each detector element and establishes the relationship between detector output and photon energy. This preliminary calibration creates a reference framework that simplifies subsequent measurements and eliminates the need for complex real-time calculations during substance identification.
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 substance identification accuracy by reducing complex calculations and improving energy discrimination, enabling better differentiation between materials, especially in security applications like identifying contraband.
Implementation Method 1
The X-ray transmission imaging technology is widely used in the fields of security, medical, etc.
Implementation Method 2
a detector configured to receive the X-ray which is emitted from the X-ray source and is transmitted through or scattered by an item to be inspected and convert the received X-ray into an output signal
Implementation Method 3
the intensity of a single-energy X-ray beam is attenuated with the exponential function of the thickness of the absorbing substance, where I0 is the ray intensity before the attenuation, I is the ray intensity after the attenuation by a material with a certain thickness, t is the mass thickness of the material; and μ represents the mass attenuation coefficient
Data Source
AI summary
The present disclosure discloses a method of substance identification of an item to be inspected using a multi-energy-spectrum X-ray imaging system, the method comprising: acquiring a transparency related vector consisting of transparency values of the item to be inspected in N energy regions, wherein N is greater than 2; calculating distances between the transparency related vector and transparency related vectors stored in the system consisting of N transparency mean values of multiple kinds of items with multiple thicknesses in the N energy regions; and identifying the item to be inspected as the item corresponding to the minimum distance. The present disclosure is based on a multi-energy-spectrum X-ray imaging system, and proposes a method of substance identification by analyzing the multi-energy-spectrum substance identification issue. Compared with the conventional dual-energy X-ray system, the multi-spectrum imaging can significantly improve the system's ability to identify substances in theory, especially in the field of security applications. The improvement of substance identification is important for contraband inspection, such as, drugs, explosives.