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US 10,539,693 B2Granted
Radionuclide detection and identification
AssigneeAustralian Nuclear Science & Technology Organization
InventorDavid Boardman
Life of this patent
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Abstract
Described herein is a method of processing a gamma ray spectrum acquired from a target. The method comprises determining whether the gamma ray spectrum of the target belongs to a first class of a plurality of classes, the first class containing reference gamma ray spectra of one or more radionuclide sources of interest, using optimal loading coefficients associated with the one or more radionuclide sources of interest, wherein the optimal loading coefficients have been obtained using Fisher linear discriminant analysis, and generating an output signal dependent on the determining.
Claims21
A method of detecting and identifying radioactive materials by processing a gamma ray spectrum acquired from a target while the target is in transit on a path, the method comprising:
- acquiring the gamma ray spectrum from the target while the target is in transit on the path;
- determining whether the gamma ray spectrum of the target belongs to a first set or a second set of a plurality of sets of gamma ray spectra belonging to a library comprising previously acquired spectra and an artificial gamma ray spectrum, while the target is in transit on the path, using optimal loading coefficients associated with one or more radionuclide sources of interest having gamma ray spectra belonging to the library, wherein the gamma ray spectra in the first set are spectra of only one of the radionuclide sources of interest, and the gamma ray spectra in the second set are the artificial gamma ray spectrum and spectra only of radionuclide sources of interest other than the gamma ray spectra in the first set, wherein the optimal loading coefficients have been obtained using Fisher linear discriminant analysis by:
- computing a between-set scatter matrix and a within-set scatter matrix for the gamma ray spectra in the first set and the second set;
- and
- computing the optimal loading coefficients from generalized eigenvector corresponding to largest generalized eigenvalue of the between-set and within-set scatter matrices;
- repeating the determining for each radionuclide source of interest having gamma ray spectra in the library;
- generating an output signal dependent on the repeated determining;
- and
- operating a preventative measure on the path of the target based on the output signal;
- wherein:
- the artificial gamma ray spectrum which comprises one of (i) a constant value with an additive Gaussian noise component and (ii) a quasi-linear spectrum with the additive Gaussian noise component.
8 more elements
An apparatus for detecting and identifying radioactive materials of a target while the target is in transit on a path, the apparatus comprising:
- a gamma ray detector configured to acquire a gamma ray signal from the target while the target is in transit on the path;
- an amplifier configured to amplify the gamma ray signal acquired by the gamma ray detector to thereby form an amplified gamma ray signal;
- a multichannel analyzer configured to partition the amplified gamma ray signal into energy bins, thereby generating a gamma ray spectrum;
- a memory configured to store the generated gamma ray spectrum, and
- a processor configured to execute computer program code to cause the processor to perform a method of detecting and identifying radioactive materials by processing the gamma ray spectrum of the target while the target is in transit on the path, the computer program code comprising:
- code for acquiring the gamma ray spectrum from the target while the target is in transit on the path;
- code for determining whether the gamma ray spectrum of the target belongs to a first set or a second set of a plurality of sets of gamma ray spectra belonging to a library comprising previously acquired spectra and an artificial gamma ray spectrum, while the target is in transit on the path, using optimal loading coefficients associated with one or more radionuclide sources of interest having gamma ray spectra belonging to the library, wherein the gamma ray spectra in the first set are spectra of only one of the radionuclide sources of interest, and the gamma ray spectra in the second set are the artificial gamma ray spectrum and spectra only of radionuclide sources of interest other than the gamma ray spectra in the first set, wherein the optimal loading coefficients have been obtained using Fisher linear discriminant analysis by:
- computing a between-set scatter matrix and a within-set scatter matrix for the gamma ray spectra in the first set and the second set;
- and
- computing the optimal loading coefficients from generalized eigenvector corresponding to largest generalized eigenvalue of the between-set and within-set scatter matrices;
- code for repeating the determining for each radionuclide source of interest having gamma ray spectra in the library;
- code for generating an output signal dependent on the repeated determining;
- and
- code for operating a preventative measure on the path of the target based on the output signal, wherein:
- the artificial gamma ray spectrum comprises one of (i) a constant value with an additive Gaussian noise component and (ii) a quasi-linear spectrum with the additive Gaussian noise component.
12 more elements
A non-transitory tangible computer readable storage medium having a computer program recorded thereon, the computer program being executable by a computer apparatus to cause the computer apparatus to execute a method of detecting and identifying radioactive materials by processing a gamma ray spectrum acquired from a target while the target is in transit on a path, said computer program comprising:
- code for acquiring the gamma ray spectrum from the target while the target is in transit on the path;
- code for determining whether the gamma ray spectrum of the target belongs to a first set or a second set of a plurality of sets of gamma ray spectra belonging to a library comprising previously acquired spectra and an artificial gamma ray spectrum, while the target is in transit on the path using optimal loading coefficients associated with one or more radionuclide sources of interest having gamma ray spectra belonging to the library, wherein the gamma ray spectra in the first set are spectra of only one of the radionuclide sources of interest, and the gamma ray spectra in the second set are the artificial gamma ray spectrum and gamma ray spectra only of radionuclide sources of interest other than the gamma ray spectra in the first set, wherein the optimal loading coefficients have been obtained using Fisher linear discriminant analysis by:
- computing a between-set scatter matrix and a within-set scatter matrix for the gamma ray spectra in the first set and the second set;
- and
- computing the optimal loading coefficients from generalized eigenvector corresponding to largest generalized eigenvalue of the between-set and within-set scatter matrices;
- code for repeating the determining for each radionuclide source of interest having gamma ray spectra in the library;
- code for generating an output signal dependent on the repeated determining;
- and
- code for operating a preventative measure on the path of the target based on the output signal, wherein:
- the artificial gamma ray spectrum comprises one of (i) a constant value with an additive Gaussian noise component and (ii) a quasi-linear spectrum with the additive Gaussian noise component.
7 more elements
Dependencies are inferred from the claim text.