ANOMALY DETECTION OF RADIOLOGICAL SIGNATURES
First Claim
1. A method for determining the presence or absence of anomalous radioactive materials in a target in a detection zone, said method comprising:
- (i) obtaining a target gamma ray spectrum from the target;
(ii) preparing, from the target gamma ray spectrum, a target data set comprising a plurality of intensity values, each intensity value being associated with an energy bin representing a gamma ray energy or range of gamma ray energies in the target gamma ray spectrum;
(iii) pre-processing the target data set;
(iv) performing Principal Component Analysis (PCA) on a correlation matrix of a pre-processed data library so as to generate principal components for a principal component space;
(v) projecting the pre-processed target data set and the pre-processed data library into the principal component space;
(vi) determining a distance between the projected pre-processed target data set and one or more clusters of the projected pre-processed data library in the principal component space; and
(vii) comparing the distance with a predetermined threshold distance so as to determine if an anomalous radioactive material is present in the target,whereby either;
if the distance is greater than or equal to the threshold distance, a signal is generated in response to the presence of the anomalous radioactive material in the target;
orif the distance is less than the threshold distance, a signal is generated in response to the absence of the anomalous radioactive material in the target.
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Abstract
Described herein is a method for determining the presence or absence of anomalous radioactive materials in a target in a detection zone. In the method, a target gamma ray spectrum is obtained from the target and a target data set is prepared from the target gamma ray spectrum. This data set comprise a plurality of intensity values, each intensity value being associated with an energy bin representing a gamma ray energy or range of gamma ray energies in the target gamma ray spectrum. The target data set is then pre-processed and projected into a principal component space which contains a pre-processed data library projected into the principal component space. A distance is then determined between the projected pre-processed target data set and one or more clusters of the projected pre-processed data library in the principal component space and this distance is compared with a predetermined threshold distance so as to determine if an anomalous radioactive material is present in the target.
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Citations
32 Claims
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1. A method for determining the presence or absence of anomalous radioactive materials in a target in a detection zone, said method comprising:
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(i) obtaining a target gamma ray spectrum from the target; (ii) preparing, from the target gamma ray spectrum, a target data set comprising a plurality of intensity values, each intensity value being associated with an energy bin representing a gamma ray energy or range of gamma ray energies in the target gamma ray spectrum; (iii) pre-processing the target data set; (iv) performing Principal Component Analysis (PCA) on a correlation matrix of a pre-processed data library so as to generate principal components for a principal component space; (v) projecting the pre-processed target data set and the pre-processed data library into the principal component space; (vi) determining a distance between the projected pre-processed target data set and one or more clusters of the projected pre-processed data library in the principal component space; and (vii) comparing the distance with a predetermined threshold distance so as to determine if an anomalous radioactive material is present in the target, whereby either; if the distance is greater than or equal to the threshold distance, a signal is generated in response to the presence of the anomalous radioactive material in the target;
orif the distance is less than the threshold distance, a signal is generated in response to the absence of the anomalous radioactive material in the target. - View Dependent Claims (2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 32)
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8. (canceled)
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17. An apparatus for determining the presence or absence of anomalous radioactive materials in a target in a detection zone, said apparatus comprising:
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a detector for obtaining a target gamma ray spectrum from the target, a memory for storing the target gamma ray spectrum and a pre-processed data library, a processor coupled to the memory for preparing, from the target gamma ray spectrum, a target data set comprising a plurality of intensity values, each bin being associated with an energy bin representing a gamma ray energy or range of gamma ray energies in the target gamma ray spectrum;
pre-processing the target data set;
performing Principal Component Analysis (PCA) on a correlation matrix of a pre-processed data library so as to generate principal components for a principal component space;
projecting the pre-processed target data set and the pre-processed data library into the principal component space;
determining a distance between the projected pre-processed target data set and one or more clusters of the projected pre-processed data library in the principal component space; and
comparing the distance with a predetermined threshold distance so as to determine if an anomalous radioactive material is present in the target, whereby either (a) if the distance is greater than or equal to the threshold distance a signal is generated in response to the presence of the anomalous radioactive material in the target or (b) if the distance is less than the threshold distance a signal is generated in response to the absence of the anomalous radioactive material in the target; andan output device for (a) accepting the signal when an anomalous radioactive material is present in the target in order to generate a physical response to the presence of the anomalous radioactive material or for (b) accepting the signal when an anomalous radioactive material is absent in the target in order to generate a physical response to the absence of the anomalous radioactive material. - View Dependent Claims (18)
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19-22. -22. (canceled)
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23. A computer readable storage medium having a computer program recorded thereon, the program being executable by a computer apparatus to make the computer determine the presence or absence of anomalous radioactive materials in a target in a detection zone, said program comprising:
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code for preparing from a target gamma ray spectrum a target data set comprising a plurality of intensity values, each intensity value being associated with an energy bin representing a gamma ray energy or range of gamma ray energies in the target gamma ray spectrum; code for pre-processing the target data set; code for performing Principal Component Analysis (PCA) on a correlation matrix of a pre-processed data library so as to generate principal components for a principal component space; code for projecting the pre-processed target data set and the pre-processed data library into the principal component space; code for determining a distance between the projected pre-processed target data set and one or more clusters of the projected pre-processed data library in the principal component space; and code for comparing the distance with a predetermined threshold distance so as to determine if an anomalous radioactive material is present in the target, - View Dependent Claims (24)
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25-31. -31. (canceled)
Specification