Explosive detection method, apparatus, and computer-readable storage medium

Abstract

Embodiments of the present application provide an explosive detection method, comprising: receiving a detection signal to generate a detection spectrum, the detection spectrum being a spectrum of gamma rays generated by a reaction between a to-be-detected object and neutrons; deducting a detection background in the detection spectrum to obtain a first processed spectrum; deducting a characteristic peak at a nickel peak position in the first processed spectrum to obtain a second processed spectrum; and determining whether the to-be-detected object contains an explosive based on the second processed spectrum. Embodiments of the present application also provide an explosive detection device and a computer-readable storage medium.

Description

Technical Field

[0001] This application relates to the field of neutron detection technology, specifically to a method, apparatus, and computer-readable storage medium for detecting explosives. Background Technology

[0002] In certain special locations, such as densely populated areas, it is often necessary to detect explosives to ensure safety. Using neutron detection technology can effectively improve the accuracy of explosive detection, but in some cases, false detections may still occur. Summary of the Invention

[0003] In view of the above problems, this application is made in order to provide an explosive detection method, apparatus and computer-readable storage medium that overcomes or at least partially solves the above problems.

[0004] According to a first aspect of the embodiments of this application, an explosive detection method is provided, comprising: receiving a detection signal to generate a detection spectrum, the detection spectrum being a spectrum of gamma rays generated by the reaction of a analyte with a neutron; subtracting the detection background from the detection spectrum to obtain a first processed spectrum; subtracting the characteristic peak at the nickel peak position in the first processed spectrum to obtain a second processed spectrum; and determining whether the analyte contains an explosive based on the second processed spectrum.

[0005] According to a second aspect of the embodiments of this application, an explosive detection device is provided, comprising: a detection chamber for containing a test object; a neutron source for emitting neutrons into the detection chamber; a detection unit for detecting gamma rays generated after the neutrons react to generate a detection signal; and one or more processors, the one or more processors being configured to: receive the detection signal to generate a detection spectrum, the detection spectrum being the spectrum of gamma rays generated by the reaction between the test object and neutrons in the detection chamber; subtract the detection background from the detection spectrum to obtain a first processed spectrum; subtract the characteristic peak at the nickel peak position in the first processed spectrum to obtain a second processed spectrum; and determine whether the test object contains an explosive based on the second processed spectrum.

[0006] According to a third aspect of the embodiments of this application, a computer-readable storage medium is provided that stores computer instructions thereon, which, when executed by a computer, implement the method as described in the first aspect of the embodiments of this application.

[0007] The explosive detection method, apparatus, and computer-readable storage medium provided in this application can reduce the probability of misjudgment during explosive detection. Attached Figure Description

[0008] Figure 1 This is a flowchart of an explosive detection method according to an embodiment of this application;

[0009] Figure 2This is a schematic diagram of the spectra obtained from neutron detection of blank samples, explosives, and stainless steel.

[0010] Figure 3 This is a schematic diagram of the first calibration spectrum of multiple detection units before fitting;

[0011] Figure 4 This is a schematic diagram of the first calibration spectrum of multiple detection units after fitting.

[0012] Figure 5 This is a schematic diagram of an explosive detection device according to an embodiment of this application. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only one embodiment of this application, and not all embodiments. All other embodiments obtained by those skilled in the art based on the described embodiments of this application without creative effort are within the scope of protection of this application.

[0014] It should be noted that, unless otherwise defined, the technical or scientific terms used in this application should have the ordinary meaning understood by a person with ordinary skill in the art to which this application pertains. Where the terms "first," "second," etc., are used throughout the text, they are used only to distinguish similar objects and should not be construed as indicating or implying their relative importance, order of precedence, or implicitly specifying the number of technical features indicated. It should be understood that the data in the descriptions of "first," "second," etc., can be interchanged where appropriate. Where "and / or" appears throughout the text, it means that it includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution that simultaneously satisfies A and B.

[0015] The embodiments of this application first provide an explosive detection method, referring to... Figure 1 ,include:

[0016] Step S102: Receive the detection signal to generate a detection spectrum. The detection spectrum here is the spectrum of gamma rays generated by the reaction of the analyte with neutrons.

[0017] Step S104: Subtract the detection background from the detection spectrum to obtain the first processed spectrum.

[0018] Step S106: Subtract the characteristic peak at the nickel peak position in the first processed spectrum to obtain the second processed spectrum.

[0019] Step S108: Determine whether the test sample contains explosives based on the second processing spectrum.

[0020] In step S102, as an example, the analyte can be placed in a neutron environment, such as a detection chamber equipped with a neutron source. Then, a detection unit is used to detect the gamma rays generated by the reaction between the analyte and the neutron, thereby generating a detection signal. The detection unit here can refer to any suitable neutron detector in the art, such as a NaI(Tl) crystal scintillation detector. The detection signal generated by the detection unit is usually an analog signal. After receiving the detection signal, it can be processed into a digital signal using an analog-to-digital converter, and then a spectrum is formed. Besides the above method, those skilled in the art can obtain the detection spectrum using any suitable method, and there is no limitation thereto.

[0021] After obtaining the detection spectrum, the detection background needs to be subtracted from the detection spectrum in step S104 to obtain the first processed spectrum. The detection background refers to the non-detection signal detected by the detection unit that is superimposed on the signal to be tested. Due to the presence of cosmic rays and natural radioactivity in the environment, all detection units will generate some detection background. This detection background varies significantly with the size and type of the detector, and also with the degree of shielding around the detector. Subtracting the detection background can effectively reduce the influence of environmental radiation and noise, thereby improving the accuracy of explosive detection.

[0022] The detection background can be pre-calibrated. In some embodiments, the detection background can be determined by testing a blank sample before testing. For example, testing can be performed without sample injection, and the spectrum obtained at this time can be determined as the detection background. Those skilled in the art can also choose other suitable methods to determine the detection background, and there is no limitation thereto.

[0023] After obtaining the first processed spectrum, the characteristic peak at the nickel peak position in the first processed spectrum needs to be subtracted in step S106 to obtain the second processed spectrum. During explosive detection, most test objects misidentified as explosives are those with stainless steel outer packaging or containing stainless steel materials, such as thermos cups. This application proposes that these test objects are misidentified because the stainless steel material contains nickel.

[0024] Specifically, you can refer to Figure 2 , Figure 2The image shows the spectra obtained from neutron detection of blank samples, stainless steel, and explosives. Curve L1 is the spectrum of the blank sample, curve L2 is the spectrum of the explosive, and curve L3 is the spectrum of the stainless steel sample. It can be observed that compared with L1, L2 and L3 show an increase in energy. Specifically, the reaction of nitrogen in the explosive with neutrons results in the characteristic peak of nitrogen in L2, and the reaction of nickel in the stainless steel with neutrons results in the characteristic peak of nickel in L3. Furthermore, the energy of the nickel characteristic peak in L3 is higher, close to the energy of the nitrogen characteristic peak in L2. This may lead to stainless steel being mistakenly detected as explosive during the detection process.

[0025] Therefore, in this embodiment, the characteristic peak at the nickel peak position in the first processed spectrum is subtracted to obtain the second processed spectrum. The detection of explosives is then performed based on the second processed spectrum, thereby eliminating interference from stainless steel materials contained in the analyte and reducing false positives. The nickel peak position can be determined through pre-calibration. The specific calibration method can be selected by those skilled in the art based on the actual situation. Methods for calibrating the nickel peak position will also be provided in the relevant sections below, and will not be elaborated further here.

[0026] It is understandable that even if the analyte itself does not contain stainless steel, step S106 can still be performed to remove the characteristic peak at the nickel peak position in the first processed spectrum. This will not affect its normal detection. Therefore, in this embodiment, it is not necessary to first determine whether the analyte contains stainless steel before determining whether step S106 needs to be performed, which ensures both the accuracy and efficiency of the detection.

[0027] After obtaining the second processed spectrum, it can be used to determine whether the test object is an explosive. Those skilled in the art can refer to the neutron detection method provided in the related art to implement step S108. For example, the second processed spectrum can be compared and analyzed with the spectrum of the explosive to determine whether the test object contains an explosive.

[0028] In some embodiments, the presence of explosives in the analyte can be determined based on the characteristic peaks at the nitrogen and chlorine peaks in the second processed spectrum. Specifically, the presence of uranium explosives can be determined using gamma rays generated by the reaction of nitrogen and chlorine with neutrons. While related technologies typically use only the characteristic peak at the nitrogen peak for explosive detection, this embodiment uses both the nitrogen and chlorine peaks for combined detection, thereby further improving detection accuracy, ensuring comprehensiveness, and reducing the risk of missed detections.

[0029] In some embodiments, the explosive detection method further includes determining the detection background and nickel peak position before detecting the analyte.

[0030] In some embodiments, as described above, the detection background can be determined by receiving the detection signal in a detection chamber without the analyte being placed there. Once the detection background is determined, the nickel peak position can be determined based on the iron peak position within the detection background.

[0031] Understandably, the nickel peak position can be directly calibrated by testing stainless steel materials. However, direct calibration of the nickel peak position may be affected by interference from other radiation. Therefore, this embodiment proposes using the iron peak position for nickel peak position calibration. The iron peak position and the nickel peak position largely overlap, so the calibrated iron peak position can be directly used as the nickel peak position, or the peak position near the calibrated iron peak position can be determined as the nickel peak position. The iron peak position calibration is less affected by interference. Therefore, determining the nickel peak position based on the iron peak position can more accurately calibrate the nickel peak position, improve the accuracy of detection, and avoid unnecessary interference to the detection results caused by incorrect nickel peak position calibration.

[0032] In some embodiments, multiple detection units can be used to further improve the accuracy of detection during the detection process. Specifically, multiple detection spectra can be generated by receiving the detection signals of each of the multiple detection units. Then, the detection background in each detection spectrum can be subtracted to obtain multiple first processed spectra, and the characteristic peaks at the nickel peak positions in each first processed spectrum can be subtracted to obtain multiple second processed spectra. Finally, the presence of explosives in the analyte can be determined based on the multiple second processed spectra.

[0033] It should be noted that since the positions of the multiple detection units will inevitably differ, the detection background and nickel peak position of each detection unit will also differ. Therefore, it is necessary to determine the detection background and nickel peak position of each detection unit before detection, and then use the detection background and nickel peak position of each detection unit to process the detection spectrum to obtain the first processed spectrum and the second processed spectrum.

[0034] In some embodiments, the detection unit needs to be calibrated before explosive detection. Calibrating the detection unit ensures the accuracy of the detection signal obtained by the detection unit, thereby improving the accuracy of explosive detection.

[0035] In some embodiments, calibrating the detection unit may specifically include: receiving the detection signal of the detection unit to generate a first calibration spectrum and a second calibration spectrum in a state where no test object is placed in the detection chamber, and then calibrating the detection unit based on the first calibration spectrum and the second calibration spectrum.

[0036] In this embodiment, the first calibration spectrum is the spectrum of gamma rays generated by the reaction between the shielding unit of the detection chamber and the neutron, and the second calibration spectrum is the spectrum of gamma rays generated by the reaction between the encapsulation material of the detection unit and the neutron.

[0037] Understandably, to ensure that neutrons are concentrated in the detection chamber and do not emit radiation to the outside, a shielding unit is required for the detection chamber. This shielding unit can be made of materials such as polyethylene or boron-containing polyethylene. The gamma rays generated by the reaction of the shielding unit with neutrons may affect the detection signal of the detection unit. The detection unit itself needs to be encapsulated in packaging materials that form a protective layer against neutron radiation, thus ensuring the durability of the detection unit. Similarly, the gamma rays generated by the reaction of the packaging material with neutrons may also affect the detection signal of the detection unit. Therefore, in this embodiment, the detection unit is calibrated using a first calibration spectrum and a second calibration spectrum to maximize the accuracy of the detection signal.

[0038] As an example, the detection unit can be calibrated using the energies corresponding to typical characteristic peaks in the first and second calibration spectra. For instance, the shielding material used in the shielding unit typically contains a large amount of hydrogen; therefore, in one embodiment, the characteristic peak of hydrogen in the first calibration spectrum, with a corresponding energy of 2.23 MeV, can be used for calibration. The encapsulation material of the detection unit typically contains iron; therefore, in one embodiment, the characteristic peak of iron in the second calibration spectrum, with a corresponding energy of 7.6 MeV, can be used for calibration.

[0039] In some implementations, as described above, the locations of multiple detection units are different. This leads to inconsistent relationships between the energy and the results of multiple detection units. Consequently, a large amount of calculation is required in the subsequent process of determining whether the test object contains explosives based on the second processing spectrum corresponding to each of the multiple detection units.

[0040] To facilitate the analysis of the second processing spectrum of multiple detection units, in this embodiment, the detection signal of each detection unit can be fitted based on the first calibration spectrum corresponding to each of the multiple detection units before detection. Fitting the detection signal is to unify the relationship between the channel address and energy of the multiple detection units into a specific relationship, so that the energy spectrum curves measured by each detection unit can be displayed in the same coordinate system, which facilitates the subsequent analysis of the results.

[0041] Specifically, you can refer to Figure 3 and Figure 4 , Figure 3 This is a schematic diagram of the first calibration spectrum of each detection unit before fitting. Figure 4 This is a schematic diagram of the first calibration spectrum of each detection unit after fitting. As an example, characteristic peaks in the first calibration spectrum, such as the characteristic peaks of hydrogen, can be used to fit multiple detection units. Figure 3In the first calibration spectrum obtained from each detection unit, the position of hydrogen peak 31 differs, and Figure 4 After fitting, the positions of hydrogen peak 31 in the first calibration spectrum obtained by each detection unit are roughly the same.

[0042] In some other embodiments, those skilled in the art may also select characteristic peaks in other spectra to fit multiple detection units, and are not limited to the first calibration spectrum, nor to the hydrogen peak in the first calibration spectrum.

[0043] Embodiments of this application also provide an explosive detection device, referring to... Figure 5 The device includes: a detection chamber 51 for containing the analyte; a neutron source 52 for emitting neutrons into the detection chamber 51; a detection unit 53 for detecting the gamma rays generated after the neutrons react to generate a detection signal; and one or more processors 54, which are configured to: receive the detection signal to generate a detection spectrum, the detection spectrum being the spectrum of gamma rays generated by the reaction between the analyte and the neutrons; subtract the detection background from the detection spectrum to obtain a first processed spectrum; subtract the characteristic peak at the nickel peak position in the first processed spectrum to obtain a second processed spectrum; and determine whether the analyte contains an explosive based on the second processed spectrum.

[0044] The neutron source 52 can be set on one wall of the detection chamber 51, while the detection unit 53 can be set on one or more other walls of the detection chamber 51. The specific arrangement of the neutron source 52 and the detection unit 53 can be selected by those skilled in the art according to the actual situation, and there are no specific restrictions.

[0045] The neutrons emitted by the neutron source 52 can be fast neutrons of 2.5 MeV. A moderator can be placed between the neutron source 52 and the object to be tested to convert the neutrons reaching the object to test into thermal neutrons. In some embodiments, the neutron source 52 may be equipped with a position adjustment device, a collimation device, etc., so that the neutrons emitted by the neutron source 52 can be concentrated at a predetermined location on the object to be tested. In some embodiments, during the detection process, the object to be tested can first be preliminarily detected to identify suspicious areas that may contain explosives. Then, the neutrons emitted by the neutron source 52 can be concentrated in these suspicious areas for detection to further improve the accuracy of the detection and avoid the influence of other interfering factors.

[0046] The detection unit 53 can employ a NaI(Tl) crystal scintillation detector. Specifically, each detection unit 53 can be equipped with three cable connectors, including a high-voltage connector for connecting to the power supply of the photomultiplication circuit, a preamplifier voltage connector located on the detector housing, and a preamplifier module signal connector. As described above, the detection unit 53 can be encapsulated in a protective layer to improve its service life. The encapsulation material can form a protective layer; for example, the encapsulation material is stainless steel coated with a LiF protective layer. In some embodiments, to ensure that the detection unit 53 can operate normally under low temperature conditions, a thermocouple or other heating device can be provided. In some embodiments, to ensure that the detection unit 53 can operate normally under high temperature conditions, a cooling fan or other cooling device can be provided. In some embodiments, as described above, multiple detection units 53 can be provided.

[0047] In some embodiments, the explosive detection device may also be provided with a transmission unit ( Figure 5 (Not shown in the image), the transmission unit can be, for example, a conveyor belt, a robotic arm, or other device, which can send the object to be tested into the detection chamber 51 and remove the object to be tested from the detection chamber 51, thereby enabling continuous detection of multiple objects to be tested.

[0048] In some embodiments, as described above, the explosive detection device may be provided with a shielding unit that can prevent neutrons in the detection chamber 51 from leaking outwards and can also prevent radiation from the external environment from interfering with the detection environment in the detection chamber 51. The shielding unit may be made of materials such as polyethylene, boron-containing polyethylene, or other suitable neutron shielding materials, without specific limitations.

[0049] One or more processors 54 may be electrically connected to the detection unit 53, and one or more processors 54 may be used to implement the explosive detection method described in any of the embodiments above.

[0050] In some embodiments, one or more processors are further configured to: receive a detection signal to determine the detection background and nickel peak position when the analyte is not placed in the detection chamber. In some embodiments, one or more processors 54 are specifically configured to: determine the nickel peak position based on the iron peak position in the detection background. As described above, the nickel peak position can be determined more accurately by using the iron peak position, thereby improving the accuracy of the detection results.

[0051] It should be noted that when conducting continuous testing on multiple analytes, it is only necessary to determine the background and nickel peak position once before testing, and the background and nickel peak position can be used directly in subsequent testing.

[0052] In some embodiments, one or more processors are further configured to calibrate the detection units and / or fit the detection signals of multiple detection units. Specific calibration and fitting methods can be found in the descriptions in the relevant sections above and will not be repeated here. Similarly, in the process of continuously detecting multiple analytes, only the calibration and fitting of the detection units need to be performed sequentially before detection.

[0053] In some embodiments, the detection device may further include an indicator unit, which can be used to indicate the detection results of one or more processors 54. For example, the indicator unit may include a display that can indicate different detection results by means of different colors, or the indicator unit may include a voice indicator device that can indicate different detection results by voice.

[0054] Embodiments of this application also provide a computer-readable storage medium storing computer instructions thereon, which, when executed by a computer, can implement the explosive detection method described in any of the embodiments above.

[0055] For the purposes of this specification, "computer-readable storage medium" can be any means that can contain, store, communicate, propagate, or transmit a program for use in or in conjunction with an instruction execution system, apparatus, or device. More specific examples of computer-readable media (a non-exhaustive list) include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Furthermore, a computer-readable medium can even be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optical scanning of the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0056] It should be understood that various parts of this application can be executed using hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be executed using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if executed in hardware, as in another embodiment, it can be executed using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for performing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0057] Those skilled in the art will understand that all or part of the steps of the above-described implementation method can be performed by instructing related hardware through a program. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0058] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be executed in hardware or as a software functional module. If the integrated module is executed as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0059] It is understood that the above embodiments are exemplary and should not be construed as limiting the present application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present application.

Claims

1. A method for detecting explosives, comprising: Receive detection signals to generate a detection spectrum, which is the spectrum of gamma rays generated by the reaction of the analyte with neutrons; Subtracting the detection background from the detection spectrum yields the first processed spectrum; The characteristic peak at the nickel peak position in the first processed spectrum is removed to obtain the second processed spectrum; Based on the second processed spectrum, determine whether the test sample contains the explosive; Before detecting the analyte, determine the background level and the nickel peak position; Determining the detection background and the nickel peak position includes: The detection signal is received to determine the detection background when the test object is not placed in the detection chamber. The nickel peak position is determined based on the iron peak position in the background detection.

2. The method according to claim 1, wherein, The step of determining whether the test sample contains the explosive based on the second processed spectrum includes: The presence of the explosive in the analyte is determined based on the characteristic peaks at the nitrogen and chlorine peaks in the second processed spectrum.

3. The method according to claim 1, wherein, The step of receiving detection signals to generate detection spectra includes: receiving the detection signals of each of a plurality of detection units to generate a plurality of detection spectra; The step of subtracting the detection background from the detection spectrum to obtain the first processed spectrum includes: subtracting the detection background from each of the detection spectra to obtain multiple first processed spectra; The step of subtracting the characteristic peak at the nickel peak position in the first processed spectrum to obtain the second processed spectrum includes: subtracting the characteristic peak at the nickel peak position in each of the first processed spectra to obtain multiple second processed spectra; Determining whether the test object contains the explosive based on the second processed spectrum includes: determining whether the test object contains the explosive based on multiple second processed spectra.

4. The method according to claim 3, further comprising: Before detecting the analyte, the detection background and the nickel peak position of each detection unit are determined respectively.

5. The method according to claim 3, further comprising: The detection unit is calibrated before the test object is detected.

6. The method according to claim 5, wherein, The calibration of the detection unit includes: In a state where the test object is not placed in the detection chamber, the detection signal of the detection unit is received to generate a first calibration spectrum and a second calibration spectrum, wherein the first calibration spectrum is the spectrum of gamma rays generated by the reaction between the shielding unit of the detection chamber and the neutron, and the second calibration spectrum is the spectrum of gamma rays generated by the reaction between the encapsulation material of the detection unit and the neutron. The detection unit is calibrated based on the first calibration spectrum and the second calibration spectrum.

7. The method according to claim 6, further comprising: Before detecting the analyte, the detection signals of the multiple detection units are fitted based on the first calibration spectrum corresponding to each of the multiple detection units.

8. An explosive detection device, comprising: The testing chamber is used to hold the samples to be tested. A neutron source is used to emit neutrons into the detection chamber; The detection unit is used to detect the gamma rays generated after the neutrons react to generate a detection signal; as well as One or more processors, said one or more processors being used for: The detection signal is received to generate a detection spectrum, which is the spectrum of gamma rays generated by the reaction of the analyte with the neutron; Subtracting the detection background from the detection spectrum yields the first processed spectrum; The characteristic peak at the nickel peak position in the first processed spectrum is removed to obtain the second processed spectrum; Based on the second processed spectrum, determine whether the test sample contains the explosive; The one or more processors are also used for: When the analyte is not placed in the detection chamber, the detection signal is received to determine the detection background and the nickel peak position; the nickel peak position is determined based on the iron peak position in the detection background.

9. A computer-readable storage medium having stored thereon computer instructions that, when executed by a computer, implement the method as described in any one of claims 1-7.

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