An imaging method, apparatus, and system based on muon flow transmission and track migration.

Abstract

This invention provides an imaging method, apparatus, and system based on muon flow transmission and track offset, relating to the field of muon imaging technology. The method includes: acquiring a first position recorded by a first muon detector before each muon enters the object under test, and a second position recorded by a second muon detector after each muon exits the object under test; constructing a first transmission track of the same muon when it enters the object under test based on the first and second positions of the same muon; determining the intersection of the first transmission track with a first imaging plane of the object under test, thereby obtaining a first transmission point of the muon on the first imaging plane; calculating the transmission ratio of the muon on the first imaging plane of the object under test based on the number of first transmission points in the first imaging plane; and generating an image of the object under test based on the transmission ratio of the muon on the first imaging plane of the object under test. This improves the spatial resolution of muon imaging and enables imaging of millimeter-scale material structures.

Description

Technical Field

[0001] This invention relates to the field of muon imaging technology, and in particular to an imaging method, apparatus and system based on muon flow transmission and track offset. Background Technology

[0002] Muon imaging technology achieves imaging of matter through the absorption or deflection effects of muons. Muon imaging technology includes two main categories: MTR (Muon Transmission Radiography) and MST (Muon Scattering Tomography). MTR measures the density of matter by flux attenuation and is commonly used in geological monitoring (such as volcanoes), as well as archaeology and mineral exploration. MST utilizes the Coulomb scattering angle information of muons as they penetrate objects, enabling rapid detection of high-density materials. This characteristic gives MST a unique advantage in nuclear safety fields (such as fuel rod monitoring and shielded uranium / plutonium detection).

[0003] In related technologies, muon imaging based on cosmic rays has already achieved imaging of matter at scales from meters to sub-centimeters. Although the resolution of current muon detectors has reached the hundreds to tens of micrometers, the spatial resolution of cosmic ray-based muon imaging technology has not improved accordingly. In other words, the measured spatial resolution of muon imaging technology remains at the centimeter level, making it difficult to image smaller-scale material structures. Summary of the Invention

[0004] The purpose of this invention is to provide an imaging method, apparatus, and system based on muon flow transmission and track migration, so as to improve the spatial resolution of muon imaging and enable imaging of millimeter-scale material structures. The specific technical solution is as follows:

[0005] In a first aspect, to achieve the above objectives, embodiments of the present invention provide an imaging method based on muon flow transmission and track offset. The method includes: acquiring a first position recorded by a first muon detector before each muon enters the object under test, and a second position recorded by a second muon detector after each muon exits the object under test; constructing a transmission track of the same muon when it enters the object under test, based on the first and second positions of the same muon, as a first transmission track; determining the intersection of the first transmission track with a first imaging plane of the object under test, and obtaining the transmission point of the muon on the first imaging plane, as a first transmission point; calculating the transmission ratio of the muon on the first imaging plane of the object under test based on the number of first transmission points in the first imaging plane; and generating an image of the object under test based on the transmission ratio of the muon on the first imaging plane of the object under test.

[0006] Optionally, calculating the transmittance ratio of a muon on the first imaging plane of the object under test based on the number of first transmission points in the first imaging plane includes: dividing the first imaging plane into multiple sub-regions as first sub-regions; for each first sub-region, determining a target transmission point from the first transmission points in that first sub-region; for the same muon, constructing an incident trajectory of the muon when it enters the object under test based on multiple first positions of the muon; determining the intersection of the incident trajectory and the first imaging plane to obtain the incident point of the muon when it enters the object under test; for each first sub-region, determining a target incident point from the incident points in that first sub-region; and calculating the ratio of the number of target transmission points to the number of target incident points in that first sub-region to obtain the transmittance ratio of the muon in that first sub-region.

[0007] Optionally, the target transmission point is determined by the following method: for the same muon, based on multiple second positions of the muon, construct the exit trajectory of the muon when it exits from the test object; determine the angle between the incident trajectory and the exit trajectory of the muon to obtain the scattering angle of the muon; if the scattering angle of the muon is less than a first threshold, determine the first transmission point of the muon as the target transmission point.

[0008] And / or,

[0009] For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, determine the first transmission point of the muon as the target transmission point.

[0010] Optionally, the target transmission point is determined in the following way: for the same muon, the distance from a second position of the muon to the incident track of the muon is calculated as the target distance; if the target distance of the muon is less than a third threshold, the first transmission point of the muon is determined as the target transmission point.

[0011] And / or,

[0012] For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, determine the first transmission point of the muon as the target transmission point.

[0013] Optionally, the target incident point is determined in the following way: for the same muon, the angle between the incident trajectory of the muon and the incident direction of the muon flow is determined to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, the incident point of the muon is determined as the target incident point.

[0014] Optionally, calculating the transmission ratio of muons on the first imaging plane of the test object based on the number of first transmission points in the first imaging plane includes: obtaining a transmission point distribution matrix of muons transmitted in the second imaging plane when the test object is not placed; wherein, an element in the transmission point distribution matrix represents the number of second transmission points of muons in a second sub-region of the second imaging plane; dividing the first imaging plane into multiple sub-regions as first sub-regions; for each first sub-region, calculating the ratio of the number of first transmission points in the first sub-region to the number of second transmission points in the corresponding second sub-region to obtain the transmission ratio of muons in the first sub-region.

[0015] Optionally, the transmission point distribution matrix is ​​determined by: obtaining the third position of the muon passing through the first muon detector and the fourth position of the muon passing through the second muon detector when no object is placed; constructing the transmission track of the muon's movement based on the third and fourth positions of the same muon, as the second transmission track; determining the intersection of the second transmission track with the second imaging plane to obtain the transmission point of the muon on the second imaging plane, as the second transmission point; and dividing the second imaging plane into multiple sub-regions, as the second sub-regions.

[0016] Secondly, in order to achieve the above objectives, embodiments of the present invention provide an imaging system based on muon flow transmission and track migration, the imaging system comprising: multiple muon detectors, a timing module, a positioning module, a coincidence module, and a data processing module;

[0017] Each muon detector inputs the signal generated when a muon hits the detector to the timing module and the positioning module.

[0018] The timing module determines the moment when a muon is struck by a muon in a muon detector based on the signal input from the muon detector, and inputs the moment when the muon is struck by each muon detector to the coincidence module.

[0019] The matching module, based on the impact time of the muon in each muon detector, if it is determined that the impact time of each muon detector belongs to the same muon, inputs a trigger signal to the data processing module;

[0020] The positioning module determines the hit position of the muon on the muon detector based on the signal input from the muon detector, and inputs the hit positions of the muon on each muon detector to the data processing module.

[0021] The data processing module, based on the trigger signal input to the conformity module and the hit position of the muon in each muon detector, executes the imaging method based on muon flow transmission and track shift as described in any of the first aspects.

[0022] Thirdly, in order to achieve the above objectives, embodiments of the present invention provide an imaging device based on muon flow transmission and track migration, the device comprising:

[0023] The position acquisition module is used to acquire the first position recorded by the first muon detector before each muon enters the object under test, and the second position recorded by the second muon detector after each muon exits the object under test.

[0024] The transmission track determination module is used to construct the transmission track of the same muon when it enters the object under test, based on the first and second positions of the same muon, as the first transmission track.

[0025] The transmission point determination module is used to determine the intersection of the first transmission track with the first imaging plane of the object under test, and obtain the transmission point of the muon on the first imaging plane, which is taken as the first transmission point.

[0026] A transmission ratio determination module is used to calculate the transmission ratio of muons in the first imaging plane of the object under test based on the number of first transmission points in the first imaging plane.

[0027] An image generation module is used to generate an image of the test object based on the transmittance ratio of the muon on the first imaging plane of the test object.

[0028] Optionally, the transmission ratio determination module is specifically used for: dividing the first imaging plane into multiple sub-regions as first sub-regions; for each first sub-region, determining a target transmission point from the first transmission points in the first sub-region; for the same muon, constructing an incident trajectory of the muon when it enters the object under test based on multiple first positions of the muon; determining the intersection of the incident trajectory and the first imaging plane to obtain the incident point of the muon when it enters the object under test; for each first sub-region, determining a target incident point from the incident points in the first sub-region; and calculating the ratio of the number of target transmission points to the number of target incident points in the first sub-region to obtain the transmission ratio of the muon in the first sub-region.

[0029] Optionally, the device further includes a first target transmission point determination module, configured to: construct, based on multiple second positions of the same muon, the emission trajectory of the muon when it is emitted from the test object; determine the angle between the incident trajectory and the emission trajectory of the muon to obtain the scattering angle of the muon; and if the scattering angle of the muon is less than a first threshold, determine the first transmission point of the muon as the target transmission point.

[0030] And / or,

[0031] For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, determine the first transmission point of the muon as the target transmission point.

[0032] Optionally, the device further includes a second target transmission point determination module, configured to: for the same muon, calculate the distance from a second position of the muon to the incident trajectory of the muon as the target distance; if the target distance of the muon is less than a third threshold, determine the first transmission point of the muon as the target transmission point;

[0033] And / or,

[0034] For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, determine the first transmission point of the muon as the target transmission point.

[0035] Optionally, the device further includes a target incident point determination module, configured to: for the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than a second threshold, determine the incident point of the muon as the target incident point.

[0036] Optionally, the transmission ratio determination module is specifically used for: acquiring a transmission point distribution matrix of muons transmitted through the second imaging plane when no object is placed; wherein, an element in the transmission point distribution matrix represents the number of second transmission points of muons in a second sub-region of the second imaging plane; dividing the first imaging plane into multiple sub-regions as first sub-regions; for each first sub-region, calculating the ratio of the number of first transmission points in the first sub-region to the number of second transmission points in the corresponding second sub-region, to obtain the transmission ratio of muons in the first sub-region.

[0037] Optionally, the device further includes: a transmission point distribution matrix acquisition module, used to: acquire the third position of the muon passing through the first muon detector and the fourth position passing through the second muon detector when no object is placed; construct the transmission track of the muon's movement based on the third and fourth positions of the same muon, as a second transmission track; determine the intersection of the second transmission track with the second imaging plane to obtain the transmission point of the muon on the second imaging plane, as a second transmission point; divide the second imaging plane into multiple sub-regions, as second sub-regions; count the number of second transmission points in each second sub-region to obtain the transmission point distribution matrix.

[0038] This invention also provides an electronic device, comprising: a memory for storing a computer program; and a processor for executing the program stored in the memory to implement any of the imaging methods based on muon flow transmission and track migration described above.

[0039] This invention also provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements any of the imaging methods described above based on muon flow transmission and track migration.

[0040] This invention also provides a computer program product containing instructions that, when run on a computer, cause the computer to execute any of the imaging methods based on muon flow transmission and track migration described above.

[0041] Beneficial effects of the embodiments of the present invention:

[0042] The technical solution provided by this invention involves obtaining the first position of each muon before entering the object under test, recorded by a first muon detector, and the second position of each muon after exiting the object under test, recorded by a second muon detector; constructing a first transmission track of the muon when it enters the object under test based on the first and second positions of the same muon; determining the intersection of the first transmission track with the first imaging plane of the object under test to obtain the first transmission point of the muon on the first imaging plane; calculating the transmission ratio of the muon on the first imaging plane of the object under test based on the number of first transmission points in the first imaging plane; and generating an image of the object under test based on the transmission ratio of the muon on the first imaging plane of the object under test.

[0043] Based on the above processing, the scattering of muons in the object under test causes the constructed muon transmission track to deviate from the actual muon trajectory. The distance of this deviation is called the transmission offset. The distribution of the transmission offset varies due to differences in the surface density of the material along the incident direction. At the boundary between the object under test and the background region, the difference in the distribution of the transmission offset causes some transmission points originating from high-density regions to shift to adjacent low-density regions, while fewer transmission points shift from low-density regions to high-density regions. This phenomenon alters the transmission ratio distribution near the boundary of the object under test, resulting in a decrease in the transmission ratio near the boundary of high-density regions and an increase in the transmission ratio near the boundary of low-density regions. The difference in transmission ratio between high-density and low-density regions amplifies the variation in transmission ratio at the boundary of the object under test, thereby producing an edge sharpening effect on the generated image, improving spatial resolution, and enabling imaging of millimeter-scale material structures.

[0044] Of course, implementing any product or method of the present invention does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0046] Figure 1 A structural diagram of an imaging system based on muon flow transmission and track migration provided in an embodiment of the present invention;

[0047] Figure 2 A schematic diagram of the device mounting position for an imaging system based on muon flow transmission and track offset provided in an embodiment of the present invention;

[0048] Figure 3 A flowchart illustrating an imaging method based on muon flow transmission and track migration, provided for an embodiment of the present invention;

[0049] Figure 4 A schematic diagram illustrating the principle of the first imaging method based on muon flow transmission and track migration provided in this embodiment of the invention;

[0050] Figure 5 A schematic diagram of the second imaging method based on muon flow transmission and track migration provided in an embodiment of the present invention;

[0051] Figure 6 A schematic diagram of a sample provided in an embodiment of the present invention;

[0052] Figure 7 The imaging method based on muon flow transmission and track migration provided in the embodiments of the present invention generates Figure 6 The first image of the sample shown;

[0053] Figure 8 The imaging method based on muon flow transmission and track migration provided in the embodiments of the present invention generates Figure 6 The second image of the sample shown;

[0054] Figure 9 The imaging method based on muon flow transmission and track migration provided in the embodiments of the present invention generates Figure 6 The third image of the sample shown;

[0055] Figure 10 A structural diagram of an imaging device based on muon flow transmission and track offset provided in an embodiment of the present invention;

[0056] Figure 11 This is a structural diagram of an electronic device provided in an embodiment of the present invention. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art based on the present invention are within the scope of protection of the present invention.

[0058] Among related technologies, MST technology uses the PoCA (Nearest Neighbor Algorithm) to image matter. The PoCA algorithm approximates the actual multiple scattering process of muons within matter using a single scattering angle. This approximation has poor accuracy in pinpointing the spatial location of scattering, i.e., the location of the matter itself. MTR technology, on the other hand, only focuses on the transmittance of the matter, neglecting information such as the position and direction of the muon tracks. These limitations of related technologies result in the measured spatial resolution of muon imaging technology remaining at the centimeter level, making it difficult to image smaller-scale material structures.

[0059] To solve the above problem, see Figure 1 , Figure 1 This is a structural diagram of an imaging system 100 based on muon flow transmission and track migration provided in an embodiment of the present invention. The imaging system 100 includes: a plurality of muon detectors 101 ( Figure 1 (Taking two muon detectors 101 as an example for explanation), timing module 102, positioning module 103, coincidence module 104, and data processing module 105.

[0060] Multiple muon detectors 101 are respectively positioned upstream and downstream of the object being measured. The upstream muon detector 101 (i.e., the first muon detector in subsequent embodiments) is used to record the first position that the muon passes through before entering the object being measured. The downstream muon detector 101 (i.e., the second muon detector in subsequent embodiments) is used to record the second position that the muon passes through after exiting the object being measured.

[0061] Upstream refers to the direction starting from the object being measured and moving in the opposite direction to the incident direction of the muon stream. Downstream refers to the direction starting from the object being measured and moving in the same direction as the incident direction of the muon stream.

[0062] The number and arrangement of the muon detectors 101 are determined by technicians according to their needs. Figure 1 The two muon detectors 101 shown are arranged according to Figure 2 As shown, the object under test 201 is placed on the support 202, the incident direction of the muon stream is vertically downward, one muon detector 101 is set above the object under test 201, and the other muon detector 101 is set below the object under test 201.

[0063] If there are three muon detectors 101, two muon detectors 101 can be installed upstream of the object being measured, and one muon detector 101 can be installed downstream of the object being measured. Alternatively, one muon detector 101 can be installed upstream of the object being measured, and two muon detectors 101 can be installed downstream of the object being measured. If there are four muon detectors 101, two muon detectors 101 can be installed upstream of the object being measured, and two muon detectors 101 can be installed downstream of the object being measured.

[0064] When a muon moves, it passes by muon detector 101. If it hits muon detector 101, the muon detector 101 will generate a signal. The muon detector 101 inputs the signal generated when the muon hits it to timing module 102 and positioning module 103. Timing module 102, based on the signal input from muon detector 101, determines the moment the muon hits that muon at that muon detector 101 and inputs the moment of impact of the muon at each muon detector 101 to matching module 104. Matching module 104, based on the moment of impact of the muon at each muon detector 101 input from timing module 102, if it determines that the moment of impact at each muon detector 101 belongs to the same muon, inputs a trigger signal to data processing module 105. Positioning module 103, based on the signal input from muon detector 101, determines the position of the muon hitting that muon at that muon detector 101 and inputs the position of the muon hitting each muon detector 101 to data processing module 105. The data processing module 105, based on the trigger signal input by the conformity module 104 and the hit position of the muons in each muon detector 101, executes the imaging method based on muon flow transmission and track offset provided in this embodiment of the invention to generate an image of the object under test.

[0065] The various modules in the imaging system can be implemented using different devices as needed. For example, the muon detector 101 includes a detection structure (such as electrodes). When a muon strikes the detection structure, the electrons generated by the muon passing through the air gap are deposited on the detection structure, producing a change in electrical charge. This change in electrical charge is represented by the generated current (or voltage). The following explanation uses current as an example. The muon detector 101 reads the current generated by the detection structure at different times to obtain the first time signal. The first time signal is an analog signal. The horizontal axis of the first time signal represents time, and the vertical axis (i.e., amplitude) represents current.

[0066] Different measurement points are set on the detection structure. For example, the two ends of the electrode are two measurement points. The muon strikes at different locations, and the current generated when the muon strikes reaches the detection point at different times. The muon detector 101 reads the current generated at the measurement point in the detection structure at different times to obtain the first position signal.

[0067] Each measurement point acquires a first position signal, and multiple first position signals acquired from multiple measurement points represent the impact position of the muon. The first position signal is an analog signal. The horizontal axis of the first position signal represents time, and the vertical axis (i.e., amplitude) represents current. Both the first time signal and the first position signal are signals generated when the muon hits the muon detector 101.

[0068] The timing module 102 can be a first timing discriminator. The first time signal acquired by the muon detector 101 is directly input to the first timing discriminator. Alternatively, a first amplifier can be placed between the muon detector 101 and the first timing discriminator. The first time signal acquired by the muon detector 101 is input to the first amplifier. The first amplifier amplifies the first time signal and inputs the amplified first time signal to the first timing discriminator. The first timing discriminator can be a leading-edge timing discriminator. The first amplifier can be an FTA (Fast Timing Amplifier).

[0069] The first timing discriminator performs threshold discrimination on the received first time signal. That is, when the amplitude of a moment in the first time signal is greater than the fourth threshold, it determines that the moment is the moment when the muon hits the muon detector 101, and sets the amplitude of the time period to which the moment of impact belongs to a first specified value (such as 1). When the amplitude of the moment is less than the fourth threshold, it determines that the moment is not the moment when the muon hits the muon detector 101, and sets the amplitude of the time period to which the moment belongs to a second specified value (such as 0), thus obtaining the second time signal.

[0070] A time period is defined as a period of time centered on that moment, and of a first specified duration, where the first specified duration is less than the interval between two adjacent moments. The second time signal is a logic signal, in which the amplitude of the moment the muon is hit is 1, and the amplitude of other moments is 0.

[0071] The matching module 104 can be a matching plug-in. The first timing discriminator inputs a second time signal to the matching plug-in. For each received second time signal, the matching plug-in determines the signal segment within a specified time window and performs logical operations on each signal segment to obtain the target operation result. The target operation result indicates whether each signal segment within the specified time window belongs to the same muon, that is, whether each hit moment in the signal segment belongs to the same muon, meaning that each signal segment is generated by multiple muon detectors that hit the same muon detector sequentially during the movement of a single muon.

[0072] Depending on the number and configuration of the muon detectors 101, the conformance plug-in employs different logical operation methods.

[0073] For example, if two muon detectors 101 are installed upstream of the object being measured, and two muon detectors 101 are installed downstream of the object being measured, an OR operation is performed on the signal segments of the second time signals corresponding to the two upstream muon detectors 101 to obtain a first operation result. An OR operation is then performed on the signal segments of the second time signals corresponding to the two downstream muon detectors 101 to obtain a second operation result. A AND operation is then performed on the first and second operation results to obtain the target operation result.

[0074] Alternatively, if a muon detector 101 is installed upstream of the object being measured and another muon detector 101 is installed downstream of the object being measured, a bitwise AND operation is performed on the signal segments of the second time signal corresponding to the upstream muon detector 101 and the signal segments of the second time signal corresponding to the downstream muon detector 101 to obtain the target calculation result.

[0075] A result of 1 indicates that signal segments within the specified time window belong to the same muon. A result of 0 indicates that signal segments within the specified time window do not belong to the same muon.

[0076] If the signal segments within the specified time window do not belong to the same muon, it is determined that the impact times of the various muon detectors 101 do not belong to the same muon, and no signal is output. The system then continues to detect whether the signal segments within the next specified time window belong to the same muon. If the signal segments within the specified time window belong to the same muon, it is determined that the impact times of the various muon detectors 101 belong to the same muon, and a trigger signal is input to the data processing module 105.

[0077] When using the detection time in the second position signal to represent the hit position of the muon in the muon detector 101, the positioning module 103 can be a second timing discriminator. The first position signal collected by the muon detector 101 is directly input to the second timing discriminator. Alternatively, a second delay line, a second amplifier, and a filter can be sequentially arranged between the muon detector 101 and the second timing discriminator. The first position signal collected by the muon detector 101 is input to the second amplifier through the second delay line. The second amplifier amplifies the first position signal and inputs the amplified first position signal to the filter. The filter filters the amplified first position signal and inputs the filtered first position signal to the second timing discriminator.

[0078] The second timing discriminator performs over-threshold discrimination on the received first position signal. Specifically, if the amplitude of the first position signal at a certain moment is greater than the fifth threshold, this moment is the detection moment when the charge generated after the muon hits the detection structure and reaches the measurement point. Therefore, this detection moment is determined to be usable to represent the impact position of the muon hitting the muon detector 101, and the amplitude of the time period to which this detection moment belongs is set to a first specified value (e.g., 1). Conversely, if the amplitude of this moment is less than the fifth threshold, this moment is not the detection moment when the charge generated after the muon hits the detection structure and reaches the measurement point. Therefore, this moment is determined to be unusable to represent the impact position of the muon hitting the muon detector 101, and the amplitude of the time period to which this moment belongs is set to a second specified value (e.g., 0), thus obtaining the second position signal. In the second position signal, the amplitude at the muon detection moment is 1, and the amplitude at other moments is 0. The second timing discriminator can be a leading-edge timing discriminator. The second amplifier can be a fast-time amplifier. The filter can be a TFA (Quad Timing Filter Amplifier).

[0079] The data processing module 105 may include a data converter and a processor. The matching plug, upon determining that the impact time of each muon detector 101 belongs to the same muon, inputs a trigger signal to the data converter.

[0080] The first timing discriminator can directly input the second timing signal to the data converter. Alternatively, a first delay line can be provided between the first timing discriminator and the data converter, through which the second timing signal is input to the data converter, so that the second timing signal and the second position signal arrive at the data converter simultaneously. Furthermore, when the data converter does not support processing logic signals, a first charge transfer board can be provided between the first delay line and the data converter to convert the second timing signal into a processable charge signal, and then input the converted second timing signal to the data converter.

[0081] The second timing discriminator can directly input the second position signal to the data converter. Alternatively, when the data converter does not support processing logic signals, a second charge transfer board can be set between the second timing discriminator and the data converter to convert the second position signal into a processable charge signal, and then input the converted second position signal to the data converter.

[0082] The data converter, upon receiving a trigger signal, begins recording the received second time signal and second position signal, and stops recording when the recording duration reaches a second specified duration. The recorded second time signal and second position signal for the second specified duration belong to the same muon. Analog-to-digital conversion is performed on the second time signal and second position signal of the same muon to obtain the target data of that muon, and this target data is input to the processor. The target data of a muon includes the impact time of the muon hitting each muon detector 101, and the detection time of the current generated by the muon hitting the muon detector 101 at different measurement points. The detection times at multiple measurement points indicate the impact position of the muon hitting the muon detector 101.

[0083] The processor receives target data. Based on the impact time of the same muon hitting each muon detector 101 in the target data, and the detection time of the current generated by the muon hitting the muon detector 101 reaching different measurement points, it determines the impact position of the muon in the muon detector 101 and the order in which the muons hit each impact position. If the muon hits the upstream muon detector 101 first and then the downstream muon detector 101, the impact position of the muon in the upstream muon detector 101 is obtained, which is the first position the muon passes through before entering the object being measured. The impact position of the muon in the downstream muon detector 101 is obtained, which is the second position the muon passes through after exiting the object being measured. Based on the first and second positions of the same muon, construct the first transmission track of the muon when it enters the object under test; determine the intersection of the first transmission track with the first imaging plane of the object under test, and obtain the first transmission point of the muon in the first imaging plane; calculate the transmission ratio of the muon in the first imaging plane of the object under test based on the number of first transmission points in the first imaging plane; generate an image of the object under test based on the transmission ratio of the muon in the first imaging plane of the object under test.

[0084] See Figure 3 , Figure 3 A flowchart of an imaging method based on muon flow transmission and track migration provided in this embodiment of the invention is shown. This method is applied to electronic devices and includes the following steps:

[0085] S301: Obtain the first position of each muon before entering the object being measured, as recorded by the first muon detector, and the second position of each muon after exiting the object being measured, as recorded by the second muon detector.

[0086] S302: Based on the first and second positions of the same muon, construct the transmission track of the muon when it enters the test object as the first transmission track.

[0087] S303: Determine the intersection point of the first transmission track with the first imaging plane of the object under test, and obtain the transmission point of the muon on the first imaging plane, which is taken as the first transmission point.

[0088] S304: Calculate the transmittance ratio of muons on the first imaging plane of the object under test based on the number of first transmission points in the first imaging plane.

[0089] S305: Generate an image of the object under test based on the transmittance ratio of muons on the first imaging plane of the object.

[0090] Based on the imaging method based on muon flow transmission and track offset provided in this invention, muon scattering in the object under test causes the constructed muon transmission track to shift relative to the actual muon motion track, i.e., track offset occurs. The distance of the transmission track offset is called the transmission offset. The distribution of the transmission offset varies due to differences in the surface density of the material along the incident direction. At the boundary between the object under test and the background region, the difference in the distribution of the transmission offset causes some transmission points originating from high-density regions to shift to adjacent low-density regions, while fewer transmission points shift from low-density regions to high-density regions. This phenomenon alters the transmission ratio distribution near the boundary of the object under test (which originally approximates a step function distribution), resulting in a decrease in the transmission ratio near the boundary of high-density regions and an increase in the transmission ratio near the boundary of low-density regions. The difference in transmission ratio between high-density and low-density regions amplifies the variation in transmission ratio at the boundary of the object under test, thereby producing an edge sharpening effect on the generated image, improving spatial resolution, and enabling imaging of millimeter-scale material structures.

[0091] In step S301, muons are generated by the decay of π mesons in cosmic rays. Muons have strong penetrating power and can be applied to non-destructive imaging of cultural relics and historical sites, geological exploration, and tunnel structure inspection.

[0092] Muons are naturally occurring particles. Muons in cosmic rays pass through the Earth's atmosphere at extremely high speeds and form a stream of muons containing multiple muons when they reach the Earth's surface.

[0093] In this embodiment of the invention, a muon detector can be used to detect natural muon streams and determine the locations where muons pass through. Alternatively, an artificial muon stream can be generated using a muon beam device, and a muon detector can be used to detect the generated muon stream and determine the locations where muons pass through.

[0094] The position of a muon can be represented using its coordinates in the target coordinate system. The target coordinate system is a three-dimensional coordinate system. The Z-axis of the target coordinate system represents the incident direction of the muon stream. For cosmic rays, the vertically downward direction is the incident direction of the muon stream. For muon streams generated using a muon beam device, the incident direction of the muon stream is the direction in which the muon stream was emitted.

[0095] For example, the incident direction of the muon stream is vertically downward, meaning that the muons move in a vertically downward direction. When imaging the object under test, the object can be placed on a support (such as a shelf), and a set of muon detectors (i.e., the first muon detector) can be placed upstream of the object, and a set of muon detectors (i.e., the second muon detector) can be placed downstream of the object.

[0096] Before entering the object being measured, the muon passes through the first muon detector upstream, which records its initial position. After exiting the object, the muon passes through the second muon detector downstream, which records its initial position.

[0097] The first and second muon detectors, through detection methods and their own placement, can determine the three-dimensional position of a single muon in the target coordinate system. Alternatively, they can provide the x-coordinate (i.e., the two-dimensional position of the muon in the XZ plane) corresponding to a certain z-coordinate in the target coordinate system, and the y-coordinate (i.e., the two-dimensional position of the muon in the YZ plane) corresponding to another z-coordinate.

[0098] Both the first and second muon detectors can record the positions of valid muons. The number of first and second muon detectors can be set as needed. For example, the number of first and second muon detectors can be set to 2. Alternatively, the number of first and second muon detectors can be set to 1, etc.

[0099] Muon detectors can be RPC (Resistive Plate Chamber), GEM (Gas Electron Multiplier), MicroMegas, silicon pixel (microstrip) detectors, etc.

[0100] Regarding step S302, if there are multiple first muon detectors, multiple first positions of a muon will be recorded. If there are multiple second muon detectors, multiple second positions of the same muon will be recorded. Accordingly, by fitting the multiple first and multiple second positions of the muon, the transmission track (i.e., the first transmission track) when the muon enters the object under test can be constructed.

[0101] Different fitting methods can be selected based on different construction requirements. For example, if a straight line is fitted based on multiple first and second positions of the muon, the constructed first transmission track will be a straight line. If a curve is fitted based on multiple first and second positions of the muon, the constructed first transmission track will be a curve.

[0102] like Figure 4 As shown, the upstream detector array contains two first muon detectors. The upstream detector array recorded the positions of two particles (i.e., muons). Point A represents one first position of the muon recorded by the first first muon detector, and point B represents another first position of the muon recorded by the second first muon detector.

[0103] The downstream detector array contains two second muon detectors. The downstream detector array recorded the positions of two particles (i.e., muons). Point C indicates that the first second muon detector recorded one second position of the muon, and point D indicates that the second second muon detector recorded another second position of the muon.

[0104] Correspondingly, straight line fitting is performed on the first position shown at point A, the first position shown at point B, the second position shown at point C, and the second position shown at point D to obtain the first transmission track of the muon.

[0105] Different line fitting methods can be selected based on different fitting requirements. For example, by using the z-coordinates at the first and second positions as independent variables and the x and y coordinates as dependent variables, the least squares method can be used to fit a straight line to obtain the first transmission track of the muon.

[0106] If there is one first muon detector and one second muon detector, and for the same muon, there is one first position and one second position, then the straight line connecting the first position and the second position of the muon is determined to obtain the first transmission track of the muon when it enters the object being measured.

[0107] like Figure 5 As shown, the upstream detector group contains a first muon detector. Point E indicates a first position of the particle (i.e., the muon) recorded by this first muon detector. The downstream detector group contains a second muon detector. Point F indicates a second position of the muon recorded by this second muon detector. The straight line connecting points E and F is the first transmission track of the muon.

[0108] For step S303, the first imaging plane of the object under test is within the thickness range of the object under test. For example, the first imaging plane is perpendicular to the incident direction of the muon flow, that is, the first imaging plane is the XY plane at the z-coordinate within the thickness range of the object under test in the target coordinate system.

[0109] The intersection of the first transmission track of a muon with the first imaging plane of the object under test is the first transmission point of the muon. The first transmission track is a constructed transmission track, and the first transmission point is also a constructed transmission point. Accordingly, for each muon, a first transmission point of that muon in the first imaging plane of the object under test can be constructed.

[0110] like Figure 4 and Figure 5 As shown, GH represents the thickness of the imaging sample (i.e., the object under test), and the imaging plane α of the object under test (i.e., the first imaging plane) is a horizontal plane within the range of GH. The intersection of the first transmission track of the muon with the imaging plane α of the object under test is the first transmission point.

[0111] In step S304, the electronic device counts the number of first transmission points in the first imaging plane of the object under test, and calculates the transmission ratio of muons in the first imaging plane of the object under test based on the number of first transmission points in the first imaging plane of the object under test.

[0112] The electronic device calculates the transmittance of muons on the first imaging plane of the object under test in the following manner:

[0113] Method 1: To improve image quality, step S304 may include the following steps:

[0114] The first imaging plane is divided into multiple sub-regions, designated as the first sub-region. For each first sub-region, a target transmission point is determined from the first transmission points within that sub-region. For the same muon, an incident trajectory is constructed based on multiple first positions of the muon when it enters the object under test. The intersection of the incident trajectory and the first imaging plane is determined to obtain the incident point of the muon when it enters the object under test. For each first sub-region, a target incident point is determined from the incident points within that sub-region. The ratio of the number of target transmission points to the number of target incident points in the first sub-region is calculated to obtain the muon transmission ratio in that first sub-region.

[0115] The size of the first imaging plane of the object being measured is the same as the detection range of the muon detector. The first imaging plane is divided into multiple sub-regions (i.e., the first sub-regions). Each of the first sub-regions may contain incident points and transmission points.

[0116] For each first sub-region, the target transmission point is determined from the first transmission point in that sub-region. The number of target transmission points in each sub-region is counted to obtain the transmission point distribution matrix of the muon on the first imaging plane (which can be called the target transmission point distribution matrix).

[0117] For example, if the first imaging plane is divided into M×N first sub-regions, then the target transmission point distribution matrix is ​​M×N dimensional. The element in the i-th row and j-th column of the target transmission point distribution matrix represents the number of target transmission points in the first sub-region in the i-th row and j-th column of the first imaging plane.

[0118] If there are multiple first muon detectors, multiple first positions of the muon will be recorded. Based on the multiple first positions of the muon, the incident trajectory of the muon entering the object being measured can be constructed.

[0119] For example, Figure 4 As shown, there are two first muon detectors. Assuming that muons do not deflect before entering the object, the incident trajectory of the muon entering the object is obtained by connecting the first position recorded by the first muon detector (point A) and the first position recorded by the second first muon detector (point B). Alternatively, if the number of first muon detectors is greater than two, the incident trajectory of the muon entering the object can be obtained by fitting multiple first positions.

[0120] Due to the geometric limitations of the muon detector, the location of the incident track of a muon is within the sensitive area (i.e., detection range) of the downstream second muon detector. For muons whose incident tracks do not meet this limitation, the incident track of the muon is removed, that is, the incident point and transmission point of the muon are not used for imaging.

[0121] The intersection of the incident tracks of muons with the first imaging plane of the object being measured is the incident point of the muon. Accordingly, each muon has one incident point in the first imaging plane of the object being measured.

[0122] For each first sub-region, the target incident point is determined from the incident transmission points within that first sub-region. The number of target incident points in each first sub-region is counted to obtain the incident point distribution matrix of muons on the first imaging plane of the object under test.

[0123] For example, if the first imaging plane is divided into M×N sub-regions, then the incident point distribution matrix is ​​M×N dimensional. The element in the i-th row and j-th column of the incident point distribution matrix represents the number of target incident points in the first sub-region in the i-th row and j-th column of the first imaging plane.

[0124] In one implementation, when determining the target transmission point in the first sub-region, all first transmission points in the first sub-region can be used as the target transmission point. Similarly, when determining the target incident point in the first sub-region, all incident points in the first sub-region can be used as the target incident point.

[0125] In another implementation, to suppress noise interference, the electronic device determines the target transmission point in the following manner:

[0126] Method 1: Determine the first transmission point that satisfies the scattering angle constraint and / or the incident angle constraint as the target transmission point.

[0127] The electronic device determines whether the first transmission point satisfies the scattering angle constraint in the following manner:

[0128] If there are multiple second muon detectors, and for the same muon, there are multiple second positions for that muon, the exit trajectory of the muon when it exits the test object is determined based on these multiple second positions. Then, the angle between the incident trajectory and the exit trajectory of the muon is determined, thus obtaining the scattering angle of the muon.

[0129] like Figure 4 As shown, there are two second muon detectors. Assuming that the muon does not deflect after exiting the object, the exit trajectory of the muon is obtained by connecting the second position recorded by the first second muon detector (point C) and the second position recorded by the second second muon detector (point D). Alternatively, if the number of second muon detectors is greater than two, a straight line can be fitted based on multiple second positions to obtain the exit trajectory of the muon. The angle θ between the incident trajectory and the exit trajectory is the scattering angle of the muon.

[0130] If a muon has a large scattering angle, it indicates that the first transmission track of the muon is significantly deviated. In this case, the transmission point may be an artifact caused by the large deviation of the first transmission track, and the first transmission point of the muon needs to be removed.

[0131] Correspondingly, if the scattering angle of the muon is less than the first threshold, then the first transmission point of the muon satisfies the scattering angle constraint, and the first transmission point of the muon is determined as the target transmission point. By using the scattering angle constraint, muons whose actual motion trajectory is closer to a straight path are retained, the artifacts caused by muons with large transmission track offsets are removed, and the transmission points of muons with excessively large scattering angles are eliminated. This can enhance the contrast difference of imaging between regions with different surface density and improve spatial resolution.

[0132] The electronic device determines whether the first transmission point satisfies the incident angle constraint in the following manner:

[0133] For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon. For example... Figure 4 As shown, the angle β between the extension of the incident track and the incident direction is the incident angle of the muon.

[0134] If the incident angle of the muon is less than the second threshold, then the first transmission point of the muon satisfies the incident angle constraint, and the first transmission point of the muon is determined as the target transmission point.

[0135] Method 2: Determine the first transmission point that satisfies the distance constraint and / or the incident angle constraint as the target transmission point.

[0136] The electronic device determines whether the first transmission point satisfies the scattering angle constraint in the following manner:

[0137] If the detector array downstream of the object being measured has only one second muon detector, and for the same muon, if there is only one second position for that muon, it is impossible to fit the exit trajectory of the muon emitted from the object being measured. The electronic equipment calculates the distance from the second position of the muon to the incident trajectory of the muon (i.e., the target distance).

[0138] The greater the target distance, the larger the scattering angle of the muon, indicating that the first transmission track of the muon is deviated significantly. Therefore, the transmission point may be an artifact caused by the large deviation of the first transmission track, and the first transmission point of the muon needs to be removed.

[0139] Correspondingly, if the target distance of the muon is less than the third threshold, the first transmission point of the muon satisfies the distance constraint, and the first transmission point of the muon is determined as the target transmission point. Using the target distance to represent the size of the muon's scattering angle can achieve the retention of muons whose actual motion trajectory is closer to a straight path, remove the artifacts caused by muons with large transmission track offsets, enhance the contrast difference of imaging between regions with different surface density, and improve spatial resolution.

[0140] The electronic device determines whether the first transmission point satisfies the incident angle constraint in the following manner: for the same muon, the angle between the incident trajectory of the muon and the incident direction of the muon flow is determined to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, the first transmission point of the muon is determined as the target transmission point.

[0141] In some embodiments, in order to suppress noise interference, the electronic device determines the target incident point in the following manner:

[0142] For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, determine the incident point of the muon as the target incident point.

[0143] For each first sub-region, the ratio of the number of target transmission points to the number of target incident points in that first sub-region is calculated to obtain the muon transmission ratio in that first sub-region. That is, for each element in the target transmission point distribution matrix, the ratio of that element to the corresponding element in the incident point distribution matrix is ​​calculated to obtain the muon transmission ratio matrix (which can be called the first transmission ratio matrix) on the first imaging plane of the object being measured.

[0144] For example, the ratio of the element in the i-th row and j-th column of the target transmission point distribution matrix to the element in the i-th row and j-th column of the incident point distribution matrix is ​​used to obtain the element in the i-th row and j-th column of the first transmission ratio matrix. Furthermore, the element in the i-th row and j-th column of the first transmission ratio matrix represents the transmission ratio of muons in the first sub-region in the i-th row and j-th column of the first imaging plane of the object being measured.

[0145] In some embodiments, in order to suppress noise interference, before calculating the transmission ratio of the muon on the first imaging plane of the object under test, the incident point distribution matrix can be pre-smoothed to obtain the processed incident point distribution matrix, and the target transmission point distribution matrix can be pre-smoothed to obtain the processed target transmission point distribution matrix.

[0146] For example, mean filtering and median filtering methods are used to filter the incident point distribution matrix and the target transmission point distribution matrix, respectively. Furthermore, since the muon's incident point on the analyte is unaffected by different substances, the incident point distribution matrix does not contain information about the analyte. Therefore, the pre-smoothing intensity of the incident point distribution matrix is ​​higher than that of the target transmission point distribution matrix, meaning the area of ​​the incident point distribution matrix participating in the pre-smoothing process is larger.

[0147] Then, for each element in the processed target transmission point distribution matrix, the ratio of that element to the corresponding element in the processed incident point distribution matrix is ​​calculated to obtain the first transmission ratio matrix of the muon on the first imaging plane of the object under test.

[0148] In some embodiments, when calculating the transmittance ratio matrix of the muon on the first imaging plane of the object under test, the elements in the incident point distribution matrix, as the denominator, cannot be too small; otherwise, the error in the calculated transmittance ratio will be too large. If the elements in the incident point distribution matrix are less than the sixth threshold (i.e., the denominator is not large enough), the transmittance ratio of the first sub-region corresponding to that element can be directly set to zero or empty. Setting the transmittance ratio to zero (or empty) is used to indicate that the transmittance ratio of the first sub-region is invalid data.

[0149] Method 2, in a simplified case, can be implemented by setting only two muon detectors, namely one upstream and one downstream. This can achieve significant optimization in imaging quality and detector cost, and can be extended to beam muon imaging technology.

[0150] Accordingly, step S304 may include the following steps:

[0151] When no object is placed, obtain the transmission point distribution matrix of muons transmitted through the second imaging plane. Each element in the transmission point distribution matrix represents the number of second transmission points of muons in the second sub-region of the second imaging plane. Divide the first imaging plane of the object into multiple sub-regions, designated as the first sub-region. For each first sub-region, calculate the ratio of the number of first transmission points in that first sub-region to the number of second transmission points in the corresponding second sub-region to obtain the muon transmission ratio in that first sub-region.

[0152] The electronic device divides the first imaging plane into multiple first sub-regions and counts the number of first transmission points in each sub-region to obtain the transmission point distribution matrix of the muon on the first imaging plane (which can be called the first transmission point distribution matrix).

[0153] If only one first muon detector is set upstream of the object being measured and only one second muon detector is set downstream, it is impossible to determine the incident trajectory of the muon entering the object being measured, the incident point of the muon on the first imaging plane, and the exit trajectory of the muon after exiting the object being measured.

[0154] Consequently, the incident point distribution matrix of muons on the first imaging plane cannot be obtained. The electronic device acquires a set of data under the same environmental conditions without a test object, that is, it acquires the transmission point distribution matrix (which can be called the second transmission point distribution matrix) of muons transmitted through the second imaging plane when no test object is placed. The method for acquiring the second transmission point distribution matrix is ​​described in the following embodiments.

[0155] The second imaging plane is the same position and size as the first imaging plane when no object is placed in the environment. The second imaging plane is divided into second sub-regions in the same way as the first imaging plane is divided into first sub-regions. Correspondingly, the dimension of the second transmission point distribution matrix is ​​the same as the dimension of the first transmission point distribution matrix. For example, if the first imaging plane is divided into M×N sub-regions, both the second and first transmission point distribution matrices are M×N dimensional.

[0156] Furthermore, for each first sub-region, the ratio of the number of first transmission points in that first sub-region to the number of second transmission points in the corresponding second sub-region is calculated to obtain the muon transmission ratio in that first sub-region. That is, for each element in the first transmission point distribution matrix, the ratio of that element to the corresponding element in the second transmission point distribution matrix is ​​calculated to obtain the muon transmission ratio matrix (which can be called the second transmission ratio matrix) on the first imaging plane of the object under test.

[0157] For example, the ratio of the element in the i-th row and j-th column of the first transmission point distribution matrix to the element in the i-th row and j-th column of the second transmission point distribution matrix is ​​calculated to obtain the element in the i-th row and j-th column of the second transmission ratio matrix. Furthermore, the element in the i-th row and j-th column of the second transmission ratio matrix represents the transmission ratio of muons in the first sub-region in the i-th row and j-th column of the first imaging plane of the object being measured.

[0158] In some embodiments, to suppress noise interference, before calculating the transmittance ratio of the muon on the first imaging plane of the object under test, the first transmission point distribution matrix can be pre-smoothed to obtain a processed first transmission point distribution matrix, and the second transmission point distribution matrix can be pre-smoothed to obtain a processed second transmission point distribution matrix. For example, mean filtering, median filtering, etc., can be used to filter the first and second transmission point distribution matrices, respectively.

[0159] For each element in the processed first transmission point distribution matrix, the ratio of that element to the corresponding element in the processed second transmission point distribution matrix is ​​calculated to obtain the second transmission ratio matrix of the muon on the first imaging plane of the object under test.

[0160] In some embodiments, the electronic device may use simulation to obtain the second transmission point distribution matrix of muons transmitted through the second imaging plane when no object is placed. Alternatively, the second transmission point distribution matrix of muons transmitted through the second imaging plane when no object is placed may be determined in the following manner:

[0161] When no object is placed, the muon passes through the third position of the first muon detector and the fourth position of the second muon detector. Based on the third and fourth positions of the same muon, the transmission path of the muon's motion is constructed as the second transmission track. The intersection of the second transmission track with the second imaging plane is determined, and the transmission point of the muon on the second imaging plane is obtained as the second transmission point. The second imaging plane is divided into multiple sub-regions as the second sub-regions. The number of second transmission points in each second sub-region is counted to obtain the second transmission point distribution matrix.

[0162] If the object being imaged is placed in an air environment, the muons will move in the air when the object is not placed. If the object being imaged is placed in a vacuum environment, the muons will move in the same vacuum environment when the object is not placed. If the object being imaged is placed in a different gaseous environment, the muons will move in the same other gaseous environment when the object is not placed.

[0163] When no object is placed in the environment, the third position traversed by the muon is detected using the first muon detector, and the fourth position traversed by the muon is detected using the second detector. Based on the third and fourth positions of the same muon, the transmission track of the muon's movement (i.e., the second transmission track) can be constructed.

[0164] like Figure 5 As shown, after the imaging sample (i.e., the object under test) is removed, the muon moves in the environment without the object under test. The third position (i.e., point J) of the muon passing through the first muon detector is recorded using the first muon detector. The fourth position (i.e., point K) of the muon passing through the second muon detector is recorded using the second muon detector. Connecting the third position (i.e., point J) and the fourth position (i.e., point K) of the same muon, the transmission track of the muon moving in the air (i.e., the second transmission track) is obtained. The imaging plane γ (i.e., the second imaging plane) without the object under test is at the same horizontal height as the imaging plane α (i.e., the first imaging plane) of the object under test, and the size of the imaging plane γ is the same as the size of the imaging plane α of the object under test.

[0165] The intersection point of the second transmission track with the second imaging plane is determined, thus obtaining the transmission point of the muon on the second imaging plane (i.e., the second transmission point). Following the same division method as the first imaging plane, the second imaging plane is divided into multiple sub-regions (i.e., second sub-regions), and the number of second transmission points in each second sub-region is counted to obtain the second transmission point distribution matrix.

[0166] For step S305, since muons have different transmittance ratios in materials of different densities, the first sub-region is filled with a color corresponding to the transmittance ratio based on the transmittance ratio of muons in the first imaging plane of the object being measured, thereby obtaining an image of the object being measured.

[0167] A blank image is generated, and then divided into multiple sub-images using the same division method as the first imaging plane. Each sub-image in the blank image corresponds one-to-one with the first sub-region.

[0168] In one implementation, according to a preset correspondence between transmittance ratio ranges and colors, for each first sub-region, the color corresponding to the transmittance ratio range to which the transmittance ratio of the first sub-region belongs is determined, and the corresponding color is filled into the sub-image corresponding to the first sub-region to obtain an image of the object under test.

[0169] In another implementation, the mapping bar in the colorbar tool is pre-set, and the maximum and minimum values ​​of the transmittance ratio in each first sub-region are input. Using the colorbar tool, the color corresponding to the transmittance ratio is filled into the sub-image corresponding to the first sub-region according to the transmittance ratio of the muon in each first sub-region of the first imaging plane of the object under test, so as to obtain the image of the object under test.

[0170] The imaging method based on muon flow transmission and track migration provided by embodiments of the present invention will be described below with reference to examples. Figure 6 As shown, a PKU model composed of multiple copper sheets is used as the sample to be tested. The copper sheets are 40mm × 40mm × 2mm in size, so the sample has a millimeter-scale material structure. That is, the width of the transverse sidewall of the letter "P" is 40mm, the width of the longitudinal sidewall of the letter "K" is 40mm, and the thickness of each sidewall is 2mm.

[0171] According to the method provided in the embodiments of the present invention, Figure 6 The sample shown was imaged to obtain... Figures 7 to 9 The image of the sample is shown. The sample image has a size of 280 mm in the X direction and 280 mm in the Y direction. Furthermore, the imaging plane of the sample is the plane with a Z coordinate of -42.3 mm in the target coordinate system.

[0172] Figure 7 An image of a sample is generated using the first position of muons recorded by two upstream muon detectors and the second position of muons recorded by two downstream muon detectors, according to the method provided in the embodiments of the present invention.

[0173] Figure 7 The right side shows the colorbar used by the colorbar tool to generate the sample image. 0.2 to 1.0 represents the transmittance of muons on the sample's imaging plane; different colors in the colorbar correspond to different transmittance ranges. The left side shows the sample image.

[0174] Figure 8 To generate an image of a sample, the method provided in this embodiment of the invention uses the first position of the muons recorded by two upstream muon detectors and the second position of the muons recorded by two downstream muon detectors, and combines the scattering angle to constrain the transmission point of the muons.

[0175] Figure 8 The right side shows the colorbar used by the colorbar tool to generate the sample image. 0.1 to 0.8 represents the transmittance of muons on the sample's imaging plane; different colors in the colorbar correspond to different transmittance ranges. The left side shows the sample image.

[0176] Figure 9 An image of a sample is generated using the third position of a muon recorded by an upstream muon detector and the fourth position of a muon recorded by a downstream muon detector, according to the method provided in the embodiments of the present invention.

[0177] Figure 9The right side shows the colorbar used by the colorbar tool to generate the sample image. 0.5 to 2.50 represents the transmittance of muons on the sample's imaging plane; different colors in the colorbar correspond to different transmittance ranges. The left side shows the sample image.

[0178] The imaging method based on muon flow transmission and track offset provided in this invention achieves a paradigm breakthrough by integrating the absorption and scattering signals of muons by matter. Specifically, it utilizes the positioning capability of the near-linear transmission trajectory of muons to improve the spatial resolution of matter imaging. Simultaneously, it constructs the transmission point offset of muons through scattering information to sharpen the imaging edges of matter or enhance the contrast of different surface density regions of matter. This represents a revolution at the physical observation level, fully leveraging the sub-millimeter-level positional resolution advantage of modern muon detectors. Compared to the existing PoCA algorithm, it achieves improved spatial resolution in matter imaging, enabling millimeter-level imaging of matter by cosmic ray muons, and its feasibility has been experimentally verified.

[0179] and Figure 3 For the corresponding method embodiments, see [link to relevant documentation]. Figure 10 , Figure 10 This invention provides a structural diagram of an imaging device based on muon flow transmission and track migration, comprising:

[0180] The position acquisition module 1001 is used to acquire the first position of each muon before entering the object being tested, as recorded by the first muon detector, and the second position of each muon after exiting the object being tested, as recorded by the second muon detector.

[0181] The transmission track determination module 1002 is used to construct the transmission track of the muon when it enters the object under test based on the first and second positions of the same muon, as the first transmission track.

[0182] The transmission point determination module 1003 is used to determine the intersection of the first transmission track with the first imaging plane of the object under test, and obtain the transmission point of the muon on the first imaging plane as the first transmission point.

[0183] Transmission ratio determination module 1004 is used to calculate the transmission ratio of muon in the first imaging plane of the object under test based on the number of first transmission points in the first imaging plane.

[0184] Image generation module 1005 is used to generate an image of the test object based on the transmittance ratio of the muon on the first imaging plane of the test object.

[0185] Optionally, the transmission ratio determination module 1004 is specifically used for: dividing the first imaging plane into multiple sub-regions as first sub-regions; for each first sub-region, determining a target transmission point from the first transmission points in the first sub-region; for the same muon, constructing an incident trajectory of the muon when it enters the object under test based on multiple first positions of the muon; determining the intersection of the incident trajectory and the first imaging plane to obtain the incident point of the muon when it enters the object under test; for each first sub-region, determining a target incident point from the incident points in the first sub-region; and calculating the ratio of the number of target transmission points to the number of target incident points in the first sub-region to obtain the transmission ratio of the muon in the first sub-region.

[0186] Optionally, the device further includes a first target transmission point determination module, configured to: construct, based on multiple second positions of the same muon, the emission trajectory of the muon when it is emitted from the test object; determine the angle between the incident trajectory and the emission trajectory of the muon to obtain the scattering angle of the muon; and if the scattering angle of the muon is less than a first threshold, determine the first transmission point of the muon as the target transmission point.

[0187] And / or,

[0188] For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, determine the first transmission point of the muon as the target transmission point.

[0189] Optionally, the device further includes a second target transmission point determination module, configured to: for the same muon, calculate the distance from a second position of the muon to the incident trajectory of the muon as the target distance; if the target distance of the muon is less than a third threshold, determine the first transmission point of the muon as the target transmission point;

[0190] And / or,

[0191] For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, determine the first transmission point of the muon as the target transmission point.

[0192] Optionally, the device further includes a target incident point determination module, configured to: for the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than a second threshold, determine the incident point of the muon as the target incident point.

[0193] Optionally, the transmission ratio determination module 1004 is specifically used to: acquire a transmission point distribution matrix of muons transmitted through the second imaging plane when no object is placed; wherein, an element in the transmission point distribution matrix represents the number of second transmission points of muons in a second sub-region of the second imaging plane; divide the first imaging plane into multiple sub-regions as first sub-regions; for each first sub-region, calculate the ratio of the number of first transmission points in the first sub-region to the number of second transmission points in the corresponding second sub-region to obtain the transmission ratio of muons in the first sub-region.

[0194] Optionally, the device further includes: a transmission point distribution matrix acquisition module, used to: acquire the third position of the muon passing through the first muon detector and the fourth position passing through the second muon detector when no object is placed; construct the transmission track of the muon's movement based on the third and fourth positions of the same muon, as a second transmission track; determine the intersection of the second transmission track with the second imaging plane to obtain the transmission point of the muon on the second imaging plane, as a second transmission point; divide the second imaging plane into multiple sub-regions, as second sub-regions; count the number of second transmission points in each second sub-region to obtain the transmission point distribution matrix.

[0195] Based on the imaging device based on muon flow transmission and track offset provided in this invention embodiment, muon scattering in the object under test causes the constructed muon transmission track to shift relative to the actual muon motion track, i.e., track offset occurs. The distance of the transmission track offset is called the transmission offset. The distribution of the transmission offset varies due to differences in the surface density of the material along the incident direction. At the boundary between the object under test and the background region, the difference in the distribution of the transmission offset causes some transmission points originating from high-density regions to shift to adjacent low-density regions, while fewer transmission points shift from low-density regions to high-density regions. This phenomenon alters the transmission ratio distribution near the boundary of the object under test (which originally approximates a step function distribution), resulting in a decrease in the transmission ratio near the boundary of high-density regions and an increase in the transmission ratio near the boundary of low-density regions. The difference in transmission ratio between high-density and low-density regions amplifies the variation in transmission ratio at the boundary of the object under test, thereby producing an edge sharpening effect on the generated image, improving spatial resolution, and enabling imaging of millimeter-scale material structures.

[0196] This invention also provides an electronic device, such as... Figure 11 As shown, it includes a processor 1101, a communication interface 1102, a memory 1103, and a communication bus 1104, wherein the processor 1101, the communication interface 1102, and the memory 1103 communicate with each other through the communication bus 1104.

[0197] Memory 1103 is used to store computer programs;

[0198] When processor 1101 executes the program stored in memory 1103, it performs the following steps:

[0199] The method involves acquiring the first position of each muon before entering the object under test, recorded by the first muon detector, and the second position of each muon after exiting the object under test, recorded by the second muon detector. Based on the first and second positions of the same muon, a transmission track of the muon when entering the object under test is constructed as the first transmission track. The intersection of the first transmission track with the first imaging plane of the object under test is determined to obtain the transmission point of the muon on the first imaging plane, which is taken as the first transmission point. Based on the number of first transmission points in the first imaging plane, the transmission ratio of the muon on the first imaging plane of the object under test is calculated. Based on the transmission ratio of the muon on the first imaging plane of the object under test, an image of the object under test is generated.

[0200] The communication bus mentioned in the above electronic devices can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc. For ease of illustration, only one thick line is used to represent it in the diagram, but this does not mean that there is only one bus or one type of bus.

[0201] The communication interface is used for communication between the aforementioned electronic devices and other devices.

[0202] The memory may include random access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0203] The processors mentioned above can be general-purpose processors, including central processing units (CPUs), network processors (NPs), etc.; they can also be digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0204] In another embodiment of the present invention, a computer-readable storage medium is also provided, which stores a computer program that, when executed by a processor, implements the steps of any of the imaging methods based on muon flow transmission and track migration described above.

[0205] In another embodiment of the present invention, a computer program product containing instructions is also provided, which, when run on a computer, causes the computer to perform any of the imaging methods based on muon flow transmission and track migration described in the above embodiments.

[0206] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially as a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of the present invention are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid state disk (SSD)).

[0207] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0208] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the embodiments of apparatus, systems, electronic devices, computer-readable storage media, and computer program products are basically similar to the method embodiments, and therefore the descriptions are relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0209] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. An imaging method based on muon flow transmission and track migration, characterized in that, The method includes: The first position of each muon before entering the object is recorded by the first muon detector, and the second position of each muon after exiting the object is recorded by the second muon detector. Based on the first and second positions of the same muon, the transmission track of the muon when it enters the object under test is constructed as the first transmission track. The intersection of the first transmission track with the first imaging plane of the object under test is determined, and the transmission point of the muon on the first imaging plane is obtained, which is taken as the first transmission point. Based on the number of first transmission points in the first imaging plane, the transmittance ratio of the muon in the first imaging plane of the object under test is calculated. An image of the object is generated based on the transmittance ratio of the muon on the first imaging plane of the object under test; The calculation of the transmittance ratio of muons on the first imaging plane of the object under test, based on the number of first transmission points in the first imaging plane, includes: The first imaging plane is divided into multiple sub-regions, designated as first sub-regions. For each first sub-region, a target transmission point is determined from the first transmission points within that first sub-region. For the same muon, an incident trajectory is constructed based on multiple first positions of the muon when it enters the object under test. The intersection of the incident trajectory and the first imaging plane is determined to obtain the incident point of the muon when it enters the object under test. For each first sub-region, a target incident point is determined from the incident points within that first sub-region. The ratio of the number of target transmission points to the number of target incident points in the first sub-region is calculated to obtain the transmission ratio of the muon in that first sub-region. or, A transmission point distribution matrix of muons transmitted through the second imaging plane is obtained when no test object is placed. Each element in the transmission point distribution matrix represents the number of second transmission points of muons in a second sub-region of the second imaging plane. The second imaging plane is an imaging plane of the same position and size as the first imaging plane when no test object is placed in the environment. The second imaging plane is divided into second sub-regions in the same way as the first imaging plane is divided into first sub-regions. The first imaging plane is divided into multiple sub-regions, designated as first sub-regions. For each first sub-region, the ratio of the number of first transmission points in that first sub-region to the number of second transmission points in the corresponding second sub-region is calculated to obtain the transmission ratio of muons in that first sub-region.

2. The method according to claim 1, characterized in that, The target transmission point is determined in the following way: For the same muon, based on multiple second positions of the muon, construct the exit trajectory of the muon when it exits from the test object; determine the angle between the incident trajectory and the exit trajectory of the muon to obtain the scattering angle of the muon; if the scattering angle of the muon is less than a first threshold, determine the first transmission point of the muon as the target transmission point. or, For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, determine the first transmission point of the muon as the target transmission point.

3. The method according to claim 1, characterized in that, The target transmission point is determined in the following way: For the same muon, calculate the distance from a second position of the muon to the incident trajectory of the muon, and use it as the target distance; if the target distance of the muon is less than a third threshold, determine the first transmission point of the muon as the target transmission point; or, For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; if the incident angle of the muon is less than the second threshold, determine the first transmission point of the muon as the target transmission point.

4. The method according to claim 1, characterized in that, The target incident point is determined in the following way: For the same muon, determine the angle between the incident trajectory of the muon and the incident direction of the muon flow to obtain the incident angle of the muon; If the angle of incidence of the muon is less than the second threshold, the incident point of the muon is determined as the target incident point.

5. The method according to claim 1, characterized in that, The transmission point distribution matrix is ​​determined in the following way: When no object is placed, the muon passes through the third position of the first muon detector and the fourth position of the second muon detector. Based on the third and fourth positions of the same muon, construct the transmission track of the muon's motion as the second transmission track; The intersection of the second transmission track and the second imaging plane is determined to obtain the transmission point of the muon on the second imaging plane, which is taken as the second transmission point; The second imaging plane is divided into multiple sub-regions, which are designated as the second sub-regions. The number of second transmission points in each second sub-region is counted to obtain the transmission point distribution matrix.

6. An imaging system based on muon flow transmission and track migration, characterized in that, The imaging system includes: multiple muon detectors, a timing module, a positioning module, a coincidence module, and a data processing module; Each muon detector inputs the signal generated when a muon hits the detector to the timing module and the positioning module. The timing module determines the moment when a muon is struck by a muon in a muon detector based on the signal input from the muon detector, and inputs the moment when the muon is struck by each muon detector to the coincidence module. The matching module, based on the impact time of the muon in each muon detector, if it is determined that the impact time of each muon detector belongs to the same muon, inputs a trigger signal to the data processing module; The positioning module determines the hit position of the muon on the muon detector based on the signal input from the muon detector, and inputs the hit positions of the muon on each muon detector to the data processing module. The data processing module, based on the trigger signal input to the conforming module and the hit position of the muon in each muon detector, performs the method described in any one of claims 1-5.

7. An imaging device based on muon flow transmission and track migration, characterized in that, The device includes: The position acquisition module is used to acquire the first position recorded by the first muon detector before each muon enters the object under test, and the second position recorded by the second muon detector after each muon exits the object under test. The transmission track determination module is used to construct the transmission track of the same muon when it enters the object under test, based on the first and second positions of the same muon, as the first transmission track. The transmission point determination module is used to determine the intersection of the first transmission track with the first imaging plane of the object under test, and obtain the transmission point of the muon on the first imaging plane, which is taken as the first transmission point. A transmission ratio determination module is used to calculate the transmission ratio of muons in the first imaging plane of the object under test based on the number of first transmission points in the first imaging plane. An image generation module is used to generate an image of the test object based on the transmittance ratio of the muon on the first imaging plane of the test object; The transmission ratio determination module is specifically used for: dividing the first imaging plane into multiple sub-regions as first sub-regions; for each first sub-region, determining a target transmission point from the first transmission points in that first sub-region; for the same muon, constructing an incident trajectory of the muon when it enters the test object based on multiple first positions of the muon; determining the intersection of the incident trajectory and the first imaging plane to obtain the incident point of the muon when it enters the test object; for each first sub-region, determining a target incident point from the incident points in that first sub-region; calculating the ratio of the number of target transmission points to the number of target incident points in that first sub-region to obtain the transmission ratio of the muon in that first sub-region; or, obtaining the transmission ratio of the muon when no test object is placed. A transmission point distribution matrix of muons transmitted through a second imaging plane; wherein, an element in the transmission point distribution matrix represents the number of second transmission points of muons in a second sub-region of the second imaging plane, the second imaging plane being an imaging plane of the same position and size as the first imaging plane when no object is placed in the environment, the second imaging plane being divided into second sub-regions in the same way as the first imaging plane being divided into first sub-regions; the first imaging plane is divided into multiple sub-regions as first sub-regions; for each first sub-region, the ratio of the number of first transmission points in the first sub-region to the number of second transmission points in the corresponding second sub-region is calculated to obtain the transmission ratio of muons in the first sub-region.

8. An electronic device, characterized in that, It includes a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; Memory, used to store computer programs; A processor, when executing a program stored in memory, implements the steps of the method described in any one of claims 1-5.

Images