Coding hole XRD (X-Ray Diffraction) imaging system and method based on distributed ray source

Abstract

The invention relates to the technical field of radiation imaging, in particular to a coded hole XRD (X-Ray Diffraction) imaging system and method based on a distributed ray source, and the system comprises the distributed ray source which is provided with a plurality of focuses and is used for transmitting multiple beams of multi-energy X-rays; the front collimator is used for shaping each multi-energy X-ray beam into a fan-beam multi-energy X-ray beam and ensuring that the fan-beam multi-energy X-ray beam completely covers an area to be reconstructed of a scanned object so as to generate a diffraction signal; the transmission detector is used for performing attenuation correction on the diffraction signal; the coding plate is used for coding diffraction signals generated by the object; the pixelated spectrometer is used for measuring the coded diffraction signals so as to form diffraction data; and the image reconstruction module is used for carrying out iterative optimization on the target function by utilizing the diffraction data to obtain a reconstructed image. Therefore, the problems that an existing snapshot type coding hole imaging system is poor in data condition and difficult to solve, and an existing rotary scanning coding hole imaging system is high in complexity, long in scanning time and the like are solved.

Description

Technical Field

[0001] The present invention relates to the field of radiation imaging technology, and in particular to a coded hole XRD imaging system and method based on a distributed ray source. Background Art

[0002] At present, X-rays have been widely used in security inspection and medical fields. Usually, by performing DR imaging or CT imaging on the inspected object, it is possible to obtain information about the inside of the object quickly and accurately, such as determining whether there are contraband items hidden in bags during security inspection, or checking bone morphology during medical treatment. However, these two imaging methods are only sensitive to the attenuation coefficient of the material. Although they can better distinguish high-density materials from low-density materials, such as guns and knives and daily necessities in security inspection, and soft tissues and bones in medical treatment, it is not easy to screen out different materials with similar attenuation coefficients. Relevant staff in the security inspection or medical field often need to make judgments based on experience, which greatly reduces the efficiency and accuracy of inspections. This brings new challenges to material identification and detection.

[0003] X-ray diffraction (XRD) is a new type of X-ray inspection technology that uses Rayleigh scattering between X-rays and atoms to detect materials. X-rays that interact with the atoms of the material and undergo Rayleigh scattering will further interfere with each other, forming diffraction signals with a certain spatial distribution pattern. The intensity of the diffraction signal varies with the spatial position, reflecting the atomic or molecular arrangement pattern of the scanned material, containing the microscopic structure information of the material, with strong specificity, and can be used for material identification. In the fields of security inspection and medical treatment, although some different substances have similar elemental composition, density, and attenuation coefficient, such as drugs and daily necessities, cancerous tissue and fat, etc., the completely different molecular structures make the diffraction signals of these substances have obvious differences. Therefore, in theory, XRD can achieve accurate detection and identification of drugs, explosives, breast cancer, etc.

[0004] In order to meet the needs of high-precision and efficient detection, XRD systems suitable for security inspection and medical fields should be able to image multiple points in the scanned area at the same time, mainly including the following two types: snapshot coded hole imaging system and rotation scanning coded hole imaging system. The snapshot coded hole imaging system reconstructs the diffraction spectrum of the object through a single scan. The scanning speed is fast and imaging can be achieved in tens of seconds, but its data conditions are poor, and the reconstructed diffraction spectrum often has obvious errors, which affects the reliability of material identification. In addition, due to the geometric limitations of the system, its resolution in the direction of the X-ray optical path is poor, and the difference between the minimum resolvable pixel size and the detector pixel size can reach more than ten times, resulting in the diffraction spectrum information in a single pixel being mixed by the diffraction spectra of multiple substances, making it difficult to detect smaller targets. The rotation scanning coded hole imaging system realizes scanning at multiple angles by rotating the object, which greatly improves the data conditions and can reconstruct accurate diffraction spectra in the scanned area. Its resolution can be close to 1 mm, but the system requires an additional mechanical rotating structure, which increases the requirements for the equipment, increases the complexity of the equipment, and also requires a longer scanning time. Therefore, it is necessary to design a new XRD coded hole imaging system to combine the advantages of the above two systems to achieve fast and accurate diffraction spectrum reconstruction. Summary of the invention

[0005] The present invention provides a coded hole XRD imaging system and method based on a distributed ray source, so as to solve the problems of poor data conditions and difficult solutions of existing snapshot coded hole imaging systems, high complexity and long scanning time of existing rotary scanning coded hole imaging systems, etc.

[0006] The first aspect of the present invention provides a coded hole XRD imaging system based on a distributed ray source, comprising: a distributed ray source, used to form an X-ray source of different arrangements according to target requirements to emit multiple beams of multi-energy X-rays; a front collimator, the front collimator is arranged on the propagation path of the multiple beams of multi-energy X-rays, and is used to shape each beam of multi-energy X-rays into a fan beam of multi-energy X-rays, and ensure that all fan beams of multi-energy X-rays can completely cover the area to be reconstructed of the scanned object to generate a diffraction signal; a transmission detector, the transmission detector is arranged on the propagation path of the multiple beams of multi-energy X-rays, and is used to attenuate the diffraction signal; a coding plate, the coding plate is arranged parallel to the receiving surface of the pixelated spectrometer, and is used to encode the diffraction signal to obtain the encoded diffraction signal; a pixelated spectrometer, the pixelated spectrometer is arranged on the propagation path of the encoded diffraction signal, and is used to measure the encoded diffraction signal to form diffraction data; an image reconstruction module, used to iteratively optimize a preset objective function using the diffraction data to obtain a reconstructed image of the area to be reconstructed.

[0007] Optionally, the distributed ray source includes a plurality of focal points, the arrangement of the plurality of focal points is determined according to the structural characteristics of the scanned object, and the operating voltage, current and beam emission time of each focal point are independently set.

[0008] Optionally, the encoding plate is a thin plate made of a highly absorbent material, a plurality of through holes are provided on the thin plate, and an arrangement of the plurality of through holes is determined according to the structural characteristics of the scanned object.

[0009] Optionally, the expression of the preset objective function is:

[0010]

[0011] in, is the diffraction spectrum of the scanned object to be estimated, ω t is the weight factor corresponding to the data of each focus in sequence, H (t) is the system matrix corresponding to each beam output, I (t) is the diffraction data collected by the pixelated spectrometer. Its elements represent the photon counts collected by a detector pixel in one energy channel, and R(f) is the regularization term.

[0012] Optionally, it also includes: a carrying device for carrying the distributed ray source, the front collimator, the transmission detector, the encoding plate and the pixelated spectrometer.

[0013] Optionally, it also includes: a transport device for transporting the scanned object into or out of the imaging area.

[0014] The second aspect of the present invention provides a coded hole XRD imaging method based on a distributed ray source, comprising the following steps: determining a first arrangement mode and a scanning angle of the distributed ray source, a second arrangement mode of the coding plate, and a third arrangement mode of the pixelated spectrometer according to target requirements; emitting multiple beams of multi-energy X-rays to the scanned object according to the first arrangement mode and the scanning angle; shaping each beam of multi-energy X-rays into a fan-beam multi-energy X-ray, and ensuring that each fan-beam multi-energy X-ray completely covers the area to be reconstructed of the scanned object to generate a diffraction signal; encoding the diffraction signal according to the second arrangement mode to obtain an encoded diffraction signal; detecting the encoded diffraction signal according to the third arrangement mode to form diffraction data; and iteratively optimizing a preset objective function using the diffraction data to obtain a reconstructed image of the area to be reconstructed.

[0015] A third aspect of the present invention provides an electronic device, comprising: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the coded hole XRD imaging method based on a distributed ray source as described in the above embodiment.

[0016] A fourth aspect of the present invention provides a computer program product, which implements the above-mentioned coded hole XRD imaging method based on a distributed ray source when the computer program / instructions are executed by a processor.

[0017] A fifth aspect of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, which, when executed by a processor, implements the above-mentioned coded hole XRD imaging method based on a distributed ray source.

[0018] The coded hole XRD imaging system and method based on distributed ray sources proposed in the embodiments of the present invention introduce distributed ray sources to conveniently and efficiently realize multi-angle scanning of objects without introducing mechanical motion structures, enrich the collected diffraction data, improve data conditions, alleviate the pathological nature of reconstructing the diffraction spectrum of the scanned object, and achieve better reconstruction effects; in practical applications, the arrangement of distributed ray sources can be flexibly designed according to the characteristics of the scanned object, and the scanning angle can be reasonably selected to optimize the diffraction spectrum reconstruction effect of the object; it can be applied to security inspections to efficiently and accurately detect contraband such as drugs and explosives, and can also be applied to the medical field to conduct rapid inspections of diseases such as breast cancer.

[0019] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0021] Figure 1 A schematic diagram of the structure of a coded aperture XRD imaging system based on a distributed ray source provided by an embodiment of the present invention;

[0022] Figure 2 A top view of a coded aperture XRD imaging system based on a distributed ray source provided by an embodiment of the present invention;

[0023] Figure 3 Two usage methods of a coded hole XRD imaging system based on a distributed ray source provided in an embodiment of the present invention;

[0024] Figure 4 A schematic diagram of the implementation of various distributed ray source arrangements provided by an embodiment of the present invention;

[0025] Figure 5 A flowchart of a coded hole XRD imaging method based on a distributed ray source provided by an embodiment of the present invention;

[0026] Figure 6 The present invention is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention.

[0027] The attached drawings show:

[0028] 101 - distributed ray source, 102 - front collimator, 103 - transmission detector, 104 - encoding plate, 105 - pixelated spectrometer and 106 - image reconstruction module. DETAILED DESCRIPTION

[0029] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0030] The following describes a coded hole XRD imaging system and method based on a distributed ray source according to an embodiment of the present invention with reference to the accompanying drawings.

[0031] Figure 1 A schematic structural diagram of a coded aperture XRD imaging system based on a distributed ray source provided in an embodiment of the present invention.

[0032] like Figure 1 As shown, the coded aperture XRD imaging system based on a distributed ray source includes: a distributed ray source 101 , a front collimator 102 , a transmission detector 103 , a coding plate 104 , a pixelated spectrometer 105 and an image reconstruction module 106 .

[0033] Among them, the distributed ray source 101 is used to form an X-ray source of different arrangements according to target requirements to emit multiple beams of multi-energy X-rays. The front collimator 102 is arranged on the propagation path of the multiple beams of multi-energy X-rays, and is used to shape each beam of multi-energy X-rays into a fan beam of multi-energy X-rays, and ensure that all fan beams of multi-energy X-rays can completely cover the area to be reconstructed of the scanned object to generate a diffraction signal. The transmission detector 103 can be an energy integrating detector or a photon counting detector, which is arranged on the propagation path of the multiple beams of multi-energy X-rays, and is used to attenuate and correct the diffraction signal to improve the accuracy of the reconstruction result. The encoding plate 104 is arranged parallel to the receiving surface of the pixelated spectrometer 105, and is used to encode the diffraction signal to obtain the encoded diffraction signal. The pixelated spectrometer 105 is arranged on the propagation path of the encoded diffraction signal, and is used to measure the encoded diffraction signal to form diffraction data. The image reconstruction module 106 is used to iteratively optimize the preset objective function using the diffraction data, so as to comprehensively utilize the diffraction data collected during each focal point irradiation to reconstruct the XRD diffraction spectrum of the detected object at any position in the area to be reconstructed, that is, the reconstructed image of the area to be reconstructed.

[0034] In some embodiments, the distributed radiation source 101 includes a plurality of focal points, the arrangement of the plurality of focal points is determined according to the structural characteristics of the scanned object, and the operating voltage, current and beam emission time of each focal point are independently set.

[0035] In the actual implementation process, the distributed radiation source 101 includes multiple independently controllable focal points, each of which can generate multi-energy X-rays, and the distribution of the focus positions should meet the preset design requirements of the imaging system; before scanning, the spatial positions of each beam focus of the light source and the corresponding fan beam angles should be determined through system calibration and other methods.

[0036] Furthermore, during the scanning process, the beam-emitting sequence and beam-emitting times of each focus of the distributed ray source 101 can be flexibly designed according to actual needs, and the operating voltage, current and beam-emitting time of each focus can be independently set.

[0037] In some embodiments, the encoding plate 104 is a thin plate made of a highly absorbent material, and a plurality of through holes are disposed on the thin plate. The arrangement of the plurality of through holes is determined according to the structural characteristics of the scanned object.

[0038] In the actual implementation process, the coding plate 104 is a thin plate made of a highly absorbent material, on which a plurality of through holes are opened according to target requirements. The arrangement of the holes should be flexibly designed according to the actual application scenario, and the non-opening area can almost completely block the X-rays. The coding plate 104 should be arranged parallel to the receiving surface of the pixelated spectrometer.

[0039] It should be noted that the center position of the encoding plate 104 and the center position of the pixelated spectrometer 105 should also be determined according to the target requirements of the imaging system, so that the imaging system can fully collect diffraction data.

[0040] In some embodiments, the expression of the preset objective function is:

[0041]

[0042] in, is the diffraction spectrum of the scanned object to be estimated, ω t is the weight factor corresponding to the data of each focus in sequence, H (t) is the system matrix corresponding to each beam output, I (t) is the diffraction data collected by the pixelated spectrometer. Its elements represent the photon counts collected by a detector pixel in one energy channel, and R(f) is the regularization term.

[0043] In the actual implementation process, the target physical quantity to be solved in the embodiment of the present invention is the XRD diffraction spectrum of the area to be reconstructed. The area to be reconstructed is discretized into N x ×N y pixels, discretize the momentum transfer q into N q Values, tensors It can represent the target physical quantity, and its elements represents the diffraction intensity of the pixel in the i-th row and j-th column at the k-th momentum transfer amount; further, the tensor can be reshaped into a vector In this imaging system, multiple focal spots emit beams in sequence, and the collected diffraction data can form a data set Ω I = {I (t) |1≤t≤T}, I (t) The element of represents the photon count value collected by a detector pixel in an energy channel, t is the index number of the focus beam sequence, and T represents the total number of beams of all focuses. Since the spatial positions of each focus are different, they correspond to different system matrices. The system matrix at each beam is composed of the set Ω H ={H (t) |1≤t≤T}. (t) The elements in are proportional coefficients, and their physical meaning is: the photon count value generated by a unit intensity at a momentum transfer amount in the XRD diffraction spectrum of an object pixel under a detector pixel energy channel.

[0044] According to the above definition, the following objective function optimization problem (i.e., preset objective function) can be established to solve the diffraction spectrum of the object (i.e., the reconstructed image of the area to be reconstructed), and the expression is as follows:

[0045]

[0046] Among them, ω t is the weight factor corresponding to the data of each focus in sequence, R(f) is the regularization term, which can include sparse constraints, smooth constraints, basis function decomposition constraints, etc., and should be flexibly selected according to the application scenario of the system. Since the diffraction spectrum information of the object provided by the diffraction data at different viewing angles is not exactly the same, different weights ω should be assigned to them. t , in order to balance the influence of each diffraction data.

[0047] Specifically, in the embodiment of the present invention, the spatial positions of the focal points of the distributed ray source 101 are different, so the system matrices corresponding to the focal points and the coded holes and detectors are different. Here, the embodiment of the present invention introduces a weight factor in the solution process, and all the beam focus data are combined to form a global fidelity term. Further, on the basis of the global fidelity term, the spatial dimension smoothness constraint and the spectral dimension smoothness constraint are introduced, thereby obtaining the mathematical description of the reconstruction problem of the imaging system:

[0048]

[0049] in, is a tensor The differences along the x, y, and q directions are reshaped into one-dimensional vectors, and then Indicates that the objective function expression can be obtained:

[0050]

[0051] Among them, L(f) is the objective function. Use the Split-Bregman algorithm to solve the above objective function, introduce the variable z to replace f, and introduce the variable d x replace Introduce variable d y replace And introduce b z , b x , b y As the Bregman parameter, the objective function can be transformed into:

[0052]

[0053] The above objective function can be divided into multiple sub-problems and iterated alternately until convergence to obtain the final reconstruction result. n represents the number of iterations. In the nth iteration, the following sub-problems will be solved in turn to finally obtain the diffraction spectrum (i.e., the reconstructed image of the area to be reconstructed):

[0054] (1) z subproblem:

[0055]

[0056] This problem can be solved by the EM iteration method.

[0057] (2) Sub-problem d:

[0058]

[0059] The optimal solution to this problem can be obtained by using the Shrinkage method.

[0060] (3) Sub-problem:

[0061]

[0062] This problem can be solved by the Gauss-Seidel iteration method.

[0063] (4) Parameter update:

[0064]

[0065] In some embodiments, it also includes:

[0066] A carrying device, used for carrying a distributed ray source 101, a front collimator 102, a transmission detector 103, a coding plate 104 and a pixelated spectrometer 105;

[0067] The transport device is used to transport the scanned object into or out of the imaging area.

[0068] In actual implementation, the imaging system proposed in the embodiment of the present invention may also include various carrying devices for carrying major components such as light sources, inspected objects, detectors, etc.; it may also additionally include a set of simple mechanical motion devices to transport the inspected objects into or out of the imaging area, thereby forming a complete imaging system.

[0069] The workflow of the coded hole XRD imaging system based on the distributed ray source 101 proposed in the embodiment of the present invention is as follows:

[0070] like Figure 1 As shown, the XY plane is parallel to the horizontal plane, the XZ plane is the median perpendicular plane of the detector receiving surface, and the focus is located on a straight line determined by the focuses of the distributed ray source 101. The distributed ray source 101 has multiple focuses, and the figure takes three beam-out focus as an example, represented by red solid circles. At the beginning of the scan, the scanned object is transported into the target imaging area by a transport device, and X-rays are emitted from a focus of the distributed ray source 101. The slit collimator shapes the X-rays generated by each focus into a fan beam (represented by a red triangle). Each focus can share the same slit, or an independent slit can be set for each focus ( Figure 1Taking the shared as an example), the object to be detected can move along the Y direction or the Z direction (as shown by the arrow in the figure) to the imaging area, and generate a diffraction signal after being irradiated by the radiation. A ray blocker is located in the XY plane, which is used to block the X-rays from each focus and transmitted through the object; a transmission detector 103 is installed in front of the transmission blocker to collect the transmission signal for attenuation correction. The encoding plate surface is parallel to the receiving surface of the pixelated spectrometer 105, and encodes the diffraction signal. The pixelated spectrometer 105 collects the encoded diffraction data, and after the collection is completed, the focus stops emitting beams. Then the next focus starts to emit beams and collect data. After all the focuses have finished emitting beams, the diffraction data collection is completed. The image reconstruction module 106 uses the diffraction data to iteratively optimize the preset objective function, and then obtains a reconstructed image of the area to be reconstructed.

[0071] like Figure 2 As shown, the slit collimator and the transmission detector 103 are not drawn to facilitate the demonstration of the advantages of the distributed ray source 101. X-rays from different focal points of the distributed ray source 101 (represented by triangles of different colors) can scan the object under inspection from different angles and provide diffraction data under multiple viewing angles. This imaging system can be used alone to directly obtain the diffraction signal of the object under inspection and reconstruct it, such as Figure 3 (a) As shown; the imaging system can also be used as a secondary inspection device to further improve the diffraction spectrum reconstruction effect based on the additional prior information provided by the upper-level DR or CT system, such as Figure 3 (b) as shown.

[0072] The coded aperture XRD imaging system based on a distributed ray source proposed in the embodiment of the present invention is further described below through several specific embodiments.

[0073] In various application scenarios, the arrangement of the radiation sources should be flexibly designed according to the structural characteristics and diffraction spectrum characteristics of the object being detected, such as Figure 4 As shown, a rectangle with black dots represents a ray source, a cylinder represents a detected object, a black dotted frame represents a code plate 104, and a black solid frame represents a pixelated spectrometer 105. To make the schematic diagram concise and clear, Figure 4 (a) to Figure 4 In (f), the front collimator, transmission detector 103 and ray blocker are not drawn; Figure 4 (g) and Figure 4 In (h), the transmission detector 103 and the ray blocker are not drawn.

[0074] Embodiment 1

[0075] In this embodiment, the distributed ray sources are arranged as follows: Figure 4As shown in (a), the imaging system includes only one distributed ray source 101, and the number of focal spots is determined according to the actual application requirements. The diffraction signals generated by the X-rays of each focal spot are encoded by the same encoding plate 104 and then collected by the same pixelated spectrometer 105. The diffraction data is then used to iteratively optimize the preset objective function to obtain a reconstructed image of the area to be reconstructed of the scanned object.

[0076] Embodiment 2

[0077] In this embodiment, the distributed ray sources are arranged as follows: Figure 4 As shown in (b), the imaging system includes multiple distributed ray sources 101, and two adjacent ray sources form a certain angle, which can scan objects from a wider angle range. The number of focal points of each ray source is determined according to actual needs. The size of the encoding plate 104 and the pixelated spectrometer 105 should be appropriately lengthened to ensure that the diffraction signals from each ray source and each focal point are fully collected. Subsequently, the same pixelated spectrometer 105 collects diffraction data, and then uses the diffraction data to iteratively optimize the preset objective function to obtain a reconstructed image of the area to be reconstructed of the scanned object.

[0078] Embodiment 3

[0079] In this embodiment, the arrangement of the distributed ray source, the arrangement of the code plate 104 and the arrangement of the pixelated spectrometer are as follows: Figure 4 As shown in (c), the imaging system includes multiple distributed ray sources 101, and a certain angle is formed between two ray sources. Correspondingly, the imaging system also includes multiple encoding plates 104 and pixel spectrometers 105, which correspond to the ray sources one by one, so as to more fully collect the diffraction signal from each ray source and obtain better diffraction data. The preset objective function is iteratively optimized using the diffraction data to obtain a reconstructed image of the area to be reconstructed.

[0080] Embodiment 4

[0081] In this embodiment, the distributed ray sources are arranged as follows: Figure 4 As shown in (d), the imaging system includes a multi-layer ray source, each layer is composed of multiple ray sources, and two adjacent ray sources form a certain angle. The multi-layer ray source can scan different cross-sections of the object to be detected to achieve higher detection efficiency. The diffraction signal is encoded by the same encoding plate 104 and collected by the same pixelated spectrometer 105 to form diffraction data. The preset objective function is iteratively optimized using the diffraction data to obtain a reconstructed image of the area to be reconstructed. In addition to what is shown in the figure, the encoding plate 104 and the pixelated spectrometer 105 can also be arranged according to Figure 4 (c) is arranged to fully collect diffraction data.

[0082] Embodiment 5

[0083] In this embodiment, the arrangement of the code plate 104 and the detector is as follows: Figure 4 As shown in (e), two encoding plates 104 are symmetrically placed on both sides of the plane where the fan beam X-rays are located, and two pixelated spectrometers 105 are also symmetrically arranged. The arrangement of the holes on the two encoding plates 104 can be the same or different. The energy window setting, energy resolution, etc. of the pixelated spectrometer 105 can be the same or different, so as to collect diversified diffraction data and improve data conditions. After the scan is completed, the preset objective function is iteratively optimized using the diffraction data to obtain a reconstructed image of the area to be reconstructed of the scanned object.

[0084] Embodiment 6

[0085] In this embodiment, the arrangement of the code plate 104 and the detector is as follows: Figure 4 As shown in (f), the two coding plates 104 are placed asymmetrically about the plane where the fan beam X-rays are located, and the two pixelated spectrometers 105 are also placed asymmetrically. The arrangement of the through holes on the coding plate 104 and the relevant parameter settings of the pixelated spectrometer 105 are similar to those in Example 5. The two coding plates 104 with different positions can encode diffraction signals at different diffraction angles, providing richer information for reconstructing the diffraction spectrum of the detected object. After the scan is completed, the preset objective function is iteratively optimized using the diffraction data to obtain a reconstructed image of the area to be reconstructed of the scanned object.

[0086] Embodiment 7

[0087] In this embodiment, the distributed radiation source 101, the front collimator 102, the encoding plate 104, and the pixelated spectrometer 105 are arranged as follows: Figure 4 As shown in (g), the system is used to scan larger objects. Multiple ray sources are arranged adjacent to each other, and a front collimator with multiple slits shapes the X-rays generated by each ray source into a fan beam and isolates it, so that different ray sources can scan different parts of the large object. The encoding plate 104 and the pixelated spectrometer 105 are aligned and arranged to respectively collect diffraction signals from different parts of the object, thereby achieving parallel scanning, collection and diffraction spectrum reconstruction, and improving detection efficiency. In order to avoid mutual interference between diffraction signals from different parts of a large object, an isolation shielding device (omitted in the figure) can be installed between each encoding plate 104 and each pixelated spectrometer 105.

[0088] Embodiment 8

[0089] In this embodiment, the arrangement of the distributed radiation source 101 and the front collimator 102 is as follows: Figure 4(h). Multiple longitudinal slits are opened on the front collimator, corresponding to the focal points in the distributed ray source 101 one by one. This scanning method can scan multiple cross sections of the object at the same time, and reconstruct the diffraction spectrum of each point on each cross section based on the collected data. During the movement of the object, the imaging system can continuously scan to obtain the volume data of the scanned object, realize three-dimensional XRD diffraction spectrum reconstruction, and obtain a reconstructed image of the area to be reconstructed of the scanned object.

[0090] It should be noted that the various arrangements of radiation sources and encoding plates in the above embodiments are not limited to the embodiments themselves, and can be combined with each other to meet the requirements of different application scenarios.

[0091] In summary, the coded hole XRD imaging system based on a distributed ray source proposed in an embodiment of the present invention has the following features:

[0092] Beneficial effects:

[0093] (1) Multi-focus and multi-angle XRD diffraction imaging is achieved through distributed ray sources. Each focus can independently control the working voltage, current and beam emission time. The focus beam emission sequence can be optimized according to actual application requirements. The focus position can also be flexibly set, which can significantly improve the data conditions of XRD reconstruction and the quality of reconstructed XRD diffraction spectrum, facilitating subsequent material identification and detection.

[0094] (2) While improving data quality, it avoids complex mechanical devices and the movement of light sources and detectors involved in conventional methods, reduces the system's requirements for various components, simplifies the system, and can meet the requirements for miniaturization of equipment in actual scenarios such as medical treatment and security inspection.

[0095] Next, a coded hole XRD imaging method based on a distributed ray source according to an embodiment of the present invention is described with reference to the accompanying drawings.

[0096] Figure 5 A schematic flow chart of a coded hole XRD imaging method based on a distributed ray source provided in an embodiment of the present invention.

[0097] like Figure 5 As shown, the coded hole XRD imaging method based on a distributed ray source includes the following steps:

[0098] In step S501, the first arrangement mode and scanning angle of the distributed ray source, the second arrangement mode of the code plate, and the third arrangement mode of the pixelated spectrometer are determined according to the target requirements. In addition, the number of transmission detectors should be consistent with the number of pixelated spectrometers, and the relative positional relationship such as the distance and angle between the transmission detectors should also be consistent with the relative positional relationship between the pixelated spectrometers.

[0099] In step S502, multiple beams of multi-energy X-rays are emitted to the scanned object according to the first arrangement mode and scanning angle.

[0100] In step S503, each beam of multi-energy X-rays is shaped into a fan-beam multi-energy X-ray, and it is ensured that each beam of fan-beam multi-energy X-rays completely covers the to-be-reconstructed area of ​​the scanned object, so as to generate a diffraction signal.

[0101] In step S504, the diffraction signal is encoded according to the second arrangement to obtain an encoded diffraction signal.

[0102] In step S505, the encoded diffraction signal is detected according to the third arrangement to form diffraction data.

[0103] In step S506, the preset objective function is iteratively optimized using the diffraction data to obtain a reconstructed image of the area to be reconstructed.

[0104] It should be noted that the aforementioned explanation of the embodiment of the coded hole XRD imaging system based on a distributed ray source is also applicable to the coded hole XRD imaging method based on a distributed ray source of this embodiment, and will not be repeated here.

[0105] The coded hole XRD imaging method based on a distributed ray source proposed in an embodiment of the present invention has the following beneficial effects:

[0106] (1) Multi-focus and multi-angle XRD diffraction imaging is achieved through distributed ray sources. Each focus can independently control the working voltage, current and beam emission time. The focus beam emission sequence can be optimized according to actual application requirements. The focus position can also be flexibly set, which can significantly improve the data conditions of XRD reconstruction and the quality of reconstructed XRD diffraction spectrum, facilitating subsequent material identification and detection.

[0107] (2) While improving data quality, it avoids complex mechanical devices and the movement of light sources and detectors involved in conventional methods, reduces the system's requirements for various components, simplifies the system, and can meet the requirements for miniaturization of equipment in actual scenarios such as medical treatment and security inspection.

[0108] Figure 6 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. The electronic device may include:

[0109] A memory 601 , a processor 602 , and a computer program stored in the memory 601 and executable on the processor 602 .

[0110] When the processor 602 executes the program, the coded hole XRD imaging method based on the distributed ray source provided in the above embodiment is implemented.

[0111] Furthermore, the electronic device further comprises:

[0112] The communication interface 603 is used for communication between the memory 601 and the processor 602 .

[0113] The memory 601 is used to store computer programs that can be executed on the processor 602 .

[0114] The memory 601 may include a high-speed RAM memory, and may also include a non-volatile memory (non-volatile memory), such as at least one disk memory.

[0115] If the memory 601, the processor 602 and the communication interface 603 are implemented independently, the communication interface 603, the memory 601 and the processor 602 can be connected to each other through a bus and communicate with each other. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 6 Only one thick line is used in the diagram, but this does not mean that there is only one bus or only one type of bus.

[0116] Optionally, in a specific implementation, if the memory 601, the processor 602 and the communication interface 603 are integrated on a chip, the memory 601, the processor 602 and the communication interface 603 can communicate with each other through an internal interface.

[0117] The processor 602 may be a central processing unit (CPU), or an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of the present invention.

[0118] An embodiment of the present invention further provides a computer program product, and when the computer program / instructions are executed by a processor, the above-mentioned coded hole XRD imaging method based on a distributed ray source is implemented.

[0119] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, and when the program is executed by a processor, the coded hole XRD imaging method based on a distributed ray source as described above is implemented.

[0120] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0121] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "N" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0122] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present invention belong.

[0123] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in combination with these instruction execution systems, devices or apparatuses. For the purpose of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in combination with these instruction execution systems, devices or apparatuses. More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or N wirings (electronic devices), a portable computer disk box (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), a fiber optic device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically by optically scanning the paper or other medium and then editing, interpreting or processing in other suitable ways as necessary and then storing it in a computer memory.

[0124] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. If implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0125] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

[0126] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0127] The storage medium mentioned above may be a read-only memory, a magnetic disk or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person of ordinary skill in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A coded hole XRD imaging system based on a distributed ray source, characterized in that: include: Distributed ray source, used to form different arrangements of X-ray sources according to target requirements to emit multiple beams of multi-energy X-rays; A front collimator, which is arranged on the propagation path of the multiple beams of multi-energy X-rays, and is used to shape each beam of multi-energy X-rays into a fan-beam multi-energy X-ray, and ensure that all fan-beam multi-energy X-rays can completely cover the area to be reconstructed of the scanned object, so as to generate a diffraction signal; a transmission detector, which is arranged on a propagation path of the multi-beam multi-energy X-rays and is used to perform attenuation correction on the diffraction signal; A coding plate, which is arranged parallel to a receiving surface of the pixelated spectrometer and is used to encode the diffraction signal to obtain an encoded diffraction signal; a pixelated spectrometer, which is arranged on a propagation path of the encoded diffraction signal and is used to measure the encoded diffraction signal to form diffraction data; The image reconstruction module is used to iteratively optimize a preset objective function using the diffraction data to obtain a reconstructed image of the area to be reconstructed.

2. The coded hole XRD imaging system based on a distributed ray source according to claim 1, characterized in that: The distributed ray source includes a plurality of focal points, the arrangement of the plurality of focal points is determined according to the structural characteristics of the scanned object, and the operating voltage, current and beam emission time are independently set for each focal point.

3. The coded hole XRD imaging system based on a distributed ray source according to claim 1, characterized in that: The encoding plate is a thin plate made of a highly absorbent material. A plurality of through holes are arranged on the thin plate. The arrangement of the plurality of through holes is determined according to the structural characteristics of the scanned object.

4. The coded hole XRD imaging system based on a distributed ray source according to claim 1, characterized in that: The expression of the preset objective function is: in, is the diffraction spectrum of the scanned object to be estimated, R is the weight factor corresponding to the data of each focus in sequence, and H (t) is the system matrix corresponding to each beam output, I (t) is the diffraction data collected by the pixelated spectrometer. Its elements represent the photon counts collected by a detector pixel in one energy channel, and R(f) is the regularization term.

5. The coded hole XRD imaging system based on a distributed ray source according to claim 1, characterized in that: Also includes: A carrying device is used to carry the distributed ray source, the front collimator, the transmission detector, the encoding plate and the pixelated spectrometer.

6. The coded hole XRD imaging system based on a distributed ray source according to claim 1, characterized in that: Also includes: The transport device is used to transport the scanned object into or out of the imaging area.

7. A coded hole XRD imaging method based on a distributed ray source, characterized in that: The coded hole XRD imaging system based on a distributed ray source according to any one of claims 1 to 6 comprises the following steps: Determine the first arrangement mode and scanning angle of the distributed ray source, the second arrangement mode of the encoding plate, and the third arrangement mode of the pixelated spectrometer according to target requirements; emitting multiple beams of multi-energy X-rays to the scanned object according to the first arrangement mode and the scanning angle; shaping each beam of multi-energy X-rays into a fan-beam multi-energy X-ray, and ensuring that each fan-beam multi-energy X-ray completely covers the area to be reconstructed of the scanned object, so as to generate a diffraction signal; Encoding the diffraction signal according to the second arrangement to obtain an encoded diffraction signal; detecting the encoded diffraction signal according to a third arrangement to form diffraction data; The preset objective function is iteratively optimized using the diffraction data to obtain a reconstructed image of the area to be reconstructed.

8. An electronic device, characterized in that: include: A memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the coded hole XRD imaging method based on a distributed ray source as claimed in claim 7.

9. A computer program product, characterized in that When the computer program / instruction is executed by a processor, the coded hole XRD imaging method based on a distributed ray source as described in claim 7 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The program is executed by a processor to implement the coded hole XRD imaging method based on a distributed ray source as claimed in claim 7.

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