Static CT imaging system and method

Abstract

The invention provides a static CT imaging system which comprises a scanning channel used for conveying a scanned object to pass through a scanning area of the static CT imaging system; a plurality of distributed light sources; the plurality of distributed light sources at least comprise a first-class light source and a second-class light source, and the energy of a first ray emitted by a target spot of the first-class light source is higher than that of a second ray emitted by a target spot of the second-class light source; the first ray passes through a scanned object in the scanning area along a first ray path, and the second ray passes through the scanned object in the scanning area along a second ray path. The attenuation of the scanned object on the first ray along the extension direction of the first ray path is different from the attenuation of the scanned object on the second ray along the extension direction of the second ray path. The invention further provides a static CT imaging method.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of radiation scanning, and more particularly, to a static CT imaging system and a static CT imaging method. BACKGROUND

[0002] Computed tomography (CT) systems are widely used in industrial detection, security inspection, biomedical imaging and other fields. Traditional CT systems use a single target point X-ray source to emit rays, and reconstruct the internal structure of the object by the attenuation of the rays by the target object. However, in some practical application scenarios, the target object often attenuates the rays in a certain direction much stronger than in other directions, for example, there is a non-uniform distribution of high-density or high-absorption materials. At this time, if all scanning directions use rays of the same energy, not only can some directions not be penetrated, resulting in missing images or artifacts, but also the problem of resource waste and rising equipment costs may occur due to the high energy of the rays in some directions. SUMMARY

[0003] In view of the above problems, the present disclosure provides a static CT imaging system and a static CT imaging method.

[0004] A first aspect of the present disclosure provides a static CT imaging system, comprising: a scanning channel for conveying a scanned object through a scanning region of the static CT imaging system; a plurality of distributed light sources, at least one of the distributed light sources comprising a plurality of target points configured to be capable of respectively emitting rays; and a detector for detecting rays emitted from the plurality of distributed light sources and passing through the scanned object, wherein the plurality of distributed light sources at least includes a first type of light source and a second type of light source, the energy of first rays emitted by the target points of the first type of light source is higher than the energy of second rays emitted by the target points of the second type of light source, the first rays pass through the scanned object in the scanning region along a first ray path, the second rays pass through the scanned object in the scanning region along a second ray path, and the attenuation of the first rays by the scanned object along the extension direction of the first ray path is different from the attenuation of the second rays by the scanned object along the extension direction of the second ray path.

[0005] According to an embodiment of the present disclosure, the first type of light source is arranged on at least one side of the scanning region based on the shape of the scanned object, and the second type of light source is arranged on at least one side of the scanning region based on the shape of the scanned object; or, the first type of light source is arranged on at least one side of the scanning region based on the statistical attenuation path of the scanned object in a target CT imaging scenario, and the second type of light source is arranged on at least one side of the scanning region based on the statistical attenuation path of the scanned object in the target CT imaging scenario.

[0006] According to an embodiment of the present disclosure, the scanning region comprises at least a first side, a second side and a third side, the first side and the second side are adjacently arranged, and the first side and the third side are oppositely arranged, and one of the first type light source and the second type light source is arranged on the second side, and the other of the first type light source and the second type light source is arranged on at least one of the first side and the third side.

[0007] According to an embodiment of the present disclosure, the scanning region comprises at least a first side, a second side and a third side, the first side and the second side are adjacently arranged, and the first side and the third side are oppositely arranged, and the first type light source and the second type light source are arranged on the same side of the scanning region.

[0008] According to an embodiment of the present disclosure, the first type light source and the second type light source are arranged on the first side, the second side and the third side to form a semi-closed structure around the scanning region.

[0009] According to an embodiment of the present disclosure, the first type light source is arranged on the first side and the third side, and the second type light source is arranged on the second side, or the second type light source is arranged on the first side and the third side, and the first type light source is arranged on the second side.

[0010] According to an embodiment of the present disclosure, the second type light source comprises a first second type light source and a second second type light source, the first type light source and the first second type light source are arranged on the first side and the third side, and the second second type light source is arranged on the second side, or the second type light source comprises a first second type light source and a second second type light source, the first type light source and the first second type light source are arranged on the second side, and the second second type light source is arranged on the first side and the third side.

[0011] According to an embodiment of the present disclosure, the first type light source and the second type light source are arranged in a plane perpendicular to the conveying direction of the scanned object, or the first type light source and the second type light source are arranged in a plurality of parallel planes perpendicular to the conveying direction of the scanned object.

[0012] According to an embodiment of the present disclosure, the working voltage of the second type light source is a fixed voltage M2, and the working voltage of the first type light source is selected based on a target adjustment interval.

[0013] According to an embodiment of the present disclosure, the lower limit of the target adjustment interval is M2, the upper limit of the target adjustment interval is M1, and the difference between M1 and M2 is greater than or equal to 20kV.

[0014] According to an embodiment of the present disclosure, the first type of light source comprises N1 target points, and the second type of light source comprises N2 target points, wherein N1 and N2 are positive integers greater than or equal to 2.

[0015] According to an embodiment of the present disclosure, the arrangement length of the target points in the first type of light source and / or the second type of light source covers at least the length on either side of the scanning region in the extension direction of the scanning channel.

[0016] According to an embodiment of the present disclosure, the static CT imaging system further comprises a control interface configured to allow an operator to set the working voltage of the first type of light source according to the attribute of the scanned object.

[0017] According to an embodiment of the present disclosure, the static CT imaging system further comprises an auxiliary sensing device and a controller configured to set the working voltage of the first type of light source based on the contour information of the scanned object obtained by the auxiliary sensing device.

[0018] According to an embodiment of the present disclosure, the distributed light source is distributed in L beam faces along the conveying path of the scanned object, L is a positive integer greater than or equal to 2, wherein the working voltage of the distributed light source on the first beam face is set to M1, and the working voltage of the distributed light source on the 2-Lth beam face is set according to the degree of attenuation of the corresponding rays of the previous beam face.

[0019] According to an embodiment of the present disclosure, the static CT imaging system further comprises a controller configured to perform correction processing on the first projection data obtained by scanning the first type of light source, and perform image reconstruction based on the corrected first projection data and the second projection data obtained by scanning the second type of light source, to obtain a target reconstruction image.

[0020] According to an embodiment of the present disclosure, the detector is arranged in at least two of the first side, the second side and the third side.

[0021] The second aspect of the present disclosure provides a static CT imaging method, wherein the static CT imaging method is used in a static CT imaging system, the static CT imaging system comprises a scanning region, a plurality of distributed light sources and a detector, the plurality of distributed light sources at least comprise a first type of light source and a second type of light source, the first type of light source has a first ray emitted by a target point, and the second type of light source has a second ray emitted by a target point, the energy of the first ray is higher than the energy of the second ray, the static CT imaging method comprises: obtaining first projection data in response to the first ray passing through a scanned object in the scanning region along a first ray path; obtaining second projection data in response to the second ray passing through the scanned object in the scanning region along a second ray path; performing data processing based on the first projection data and the second projection data; and performing image reconstruction based on the processed projection data to obtain a target reconstructed image, wherein the data processing based on the first projection data and the second projection data comprises: correcting at least one of the first projection data and the second projection data by using a mapping relationship to obtain corrected first projection data and / or corrected second projection data, the mapping relationship is used to: map the first projection data into a range in which the second projection data is located, map the second projection data into a range in which the first projection data is located, or map the first projection data and the second projection data into a range in which third projection data obtained in advance is located.

[0022] According to an embodiment of the present disclosure, the data processing based on the first projection data and the second projection data specifically comprises: obtaining third projection data and fourth projection data obtained by scanning at least one reference material under a preset energy condition by using the first type of light source and the second type of light source; constructing an initial mapping relationship of the first type of light source and the second type of light source based on the third projection data and the fourth projection data, wherein the initial mapping relationship is represented as mapping the third projection data into a range in which the fourth projection data is located; performing primary correction on the first projection data based on the initial mapping relationship to obtain primary corrected first projection data; constructing an initial reconstructed image based on the primary corrected first projection data and the second projection data; calculating a theoretical attenuation value based on the initial reconstructed image, updating the initial mapping relationship based on the theoretical attenuation value to obtain an updated mapping relationship; performing secondary correction on the primary corrected first projection data based on the updated mapping relationship to obtain secondary corrected first projection data; and repeating the process of constructing a reconstructed image, the process of updating a mapping relationship, and the process of correcting first projection data until a preset iteration stopping condition is reached to obtain multiple corrected first projection data.

[0023] According to an embodiment of the present disclosure, the image reconstruction based on the processed projection data to obtain a target reconstructed image specifically comprises: constructing the target reconstructed image based on the first projection data and the second projection data.

[0024] According to an embodiment of the present disclosure, the data processing based on the first projection data and the second projection data specifically comprises: obtaining third projection data and fourth projection data obtained by scanning at least one reference material under a preset energy condition by the first light source and the second light source; constructing an initial mapping relationship of the first light source and the second light source based on the third projection data and the fourth projection data, wherein the initial mapping relationship is represented as mapping the fourth projection data into a range of the third projection data; performing a primary correction on the second projection data based on the initial mapping relationship to obtain the primary corrected second projection data; constructing an initial reconstructed image based on the primary corrected second projection data and the first projection data; calculating a theoretical attenuation value based on the initial reconstructed image, updating the initial mapping relationship based on the theoretical attenuation value to obtain an updated mapping relationship; performing a secondary correction on the primary corrected second projection data based on the updated mapping relationship to obtain the secondary corrected second projection data; and repeating the processes of constructing the reconstructed image, updating the mapping relationship, and correcting the second projection data until a preset iteration stopping condition is reached to obtain the multiple corrected second projection data.

[0025] According to an embodiment of the present disclosure, the image reconstruction based on the processed projection data to obtain a target reconstructed image specifically comprises: constructing the target reconstructed image based on the first projection data and the second projection data.

[0026] According to an embodiment of the present disclosure, the data processing based on the first projection data and the second projection data specifically comprises: obtaining third projection data and fourth projection data obtained by scanning at least one reference material under a preset energy condition by the first light source and the second light source; constructing an initial mapping relationship of the first light source and the second light source based on the third projection data and the fourth projection data, wherein the initial mapping relationship is represented as mapping the fourth projection data and the third projection data into a range in which target projection data obtained in advance is located; performing primary correction on the first projection data and the second projection data based on the initial mapping relationship to obtain primary corrected first projection data and primary corrected second projection data; constructing an initial reconstructed image based on the primary corrected second projection data and the primary corrected first projection data; calculating a theoretical attenuation value based on the initial reconstructed image, updating the initial mapping relationship based on the theoretical attenuation value to obtain an updated mapping relationship; performing secondary correction on the primary corrected first projection data and the primary corrected second projection data based on the updated mapping relationship to obtain secondary corrected first projection data and secondary corrected second projection data; and repeating the process of constructing a reconstructed image, the process of updating the mapping relationship, and the process of correcting the first projection data and the second projection data until a preset iteration stopping condition is reached, to obtain multiple corrected first projection data and multiple corrected second projection data.

[0027] According to an embodiment of the present disclosure, the image reconstruction based on the processed projection data to obtain a target reconstructed image specifically comprises: constructing a target reconstructed image based on the multiple corrected first projection data and the multiple corrected second projection data.

[0028] According to an embodiment of the present disclosure, the third projection data and the fourth projection data obtained by scanning at least one reference material specifically comprises: selecting at least one reference material; scanning the reference material with different thicknesses by using the first light source and the second light source to obtain the third projection data and the fourth projection data; and obtaining the initial mapping relationship based on the third projection data and the fourth projection data.

[0029] According to an embodiment of the present disclosure, the reference material comprises at least two kinds, and the constructing of the initial mapping relationship of the first light source and the second light source based on the third projection data and the fourth projection data comprises obtaining the initial mapping relationship by using a target optimization function, and the target optimization function is represented as:

[0030]

[0031] Wherein, m is the number of reference materials, h is the thickness of the material, K is the voltage value set in the running process of the first light source, is the third projection data, is the fourth projection data, R(f k ) is a regular term constraint, f k represents the initial mapping relationship.

[0032] According to the embodiments of the present disclosure, the reference materials include at least two, and the initial mapping relationship between the first light source and the second light source is constructed based on the third projection data and the fourth projection data, which includes obtaining the initial mapping relationship by using a target optimization function, and the target optimization function is represented as:

[0033]

[0034] Wherein, m is the number of reference materials, h is the thickness of the material, K is the voltage value set in the running process of the first light source, is the third projection data, is the fourth projection data, R(f k ) is a regular term constraint, f k represents the initial mapping relationship.

[0035] According to the embodiments of the present disclosure, the reference materials include at least two, and the initial mapping relationship between the first light source and the second light source is constructed based on the third projection data and the fourth projection data, which includes obtaining the initial mapping relationship by using a target optimization function, and the target optimization function is represented as:

[0036]

[0037] Wherein, m is the number of reference materials, h is the thickness of the material, K is the voltage value set in the running process of the first light source, is the third projection data and the fourth projection data, is the target projection data, R(f k ) is a regular term constraint, f k represents the initial mapping relationship.

[0038] According to the embodiments of the present disclosure, the preset iteration stopping condition includes reaching a preset iteration number or a change difference of two reconstructed images reaching a preset threshold.

[0039] According to embodiments of the present disclosure, by arranging multiple distributed light sources and dividing them into at least two types of light sources with different energy levels, the system can selectively configure light beams with appropriate energy levels according to the attenuation difference of the light beams in different directions of the scanned object, thereby effectively avoiding the problems of high-energy redundancy or low-energy penetration in traditional systems, and improving the penetration effect and energy efficiency matching capability of the overall imaging. At the same time, since the system arranges local high-energy light sources only in specific high-attenuation directions, rather than using high-energy light beams in all directions, it significantly reduces the dependence of the overall system on high-energy light sources while meeting the imaging penetration requirements, which helps to control energy consumption, reduce radiation dose, and reduce the cost of light source configuration. BRIEF DESCRIPTION OF DRAWINGS

[0040] The above and other objects, features and advantages of the present disclosure will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:

[0041] Figure 1 is a structural schematic diagram of a ray scanning imaging system according to some example embodiments of the present disclosure;

[0042] Figure 2 is a structural schematic diagram of a static CT imaging system based on distributed light sources according to some example embodiments of the present disclosure;

[0043] Figure 3A is a schematic diagram of a static CT imaging system with two types of light sources arranged on different sides according to some example embodiments of the present disclosure;

[0044] Figure 3B is a schematic diagram of a static CT imaging system with two types of light sources arranged on different sides according to other example embodiments of the present disclosure;

[0045] Figure 3C is a schematic diagram of a static CT imaging system with two types of light sources arranged on the same side according to some example embodiments of the present disclosure;

[0046] Figure 3D is a schematic diagram of a static CT imaging system with two types of light sources arranged on the same side according to other example embodiments of the present disclosure;

[0047] Figure 3E is a schematic diagram of a static CT imaging system including a detector arrangement according to some example embodiments of the present disclosure;

[0048] Figure 3F is a schematic diagram of a static CT imaging system with end points of a target point array aligned with the boundary of a scanning region according to some example embodiments of the present disclosure;

[0049] Figure 4A A schematic diagram showing an arrangement of spatial positions of a type-1 light source and a type-2 light source according to some embodiments of the present disclosure is shown;

[0050] Figure 4B A schematic diagram showing an arrangement of spatial positions of a type-1 light source and a type-2 light source according to some other embodiments of the present disclosure is shown;

[0051] Figure 5A A schematic diagram of a static CT imaging system including a control module according to some embodiments of the present disclosure is shown schematically;

[0052] Figure 5B A schematic diagram showing that a distributed light source according to some embodiments of the present disclosure can be arranged along L beam faces of a conveying path of a scanned object is shown schematically;

[0053] Figure 6 A flowchart of a static CT imaging method according to embodiments of the present disclosure is shown schematically; and

[0054] Figure 7 A flowchart of a method of data processing in a static CT imaging method according to embodiments of the present disclosure is shown schematically. DETAILED DESCRIPTION

[0055] Embodiments of the present disclosure will be described herein below with reference to the accompanying drawings. It is to be understood, however, that the description is merely exemplary and is not intended to limit the scope of the present disclosure. In the following detailed description of embodiments of the present disclosure, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that one or more embodiments of the present disclosure can be practiced without these specific details. In other instances, well-known structures and

[0056] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. As used herein, the term "includes" and tautological equivalents thereof, means that the named features, steps, operations and / or components are present, but does not exclude the presence or addition of one or more other features, steps, operations or components.

[0057] All terms used herein including technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art unless otherwise defined herein. It should be noted that the terms used herein are defined as consistent with the context of the specification, and should not be interpreted in an idealized or overly formal way.

[0058] It should be noted that, in this document, computed tomography (CT) scanning imaging refers to converting analog signals received by a detector after tomography scanning of an object to be scanned into digital signals, calculating attenuation coefficients of each pixel by an electronic computer, and reconstructing an image, so as to display the tomographic structure of each part of the object to be scanned.

[0059] In the following, embodiments of the present disclosure will be described in detail with reference to a CT imaging system for luggage as an example. It should be understood that embodiments of the present disclosure are not limited to the CT imaging scenario for luggage, and can be applied to various scanning imaging scenarios. For example, it can be applied to scanning imaging scenarios including various different inspection objects, including but not limited to vehicle scanning imaging, luggage / packaging scanning imaging, human or animal scanning imaging, organ / tissue scanning imaging, small object scanning imaging, large object scanning imaging such as container, etc. It should be noted that the description of the scanning imaging scenario here is not an exhaustive description, and the following exemplary description should not be understood as a limitation on the protection scope of the present disclosure.

[0060] Figure 1 is a structural schematic diagram of a ray scanning imaging system according to some exemplary embodiments of the present disclosure. In Figure 1 , a CT imaging system based on X-ray scanning is schematically shown as an example of the ray scanning imaging system. As Figure 1As shown, the CT imaging system according to this embodiment includes: a gantry 20, a transport mechanism 40, a controller 50, a data processing device 60 (e.g., a computer), a scanning channel 80, etc. The gantry 20 includes a light source 10, such as an X-ray machine, that emits X-rays for examination, and a detection and acquisition device 30. The scanning channel 80 extends along a first direction z and is used to place the object to be scanned 70 during imaging. For example, at least a portion of a support device may be disposed in the scanning channel 80, and the object to be scanned 70 may be placed on the support device. During scanning, the object to be scanned 70 may remain stationary in the imaging area. As another example, at least a portion of the transport mechanism 40 is disposed in the scanning channel 80. The transport mechanism 40 carries the object to be scanned (e.g., luggage to be inspected) 70 through the scanning area between the light source 10 and the detection and acquisition device 30 of the gantry 20. The transport mechanism 40 can move the object to be scanned 70 along the first direction z, while the rays emitted by the light source 10 can pass through the object to be scanned 70 to perform a CT scan. The detection and acquisition device 30 includes, for example, a detector and data acquisition unit with an integrated modular structure, such as a flat panel detector, for detecting X-rays transmitted through the scanned object 70, obtaining analog signals, and converting the analog signals into digital signals to output projection data of the scanned object 70 onto the X-rays. The controller 50 is used to control the synchronous operation of all parts of the entire system. The data processing device 60 is used to process the data acquired by the data acquisition unit, process and reconstruct the data, and output the results.

[0061] like Figure 1 As shown, the light source 10 is placed on one side of the object being scanned 70, and the detection and acquisition device 30 is placed on the other side of the object being scanned 70. The device includes a detector and a data acquisition unit for acquiring transmission data and / or multi-angle projection data of the object being scanned 70. The data acquisition unit includes a data amplification and shaping circuit, which can operate in (current) integration mode or pulse (counting) mode. The data output cable of the detection and acquisition device 30 is connected to the controller 50 and the data processing device 60, and the acquired data is stored in the data processing device 60 according to a trigger command.

[0062] In an embodiment of the present disclosure, a ray scanning imaging module can be deployed in the data processing device 60, and an image recognition model or a target recognition model can be deployed in the ray scanning imaging module. The ray scanning imaging module can use the image recognition model or the target recognition model to identify the collected field data (e.g., a ray scanning image), and the identification can include target detection, e.g., detecting a target object or an object of interest in the ray scanning image. For example, the target object or the object of interest can be various types of contraband. It should be understood that the specific category of the target object or the object of interest depends on the scanning imaging field where the ray scanning imaging system is arranged, or in other words, the specific category of the target object or the object of interest is determined by the user of the ray scanning imaging system according to specific scanning imaging needs, which can be dynamically adjusted according to scanning imaging needs.

[0063] In an embodiment of the present disclosure, the light source 10 can be an X-ray machine, for example, and a suitable X-ray machine target point size can be selected according to the resolution of imaging. In other embodiments, an X-ray machine can not be used, and an X-ray beam can be generated using a linear accelerator or the like.

[0064] In an embodiment of the present disclosure, to adapt to higher energy or higher flux imaging needs, a device capable of generating a high-energy X-ray beam such as a linear accelerator (LINAC) can be used as a modular distributed light source unit. The linear accelerator has a higher energy regulation range and stronger penetration ability, and is suitable for object detection scenarios such as metal and multi-layer composite materials that significantly attenuate traditional X-rays. After being introduced into a distributed structure, a mixed type multi-energy imaging system can be constructed to achieve more extensive detection adaptability for various object types.

[0065] For example, the distributed light source can support independent control at the module level, and the number and layout of target points can be flexibly configured according to the morphology and attenuation characteristics of the actual scanned object, and are not limited to ring, rectangular, or any asymmetric arrangement.

[0066] The detection and acquisition device 30 includes an X-ray detector and a data acquisition circuit, etc. The X-ray detector can use a solid-state detector, a gas detector, or other detectors, and embodiments of the present disclosure are not limited thereto. The data acquisition circuit includes a readout circuit, an acquisition trigger circuit, and a data transmission circuit, etc.

[0067] The combination of the controller 50 and the data processing device 60, for example, includes a computer device installed with a control program and a data processing program, which is responsible for completing the control of the operation process of the CT imaging device, including mechanical rotation, electrical control, safety interlock control, etc., reconstructing a CT image from projection data, training an image recognition model or a target recognition model, and identifying a ray scanning image using the trained image recognition model or target recognition model, etc.

[0068] In embodiments of the present disclosure, the distributed light source includes a plurality of target points (also referred to as focal points). For example, a plurality of X-ray target points can be arranged in high density within a ray tube vacuum cavity. Compared with a conventional single light source, the distributed light source has a plurality of independent ray emitting points, which can work independently and be controlled individually. For example, the distributed light source developed by the applicant of the present disclosure can integrate hundreds of ray target points in one ray tube, and each target point can be independently controlled and quickly switched as required. For example, the emission of each target point can be precisely regulated, including parameters such as the intensity and emission time of the rays, so that when performing CT scanning, the output of the rays can be flexibly adjusted according to different scanning sites, object densities and other factors, thereby obtaining higher quality images. For example, the intensity distribution of the X-ray beam can be modulated by controlling the intensity of different target points to adapt to the imaging needs of different objects. For another example, by using a distributed light source with multiple target points, fast scanning and imaging capabilities can be achieved. Due to the provision of multiple ray target points, the distributed light source can simultaneously or quickly sequentially scan the target object from multiple different positions, greatly improving the scanning speed. Compared with the conventional CT scanning method, the complete image information of the object can be obtained in a shorter time, which is of great significance for scenarios that require fast imaging, such as security checks. For another example, high-quality imaging effects can be achieved, and the coordinated work of multiple target points and the precise control capability enable the distributed light source to provide images with higher resolution and lower noise. When imaging complex objects or microstructures, the internal structure and details of the object can be more clearly presented, providing more accurate information.

[0069] Figure 2 A structural schematic diagram of a static CT imaging system based on a distributed light source according to some example embodiments of the present disclosure is schematically shown.

[0070] Referring to Figure 2 The static CT imaging system 200 can include a light source 220 arranged in a ring around a scanning area 210, specifically, a distributed light source can be provided, and a plurality of target points (circles in the periphery of the figure) of the light source are uniformly arranged on the outer periphery of the scanning area 210 to form a light source array surrounding the scanned object 230. Among them, the target points of the light source 220 are arranged along the periphery of the scanned object to form a regular and symmetrical point array structure, so that relatively consistent ray projections can be obtained at each angle to support multi-angle image acquisition.

[0071] Through the ring layout, the system can obtain ray projections in multiple directions to perform CT reconstruction. This layout is particularly suitable for fixed security CT systems, industrial non-destructive testing pipelines and other fields, and can realize the high-throughput scanning requirement of "non-rotation, static imaging" of the detected object.

[0072] However, in this embodiment, the distributed light source 220 can adopt the same type of ray emitting device, regardless of its position or orientation, and the rays emitted thereby have substantially uniform energy. Therefore, in the case where the scanned object has a structure or material that is not uniform (for example, there is a high-density metal or heavy object in a certain direction), since the energy of the rays in all directions is uniform, it is difficult to effectively penetrate the high-attenuation area, and image information in this direction may be missing or have serious artifacts.

[0073] The inventors have found in their research that the material of the scanned object often has directional differences, for example, some directions contain high-density or strongly absorbing materials, resulting in a significantly higher ray attenuation in that direction than in other directions. In this case, if the same energy rays are used in all scanning directions, it is easy to cause image missing or artifacts in some directions due to the inability to penetrate. While increasing the energy of the rays to ensure uniform penetration ability, it also leads to energy redundancy in other directions, which not only increases the cost of the device but also wastes resources. Therefore, the existing static CT imaging system usually tends to configure a high-energy light source to meet the imaging needs of the most unfavorable direction, but this "one-size-fits-all" solution is not ideal in terms of energy efficiency and imaging quality.

[0074] In addition, the conventional single-energy light source usually has a slow response speed when switching between different energy states, which makes it difficult to meet the needs of efficient and flexible multi-energy imaging, limiting the adaptability of the static CT imaging system in complex detection environments. In particular, in a static CT imaging system that requires rapid and multi-angle acquisition, the limitations of this single-point dynamic adjustment method are more prominent.

[0075] Based on this, the embodiments of the present disclosure provide a static CT imaging system, which can arrange high-energy ray light sources and low-energy ray light sources according to the attenuation characteristic differences of the scanned object in different directions, wherein the high-energy ray light sources are used to penetrate high-attenuation directions, and the low-energy ray light sources are used to penetrate low-attenuation directions, so as to achieve precise matching of energy and attenuation. The light sources of different energies not only optimize the allocation of ray resources, improve the image penetration quality and imaging efficiency, but also reduce the dependence of the overall system on high-power devices, and have good energy saving, scalability and complex structure detection capability.

[0076] For example, some example embodiments of the present disclosure provide a static CT imaging system, comprising: a scanning channel for conveying a scanned object through a scanning region of the static CT imaging system; a plurality of distributed light sources, at least one of the distributed light sources comprising a plurality of target points configured to respectively emit rays; and a detector for detecting rays emitted from the plurality of distributed light sources and passing through the scanned object, wherein the plurality of distributed light sources at least comprises a first type of light source and a second type of light source, target points of the first type of light source emit first rays with higher energy than second rays emitted by target points of the second type of light source, the first rays pass through the scanned object in the scanning region along a first ray path, the second rays pass through the scanned object in the scanning region along a second ray path, and the scanned object has higher attenuation to the first rays along an extension direction of the first ray path than to the second rays along an extension direction of the second ray path.

[0077] In this embodiment, by arranging a plurality of distributed light sources and dividing them into at least two types of light sources with different energy levels, the system can selectively configure rays with appropriate energy levels according to the attenuation difference of the scanned object in different directions, thereby effectively avoiding the problems of high energy redundancy or insufficient penetration of low energy in traditional systems, and improving the penetration effect and energy efficiency matching ability of the overall imaging. At the same time, since the system uses local high-energy light sources to arrange only in specific high-attenuation directions, rather than uniformly using high-energy rays in all directions, the overall system's dependence on high-energy light sources is significantly reduced while meeting the imaging penetration requirements, which helps to control energy consumption, reduce radiation dose, and reduce light source configuration costs.

[0078] The inventors have also found through research that in actual imaging processes, the data generated by rays of different energy levels have obvious differences in gray scale distribution, noise level, and attenuation characteristics, etc. If these differences are not handled specifically, it is easy to cause artifacts and distortion in the image reconstruction process, reducing detection accuracy. At the same time, there are limited technical means in the prior art for effectively and real-time adjusting and matching the light source voltage and the detected object's ray attenuation distribution characteristics.

[0079] Based on this, the embodiments of the present disclosure provide a static CT imaging method suitable for an imaging system with multiple distributed light sources and detectors, wherein the distributed light sources at least include a first type of light source and a second type of light source with different energies, the first type of light source is used to emit high-energy rays to penetrate high-attenuation structures, and the second type of light source is used to emit low-energy rays to improve the imaging contrast of low-density areas. The method acquires first projection data and second projection data after high-energy rays and low-energy rays pass through the scanned object respectively, and performs data processing on the first projection data and the second projection data, and finally reconstructs a target image with higher penetration ability and clearer details, thereby significantly improving the imaging quality and adaptability of the imaging system in complex structures and multi-material environments.

[0080] For example, the process of data processing can include: based on the scanning results of at least one reference material by the first type of light source and the second type of light source, constructing an initial mapping relationship, mapping the high-energy projection data to the low-energy response range, and performing a preliminary correction on the first projection data, and then constructing an initial image in combination with the second projection data; subsequently, based on the theoretical attenuation value inversely deduced from the image, updating the initial mapping relationship, and repeatedly performing correction, reconstruction and mapping relationship iteration based on the updated initial mapping relationship until a preset stopping condition is met, and finally generating a high-precision target reconstruction image by using the first projection data and the second projection data after multiple corrections.

[0081] In this embodiment, the complete closed-loop mechanism of constructing a multi-energy mapping relationship based on a reference material, inversely deducing physical properties combined with a reconstruction image, iteratively correcting high-energy projection data, and fusing low-energy data to reconstruct an image effectively solves the problem of inconsistent data caused by the difference in spectral response between the first type of light source and the second type of light source. This method not only improves the numerical alignment and physical consistency between the projection data, but also significantly improves the accuracy and detail restoration ability of image reconstruction, reduces artifacts and boundary errors, thereby enhancing the versatility, robustness and engineering application value of the system.

[0082] Figure 3A A schematic diagram of a static CT imaging system with two types of light sources arranged on different sides is schematically shown. Figure 3B A schematic diagram of a static CT imaging system with two types of light sources arranged on different sides is schematically shown. Figure 3C A schematic diagram of a static CT imaging system with two types of light sources arranged on the same side is schematically shown. Figure 3D A schematic diagram of a static CT imaging system with two types of light sources arranged on the same side is schematically shown. Figure 3E A schematic diagram of a static CT imaging system including a detector arrangement is schematically shown. Figure 3FFIG. 1 shows a schematic diagram of a static CT imaging system with end-point and scan region boundary alignment of a target array, according to some example embodiments of the present disclosure.

[0083] Referring to Figures 3A-3F In some example embodiments, the static CT imaging system 300 can include a scan passage 310, a light source 320, and a detector 330.

[0084] The scan passage 310 is configured to transport the scanned object 340 through the scan region 311 of the system. For example, the scan passage 310 is a linear structure suitable for a scenario where the scanned object 340 is transported in a straight line or on a conveyor belt, such as a security checkpoint or an industrial production line. The structure and size of the scan passage 310 can be adjusted according to the maximum outer dimension of the scanned object 340 to ensure effective matching of the imaging region and the scanned object.

[0085] The light source 320 can include a plurality of distributed light sources arranged around the periphery of the scan passage 310. For example, the plurality of distributed light sources is M distributed light sources, where M is a positive integer greater than or equal to 2.

[0086] The detector is configured to receive the rays emitted from the light source 320 and penetrating the scanned object 340. The detector can be a linear array or a planar array structure, and the specific structure can be selected according to application requirements, for example, a planar array flat panel detector can be used in security checks. The detector is configured to collect ray intensity data penetrating in different directions and with different energies, which is subsequently transmitted to an image reconstruction module for multi-angle fusion and imaging. Figure 3E The detector 330 and the light source 320 can be arranged in a relative structure.

[0087] Referring to Figures 3A-3F The distributed light source can include a plurality of target points and be arranged in a dot array around the peripheral region of the scan passage 310. Each target point can be independently excited and emit rays, achieving emission control and switching in spatial position. For example, the distributed light source module can include four target points, each of which can be independently excited to emit a ray beam to different spatial positions of the scan region 311, as shown in FIG. 2A. Figures 3A-3F The 24 target points shown in FIG. 2B can correspond to 6 distributed light sources. For example, each distributed light source module can include eight target points, each of which can be independently excited to emit a ray beam to different spatial positions of the scan region 311, as shown in FIG. 2B. Figures 3A-3F The 24 target points shown in FIG. 2C can correspond to 3 distributed light sources.

[0088] Referring to Figures 3A-3FIn some exemplary embodiments, the distributed light source 320 comprises a first type of light source 321 and a second type of light source 322. The first type of light source 321 and the second type of light source 322 can be configured with a plurality of independently controlled target points. For example, the first type of light source 321 comprises N1 target points, and the second type of light source 322 comprises N2 target points, where N1 and N2 are both positive integers greater than or equal to 2. Each target point can be independently excited and controlled with an independent voltage, and the values of N1 and N2 can be selected according to the size of the scanning region and the required resolution. For example, N1 and N2 can be selected as 4, 8 or more, respectively, to ensure fine and uniform coverage of each side.

[0089] Further, to ensure effective coverage and complete imaging of each side of the scanning region, the spatial arrangement length of the target point array of the first type of light source and / or the second type of light source should be at least able to cover the length of any side of the scanning region. That is, the end points of the target point array should be beyond or aligned with the boundary of the scanning region 311 in spatial layout, to avoid dead angles or blank areas in ray projection, thereby ensuring the overall structural information of the scanned object to be fully acquired.

[0090] Specifically, referring to Figure 3F To ensure the continuity of ray coverage and the integrity of image reconstruction of the scanning region 311 in multiple side directions, the target point array (including the point array composed of the first type of light source 321 and / or the second type of light source 322) arranged on each side should have a spatial arrangement length that is at least equal to the boundary length of the scanning region 311, and preferably should also be appropriately longer to avoid imaging dead angles. For example, when the heights of the left and right sides of the scanning region 311 are H meters and the length of the bottom side is W meters, the lengths of the target point arrays arranged vertically on the left and right sides should be at least H, and the length of the target point array on the bottom side should be at least W.

[0091] Referring to Figure 3A In preferred embodiments, a few more target point units can be added at each end as redundancy to adapt to the structural offset or size slightly exceeding the boundary of the scanned object.

[0092] Continuing to refer to Figure 3AThe attenuation of the first ray L1 by the scanned object along the extension direction of the first ray path (e.g., the extension direction of the path where the first ray L1 is located) can be different from the attenuation of the second ray L2 by the scanned object along the extension direction of the second ray path (e.g., the extension direction of the path where the first ray L2 is located), which can be caused by various reasons such as different sizes, different distribution densities, different degrees of attenuation of internal objects, and the like of the scanned object in different directions. For example, the scanned object has a larger geometric size in the first ray path direction and a smaller size in the second ray path direction. For example, a horizontally placed luggage has a larger horizontal length than a vertical height, resulting in a longer horizontal ray path and stronger attenuation. For example, the density distribution of the scanned object in different directions is different, such as being filled with high-density metals, ceramics, or battery packs in a certain direction, and being mainly low-density materials such as clothes, foams, and the like in another direction, which will directly cause the attenuation of the same energy ray to be significantly different when penetrating in different directions. For example, the scanned object can include multiple local superposition structures, cavities, or layers in a certain direction, thereby causing the ray path in this direction to be more complex and more prone to scattering and absorption; and the structure is more uniform in another direction, and the attenuation is smaller. By spatially optimizing and arranging the first light source and the second light source according to the attenuation characteristics of the detected object in each direction, the overall radiation dose and energy loss of the system can be significantly reduced while ensuring the integrity of the image.

[0093] According to an embodiment of the present disclosure, by spatially optimizing and arranging the first light source 321 and the second light source 322 according to the structural characteristics and attenuation path of the scanned object, the system can realize multi-dimensional collaborative imaging. For example, if there is a known high-attenuation risk in a certain direction, the first light source 321 is arranged in this area to enhance the penetration ability; and the second light source 322 is preferentially deployed in other directions to improve efficiency and control the overall energy consumption of the system.

[0094] It should be noted that the embodiments of the present disclosure do not limit the distributed light source to only two types. In actual applications, the distributed light source can also be refined into three types, four types, or even more types of energy levels according to the complexity of the specific imaging task. Different types of light sources can use different target structures, different voltage control strategies, or different emission mechanisms (such as a combination of pulse and continuous) to adapt to various application scenarios.

[0095] Further, the "first light source" and "second light source" in the embodiments are not limited to two physically completely different device modules. In some embodiments, multiple targets in the same light source module can also support high-low voltage switching, thereby constituting different types of emission units at the logical level. In addition, the classification is not limited to a fixed layout, but can also be dynamically adjusted by software strategy to realize the reconfiguration capability based on task changes.

[0096] The distributed light source arrangement in the embodiments of the present disclosure is not limited to ring, matrix or specific angle symmetrical layout, and can also adopt non-uniform, asymmetric or customized arrangement optimized for specific structures. For example, in a security inspection system, an energy enhancement layout of lower density on the top and higher density on the bottom can be adopted, and in industrial defect detection, path projection simulation can be combined with a model to pre-configure an optimal energy distribution scheme.

[0097] With reference to Figure 3A , the scanning area 311 can be divided into multiple sides, such as a first side 3111, a second side 3112 and a third side 3113, as viewed along the extension direction of the scanning channel 310. The first side 3111 and the second side 3112 are adjacently arranged, for example, as the left side and the lower side of the scanning area 311, respectively, and the first side 3111 and the third side 3113 are oppositely arranged, for example, as the upper and lower sides or the left and right sides.

[0098] With reference to Figure 3A , the first side 3111 is provided with a first type of light source 321 for emitting high-energy first rays L1 to penetrate and collect the region of high attenuation direction in the scanned object; and the second side 3112 is provided with a second type of light source 322 for emitting low-energy second rays L2 to image and supplement the low-attenuation region in the scanned object.

[0099] In some example embodiments, the same side of the scanning area 311 is provided with both the first type of light source 321 and the second type of light source 322. For example, a target point array of different energies can be combined on the same side of the scanning area 311 to form a same-direction multi-energy ray beam.

[0100] Correspondingly, the detector 330 can be arranged on multiple sides of the scanning area, specifically including at least two of the first side 3111, the second side 3112 and the third side 3113. For example, the detector 330 is arranged on the first side 3111 and the third side 3113, corresponding to the left-right or front-back opposite arrangement positions of the scanning channel, to form a shooting structure with the distributed light source. For example, the detector is arranged on the second side 3112 and the third side 3113, for example, located at the bottom and the side of the scanning channel, suitable for the configuration scenario of the distributed light source emitting from the top or the oblique side. For example, the detector 330 can be arranged on all three sides (refer to Figure 3E ), combined with the asymmetric energy configuration and multi-path emission strategy of the distributed light source, to realize multi-angle and multi-dimensional composite imaging.

[0101] In the embodiments of the present disclosure, the arrangement of the detectors can be flexibly configured according to the actual light source arrangement, spatial structure, scanned object characteristics and imaging resolution requirements; the multiple detector modules can be uniformly controlled or independently acquired, and support on-demand synchronous or asynchronous data transmission and fusion processing. In addition, the detectors can also be configured with different detection sensitivity, resolution or dynamic range, to meet the differentiated design requirements of different directions of imaging.

[0102] It should be noted that the "first side", "second side" and "third side" in the embodiments of the present disclosure are only examples and are not limited to the absolute physical up, down, left and right relationships, and their division manner can be flexibly defined according to the system installation direction, channel arrangement form and the in-out path of the scanned object. At the same time, the arrangement of different types of light sources can also be adjusted or combined according to task requirements, for example, mixed light sources are arranged on multiple sides to improve the overall flexibility and energy scheduling capability of the system.

[0103] Referring to Figures 3A-3F The first type of light source 321 and the second type of light source 322 can be flexibly arranged on multiple sides of the scanning area 311 according to the specific shape and structural characteristics of the scanned object.

[0104] In some example embodiments, the first type of light source 321 and the second type of light source 322 can be arranged on different sides of the scanning area 311 to form a semi-closed structure around the scanning area 311. The semi-closed structure here refers to that the light sources are arranged in a partially open manner around the outside of the scanning channel to form an incomplete closed surrounding structure similar to "U-shaped" or "C-shaped", so as to smoothly pass through the scanning channel for the scanned object, while meeting the projection requirements of multiple directions.

[0105] Referring to Figure 3A When the width of the scanned object is significantly greater than the height (for example, flat luggage, wide containers), the system can mainly deploy the first type of light source 321 with higher energy on the opposite sides (for example, the first side 3111 and the third side 3113) of the scanning area 311 to ensure effective penetration of the relatively thick structure in the horizontal direction; and the second type of light source 322 with lower energy is configured on the bottom side (for example, the second side 3112) to adapt to the relatively thin or low-density area, thereby avoiding unnecessary high-energy radiation and achieving effective control of the radiation dose.

[0106] Referring to Figure 3BWhen the height of the scanned object is greater than the width (for example, a vertically placed package or container), the system can arrange two types of light sources 322 on the opposite sides of the scanning area 311 (for example, the first side 3111 and the third side 3113) so that the opposite homogeneous and weakly attenuated areas achieve efficient penetration of low-energy rays, and a type 1 light source 321 is arranged on the bottom side (for example, the second side 3112) to provide necessary penetration enhancement for the locally existing high-attenuation area.

[0107] Referring to Figure 3C For a scanned object with complex structure or diversified internal components, a combination of multiple energy levels of light sources can also be simultaneously arranged on the same side (for example, the first side 3111 or the second side 3112) to form a multi-energy composite ray beam, so that rich penetration information and differentiated data can be obtained in one scanning process, facilitating subsequent multi-spectrum reconstruction, material separation and identification, and advanced data analysis.

[0108] In this embodiment, the two types of light sources 322 can include a first two types of sub-light sources 3221 and a second two types of sub-light sources 3222.

[0109] Exemplarily, the type 1 light source 321 and the first two types of sub-light sources 3221 can be commonly arranged on the first side 3111 and the third side 3113; and the second two types of sub-light sources 3222 can be separately arranged on the second side 3112. This arrangement is suitable for a case where the scanned object has high-density structure areas and low-density structure areas mixed on the first side 3111 and the third side 3113 at the same time, for example, a horizontally placed device or package. In this layout, the type 1 light source 321 can effectively penetrate the high-density structure, and the first two types of sub-light sources 3221 are used for lateral supplementary rays to reduce the radiation dose of the local area. The second two types of sub-light sources 3222 arranged on the second side 3112 are used for comprehensive coverage of the bottom or other low-density areas, further optimizing the overall energy distribution and radiation dose control.

[0110] Exemplarily, the type 1 light source 321 and the first two types of sub-light sources 3221 can be commonly arranged on the second side 3112, and the second two types of sub-light sources 3222 are arranged on the first side 3111 and the third side 3113. This arrangement is suitable for a case where the scanned object has relatively complex high-attenuation and low-attenuation mixed areas on the bottom or one side, for example, a device or package containing a high-density base combined with a lightweight structure main body. Through the combined arrangement of the type 1 light source 321 and the first two types of sub-light sources 3221 on the second side 3112, energy differentiation projection in the bottom direction can be realized to improve the recognition ability of the structure details in this direction. At the same time, the second two types of sub-light sources 3222 arranged on the first side 3111 and the third side 3113 can achieve efficient coverage in the low-attenuation area, further reducing unnecessary radiation dose and improving scanning efficiency.

[0111] It should be noted that the arrangement of the light sources in the embodiments of the present disclosure is not limited to the specific cases shown in the above schematic diagrams. In actual applications, the distribution positions, quantities and relative proportions of the first type of light sources and the second type of light sources can be flexibly adjusted according to the morphological characteristics and attenuation characteristics of the scanned object. In addition, a plurality of light sources with different energy levels can be arranged on the same side to achieve more precise spatial energy adaptation and better imaging performance. In addition, for specific task requirements, the spatial layout of high-energy and low-energy light sources can also be combined or dynamically adjusted to further improve the applicability and imaging flexibility of the system.

[0112] Figure 4A A schematic diagram of the arrangement of the spatial positions of the first type of light sources and the second type of light sources is shown. Figure 4B A schematic diagram of the arrangement of the spatial positions of the first type of light sources and the second type of light sources is shown.

[0113] In combination with reference to Figures 4A-4B To achieve more flexible scanning layout and adapt to a wider range of detection requirements, the spatial positions of the first type of light sources 321 and the second type of light sources 322 can also be arranged in different planes relative to the conveying direction of the scanned object.

[0114] In combination with reference to Figure 4A The first type of light sources 321 and the second type of light sources 322 can be arranged together in a plane Z1 perpendicular to the conveying direction. That is, all distributed light sources are arranged in a cross-sectional plane perpendicular to the conveying path of the scanned object, thereby providing complete projection coverage in the cross-sectional direction of the scanned object when it passes through the scanning area. This vertical cross-sectional layout is suitable for scenarios that require fast static scanning, such as high-speed conveyor belt inspection devices for luggage and cargo at airports or stations, which can quickly obtain multi-angle ray projection data in the cross-sectional direction of the scanned object and improve the recognition ability and penetration performance of complex object structures through the combination of high-energy and low-energy light sources.

[0115] In combination with reference to Figure 4BThe first type of light source 321 and the second type of light source 322 can be arranged in multiple parallel planes Z2, Z3... Zn perpendicular to the conveying direction of the scanned object, so that the scanned object can be sequentially irradiated by multiple groups of light sources from different cross-sectional directions during movement along the conveying path. For example, the first type of light source 321 and the second type of light source 322 can be arranged in two parallel planes Z2, Z3, respectively. The second type of light source in the Z2 plane provides low-energy X-ray projection to penetrate relatively thin or low-density areas, while the first type of light source in the Z3 plane provides high-energy X-ray to penetrate deeper areas. According to embodiments of the present disclosure, during the movement of the scanned object through the entire scanning area, the system can obtain composite image data at multiple cross-sectional directions and different energy levels, thereby improving the completeness and discrimination ability of the imaging information. This layout is suitable for scenarios with higher imaging quality requirements, such as high-precision foreign object detection and material classification of goods with high-density, multi-layer nested or shielding structures, etc.

[0116] It should be noted that embodiments of the present disclosure do not limit the angles of the first plane or the second plane described above to be fixed or limited to the vertical and inclined cases described above. In actual applications, the angle of the scanning plane can be adjusted or optimized according to specific engineering requirements, the type of the scanned object, the conveying path, spatial installation constraints, or image reconstruction requirements. In addition, the combination of the first type of light source and the second type of light source is not limited to a single plane, and can be further configured in multiple planes to meet more complex and comprehensive detection requirements.

[0117] In some example embodiments, the spatial arrangement of the first type of light source 321 and the second type of light source 322 can be further optimized based on statistical attenuation path data of the scanned object in the target CT imaging scenario.

[0118] Specifically, in certain application scenarios, such as airport security, industrial non-destructive testing, intelligent logistics sorting, etc., the scanned objects exhibit relatively stable statistical characteristics in terms of structural morphology, material composition, typical placement posture, etc. For example, in aviation baggage security inspection, most luggage items are placed horizontally, with the lower region usually being high-density shoes or metal appliances, and the upper region being low-density clothing or plastic packaging; in industrial online testing, different types of components have fixed high-attenuation directions in the core region or edge structure during transmission.

[0119] Preferably, based on statistical analysis of a large amount of historical scanning data of the above typical scenarios, an average attenuation path distribution model of the scanned object in each direction can be obtained, and then a probabilistic spatial identification of the "high attenuation area", "low attenuation area" and "change area" is formed. On this basis, the system can preferentially arrange a class of light sources (high-energy light sources) in spatial positions where statistically there is a higher possibility of high attenuation path, such as the lower side or the diagonal direction; and arrange a second class of light sources (low-energy light sources) in directions with high penetration margin and low attenuation risk, such as the top, both sides or the back, etc.

[0120] The statistical attenuation path model can be predefined by the manufacturer before the system is shipped according to the application scenario, or it can be dynamically updated and optimized by continuously accumulating scanning sample data during the operation of the device. The system can also cooperate with auxiliary sensing devices (such as profile detectors) and machine learning models to quickly classify and match the objects entering the scanning area, so as to load the optimal light source arrangement strategy template corresponding to them, and realize structural adaptive scanning. In some exemplary embodiments, in order to better realize the energy control of the light source and improve the operation stability and penetration efficiency of the system, the voltage configuration strategy of the first class of light sources 321 and the second class of light sources 322 can adopt different adjustment methods.

[0121] Exemplarily, the working voltage of the second class of light sources 322 can be stabilized by using a fixed voltage M2. The selection of the fixed voltage M2 can be based on the penetration requirement of the common low-attenuation structure of the object to be scanned, to provide a lower but stable penetration ability. The fixed voltage setting can significantly simplify the power supply configuration, improve the stability of the device and reduce the complexity of the system.

[0122] Exemplarily, the first class of light sources 321 can adopt a more flexible voltage configuration method, for example, the working voltage is dynamically or statically selected based on the target adjustment interval, to adapt to different degrees of high-attenuation structure or high-density material that may be encountered during the scanning process. Specifically, the lower limit of the target adjustment interval of the first class of light sources 321 can be set as the fixed voltage M2 of the second class of light sources 322, to ensure that the first class of light sources 321 at least has the basic penetration ability of the second class of light sources 322 at the lowest voltage level; and the upper limit of the target adjustment interval is set to a higher voltage M1, to ensure that the first class of light sources 321 can provide high-energy rays significantly higher than the basic level, to meet the effective penetration requirements of metal parts, thick-walled structures, composite materials and other high-density areas.

[0123] Preferably, the voltage difference between the upper limit M1 and the lower limit M2 of the target regulation interval is at least greater than or equal to 20 kV, for example, can be 20 kV, 40 kV. By ensuring a wide enough voltage regulation range, the system can effectively configure the precise energy when facing different scanning scenarios and detected objects, ensuring sufficient penetration capability for high-attenuation structures, while avoiding radiation redundancy and energy waste caused by excessive voltage in low-attenuation areas.

[0124] Figure 5A A schematic diagram of a static CT imaging system including a control module is shown schematically. Figure 5B A schematic diagram showing that a distributed light source can be arranged along the L beam faces of the conveying path of the scanned object is shown schematically.

[0125] In embodiments of the present disclosure, the regulation mode of the voltage of the first type of light source 321 can include manual preset, automatic selection based on tasks, real-time feedback regulation, or scanning mode pre-configuration, and the like, thereby further improving the flexibility and adaptability of the system. For example, in a security inspection system, the operator can preset different voltage schemes according to the specific type of the scanned object, and the system automatically executes; and in industrial online detection, the voltage of the first type of light source can be automatically adjusted in real time based on the feedback of the front-end sensor to adapt to the detection needs of different batches or specifications of articles on the assembly line.

[0126] For example, the system includes a control interface for the operator to manually set the operating voltage of the first type of light source. The operator can manually input the voltage value or select the preset gear through the control interface or external operating equipment based on the experience judgment of the properties of the scanned object (such as object type, possible structure density, material composition, etc.), thereby configuring the voltage parameters of the first type of light source.

[0127] For example, referring to Figure 5A , the system includes an auxiliary perception device and a controller 50. For example, the auxiliary perception device can be a lidar, an infrared detector, a structured light module, or a stereo vision camera, etc. device, which is used to obtain the contour information (such as volume, contour projection, height gradient, etc.) of the scanned object before it enters the scanning area. The controller 50 determines the possible high-attenuation area or abnormal structure distribution of the object based on the contour information, and automatically selects the appropriate operating voltage value of the first type of light source in combination with the experience model or mapping rule, thereby realizing the feedforward dynamic configuration of voltage regulation.

[0128] For example, referring to Figure 5BThe distributed light sources can be arranged on L beam faces along a conveying path of the scanned object, L being a positive integer, representing a plurality of continuous projection planes (or view angle positions) arranged on the scanning path. A type of light source and / or a type II light source are arranged on each beam face to provide multi-angle and multi-section ray coverage when the scanned object passes through the system. In this embodiment, the operating voltage of the type I light source on each beam face can adopt a hierarchical control strategy: the voltage of the type I light source on the first beam face (i.e. the front projection plane when the scanned object first enters the system) is fixed as the highest value M1 to ensure the maximum penetration capability of the system on the first visible section; the voltage of the type I light source on the second to Lth beam faces is set according to the degree of attenuation of the rays of the previous beam face. The system can determine whether the degree of attenuation is too high or too low according to the gray value, the change in penetration rate or the density of the reconstructed segment collected by the detector, and adjust the voltage setting of the next beam face accordingly to realize an adaptive adjustment strategy between the beam faces.

[0129] For example, when the first beam face feedback shows high attenuation, the system will keep or increase the voltage of the light source on the second beam face; if the detection result shows that the penetration difficulty is small, the voltage of the second beam face can be appropriately reduced, so as to reduce the overall energy consumption and thermal load of the system under the premise of ensuring the imaging clarity.

[0130] It should be noted that the above control mode can be used alone or in combination as needed, and the system can be switched between manual setting and automatic adjustment to meet the actual operation needs of different complexity tasks. At the same time, the number, distribution distance and voltage adjustment step strategy of the L beam faces are not limited, and can be flexibly designed according to the actual detection object size, conveying speed and target imaging accuracy.

[0131] In the embodiments of the present disclosure, in order to solve the problem of poor consistency of projection data caused by different energy level rays, the static CT imaging system further comprises a controller for processing and fusing the projection data collected by the type I light source and the type II light source, to realize high-quality image reconstruction.

[0132] Figure 6 A flowchart of a static CT imaging method according to an embodiment of the present disclosure is schematically shown.

[0133] As shown in Figure 6 , the static CT imaging method comprises operations S610-S640.

[0134] In operation S610, first projection data is obtained in response to the first rays passing through the scanned object in the scanning region along the first ray path.

[0135] In operation S620, second projection data is obtained in response to the second rays passing through the scanned object in the scanning region along the second ray path.

[0136] In operation S630, data processing is performed based on the first projection data and the second projection data.

[0137] In some example embodiments, the data processing based on the first projection data and the second projection data comprises: correcting the first projection data by using a mapping relationship to obtain corrected first projection data, the mapping relationship being used to map the first projection data into a range in which the second projection data is located.

[0138] Figure 7 A flowchart of a method for data processing according to an embodiment of the present disclosure is schematically shown.

[0139] As shown in the flowchart, the method for data processing comprises operations S710-S790. Figure 7

[0140] In operation S710, third projection data and fourth projection data obtained by scanning at least one reference material under a preset energy condition by using the first light source and the second light source are acquired.

[0141] In operation S720, an initial mapping relationship of the first light source and the second light source is constructed based on the third projection data and the fourth projection data, wherein the initial mapping relationship is expressed as mapping the third projection data into a range of the fourth projection data.

[0142] In an embodiment of the present disclosure, a reference material common or representative in structure in a target application scenario can be selected and scanned by using the first light source and the second light source respectively. To ensure the breadth and accuracy of modeling, the reference material is prepared as test samples with different thicknesses h in the experiment, and the first light source is used to scan the test samples one by one under multiple representative voltage settings K (K belongs to a target adjustment interval), while the scanning results of the second light source under a fixed voltage M2 are acquired synchronously.

[0143] Through the above experimental process, the system can obtain the third projection data and the fourth projection data of the first light source and the second light source under different thickness and voltage combinations respectively, and establish a functional mapping relationship between the first light source projection value and the second light source projection value The mapping relationship can be expressed as:

[0144] (1)

[0145] The function f k ​The initial energy response mapping relationship is used for subsequent data correction of the system. The essence is to convert the projection data of a class of light sources collected under any thickness h and voltage K conditions into data representation aligned with the response results of the second class of light sources in the numerical domain, thereby providing a unified reference benchmark for subsequent multi-energy data fusion and image reconstruction.

[0146] In other embodiments, the initial mapping relationship can also be represented as mapping the fourth projection data into the range of the third projection data. Similarly, a reference material can be selected, the voltage condition of the second class of light sources can be adjusted, and the voltage setting K1 of the first class of light sources is fixed, and the system is scanned for test samples of different thickness h. Thus, the system can establish a functional mapping relationship between the projection value of the first class of light sources and the projection value of the second class of light sources The mapping relationship can be represented as:

[0147] (2)

[0148] In other embodiments, the initial mapping relationship is represented as mapping the fourth projection data and the third projection data into the range of the target projection data obtained in advance. Similarly, the system can construct a general normalization mapping mechanism based on the original projection data of the first class of light sources and the second class of light sources scanned on the same reference material under different imaging parameters by comparing and analyzing with the known target projection data The target projection data can come from a standard high-precision imaging device, or a high-confidence reference image data generated by combining multi-modal data fusion and inversion algorithm. The mapping relationship can be represented as:

[0149] (3)

[0150] Preferably, the reference material includes at least two or more, and has differences in density, atomic number, attenuation coefficient, etc., and can cover the typical physical properties of common objects in the target application of the system (such as metal materials, polymer materials and organic materials). Each reference material can be prepared as samples of several different thicknesses, and scanned under multiple voltage settings K of the first class of light sources and fixed voltage M2 of the second class of light sources to obtain corresponding third projection data and fourth projection data.

[0151] In order to construct a more general initial mapping relationship, the system no longer directly uses single material data to establish a simple function, but introduces a target optimization function for mapping modeling. The optimization target can be represented as:

[0152] (4)

[0153] where m is the number of the reference material, R(fk ) is a regularization term, for example, L2 norm can be selected to guarantee smoothness, or Total Variation (TV) is selected to enhance the stability and noise resistance of the model.

[0154] Similarly, in the embodiment where the initial mapping relationship can also be represented as mapping the fourth projection data into the range of the third projection data, the optimization objective can be represented as:

[0155] (5)

[0156] Similarly, in the embodiment where the initial mapping relationship is represented as mapping the fourth projection data and the third projection data into the range of the pre-acquired target projection data, the optimization objective can be represented as:

[0157] (6)

[0158] By solving the above objective function, the initial mapping relationship considering the attenuation characteristics of multiple materials can be obtained, which is significantly better than the simple fitting model under a single material, and can more effectively cope with the situation of complex structure and multiple materials of the actual scanning object.

[0159] In operation S730, the first projection data is initially corrected based on the initial mapping relationship to obtain the first projection data after initial correction. That is, the first projection data can be mapped into the second light source data domain according to the statistical energy response through the function of the initial mapping relationship, so as to eliminate the intensity drift and gray deviation caused by the energy spectrum difference, thereby obtaining the first projection data after initial correction.

[0160] Similarly, in the embodiment where the initial mapping relationship can also be represented as mapping the fourth projection data into the range of the third projection data, the second projection data can be initially corrected based on the initial mapping relationship to obtain the second projection data after initial correction.

[0161] Similarly, in the embodiment where the initial mapping relationship is represented as mapping the fourth projection data and the third projection data into the range of the pre-acquired target projection data, the first projection data and the second projection data can be initially corrected based on the initial mapping relationship to obtain the first projection data after initial correction and the second projection data after initial correction.

[0162] In operation S740, an initial reconstruction image is constructed based on the first projection data after initial correction and the second projection data.

[0163] Similarly, in the embodiment where the initial mapping relationship can also be represented as mapping the fourth projection data into the range of the third projection data, the initial reconstruction image can be constructed based on the second projection data after initial correction and the first projection data.

[0164] Similarly, in the embodiment where the initial mapping relationship is represented as mapping the fourth projection data and the third projection data into the range where the pre-acquired target projection data is located, the initial reconstructed image can be constructed based on the second projection data after the first correction and the first projection data after the first correction.

[0165] For example, the initial image can be constructed based on filtered back projection (FBP), algebraic reconstruction technique (ART, SART), or statistical iterative reconstruction method (SIR, MLEM), and the selection of the specific reconstruction algorithm can be flexibly configured according to the density of the acquisition path, the reconstruction efficiency requirement, and the image resolution target.

[0166] The initial reconstructed image can serve as an important data basis for constructing a theoretical attenuation path and optimizing a mapping relationship in a subsequent step. By analyzing the spatial distribution and density estimation of voxels in the image, the physical property parameters on each ray path can be further back-calculated for performing subsequent theoretical modeling and error correction iteration processes.

[0167] It should be noted that the initial reconstructed image is used as an intermediate result, and its gray value does not necessarily directly correspond to the true linear attenuation coefficient or material density, and further correction through multiple rounds of subsequent steps is still needed to further improve imaging consistency and physical accuracy.

[0168] At operation S750, a theoretical attenuation value is calculated based on the initial reconstructed image, and the initial mapping relationship is updated based on the theoretical attenuation value to obtain an updated mapping relationship.

[0169] After the initial image reconstruction is completed, an initial reconstructed image reflecting the density distribution and structural composition of the scanned object is obtained. Although the initial reconstructed image is generated based on the fused projection data, there is still a certain energy response deviation due to the fact that the initial mapping relationship is only derived from the reference material or statistical fitting, especially in the multi-material and multi-density sections, the projection residual error is more significant.

[0170] Therefore, first, the gray value of each voxel position in the initial reconstructed image can be used in combination with a pre-set material library, a density / attenuation coefficient mapping table, or a substance classification result based on image segmentation to assign each position r in the reconstructed image to its possible corresponding physical property parameters, including: material type (such as metal, organic matter, polymer, etc.), density or effective atomic number, and linear attenuation coefficient under the corresponding energy spectrum

[0171] Next, for each ray trajectory L, the energy integration modeling process can be performed according to the aforementioned image-recovered substance attribute model to calculate the theoretical attenuation values corresponding to the first and second light sources, respectively.

[0172] (7)

[0173] wherein, is the optical function spectrum, is the detector response spectrum, is the linear attenuation coefficient of the substance at position r for the ray at energy E, dl denotes the integration with respect to the ray path, and dE denotes the integration with respect to the energy. The theoretical attenuation values on the ray path of a type of light source are calculated using the energy spectrum of K and M2 according to the above formula, which are and respectively. The new mapping relationship is established using the methods in , and S1. .

[0174] Through the above integration, the system can obtain the ideal attenuation performance of each path under the theoretical condition, and compare and analyze the actual value in the original projection data. The difference value reflects the deviation degree of the original mapping relationship under the current physical condition, which can be used to guide the update of the new mapping function.

[0175] Exemplarily, the update strategy can adopt the following ways: based on residual minimization regression, adjusting the mapping function parameters to make the output value closer to the current theoretical attenuation; introducing a weighted correction factor, multiplying the initial mapping output by a path-related scale factor or offset term; optimizing the new mapping by minimizing the objective function.

[0176] In operation S760, the first corrected projection data is corrected again based on the updated mapping relationship to obtain the second corrected first projection data. The second correction will be based on a mapping function that is more true and closer to the actual physical attenuation behavior, effectively compensating for the previously existing energy response difference and path response error, making the data more numerically aligned.

[0177] Similarly, in the embodiment in which the initial mapping relationship can also be represented as mapping the fourth projection data into the range of the third projection data, the second corrected second projection data can be obtained by correcting the first corrected second projection data again based on the updated mapping relationship.

[0178] Similarly, in the embodiment in which the initial mapping relationship is represented as mapping the fourth projection data and the third projection data into the range of the pre-acquired target projection data, the second corrected first projection data and the second corrected second projection data can be obtained by correcting the first corrected first projection data and the first corrected second projection data again based on the updated mapping relationship.

[0179] In operation S770, it is determined whether a preset iteration stop condition is reached.

[0180] At operation S780, the process of constructing the reconstructed image, the process of updating the mapping relationship, and the process of correcting the first projection data are repeated until a preset iteration stopping condition is reached, and the first projection data after multiple corrections is obtained.

[0181] That is, each iteration includes: using the current correction result and the two-class light source data to perform image reconstruction to generate an updated image result; calculating a theoretical attenuation value based on the new image to reevaluate the accuracy of the current mapping relationship; if the preset iteration stopping condition is not reached, the mapping function is continuously optimized and used for the next round of correction to obtain updated projection data.

[0182] In some example embodiments, the iteration stopping condition can be: the structural similarity (SSIM) of the corrected image reaches stability; the number of iterations reaches an upper limit (such as 5 rounds, 10 rounds); the change between two consecutive iterations of the mapping function is lower than a threshold; the projection data residual is lower than a minimum tolerance error, and the like.

[0183] Similarly, in the embodiment in which the initial mapping relationship can also be represented as mapping the fourth projection data into the range of the third projection data, the process of constructing the reconstructed image, the process of updating the mapping relationship, and the process of correcting the second projection data can be repeated until a preset iteration stopping condition is reached, and the second projection data after multiple corrections is obtained.

[0184] Similarly, in the embodiment in which the initial mapping relationship is represented as mapping the fourth projection data and the third projection data into the range of the target projection data obtained in advance, the process of constructing the reconstructed image, the process of updating the mapping relationship, and the process of correcting the first projection data and the second projection data can be repeated until a preset iteration stopping condition is reached, and the first projection data after multiple corrections and the second projection data after multiple corrections are obtained.

[0185] Referring back to Figure 6 At operation S640, an image is reconstructed based on the processed projection data to obtain a target reconstructed image.

[0186] Exemplarily, at operation S790, a target reconstructed image is constructed based on the first projection data after multiple corrections and the second projection data. This image combines the penetration ability of high-energy rays and the structural detail performance of low-energy rays, and through multiple rounds of mapping updates and data corrections, effectively reduces the problems of artifacts, density deviation, and boundary blur, and has higher imaging credibility and analysis value.

[0187] Similarly, in the embodiment in which the initial mapping relationship can also be represented as mapping the fourth projection data into the range of the third projection data, a target reconstructed image can be constructed based on the second projection data after multiple corrections and the first projection data.

[0188] Similarly, in the embodiment where the initial mapping relationship is represented as mapping the fourth projection data and the third projection data into the range where the pre-acquired target projection data is located, the target reconstructed image can be constructed based on the multiple-corrected first projection data and the multiple-corrected second projection data. It should be noted that the above iterative process can be integrated in the image reconstruction engine to support parallel acceleration calculation, data cache optimization and intermediate state monitoring. The iterative adjustment of the mapping function can also be based on different forms such as analytical function, interpolation function, deep learning model or empirical lookup table, which has high adaptability and scalability.

[0189] The above describes the embodiments of the present disclosure. However, these embodiments are only for illustrative purposes, and are not intended to limit the scope of the present disclosure. Although each embodiment is described above separately, this does not mean that the measures in each embodiment cannot be used advantageously in combination. Without departing from the scope of the present disclosure, those skilled in the art can make various alternatives and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A static CT imaging system, characterized by, The application relates to a static CT imaging system, comprising: a scanning channel for conveying a scanned object through a scanning area of the static CT imaging system; a plurality of distributed light sources, at least one of which comprises a plurality of target points configured to respectively emit rays; and a detector for detecting rays emitted from the plurality of distributed light sources and passing through the scanned object, wherein the plurality of distributed light sources comprises at least a first type of light source and a second type of light source, the target points of the first type of light source emit first rays with higher energy than the target points of the second type of light source emit second rays, the first rays pass through the scanned object in the scanning area along a first ray path, the second rays pass through the scanned object in the scanning area along a second ray path, and the attenuation of the first rays by the scanned object along the extension direction of the first ray path is different from the attenuation of the second rays by the scanned object along the extension direction of the second ray path.

2. The system of claim 1, wherein, The first type of light source is arranged on at least one side of the scanning area based on the shape of the scanned object, and the second type of light source is arranged on at least one side of the scanning area based on the shape of the scanned object; or The first type of light source is arranged on at least one side of the scanning area based on the statistical attenuation path of the scanned object in a target CT imaging scene, and the second type of light source is arranged on at least one side of the scanning area based on the statistical attenuation path of the scanned object in the target CT imaging scene.

3. The system of claim 2, wherein, Viewed along the extension direction of the scanning channel, the scanning area comprises at least a first side, a second side and a third side, the first side and the second side are adjacently arranged, the first side and the third side are oppositely arranged, one of the first type of light source and the second type of light source is arranged on the second side, and the other of the first type of light source and the second type of light source is arranged on at least one of the first side and the third side.

4. The system of claim 2, wherein, Viewed along the extension direction of the scanning channel, the scanning area comprises at least a first side, a second side and a third side, the first side and the second side are adjacently arranged, the first side and the third side are oppositely arranged, and the first type of light source and the second type of light source are arranged on the same side of the scanning area.

5. The system of claim 4, wherein, A light source combination comprising the first type of light source and the second type of light source is arranged on the first side, the second side and the third side, forming a semi-closed structure around the scanning area.

6. The system of claim 5, wherein, The first type of light source is arranged on the first side and the third side, and the second type of light source is arranged on the second side; or The second type of light source is arranged on the first side and the third side, and the first type of light source is arranged on the second side.

7. The system of claim 5, wherein, The second type of light source comprises a first second type of light source and a second second type of light source, the first type of light source and the first second type of light source are arranged on the first side and the third side, and the second second type of light source is arranged on the second side; or The second type of light source comprises a first second type of light source and a second second type of light source, the first type of light source and the first second type of light source are arranged on the second side, and the second second type of light source is arranged on the first side and the third side.

8. The system of any one of claims 1-3, 5-7, wherein, The first type of light source and the second type of light source are arranged in a plane perpendicular to the conveying direction of the scanned object; or The first type of light source and the second type of light source are arranged in multiple parallel planes perpendicular to the conveying direction of the scanned object.

9. The system of any of claims 1-3, 5-7, wherein, The operating voltage of the second type of light source is a fixed voltage M2, and the operating voltage of the first type of light source is selected based on a target adjustment interval.

10. The system of claim 9, wherein, The lower limit of the target adjustment interval is M2, the upper limit of the target adjustment interval is M1, and the difference between M1 and M2 is greater than or equal to 20kV.

11. The system of any of claims 2-3, 5-7, 10, wherein, The first type of light source includes N1 target points, and the second type of light source includes N2 target points, both N1 and N2 are positive integers greater than or equal to 2.

12. The system of claim 11, wherein, In the extension direction of the scanning channel, the arrangement length of the target points in the first type of light source and / or the second type of light source covers at least the length on either side of the scanning area.

13. The system of claim 10, wherein, The static CT imaging system further comprises a control interface for an operator to set the operating voltage of the first type of light source according to the attributes of the scanned object.

14. The system of claim 10, wherein, The static CT imaging system further comprises an auxiliary sensing device and a controller, which sets the operating voltage of the first type of light source based on the contour information of the scanned object obtained by the auxiliary sensing device.

15. The system of claim 10, wherein, The distributed light source is distributed in L beam planes along the conveying path of the scanned object, L is a positive integer greater than or equal to 2, wherein the operating voltage of the distributed light source on the first beam plane is set to M1, and the operating voltage of the distributed light source on the 2-L beam plane is set according to the degree of attenuation of the corresponding rays of the previous beam plane.

16. The system of any one of claims 1-3, 5-7, 10, wherein, The static CT imaging system further comprises a controller configured to: correct the first projection data obtained by scanning the first type of light source, and perform image reconstruction based on the corrected first projection data and the second projection data obtained by scanning the second type of light source, to obtain a target reconstruction image.

17. The system of any one of claims 2-3, 5-7, 10, wherein, The detector is arranged in at least two of the first side, the second side and the third side.

18. A method of static CT imaging, wherein, The static CT imaging method is used in a static CT imaging system, which comprises a scanning area, a plurality of distributed light sources and a detector, the plurality of distributed light sources at least include a first type of light source and a second type of light source, the energy of the first rays emitted by the target points of the first type of light source is higher than the energy of the second rays emitted by the target points of the second type of light source, and the static CT imaging method comprises: obtaining first projection data in response to the first rays passing through the scanned object in the scanning area along a first ray path; obtaining second projection data in response to the second rays passing through the scanned object in the scanning area along a second ray path; performing data processing based on the first projection data and the second projection data; and performing image reconstruction based on the processed projection data to obtain a target reconstruction image. The data processing based on the first projection data and the second projection data comprises: correcting at least one of the first projection data and the second projection data by using a mapping relationship, to obtain corrected first projection data and / or corrected second projection data, the mapping relationship being used for: mapping the first projection data into a range in which the second projection data is located, mapping the second projection data into a range in which the first projection data is located, or mapping the first projection data and the second projection data into a range in which third projection data obtained in advance is located.

19. The method of claim 18, wherein, The data processing based on the first projection data and the second projection data comprises: obtaining third projection data and fourth projection data obtained by scanning at least one reference material under a preset energy condition by using the first light source and the second light source; constructing an initial mapping relationship of the first light source and the second light source based on the third projection data and the fourth projection data, wherein the initial mapping relationship is represented as mapping the third projection data into a range in which the fourth projection data is located; performing primary correction on the first projection data based on the initial mapping relationship, to obtain primary corrected first projection data; constructing an initial reconstruction image based on the primary corrected first projection data and the second projection data; calculating a theoretical attenuation value based on the initial reconstruction image, updating the initial mapping relationship based on the theoretical attenuation value, to obtain an updated mapping relationship; performing secondary correction on the primary corrected first projection data based on the updated mapping relationship, to obtain secondary corrected first projection data; and repeating the process of constructing a reconstruction image, the process of updating a mapping relationship, and the process of correcting first projection data, until a preset iteration stopping condition is reached, to obtain multiple times of corrected first projection data.

20. The method of claim 19, wherein, The image reconstruction based on the processed projection data comprises: constructing a target reconstruction image based on the multiple times of corrected first projection data and the second projection data.

21. The method of claim 18, wherein, The data processing based on the first projection data and the second projection data comprises: obtaining third projection data and fourth projection data obtained by scanning at least one reference material under a preset energy condition by using the first light source and the second light source; constructing an initial mapping relationship of the first light source and the second light source based on the third projection data and the fourth projection data, wherein the initial mapping relationship is represented as mapping the fourth projection data into a range in which the third projection data is located; performing primary correction on the second projection data based on the initial mapping relationship, to obtain primary corrected second projection data; constructing an initial reconstruction image based on the primary corrected second projection data and the first projection data; calculating a theoretical attenuation value based on the initial reconstruction image, updating the initial mapping relationship based on the theoretical attenuation value, to obtain an updated mapping relationship; correcting the second projection data based on the updated mapping relationship to obtain second corrected projection data; and repeating the process of constructing the reconstructed image, the process of updating the mapping relationship, and the process of correcting the second projection data until a preset iteration stopping condition is reached, to obtain multiple corrected second projection data.

22. The method of claim 21, wherein, The image reconstruction based on the processed projection data to obtain a target reconstructed image specifically includes: constructing a target reconstructed image based on the multiple corrected second projection data and the first projection data.

23. The method of claim 18, wherein, The data processing based on the first projection data and the second projection data specifically includes: obtaining third projection data and fourth projection data obtained by scanning at least one reference material under a preset energy condition by using the first light source and the second light source; constructing an initial mapping relationship of the first light source and the second light source based on the third projection data and the fourth projection data, wherein the initial mapping relationship is represented as mapping the fourth projection data and the third projection data into a range in which target projection data obtained in advance is located; performing initial correction on the first projection data and the second projection data based on the initial mapping relationship to obtain initial corrected first projection data and initial corrected second projection data; constructing an initial reconstructed image based on the initial corrected second projection data and the initial corrected first projection data; calculating a theoretical attenuation value based on the initial reconstructed image, updating the initial mapping relationship based on the theoretical attenuation value to obtain an updated mapping relationship; performing re-correction on the initial corrected first projection data and the initial corrected second projection data based on the updated mapping relationship to obtain re-correction first projection data and re-correction second projection data; and repeating the process of constructing the reconstructed image, the process of updating the mapping relationship, and the process of correcting the first projection data and the second projection data until a preset iteration stopping condition is reached, to obtain multiple corrected first projection data and multiple corrected second projection data.

24. The method of claim 23, wherein, The image reconstruction based on the processed projection data to obtain a target reconstructed image specifically includes: constructing a target reconstructed image based on the multiple corrected first projection data and the multiple corrected second projection data.

25. The method of claim 19 or 21 or 23, wherein, The third projection data and the fourth projection data obtained by scanning the at least one reference material specifically include: selecting at least one of the reference materials; scanning the reference materials of different thicknesses by using the first light source and the second light source to obtain the third projection data and the fourth projection data; and obtaining the initial mapping relationship based on the third projection data and the fourth projection data.

26. The method of claim 19, wherein, The reference materials include at least two kinds, and the constructing of the initial mapping relationship of the first light source and the second light source based on the third projection data and the fourth projection data includes obtaining the initial mapping relationship by using a target optimization function, and the target optimization function is represented as: Wherein, m is the number of reference material, h is the thickness of the substance, K is the voltage value set during the operation of a kind of light source, is the third projection data, is the fourth projection data, R(f k ) is a regular term constraint, f k represents the initial mapping relationship.

27. The method of claim 21, wherein, The reference materials include at least two kinds, and the constructing the initial mapping relationship of the first light source and the second light source based on the third projection data and the fourth projection data includes obtaining the initial mapping relationship by using a target optimization function, and the target optimization function is expressed as: Wherein, m is the number of reference material, h is the thickness of the substance, K is the voltage value set during the operation of a kind of light source, is the third projection data, is the fourth projection data, R(f k ) is a regular term constraint, f k represents the initial mapping relationship.

28. The method of claim 23, wherein, The reference materials include at least two kinds, and the constructing the initial mapping relationship of the first light source and the second light source based on the third projection data and the fourth projection data includes obtaining the initial mapping relationship by using a target optimization function, and the target optimization function is expressed as: Wherein, m is the number of reference material, h is the thickness of the substance, K is the voltage value set in the running process of a kind of light source, is the third projection data and the fourth projection data, is the target projection data, R(f k ) is a regular term constraint, f k represents the initial mapping relationship.

29. The method of any one of claims 19-28, wherein, The preset iteration stopping condition includes reaching a preset iteration number or a change difference of two reconstructed images reaching a preset threshold.

Images