Method for imaging to-be-measured object based on X-ray imaging system, X-ray imaging system and computing equipment

Abstract

The embodiment of the invention provides a method for imaging a to-be-detected object based on an X-ray imaging system, and the X-ray imaging system at least comprises a first X-ray imaging subsystem and a second X-ray imaging subsystem. A first direction of a first transmission path for transmitting the object to be detected in the first X-ray imaging subsystem is different from a second direction of a second transmission path for transmitting the object to be detected in the second X-ray imaging subsystem; the method comprises the following steps: controlling the to-be-detected object to pass through the first X-ray imaging subsystem along the first transmission path to obtain a first group of projection images for the to-be-detected object; changing the moving direction of the to-be-detected object to enable the to-be-detected object to pass through the second X-ray imaging subsystem along the second transmission path so as to obtain a second group of projection images aiming at the to-be-detected object; and obtaining a target image for the to-be-detected object at least based on the first group of projection images and the second group of projection images. By means of the method, the imaging angle range of the to-be-detected object in system detection can be increased, limited angle artifacts in the obtained target image are reduced, and the image quality of the target image is improved.

Description

Technical Field

[0001] The present application relates to the technical field of X-ray imaging, and in particular to a method for imaging an object to be measured based on an X-ray imaging system, a computing device, a computer-readable storage medium, and a computer program product. Background Art

[0002] X-ray imaging systems typically consist of two main parts: an X-ray source and a detector. The X-ray source is responsible for generating X-rays, while the detector is responsible for receiving the X-rays after they pass through the object under inspection and converting them into visual images, thereby reconstructing the internal structure information of the object under inspection. Currently, X-ray imaging systems have evolved from traditional single-source systems to multi-source systems to improve imaging efficiency and image quality. In order to obtain multi-angle projection images of the object under inspection, a common method is to use circular orbit imaging (i.e., the X-ray source and detector rotate around the object under inspection, or the X-ray source and detector are fixed while the object under inspection rotates). To date, non-circular orbit multi-source imaging has also been developed. However, the non-circular orbit multi-source imaging method still has shortcomings in terms of the imaging angle range, which can easily lead to limited-angle artifacts or information loss in the final image of the object under inspection. Summary of the Invention

[0003] An embodiment of the present application provides a method for imaging an object to be measured based on an X-ray imaging system, the X-ray imaging system comprising at least a first X-ray imaging subsystem and a second X-ray imaging subsystem, a first direction of a first transmission path for transmitting the object to be measured in the first X-ray imaging subsystem being different from a second direction of a second transmission path for transmitting the object to be measured in the second X-ray imaging subsystem, the method comprising: controlling the object to be measured to pass through the first X-ray imaging subsystem along the first transmission path to obtain a first set of projection images for the object to be measured; changing the moving direction of the object to be measured so that the object to be measured passes through the second X-ray imaging subsystem along the second transmission path to obtain a second set of projection images for the object to be measured; and obtaining a target image for the object to be measured based at least on the first set of projection images and the second set of projection images.

[0004] In some embodiments, the angle between the first direction and the second direction is a ratio of 180 degrees to N, where N represents the number of X-ray imaging subsystems included in the X-ray imaging system, and N is an integer greater than or equal to 2. For example, the first direction is perpendicular to the second direction.

[0005] In some embodiments, each X-ray imaging subsystem in the first X-ray imaging subsystem or the second X-ray imaging subsystem includes an X-ray source and a detector, the X-ray source includes a plurality of X-ray emission units, the detector includes a plurality of sub-detectors independent of each other, and the plurality of sub-detectors respectively correspond to a plurality of different positions on the first transmission path or the second transmission path.

[0006] In some embodiments, the first X-ray imaging subsystem or the second X-ray imaging subsystem includes an X-ray source and a detector, the X-ray source includes multiple X-ray emitting units, wherein obtaining a first group of projection images for the object to be measured or obtaining a second group of projection images for the object to be measured includes: controlling the object to be measured to move along the first transmission path or the second transmission path; and in response to the object to be measured reaching each of the multiple target positions on the first transmission path or the second transmission path, triggering the X-ray source and the detector to obtain multiple first projection images of the object to be measured corresponding to the multiple target positions respectively; wherein the first group of projection images or the second group of projection images includes the multiple first projection images.

[0007] In some embodiments, a distance between adjacent target positions in the plurality of target positions is smaller than a spacing between adjacent X-ray emission units in the plurality of X-ray emission units.

[0008] In some embodiments, the first X-ray imaging subsystem or the second X-ray imaging subsystem includes an X-ray source and a detector, the X-ray source includes multiple X-ray emitting units, wherein obtaining a first group of projection images for the object to be measured or obtaining a second group of projection images for the object to be measured includes: controlling the object to be measured to move along the first transmission path or the second transmission path while rotating; and in response to the object to be measured being in multiple target positions on the first transmission path or the second transmission path, triggering the X-ray source and the detector to obtain multiple second projection images of the object to be measured corresponding to the multiple target positions, respectively, wherein each target position includes the position of the target on the first transmission path or the second transmission path and the direction of the target corresponding to the object to be measured, wherein the first group of projection images or the second group of projection images includes the multiple second projection images.

[0009] In some embodiments, the angle between the target directions corresponding to adjacent target orientations in the multiple target orientations is not equal to an integer multiple of a threshold, and the threshold is the arc tangent value of the ratio of the spacing between adjacent X-ray emission units in the multiple X-ray emission units to the vertical distance from the detector to the X-ray source.

[0010] In some embodiments, the method further includes: recording the initial posture of the object to be measured before controlling the object to be measured to move or rotate along the first transmission path; in response to the object to be measured leaving the first transmission path, controlling the orientation of the object to be measured so that the object to be measured returns to the initial posture; wherein the changing the moving direction of the object to be measured so that the object to be measured passes through the second X-ray imaging subsystem along the second transmission path includes: controlling the object to be measured to enter the second X-ray imaging subsystem along the second direction in the initial posture.

[0011] In some embodiments, each of the multiple X-ray light-emitting units includes a movable X-ray tube, wherein obtaining a first set of projection images for the object to be measured or obtaining a second set of projection images for the object to be measured further includes: periodically adjusting at least one of the position and orientation of each movable X-ray tube in the multiple X-ray emission units to obtain a plurality of different orientations of the X-ray source relative to the object to be measured; triggering each movable X-ray tube in the multiple X-ray emission units and the detector to obtain a plurality of third projection images for the object to be measured, wherein the plurality of third projection images respectively correspond to the plurality of different orientations of the X-ray source relative to the object to be measured, wherein the first set of projection images or the second set of projection images also includes the plurality of third projection images.

[0012] In some embodiments, triggering each movable X-ray tube in the multiple X-ray emission units and the detector to obtain multiple third projection images of the object to be measured includes: turning on the multiple movable X-ray tubes in sequence to perform X-ray exposure of the object to be measured at different viewing angles, thereby obtaining a corresponding third projection image among the multiple third projection images.

[0013] In some embodiments, the periodic adjustment of at least one of the position and orientation of each movable X-ray tube in the plurality of X-ray emission units includes: during the period when the movable X-ray tube emission unit that is turned on among the plurality of movable X-ray tubes is in the turned-on state, adjusting at least one of the position and orientation of the previous movable X-ray tube of the turned-on movable X-ray tube.

[0014] In some embodiments, the method further includes: determining the X-ray intensity distribution and the image signal-to-noise ratio on the detector surface based on the third projection image, determining whether the X-ray intensity distribution satisfies the distribution standard that the center of the detector surface has the maximum X-ray intensity and whether the image signal-to-noise ratio is lower than a signal-to-noise ratio threshold; wherein adjusting at least one of the position and orientation of the previous movable X-ray tube of the turned-on movable X-ray tube includes: in response to the X-ray intensity distribution not satisfying the distribution standard or the image signal-to-noise ratio being higher than the signal-to-noise ratio threshold, changing at least one of the position and orientation of the previous movable X-ray tube so that the X-ray intensity distribution satisfies the distribution standard or the image signal-to-noise ratio is higher than the signal-to-noise ratio threshold.

[0015] Another embodiment of the present application provides a computing device, comprising: a memory configured to store computer-executable instructions; and a processor configured to execute the method described in any of the aforementioned embodiments when the computer-executable instructions are executed by the processor.

[0016] Another embodiment of the present application provides a computer-readable storage medium storing computer-executable instructions. When the computer-executable instructions are executed, the method described in any of the aforementioned embodiments is executed.

[0017] Another embodiment of the present application provides a computer program product, which includes a computer program. When the computer program is executed by a processor, the method described in any one of the aforementioned embodiments is implemented.

[0018] These and other advantages of the application will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Embodiments of the present application will now be described in more detail and with reference to the accompanying drawings, in which:

[0020] Figure 1 Some steps involved in a method for imaging an object to be measured based on an X-ray imaging system according to an embodiment of the present application are illustrated;

[0021] Figure 2 Used to illustrate the imaging angle range and angle sampling interval of the X-ray imaging subsystem provided according to an embodiment of the present application;

[0022] Figure 3 An example of illustrating changes in the movement directions of the first X-ray imaging subsystem, the second X-ray imaging subsystem, and the object to be measured in the X-ray imaging system provided in an embodiment of the present application;

[0023] Figure 4 An example of a first X-ray imaging subsystem or a second X-ray imaging subsystem provided according to another embodiment of the present application is shown;

[0024] Figure 5 An example of a first X-ray imaging subsystem or a second X-ray imaging subsystem provided according to another embodiment of the present application is shown;

[0025] Figure 6 Some steps involved in obtaining a first set of projection images for an object to be measured or obtaining a second set of projection images for an object to be measured according to another embodiment of the present application are shown;

[0026] Figure 7 Used to illustrate the state change of the object to be measured when passing through the first X-ray imaging subsystem or the second X-ray imaging subsystem according to the embodiment of the present application;

[0027] Figure 8 For illustration based on Figure 7 The embodiment shown in FIG1 is used to implement the change of the angular sampling interval of the X-ray imaging system;

[0028] Figure 9 The figure illustrates some processes involved in obtaining a first set of projection images or a second set of projection images of an object to be measured based on an X-ray imaging subsystem including multiple movable X-ray tubes according to another embodiment of the present application;

[0029] Figure 10 FIG2 illustrates an exemplary situation in which the positions of each movable X-ray tube are adjusted to change the orientation of the X-ray source relative to the object to be measured according to another embodiment of the present application;

[0030] Figure 11 An example of adjusting the orientation of a single movable X-ray tube is schematically illustrated. DETAILED DESCRIPTION

[0031] The following description provides the specific details of various embodiments of the present application so that those skilled in the art can fully understand and implement the various embodiments of the present application. It should be understood that the technical scheme of the present application can be implemented without some of these details. In some cases, the present application does not illustrate or describe in detail some well-known structures or functions to avoid these unnecessary descriptions from obscuring the description of the embodiments of the present application. The terms used in this application should be understood in their broadest reasonable manner, even if they are used in conjunction with the specific embodiments of the present application.

[0032] The embodiment of the present application provides a method for imaging an object to be measured based on an X-ray imaging system, wherein the X-ray imaging system includes at least a first X-ray imaging subsystem and a second X-ray imaging subsystem, wherein a first direction of a first transmission path for transmitting the object to be measured in the first X-ray imaging subsystem is different from a second direction of a second transmission path for transmitting the object to be measured in the second X-ray imaging subsystem. Figure 1 As shown, the method includes: step S101, controlling the object to be measured to pass through the first X-ray imaging subsystem along the first transmission path to obtain a first group of projection images for the object to be measured; step S102, changing the moving direction of the object to be measured so that the object to be measured passes through the second X-ray imaging subsystem along the second transmission path to obtain a second group of projection images for the object to be measured; step S103, obtaining a target image for the object to be measured based on at least the first group of projection images and the second group of projection images.

[0033] Figure 2 Schematically illustrates the principle diagram of the first X-ray imaging subsystem or the second X-ray imaging subsystem, such as Figure 2 As shown, the X-ray imaging subsystem includes a conveyor mechanism 10, a detector 20, and an X-ray source. The object 30 to be measured can be placed on the conveyor mechanism 10. Examples of the conveyor mechanism 10 include, but are not limited to, a conveyor belt. The object 30 to be measured can be directly placed on the conveyor belt. Alternatively, the conveyor mechanism 10 can also include a support structure other than the conveyor belt for directly carrying the object 30 to be measured. This application does not impose any restrictions on the specific form or composition of the conveyor mechanism. Figure 2 As shown, the X-ray source includes a plurality of X-ray emitting units X1, X2, X3, X4...Xn, and the X-ray source and the detector 20 can be respectively located on both sides of the object to be measured 30. When the object to be measured 30 is located on the conveying mechanism 10, at least a portion of the X-rays from each X-ray emitting unit can reach the object to be measured 30, and the detector 20 can receive the X-rays passing through the object to be measured 30, thereby reconstructing the internal structure information of the object to be measured. The individual X-ray emitting units X1, X2, X3, X4...Xn can be arranged along a straight line, or each X-ray emitting unit itself can also have a certain degree of spatial freedom of movement, so that the individual X-ray emitting units are arranged in a curve. The imaging angle range and the angle sampling interval of the X-ray imaging subsystem will have a certain impact on the quality of the target image finally obtained. The imaging angle range refers to the maximum angle range that all X-ray emitting units cover the object to be measured 30 in the scanning plane. The angle sampling interval reflects the discrete sampling density of the imaging subsystem on the object to be measured within the imaging angle range, which directly affects the resolution and quality of the image of the object to be measured finally obtained. With the help of Figure 2To roughly illustrate the imaging angle range and angle sampling interval of the X-ray imaging subsystem. Figure 2 As shown, the imaging angle range θ of the X-ray imaging system depends on the overall distribution length L of the X-ray emitting units in the X-ray source and the distance between the object 30 and the X-ray source. The angular sampling interval is roughly determined by the spacing d between adjacent X-ray emitting units and the distance between the object 30 and the X-ray source. The imaging angle range θ and the angular sampling interval Δθ can be roughly expressed by the following formula:

[0034]

[0035] Where L represents the overall distribution length of each X-ray emitting unit in the X-ray source, that is, Figure 2 , d represents the length of the straight line connecting the first X-ray emitting unit X1 and the last X-ray emitting unit Xn shown in the figure, d represents the spacing between adjacent X-ray emitting units. In some embodiments, the X-ray emitting units in the X-ray source can be evenly arranged, and D represents the distance from the object to be measured 30 to the X-ray source.

[0036] Further, combined with Figure 3 The aforementioned steps S101 and S102 are further explained. Figure 3 The diagram shows a first X-ray imaging subsystem and a second X-ray imaging subsystem in an X-ray imaging system. The first X-ray imaging subsystem includes a detector 20 and X-ray emitting units X1, X2...Xn, and the second X-ray imaging subsystem includes a detector 20' and X-ray emitting units X1', X2'...Xn'. A first direction D1 of a first transmission path for transmitting an object to be measured 30 in the first X-ray imaging subsystem is different from a first direction D2 of a second transmission path for transmitting an object to be measured 30 in the second X-ray imaging subsystem. Figure 3 As shown, in this example, in step S101, the object to be measured 30 is controlled to pass through the first X-ray imaging subsystem in a first posture to obtain a first set of projection images for the object to be measured, and the imaging angle range of the first X-ray imaging subsystem is α. That is, the object to be measured 30 can be maintained in a constant first posture when passing through the first X-ray imaging subsystem, and the orientation of the object to be measured 30 remains unchanged. When the object to be measured 30 leaves the first X-ray imaging subsystem, the object to be measured is maintained in the first posture, and the moving direction of the object to be measured 30 is changed so that the object to be measured 30 maintains the first posture along the second transmission path in the second X-ray imaging subsystem through the second X-ray imaging subsystem to obtain a second set of projection images for the object to be measured. That is, the object to be measured 30 still maintains the first posture when passing through the second X-ray imaging subsystem, and the orientation of the object to be measured 30 remains unchanged. As shown Figure 3As shown, when the object 30 enters the second X-ray imaging subsystem, its posture remains in the previous first posture, but its movement direction changes to a new second direction D2. The X-ray emitting units X1', X2', ..., Xn' and the detector 20' in the second X-ray imaging subsystem collect information from the object 30 to obtain a second set of projection images. The imaging angle range of the second X-ray imaging subsystem is β.

[0037] The X-ray imaging system involved in the embodiment of the present application can operate in a computed tomography (CT) imaging mode, and can also operate in a multi-view direct digital X-ray photography (multi-view DR) mode. In the CT imaging mode, a three-dimensional image of the object to be measured can be reconstructed based on the first set of imaging images and the second set of imaging images obtained previously. In the multi-view DR mode, the object to be measured is exposed and imaged by the first X-ray imaging subsystem or the imaging area of ​​the first X-ray imaging subsystem according to a pre-set part or all of the X-ray emission units to obtain different projection images, and the object to be measured can be directly analyzed and studied based on these projection images. Therefore, in step S103, in the CT imaging mode, a three-dimensional image of the object to be measured can be reconstructed based on the first set of projection images and the second set of projection images of the object to be measured, so as to obtain a target image, and a feature analysis of the object to be measured can be performed based on the target image. In the multi-view DR mode, a feature analysis of the object to be measured can be directly performed based on the first set of projection images and the second set of projection images.

[0038] By using the method for imaging the object to be measured provided in the embodiment of the present application, it is possible to achieve the splicing of the imaging angle ranges of the two imaging subsystems for the same object to be measured, that is, it is possible to achieve the maximum overall imaging angle range of the X-ray imaging system that reaches the sum of the imaging angle range α of the first X-ray imaging subsystem and the imaging angle range β of the second X-ray imaging subsystem. For a single first X-ray imaging subsystem, the imaging angle range usually does not exceed 100 degrees, and the image of the object to be measured obtained is prone to data loss, resulting in limited angle artifacts. Since the object to be measured passes through the first X-ray imaging subsystem and the second X-ray imaging subsystem with different transmission path directions in the same posture, the two X-ray imaging subsystems can scan the object to be measured from different angles or directions, thereby making up for the defect of insufficient imaging angle range of a single X-ray imaging subsystem, reducing data loss in the obtained image, effectively suppressing limited angle artifacts, and improving the quality of the target image finally obtained.

[0039] According to an embodiment of the present application, the angle between the first direction of the first transmission path and the second direction of the second transmission path is a ratio of 180 degrees to N, where N represents the number of X-ray imaging subsystems included in the X-ray imaging system, and N is an integer greater than or equal to 2. Figure 3 As shown, in some embodiments, a first direction of a first transmission path used to transmit the object 30 in the first X-ray imaging subsystem is perpendicular to a second direction of a second transmission path used to transmit the object 30 in the second X-ray imaging subsystem. This effectively reduces redundant data in the first set of projection images and the second set of projection images, which includes projection images of certain regions of the object 30 that are repeatedly acquired by the first and second X-ray imaging subsystems in the same posture or orientation.

[0040] Figure 4 FIG2 is a schematic diagram of an X-ray imaging subsystem provided according to another embodiment of the present application. Figure 2 The example shown differs in that Figure 4 The detector in the first X-ray imaging subsystem or the second X-ray imaging subsystem includes a plurality of sub-detectors that are independent of each other, for example, sub-detectors 20a, 20b and 20c, and the sub-detectors 20a, 20b and 20c correspond to a plurality of different positions on the first transmission path or the second transmission path, respectively. In this way, when the object to be measured moves through the first transmission path or the second transmission path, each sub-detector can receive X-rays that pass through the object to be measured directly above it, thereby obtaining different projection images. This is beneficial for continuously detecting a plurality of different objects to be measured 30, and each sub-detector can obtain projection images for different objects to be measured, respectively, thereby improving the detection efficiency of detecting a plurality of objects to be measured. In other embodiments, the first X-ray imaging subsystem or the second X-ray imaging subsystem may include a detector with a larger X-ray receiving surface. For example, as Figure 5 As shown, the detector 20 has a large X-ray receiving surface, for example, it can simultaneously receive X-rays from three different objects to be detected passing directly above it, so that detection of multiple objects to be detected can be achieved based on the single detector 20.

[0041] Next, the process of obtaining the first set of projection images for the object to be measured or obtaining the second set of projection images for the object to be measured in the aforementioned step S101 or S102 is further described by way of examples.

[0042] In some embodiments, as Figure 6As shown, obtaining a first set of projection images for the object to be measured or obtaining a second set of projection images for the object to be measured may include the following steps: S601, controlling the object to be measured to move along the first transmission path or the second transmission path; and S602, in response to the object to be measured reaching each of the multiple target positions on the first transmission path or the second transmission path, triggering the X-ray source and the detector to obtain multiple first projection images of the object to be measured corresponding to the multiple target positions respectively. At this time, the first set of projection images or the second set of projection images may include multiple first projection images. Thus, the first projection images corresponding to the object to be measured at different target positions can be obtained, so that a smaller angular sampling interval can be achieved. The target position can be a preset position on the first transmission path or the second transmission path, for example, Figure 7 In some embodiments, when the object to be measured reaches the aforementioned target positions pa, pb, and pc, the object to be measured can be controlled to stop moving, and the X-ray source and the detector can be turned on at the same time, so as to obtain multiple first projection images of the object to be measured corresponding to the multiple target positions pa, pb, and pc, respectively. Alternatively, the object to be measured can be controlled to pass through the positions pa, pb, and pc at a lower speed, and the X-ray source and the detector can be turned on at the same time. In some embodiments, the distance between adjacent target positions in the multiple target positions is less than the spacing between adjacent X-ray emission units in the multiple X-ray emission units. For example, Figure 7 The distance between target positions pa and pb, or between target positions pb and pc, shown in FIG, is less than the spacing d between adjacent X-ray emission units. This further reduces the aforementioned angular sampling interval, improves the spatial resolution of the target image, and enhances the image quality of the target image. In this embodiment, as the object moves along the first or second transmission path, the posture or orientation of the object remains constant; only the position of the object changes.

[0043] According to another embodiment of the present application, the obtaining of a first set of projection images for the object to be measured or the obtaining of a second set of projection images for the object to be measured may include the following steps: controlling the object to be measured to rotate while moving along the first transmission path or the second transmission path; and in response to the object to be measured being in a plurality of target orientations on the first transmission path or the second transmission path, triggering the X-ray source and the detector to acquire a plurality of second projection images of the object to be measured corresponding to the plurality of target orientations, respectively, wherein each target orientation includes the target position on the first transmission path or the second transmission path and the target direction corresponding to the object to be measured. In this case, the first set of projection images or the second set of projection images includes the plurality of second projection images. The orientation here includes the position of the object to be measured on the first transmission path or the second transmission path and the orientation or direction when it is in this position, and the direction or orientation of the object to be measured when it is in the target position is referred to as the corresponding target direction. Refer again Figure 7 The object 30 to be measured is controlled to move along the first transmission path or the second transmission path while rotating in the third direction D3. For example, when the object to be measured is at the target positions pa, pb, and pc, the orientation or direction of the object to be measured 30 is different, that is, the orientation or direction of the object to be measured changes simultaneously with the change of position. Therefore, multiple target positions can be pre-set for the object to be measured. When the object to be measured is at the calibrated position, the X-ray source and detector 20 are triggered to obtain multiple second projection images of the object to be measured when it is at the multiple calibrated positions. In some embodiments, the transmission mechanism 10 may include a position encoder and a rotating component for rotating the object to be measured. The rotating component may include an angle encoder. The position encoder and the angle encoder can respectively sense the position of the object to be measured and its direction or orientation relative to the radiation source. When the object to be measured 30 is at the aforementioned target position (target position and target direction), the position encoder and / or the angle encoder can generate a trigger signal for the X-ray source and detector, thereby turning on the X-ray source and detector 20 to obtain the second projection image of the object to be measured when it is at the aforementioned target position.

[0044] In some embodiments, the method for imaging the object to be measured based on the X-ray imaging system further includes the following steps: before controlling the object to be measured to move or rotate along the first transmission path, recording the initial posture of the object to be measured; in response to the object to be measured leaving the first transmission path, controlling the orientation of the object to be measured so that the object to be measured returns to the same initial posture. Accordingly, changing the moving direction of the object to be measured so that the object to be measured passes through the second X-ray imaging subsystem along the second transmission path includes: controlling the object to be measured to enter the second X-ray imaging subsystem along the second direction with the initial posture. In this way, even if the posture or orientation of the object to be measured changes during the process of passing through the first X-ray imaging subsystem, the posture of the object to be measured when entering the second X-ray imaging subsystem can be made the same as the posture when it enters the first X-ray imaging subsystem.

[0045] In some embodiments, the distance between the target positions corresponding to adjacent calibration positions in the aforementioned multiple target positions is less than the spacing d between adjacent X-ray emission units. Furthermore, the angle between the target directions corresponding to adjacent calibration positions in the aforementioned multiple target positions is not equal to an integer multiple of a threshold value, and the threshold value is the arc tangent value of the ratio of the spacing between adjacent X-ray emission units in the multiple X-ray emission units to the vertical distance from the detector to the X-ray source. For example, the angle between the target directions corresponding to adjacent calibration positions in the multiple target positions may be less than the threshold value. In this way, the aforementioned angular sampling interval can be further shortened, and the angular sampling capability of the imaging system and the system spatial resolution of the reconstruction result can be improved without reducing the spacing between adjacent X-ray emission units, thereby improving the image quality of the target image.

[0046] Figure 8 To illustrate based on Figure 7 The embodiment shown in FIG. 4 illustrates a variation in the angular sampling interval of the X-ray imaging subsystem. Figure 8 The angular intervals between the several different dotted lines A in the figure represent the angular sampling intervals when the X-ray source exposes and images the object to be measured when the object to be measured stays in the X-ray imaging subsystem (i.e., the object to be measured does not move or rotate), and the angular intervals between the different dotted lines B represent the angular sampling intervals when the object to be measured is exposed and imaged in the X-ray imaging subsystem according to the Figure 7 The angle sampling interval when the X-ray source in the imaging system exposes and images the object to be measured (the object to be measured is at the aforementioned multiple target positions) when the straight line direction D1 shown in FIG is moved. The angle intervals between different dotted lines C represent the angle sampling intervals when the object to be measured is exposed and imaged in the X-ray imaging system according to Figure 7The angular sampling interval when the X-ray source in the imaging system exposes and images the object to be measured (the object to be measured is in the aforementioned multiple target directions) when the rotation direction D2 shown in FIG is rotated. It can be seen that the method for imaging the object to be measured based on the X-ray imaging system provided in the embodiment of the present application can effectively reduce the angular sampling interval, thereby improving the angular sampling capability of the imaging system and the system spatial resolution of the reconstruction result without reducing the spacing between adjacent X-ray emission units in the X-ray source, thereby improving the image quality of the target image.

[0047] In some embodiments, the X-ray source is a distributed X-ray source, i.e., an X-ray source comprising multiple X-ray point sources, each of which is fixed in position. These X-ray point sources may also be referred to as sub-targets. Alternatively, the X-ray source is a multi-point X-ray tube light source comprising multiple X-ray tubes. This means that the X-ray source is composed of a group of multiple independent X-ray tubes, each of which can be independently controlled to have multi-dimensional adjustable degrees of freedom, allowing for position and orientation changes within a certain range. Therefore, in some embodiments, each of the multiple X-ray emitting units includes a movable X-ray tube. Figure 9 The diagram illustrates some processes involved in obtaining a first set of projection images or a second set of projection images for an object under test based on an X-ray imaging subsystem including multiple movable X-ray tubes. Steps S901 and S902 are the same as steps S601 and S602, respectively. However, obtaining the first set of projection images or the second set of projection images for the object under test may further include: step S903, periodically adjusting at least one of the position and orientation of each movable X-ray tube in the multiple X-ray emission units to obtain multiple different orientations of the X-ray source relative to the object under test; and step S904, triggering each movable X-ray tube in the multiple X-ray emission units and the detector to obtain multiple third projection images for the object under test, the multiple third projection images corresponding to the multiple different orientations of the X-ray source relative to the object under test. In this case, the first set of projection images or the second set of projection images includes the multiple third projection images in addition to the multiple first projection images.

[0048] Figure 10 The figure shows an exemplary situation in which the positions of the movable X-ray tubes are adjusted to change the orientation of the X-ray source relative to the object to be measured. Figure 10As shown, the positions of the first movable X-ray tube, the second movable X-ray tube, the i-th movable X-ray tube, and the n-th movable X-ray tube before adjustment are labeled P1, P2, Pi, and Pn, respectively. The new positions of the first movable X-ray tube, the second movable X-ray tube, the i-th movable X-ray tube, and the n-th movable X-ray tube after adjustment are labeled P1', P2', Pi', and Pn', respectively. Therefore, when each movable X-ray tube is at position P1, P2, Pi, and Pn, respectively, the X-ray imaging subsystem can acquire a third projection image of the object to be measured. When each movable X-ray tube is at position P1', P2', Pi', and Pn', respectively, the X-ray imaging subsystem can acquire another third projection image of the object to be measured.

[0049] By utilizing the imaging method provided in the embodiment of the present application, it is possible to achieve multiple changes in the orientation of the X-ray source relative to the object to be measured when the object to be measured passes through the X-ray imaging subsystem, thereby obtaining multiple third projection images corresponding to multiple different orientations of the X-ray source relative to the object to be measured, and finally obtaining the target image of the object to be measured based on these third projection images and the aforementioned first projection image. Therefore, it is possible to obtain projection data in more angular directions without increasing the number of original X-ray emitting units, further reduce the angular sampling interval of imaging, and increase the sampling density of the X-ray imaging system for the object to be measured, thereby further improving the resolution of the target image.

[0050] In another embodiment, for an X-ray imaging subsystem including a plurality of movable X-ray tubes, Figure 7 As in the embodiment shown, the object to be measured is controlled to move and rotate within the X-ray imaging subsystem, thereby obtaining the aforementioned multiple second projection images. In this case, the aforementioned first group of projection images or the second group of projection images includes the aforementioned multiple second projection images and the multiple third projection images.

[0051] In some embodiments, triggering each movable X-ray tube in the plurality of X-ray emitting units and the detector to acquire multiple third projection images of the object to be measured includes sequentially activating the plurality of movable X-ray tubes to expose the object to be measured to X-rays at different viewing angles, thereby obtaining a corresponding third projection image from the plurality of third projection images. Similarly, a similar approach can be employed to acquire the first and second projection images described in other embodiments of this application. That is, in this embodiment, the movable X-ray emitting units are not simultaneously activated, but are instead periodically activated and deactivated. The duration of a single cycle can be understood as the time period from when the first movable X-ray tube is activated to when the nth movable X-ray tube is activated. Compared to activating all X-ray emitting units simultaneously, activating each X-ray emitting unit sequentially allows for the acquisition of projection data from a single angle at each moment, reducing interference and improving the clarity and accuracy of image reconstruction. Furthermore, this can simplify the electronic design of the imaging system, lowering power and cooling requirements for the imaging system and reducing the cost of the imaging system. On this basis, in some embodiments, the aforementioned step S903 - periodically adjusting at least one of the position and orientation of each movable X-ray tube in the multiple X-ray emission units includes: during the period when the movable X-ray tube emission unit that is turned on among the multiple movable X-ray tubes is in the turned-on state, adjusting at least one of the position and orientation of the movable X-ray tube previous to the turned-on movable X-ray tube.

[0052] Can be combined Figure 10 To further illustrate this embodiment. For example, if the second movable X-ray tube X2 at position P2 is turned on and emits X-rays within a certain period of time, the position and / or orientation of the movable X-ray tube preceding the turned-on second movable X-ray tube (i.e., the first movable X-ray tube X1, which is currently turned off) can be adjusted so that it changes from position P1 to a new position P1'. Similarly, the position and / or orientation of each movable X-ray tube can be adjusted once within a single cycle in which each movable X-ray tube is turned on once (i.e., during the period in which a single third projection image is obtained). This embodiment can allow another X-ray tube to be moved to a target position and / or rotated to a target direction in advance when a single X-ray tube is turned on, in preparation for obtaining the next projection image, thereby improving the operating efficiency of the X-ray imaging subsystem.

[0053] According to another embodiment of the present application, the method for imaging an object to be measured based on an X-ray system further includes: determining the X-ray intensity distribution and the image signal-to-noise ratio on the detector surface based on the third projection image, determining whether the X-ray intensity distribution meets the distribution standard of having the maximum X-ray intensity at the center of the detector surface and whether the image signal-to-noise ratio is lower than a signal-to-noise ratio threshold. In this case, the aforementioned step of adjusting at least one of the position and orientation of the previous movable X-ray tube before the activated movable X-ray tube includes: in response to the X-ray intensity distribution not meeting the distribution standard or the image signal-to-noise ratio being lower than the signal-to-noise ratio threshold, changing at least one of the position and orientation of the previous movable X-ray tube so that the X-ray intensity distribution meets the distribution standard or the image signal-to-noise ratio is higher than the signal-to-noise ratio threshold. Figure 11 An example of adjusting a single movable X-ray tube is schematically illustrated. Figure 11 As shown, an X-ray tube 200 is adjusted along direction B from the previous orientation indicated by the solid rectangle to the orientation indicated by the dashed rectangle. Accordingly, the X-ray irradiation range of the X-ray tube 200 also changes from the area between the two solid arrows F1 and F2 to the area between the two dashed arrows F3 and F4. Therefore, by adjusting the position and orientation of the movable X-ray tube, the X-ray intensity distribution on the detector surface can be achieved to meet or approach the aforementioned distribution standards, or to ensure that the image signal-to-noise ratio exceeds the signal-to-noise ratio threshold. This can further improve the quality of the target image obtained.

[0054] Another embodiment of the present application provides a computing device comprising: a memory configured to store computer-executable instructions; and a processor configured to execute a method according to any one of the embodiments of the aforementioned method of imaging an object to be measured based on an X-ray imaging system when the computer-executable instructions are executed by the processor.

[0055] The method described above with reference to the flowchart can be implemented as a computer program. Another embodiment of the present application provides a computer program product, including a computer program, which, when executed by a processor, implements the method according to any of the embodiments of the aforementioned method for imaging an object to be measured based on an X-ray imaging system.

[0056] Yet another embodiment of the present application provides a computer-readable storage medium having computer-readable instructions stored thereon, which, when executed, implement the method described in any of the aforementioned embodiments of the method for imaging an object to be measured based on an X-ray imaging system.

[0057] The scope of the present application is limited solely by the appended claims. Although individual features may be included in different claims, these may possibly be advantageously combined, and the order in which the features appear in the claims does not imply any specific order in which the features must be worked. Furthermore, in the claims, the word "comprising" does not exclude other elements or steps.

Claims

1. A method for imaging an object to be measured based on an X-ray imaging system, the X-ray imaging system comprising at least a first X-ray imaging subsystem and a second X-ray imaging subsystem, wherein a first direction of a first transmission path for transmitting the object to be measured in the first X-ray imaging subsystem is different from a second direction of a second transmission path for transmitting the object to be measured in the second X-ray imaging subsystem, characterized in that: The method comprises: Controlling the object to be measured to pass through the first X-ray imaging subsystem along the first transmission path to obtain a first set of projection images of the object to be measured; changing the moving direction of the object to be measured so that the object to be measured passes through the second X-ray imaging subsystem along the second transmission path to obtain a second set of projection images of the object to be measured; A target image for the object to be measured is obtained based on at least the first group of projection images and the second group of projection images.

2. The method according to claim 1, characterized in that The angle between the first direction and the second direction is a ratio of 180 degrees to N, where N represents the number of X-ray imaging subsystems included in the X-ray imaging system, and N is an integer greater than or equal to 2.

3. The method according to any one of claims 1-2, wherein each X-ray imaging subsystem in the first X-ray imaging subsystem or the second X-ray imaging subsystem includes an X-ray source and a detector, the X-ray source includes a plurality of X-ray emission units, and the detector includes a plurality of sub-detectors independent of each other, and the plurality of sub-detectors respectively correspond to a plurality of different positions on the first transmission path or the second transmission path.

4. The method according to claim 1, wherein the first X-ray imaging subsystem or the second X-ray imaging subsystem comprises an X-ray source and a detector, the X-ray source comprises a plurality of X-ray emission units, and wherein obtaining a first set of projection images for the object to be measured or obtaining a second set of projection images for the object to be measured comprises: Controlling the object to be measured to move along the first transmission path or the second transmission path; as well as In response to the object to be measured reaching each of a plurality of target positions on the first transmission path or the second transmission path, triggering the X-ray source and the detector to acquire a plurality of first projection images of the object to be measured corresponding to the plurality of target positions, respectively; The first group of projection images or the second group of projection images includes the multiple first projection images. 5 . The method according to claim 4 , wherein a distance between adjacent target positions in the plurality of target positions is smaller than a spacing between adjacent X-ray emitting units in the plurality of X-ray emitting units.

6. The method according to claim 1, wherein the first X-ray imaging subsystem or the second X-ray imaging subsystem comprises an X-ray source and a detector, the X-ray source comprises a plurality of X-ray emission units, wherein obtaining a first set of projection images for the object to be measured or obtaining a second set of projection images for the object to be measured comprises: Controlling the object to be measured to rotate while moving along the first transmission path or the second transmission path; as well as In response to the object to be measured being in a plurality of target positions on the first transmission path or the second transmission path, triggering the X-ray source and the detector to acquire a plurality of second projection images of the object to be measured corresponding to the plurality of target positions, respectively, wherein each target position includes a position of a target on the first transmission path or the second transmission path and a target direction corresponding to the object to be measured, The first group of projection images or the second group of projection images includes the plurality of second projection images.

7. The method according to claim 6, wherein the angle between the target directions corresponding to adjacent target orientations in the multiple target orientations is not equal to an integer multiple of a threshold, and the threshold is the arc tangent value of the ratio of the spacing between adjacent X-ray emission units in the multiple X-ray emission units to the vertical distance from the detector to the X-ray source.

8. The method according to claim 6, further comprising: Before controlling the object to be measured to move or rotate along the first transmission path, recording the initial posture of the object to be measured; In response to the object to be measured leaving the first transmission path, controlling the orientation of the object to be measured so that the object to be measured returns to the initial posture; Wherein, changing the moving direction of the object to be measured so that the object to be measured passes through the second X-ray imaging subsystem along the second transmission path includes: The object to be measured is controlled to enter the second X-ray imaging subsystem along the second direction in the initial posture.

9. The method according to any one of claims 4 to 8, wherein each of the plurality of X-ray emitting units comprises a movable X-ray tube, wherein obtaining a first set of projection images for the object to be measured or obtaining a second set of projection images for the object to be measured further comprises: Periodically adjusting at least one of a position and an orientation of each movable X-ray tube in the plurality of X-ray emitting units, thereby obtaining a plurality of different orientations of the X-ray source relative to the object to be measured; triggering each movable X-ray tube in the plurality of X-ray emitting units and the detector to acquire a plurality of third projection images of the object to be measured, wherein the plurality of third projection images respectively correspond to the plurality of different orientations of the X-ray source relative to the object to be measured, The first group of projection images or the second group of projection images also includes the plurality of third projection images.

10. The method according to claim 9, wherein triggering each movable X-ray tube in the plurality of X-ray emitting units and the detector to acquire a plurality of third projection images of the object to be measured comprises: The multiple movable X-ray tubes are turned on in sequence to perform X-ray exposure of the object to be measured at different viewing angles, thereby obtaining a corresponding third projection image among the multiple third projection images.

11. The method according to claim 10, characterized in that The periodically adjusting at least one of the position and orientation of each movable X-ray tube in the plurality of X-ray emitting units comprises: While the emission unit of a turned-on movable X-ray tube among the plurality of movable X-ray tubes is in the turned-on state, at least one of a position and an orientation of a movable X-ray tube preceding the turned-on movable X-ray tube is adjusted.

12. The method according to claim 11, characterized in that The method further comprises: determining the X-ray intensity distribution and image signal-to-noise ratio on the detector surface based on the third projection image, determining whether the X-ray intensity distribution satisfies a distribution criterion that the center of the detector surface has a maximum X-ray intensity and whether the image signal-to-noise ratio is higher than a signal-to-noise ratio threshold; The adjusting of at least one of the position and orientation of the movable X-ray tube preceding the activated movable X-ray tube comprises: In response to the X-ray intensity distribution not satisfying the distribution standard or the image signal-to-noise ratio being lower than the signal-to-noise ratio threshold, at least one of the position and orientation of the previous movable X-ray tube is changed so that the X-ray intensity distribution satisfies the distribution standard or the image signal-to-noise ratio is higher than the signal-to-noise ratio threshold.

13. A computing device comprising a memory configured to store computer-executable instructions; A processor configured to perform the method according to any one of claims 1 to 12 when the computer executable instructions are executed by the processor.

14. A computer-readable storage medium storing computer-executable instructions, wherein when the computer-executable instructions are executed, the method according to any one of claims 1 to 12 is performed.

15. A computer program product comprising a computer program, which, when executed by a processor, implements the method according to any one of claims 1 to 12.

Images