Alignment method of detector and radiation source, imaging system and storage medium

Abstract

The embodiment of the invention relates to the technical field of detection imaging systems, in particular to an alignment method of a detector and a radiation source, an imaging system and a storage medium. Extracting a point set of projection points formed by projection of the small ball of the correction die body in the projection image, determining reference straight lines based on the point set of the projection points, determining a target position based on multiple reference straight lines, then calculating a deviation value between the target position and the center of the plane where the detector is located, and controlling the detector to move to the target position based on the deviation value. Therefore, the deviation value between the detector and the radiation source can be quickly and accurately calculated, the alignment can be completed only by moving the detector according to the deviation value, the operation is simple, time and labor are saved, the alignment efficiency is improved, and the use experience is improved.

Description

Technical Field

[0001] The embodiments of the present invention relate to the technical field of detection imaging systems, and in particular to a method for aligning a detector and a ray source, an imaging system, and a storage medium. Background Art

[0002] In security inspection, industrial nondestructive testing, and medical imaging, precise alignment (also known as alignment or correcting) of X-ray sources and detectors in inspection and imaging systems is crucial for image quality and directly impacts it. Detector-to-X-ray source alignment refers to the alignment of the projection of the X-ray source's central ray with the center of the detector plane. Currently, achieving precise alignment requires repeatedly moving the detector or source in multiple directions, a complex, time-consuming, and labor-intensive process that is inefficient and creates a poor user experience. Summary of the Invention

[0003] In view of this, one purpose of an embodiment of the present invention is to provide a method for aligning a detector and a radiation source, an imaging system and a storage medium, so as to solve the technical problem in the prior art that when aligning the detector and the radiation source, the detector or the radiation source needs to be repeatedly moved, which is time-consuming, labor-intensive and inefficient.

[0004] To solve the above technical problems, the embodiments of the present invention provide the following technical solutions: In a first aspect, an embodiment of the present invention provides a method for aligning a detector and a radiation source, which is applied to an imaging system. The imaging system includes a detector, a radiation source, and a calibration phantom, wherein the calibration phantom includes a plurality of small balls. The method comprises: Control the movement of the calibration phantom and obtain multiple projection images taken by the detector. The projection images are images of multiple stages when the calibration phantom moves. Each projection image contains a projection point formed by the projection of the ball. Based on the projection image, a point set of projection points in the projection image is extracted; Determine a reference straight line based on a point set of projection points in the projection image; Based on multiple reference lines, the target position is determined, where the central ray of the ray source is projected onto the plane where the detector is located; Based on the target position, the offset value between the target position and the reference position is calculated, and the reference position is the center of the plane where the detector is located; Based on the offset value, the detector is controlled to move to the target position to complete the alignment of the detector and the radiation source.

[0005] In some embodiments, extracting a point set of projection points in the projection image based on the projection image includes: Binarize the projected image; Extract the different centroids of the projection points corresponding to the balls at different positions in the projection image, and use the coordinates of the centroids as the reference coordinates of the projection points corresponding to the balls; Number each ball, and get the point set of all balls based on the number and reference coordinates.

[0006] In some embodiments, determining the reference line based on a point set of projection points in the projection image includes: Select any one of the multiple projection points as the target projection point; Determine the reference coordinates of the target projection point in each projection image to obtain multiple target coordinates; Based on multiple target coordinates, a reference straight line corresponding to the target projection point is obtained.

[0007] In some embodiments, determining the target position based on a plurality of reference lines includes: Based on multiple reference lines, construct a linear matrix equation; Solve the linear matrix equation to obtain the intersection point of the reference line, which is the target position.

[0008] In some embodiments, calculating the offset value between the target position and the reference position based on the target position includes: Get the reference position; Based on the target position and the reference position, calculating the pixel offset distance between the target position and the reference position; Multiply the pixel offset distance by the detector resolution to obtain the offset value between the target position and the reference position.

[0009] In some embodiments, the offset value includes an X-axis offset value and a Y-axis offset value, and controlling the probe to move to the target position based on the offset value includes: Determine the target orientation of the detector relative to the ray source based on the X-axis offset value and the Y-axis offset value; Based on the target position, the detector is controlled to move by the X-axis offset value and the Y-axis offset value so that the detector moves to the target position.

[0010] In some embodiments, the imaging system further comprises a guide rail disposed between the detector and the radiation source, the calibration phantom being passed through the guide rail, the guide rail being provided with a plurality of positioning points, and any two positioning points being separated by a preset distance; The control correction phantom movement and acquisition of multiple projection images captured by the detector include: Controlling the calibration phantom to move along the first direction on the guide rail to each positioning point; In response to detecting that the calibration phantom moves to the positioning point, the detector is controlled to capture a projection image to obtain a plurality of projection images.

[0011] In some embodiments, before controlling the calibration phantom to move along the first direction on the guide rail to each positioning point, the method further includes: Control the movement of the ray source or detector so that the projection image is within the field of view of the detector. The projection image is the image formed by the rays from the ray source projected onto the calibration phantom.

[0012] In a second aspect, an embodiment of the present invention provides an imaging system, comprising: A controller, a detector, a radiation source, a calibration phantom, and a guide rail, wherein the guide rail is vertically arranged between the detector and the radiation source, the calibration phantom is passed through the guide rail, the calibration phantom includes a plurality of small balls, and the guide rail is provided with a plurality of positioning points, with any two positioning points separated by a preset distance; The controller is communicatively connected to the detector, the ray source and the calibration phantom respectively; The controller includes: a processor and a memory communicatively connected to the processor; The memory stores computer program instructions executable by the processor, and when the computer program instructions are executed by the processor, the controller executes any one of the methods for aligning a detector and a radiation source proposed in the first aspect.

[0013] In a third aspect, an embodiment of the present invention provides a computer-readable storage medium, on which computer program instructions executable by a processor are stored. When the computer program instructions are executed by the processor, the computer executes any one of the detector and radiation source alignment methods proposed in the first aspect.

[0014] The embodiments of the present invention have the following beneficial effects: Different from the prior art, the alignment method of the detector and the radiation source provided by the embodiments of the present invention is applied to an imaging system, the imaging system including a detector, a radiation source and a correction phantom, the correction phantom including multiple small balls, the method including: controlling the movement of the correction phantom, and obtaining multiple projection images taken by the detector, the projection images are images of multiple stages when the correction phantom moves, each projection image has projection points formed by the projection of the small balls, based on the projection images, extracting the point set of the projection points in the projection image, based on the point set of the projection points in the projection image, determining the reference straight line, based on multiple reference straight lines, determining the target position, the target position is the position where the center ray of the radiation source is projected to the plane where the detector is located, based on the target position, calculating the offset value between the target position and the reference position, the reference position is the center of the plane where the detector is located, based on the offset value, controlling the detector to move to the target position, and completing the alignment of the detector and the radiation source.

[0015] The embodiment of the present invention uses a detector to capture multiple projection images of the correction model when it moves, extracts a point set of projection points formed by the projection of the small ball of the correction model in the projection image, determines a reference straight line based on the point set of projection points, determines a target position based on multiple reference straight lines, and then calculates the offset value between the target position and the center of the plane where the detector is located. Based on the offset value, the detector is controlled to move to the target position, thereby completing the alignment of the detector and the radiation source. In this way, the offset value between the detector and the radiation source is calculated quickly and accurately, and the alignment is completed by only moving the detector according to the offset value. The operation is simple, time-saving and labor-saving, and the alignment efficiency is improved, thereby enhancing the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for describing the prior art or embodiments. Obviously, the drawings described below only illustrate certain embodiments of the present invention and should not be construed as limiting the scope of protection. Those skilled in the art can, without inventive effort, derive other relevant drawings based on these drawings.

[0017] Figure 1a Schematic diagram of an application scenario of a method for aligning a detector and a radiation source provided by some embodiments of the present invention; Figure 1b is a top view of some embodiments of the present invention when the detector and the radiation source are not aligned; Figure 1c is a projection image captured by a detector in some embodiments of the present invention; Figure 1d is another projection image captured by the detector in some embodiments of the present invention; Figure 2a is a schematic diagram of the logical structure of an imaging system provided by some embodiments of the present invention; Figure 2b is a schematic diagram of the three-dimensional structure of an imaging system provided by some embodiments of the present invention; Figure 2c are three-view images of a calibration phantom in an imaging system provided by some embodiments of the present invention; Figure 2d are three-view images of a calibration phantom in an imaging system provided by other embodiments of the present invention; Figure 2e are three-view images of a calibration phantom in an imaging system provided by yet other embodiments of the present invention; Figure 2f is a schematic structural diagram of a guide rail in an imaging system provided by some embodiments of the present invention; Figure 2g is a schematic structural diagram of a controller in an imaging system provided by some embodiments of the present invention; Figure 3 is a flowchart of a method for aligning a detector and a radiation source provided by some embodiments of the present invention; Figure 4a is a first projection image captured by a detector in some embodiments of the present invention; Figure 4b is a second projection image captured by the detector in some embodiments of the present invention; Figure 4c is a third projection image captured by the detector in some embodiments of the present invention; Figure 5a is a schematic diagram of the positional relationship of projection points of a projected image in some embodiments of the present invention; Figure 5b is a superimposed projection image obtained by superimposing a plurality of projection images in some embodiments of the present invention; Figure 5c is connected Figure 5b A schematic diagram obtained by superimposing the coordinates of the projection points corresponding to the balls at all positions in the projection image shown in the embodiment; Figure 6a is a three-dimensional schematic diagram of the alignment of the detector and the radiation source in some embodiments of the present invention; Figure 6b is a top view of the detector and the radiation source after alignment in some embodiments of the present invention; Figure 7 is a schematic diagram of the positional relationship between a reference position and a target position in some embodiments of the present invention; Figure 8 Schematic diagram of the positional relationship between the reference position and the target position in other embodiments of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purposes and advantages of the embodiments of the present invention easier to understand, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The detailed description of the embodiments of the present invention in the drawings below does not limit the scope of protection claimed by the present invention, but only represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0019] It should be noted that, if no conflict is constituted, the various technical features involved in the embodiments of the present invention described below can be combined with each other and are all within the scope of protection of the present invention. In addition, although the functional modules are divided in the device or structural diagram and the logical order is shown in the flow chart, in some cases, the steps shown or described can be performed in a different module division than in the device or in an order different from that in the flow chart. In addition, the "first", "second", "third" and other similar expressions used herein do not limit the data and execution order, but are only for the purpose of convenience of explanation and to distinguish between the same items or similar items with basically the same functions and effects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features.

[0020] Unless otherwise defined, the technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art within the technical field of the present invention. The terms used in this specification are intended solely to describe specific embodiments and are not intended to limit the present invention. It should be understood that the term "and / or" as used in this specification includes any and all combinations of one or more of the listed items.

[0021] In security inspection, industrial nondestructive testing, and medical imaging, precise alignment (also known as alignment) of X-ray sources and detectors in inspection and imaging systems is crucial for image quality and directly impacts it. Alignment between the detector and X-ray source requires that the projection of the X-ray source's central ray coincide with the center of the detector's plane. Existing techniques require repeated multi-directional movement of the detector or source to achieve precise alignment, which is complex, time-consuming, and inefficient, resulting in a poor user experience.

[0022] In view of this, an embodiment of the present invention provides a method for aligning a detector and a ray source, which is applied to an imaging system. Figure 1a , Figure 1a FIG2 shows a schematic diagram of an application scenario of a method for aligning a detector and a radiation source provided by some embodiments of the present invention. The imaging system 100 includes a controller ( Figure 1a The controller includes a detector 110, a radiation source 120, and a calibration phantom 130 (not shown), each of which is communicatively connected to the controller. The calibration phantom 130 includes a plurality of small balls 131. It is worth noting that the spacing, arrangement, and number of the small balls 131 in the calibration phantom 130 can be adjusted based on actual needs, and this embodiment of the present invention does not impose any specific limitations on this. It should be understood that to ensure the quality of the projected image, the spacing between the small balls 131 should be set within an appropriate range, preferably any suitable distance between 3 and 8 cm.

[0023] See also Figure 1b, Figure 1b The schematic diagram shows a top view of the detector 110 when it is misaligned with the radiation source 120. Point O1 is the position where the central ray of the radiation source 120 is projected onto the plane where the detector 110 is located, and point O2 is the center of the plane where the detector 110 is located. Therefore, it can be seen that there is a deviation between points O1 and O2, that is, the detector 110 is misaligned with the radiation source 120.

[0024] Specifically, the controller controls the movement of the calibration phantom 130 and obtains multiple projection images captured by the detector 110 when the calibration phantom 130 moves. The projection images are images of multiple stages of the movement of the calibration phantom 130, and each projection image has a projection point formed by the projection of the ball 131. For example, the controller controls the movement of the calibration phantom 130 along the first direction N, wherein the detector 110 captures the calibration phantom 130 multiple times when the calibration phantom 130 moves along the first direction N, thereby obtaining multiple projection images. For example, please refer to Figure 1c and Figure 1d , Figure 1c and Figure 1d The projection images PD1 and PD2 captured by the detector 110 are shown respectively. The projection image PD1 includes projection points G1, G2, G3, G4, G5, and G6, where projection point G1 corresponds to position W1, projection point G2 corresponds to position W2, projection point G3 corresponds to position W3, projection point G4 corresponds to position W4, projection point G5 corresponds to position W5, and projection point G6 corresponds to position W6. The projection image PD2 includes projection points H1, H2, H3, H4, H5, and H6, where projection point H1 corresponds to position W1, projection point H2 corresponds to position W2, projection point H3 corresponds to position W3, projection point H4 corresponds to position W4, projection point H5 corresponds to position W5, and projection point H6 corresponds to position W6.

[0025] Then, based on the projection image, a point set of projection points in the projection image is extracted. Each projection image includes projection points formed by the projection of the ball 131, for example, Figure 1c The projected image PD1 shown includes projection points G1, G2, G3, G4, G5 and G6. Figure 1d The projection image PD2 shown includes projection points H1, H2, H3, H4, H5, and H6. For example, an image processing algorithm is used to process all projection images, obtain the projection points in all projection images, extract the centroid coordinates of the projection points corresponding to each position, and combine the centroid coordinates of the projection points at corresponding positions in all projection images to obtain a point set corresponding to each position. For example Figure 1c and Figure 1dIn the projected images PD1 and PD2 shown, the centroid coordinates of projected points G1 and H1 corresponding to position W1 are extracted and combined to obtain the point set GH1 corresponding to position W1. The centroid coordinates of projected points G2 and H2 corresponding to position W2 are extracted and combined to obtain the point set GH2 corresponding to position W2. This process continues in this way until point sets corresponding to all positions are obtained.

[0026] Next, a reference line is determined based on the point set of projection points in the projected image. For example, all centroid coordinates in the point set corresponding to each position are connected to obtain a reference line corresponding to that point set. For example, for position W1, the centroid coordinates of projection points G1 and H1 are connected to obtain a corresponding reference line. For position W2, the centroid coordinates of projection points G2 and H2 are connected to obtain a corresponding reference line. This process is repeated to obtain reference lines corresponding to all point sets, thereby obtaining multiple lines.

[0027] Next, based on the multiple reference lines, the target position is determined. The target position is the position where the central ray of the radiation source 120 is projected onto the plane where the detector 110 is located. Specifically, a line equation is constructed for each reference line. The line equations of the multiple reference lines are combined to obtain a line matrix equation. The line matrix equation is then solved to obtain the target position.

[0028] Finally, the center of the plane where the detector 110 is located (i.e., the reference position) is obtained, and the offset between the target position and the reference position is calculated based on the target position. Based on the offset value, the controller controls the detector 110 to move to the target position, completing the alignment between the detector 110 and the radiation source 120.

[0029] The embodiment of the present invention uses a detector to capture multiple projection images of the correction model when it moves, extracts a point set of projection points formed by the projection of the small ball of the correction model in the projection image, determines a reference straight line based on the point set of projection points, determines a target position based on multiple reference straight lines, and then calculates the offset value between the target position and the center of the plane where the detector is located. Based on the offset value, the detector is controlled to move to the target position, thereby completing the alignment of the detector and the radiation source. In this way, the offset value between the detector and the radiation source is calculated quickly and accurately, and the alignment is completed by only moving the detector according to the offset value. The operation is simple, time-saving and labor-saving, and the alignment efficiency is improved, thereby enhancing the user experience.

[0030] It should be understood that Figure 1aThis is merely a schematic illustration of how the calibration phantom is used to align the detector and radiation source, and does not limit the structure, type, or number of imaging systems in other application scenarios or embodiments. For example, in other application scenarios or embodiments, the calibration phantom may be moved in other directions, such as in the opposite direction of the first direction N, or the detector or radiation source may be moved to capture a projection image through the detector.

[0031] In order to facilitate understanding of the method for aligning a detector and a ray source provided by an embodiment of the present invention, the imaging system provided by an embodiment of the present invention is first introduced in detail.

[0032] See also Figure 2a , Figure 2a The structural diagram of the imaging system provided by some embodiments of the present invention is schematically shown.

[0033] Specifically, such as Figure 2a As shown, the imaging system 100 includes a controller 150 , a detector 110 , a ray source 120 , a calibration phantom 130 and a guide rail 140 . The controller 150 is communicatively connected to the detector 110 , the ray source 120 and the calibration phantom 130 , respectively.

[0034] See also Figure 2b The guide rail 140 is vertically arranged between the detector 110 and the radiation source 120, and the calibration phantom 130 is passed through the guide rail 140. The calibration phantom 130 includes a plurality of small balls 131. It should be understood that the spacing, arrangement, and number of the small balls 131 of the calibration phantom 130 can be set according to actual needs, and the embodiment of the present invention does not impose any limitation on this. The guide rail 140 serves as a carrier of the calibration phantom 130, enabling the calibration phantom 130 to move in a stable direction, so that the detector 110 can capture a high-quality projection image, which facilitates the alignment of the detector 110 and the radiation source 120.

[0035] In the embodiment of the present invention, any suitable material and shape of the calibration phantom 130 can be selected according to actual needs. For example, see Figure 2c 、 Figure 2d and Figure 2e , Figure 2c 、 Figure 2d and Figure 2e Three views of the calibration phantom 130 provided by some embodiments of the present invention are respectively shown.

[0036] See also Figure 2f , a plurality of positioning points 141 are provided on the guide rail 140, wherein, Figure 2fThe guide rail 140 is shown with seven positioning points, designated P1-P7, and any two positioning points 141 are separated by a predetermined distance d. It will be appreciated that by setting the positioning points 141, when the calibration phantom 130 moves to each positioning point, the detector 110 is controlled to capture a projection image. This ensures that the projection points formed by each ball 131 on the projection image are spaced apart, facilitating the acquisition of the coordinates of each projection point. Clearly, when moving the calibration phantom 130, movement can begin at any positioning point or not. If movement begins at a positioning point, the detector 110 can be controlled to capture a projection image when the calibration phantom 130 begins moving. If movement does not begin at a positioning point, the detector 110 can be controlled to capture a projection image when the calibration phantom 130 moves to a positioning point.

[0037] It is understood that the distance between any two positioning points 141 can be the same or different. In the embodiment of the present invention, the distance d between them is set to be the same in order to facilitate the subsequent identification of the projection point and the calculation of the target position. In some embodiments, the distance between any two positioning points 141 can also be set to be different according to actual needs. In addition, Figure 2f The guide rail 140 is merely schematically shown to be provided with positioning points 141 , which does not impose any limitation on the number, position, spacing, style, etc. of the positioning points.

[0038] See also Figure 2g , Figure 2g The following schematically shows the structure of a controller in an imaging system provided by some embodiments of the present invention.

[0039] like Figure 2g As shown, the controller 150 includes at least one processor 151 and a memory 152 that are communicatively connected. Figure 2g In the example, the bus system 153 is connected to a processor. The various components in the controller 150 are coupled together through the bus system 153, and the bus system 153 is used to realize the connection and communication between the various components. It is easy to understand that the bus system 153 includes not only a data bus, but also a power bus, a control bus, and a status signal bus. However, for the sake of clarity and brevity, Figure 2g In FIG, various buses are labeled as bus system 153. It can be understood that Figure 2g The structure shown in the embodiment is only for illustration and does not impose any limitation on the structure of the controller. Figure 2g The structures shown may have more or fewer components, or may have Figure 2g Different configurations of the structure are shown.

[0040] Specifically, the processor 151 is used to provide computing and control capabilities to control the controller 150 to perform corresponding tasks, such as controlling the controller 150 to perform any of the detector and radiation source alignment methods provided in the embodiments of the present invention, or to perform the steps in any possible implementation of any of the detector and radiation source alignment methods provided in the embodiments of the present invention. Those skilled in the art will understand that the processor 151 can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0041] Memory 152, as a non-transitory computer-readable storage medium, can be used to store non-transitory software programs, non-transitory computer-executable programs, instructions, and modules, such as the programs, instructions, and modules corresponding to the detector and radiation source alignment method in the embodiments of the present invention. In some embodiments, memory 152 may include a program storage area and a data storage area. The program storage area may store an operating system and application programs required for at least one function, and the data storage area may store data created based on the use of processor 151. By running the non-transitory software programs, instructions, and modules stored in memory 152, processor 151 executes various functional applications and data processing of controller 150 to implement any of the detector and radiation source alignment methods provided in the embodiments of the present invention, or to perform the steps of any possible implementation of any of the detector and radiation source alignment methods provided in the embodiments of the present invention. In some embodiments, memory 152 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state memory device. In some embodiments, memory 152 may also include memory located remotely from processor 151, which may be connected to processor 151 via a communication network. It is understandable that examples of the above-mentioned communication network include but are not limited to the Internet, corporate intranet, local area network, mobile communication network and combinations thereof.

[0042] As can be understood from the foregoing, any detector and radiation source alignment method provided in the embodiments of the present invention may be implemented by any suitable type of controller having certain computing and control capabilities, for example, the controller 150 described above. In some feasible implementations, any detector and radiation source alignment method provided in the embodiments of the present invention may be implemented by a processor executing computer program instructions stored in a memory.

[0043] The method for aligning a detector and a radiation source provided by an embodiment of the present invention will be described in detail below in conjunction with exemplary applications and implementations of the controller provided by an embodiment of the present invention.

[0044] See also Figure 3 , Figure 3 A schematic flow chart of a method for aligning a detector and a radiation source provided in some embodiments of the present invention is shown.

[0045] Those skilled in the art will appreciate that the detector and ray source alignment method provided in the embodiments of the present invention can be applied to the aforementioned controller (e.g., controller 150). Specifically, the detector and ray source alignment method is executed by one or at least two processors of the controller.

[0046] like Figure 3 As shown, the method for aligning the detector and the radiation source includes but is not limited to the following steps S100-S600: S100: Control the movement of the calibration phantom and obtain multiple projection images captured by the detector.

[0047] In this step, the projected images are images of the calibration phantom at multiple stages of movement. These stages refer to the process of capturing multiple images by the detector while controlling the calibration phantom's movement. Each projected image includes projection points formed by the projection of the balls, with each ball corresponding to a projection point. That is, each ball forms a corresponding projection point in each projected image.

[0048] In this embodiment, when alignment between the detector and the radiation source is required, the calibration phantom is controlled to move in any direction or along a predetermined path, and the detector is controlled to capture projection images at multiple stages of movement. Each time the calibration phantom moves a certain distance, the detector is controlled to capture a corresponding projection image. For each additional distance the calibration phantom moves, the detector is controlled to capture a corresponding projection image, thereby capturing multiple projection images. After capturing multiple projection images, the detector transmits these images to the controller, which then acquires the multiple projection images.

[0049] For example, see Figure 4a 、 Figure 4b and Figure 4c , Figure 4a 、 Figure 4b and Figure 4c The first projection image (i.e., projection image PP1), the second projection image (i.e., projection image PP2), and the third projection image (i.e., projection image PP3) obtained by the detector are shown respectively. Figure 2d The calibration phantom shown is photographed, so the projection image PP1 obtained by the photography includes projection points C1 to C8, the projection image PP2 includes projection points D1 to D8, and the projection image PP3 includes projection points E1 to E8.

[0050] For example, in some embodiments, controlling the movement of the calibration phantom and acquiring multiple projection images captured by the detector specifically includes but is not limited to the following steps S110-S120: S110: Control the calibration phantom to move along the first direction on the guide rail to each positioning point.

[0051] S120: In response to detecting that the calibration phantom moves to the positioning point, the detector is controlled to capture a projection image to obtain a plurality of projection images.

[0052] In this embodiment, the imaging system further includes a guide rail provided between the detector and the ray source, the calibration phantom passes through the guide rail, and the guide rail is provided with a plurality of positioning points, and any two positioning points are separated by a preset distance.

[0053] Specifically, the calibration phantom is controlled to move along the guide rails in a first direction, moving to each positioning point. A position sensor or encoder is used to detect whether the calibration phantom has reached the positioning point. For each positioning point, if the calibration phantom is detected to have reached the positioning point, the detector is controlled to capture a corresponding projection image. Thus, each time the calibration phantom moves to a positioning point, the detector is controlled to capture a corresponding projection image, thereby generating multiple projection images.

[0054] In some embodiments, before controlling the calibration phantom to move along the first direction on the guide rail to each positioning point, the method for aligning the detector and the radiation source further includes but is not limited to the following steps S101: S101: Control the movement of the ray source or detector so that the projected image is within the field of view of the detector.

[0055] In this step, the projected image is an image formed by the rays from the ray source projected onto the calibration phantom, that is, the rays from the ray source projected onto the plane where the detector is located, passing through the calibration phantom and forming an image on the plane where the detector is located.

[0056] Specifically, to enable the detector to capture the projection image, before controlling the calibration phantom to move along the guide rails in the first direction to each positioning point, the radiation source or detector is controlled to move and the projection image is captured in real time to determine whether the captured projection image is within the detector's field of view. If the projection image is not within the detector's field of view, the position of the radiation source or detector is further adjusted until the projection image is within the detector's field of view.

[0057] S200: Based on the projection image, extract a point set of projection points in the projection image.

[0058] Specifically, the projection images are processed to identify and extract the locations of projection points formed by multiple balls from each projection image. Exemplarily, the projection images are grayscaled and converted to grayscale images. Methods such as Gaussian filtering and median filtering are used to remove noise from the grayscale images. Histogram equalization or adaptive contrast enhancement techniques are used to enhance the difference between the ball projection points and the background. An edge detection algorithm (such as the Canny algorithm) is then used to identify contours in the grayscale image. Based on the circular or nearly circular nature of the ball projection points, a Hough transform is used to detect circular regions in the grayscale image. For each identified projection point region (circular region), the center of mass coordinates are calculated and used as the coordinates of the projection point in the grayscale image. Finally, based on the ball's position, the coordinates of the projection points corresponding to the identified balls at corresponding positions in all projection images are combined to obtain a point set of projection points corresponding to each ball position. This point set of projection points is then used to fit a reference line.

[0059] For example, see Figure 5a The projection points C1 to C8 of the projection image PP1 (the projection points D1 to D8 of the projection image PP2 / the projection points E1 to E8 of the projection image PP3) correspond to ball 1 at position AD1, ball 2 at position AD2, ball 3 at position AD3, ball 4 at position AD4, ball 5 at position AD5, ball 6 at position AD6, ball 7 at position AD7 and ball 8 at position AD8, respectively.

[0060] See also Figure 5b , Figure 5bThe point sets corresponding to the balls at all positions are shown, that is, the coordinates of the projection points C1, D1 and E1 corresponding to the ball 1 at position AD1 constitute the first point set CDE1, the coordinates of the projection points C2, D2 and E2 corresponding to the ball 2 at position AD2 constitute the second point set CDE2, the coordinates of the projection points C3, D3 and E3 corresponding to the ball 3 at position AD3 constitute the third point set CDE3, the coordinates of the projection points C4, D4 and E4 corresponding to the ball 4 at position AD4 constitute the fourth point set CDE4, the coordinates of the projection points C5, D5 and E5 corresponding to the ball 5 at position AD5 constitute the fifth point set CDE5, the coordinates of the projection points C6, D6 and E6 corresponding to the ball 6 at position AD6 constitute the sixth point set CDE6, the coordinates of the projection points C7, D7 and E7 corresponding to the ball 7 at position AD7 constitute the seventh point set CDE7, and the coordinates of the projection points C8, D8 and E8 corresponding to the ball 8 at position AD8 constitute the eighth point set CDE8. It can be understood that Figure 5b The schematic diagram shown is an image formed by superimposing the projection image PP1, the projection image PP2 and the projection image PP3 based on the center of the detector (i.e., point O2), so as to extract the point set of projection points corresponding to the ball at each position, and it is also beneficial for the subsequent determination of the reference straight line based on the point set of projection points.

[0061] In some embodiments, based on the projection image, extracting a point set of projection points in the projection image includes but is not limited to the following steps S210-S230: S210: performing binarization processing on the projected image.

[0062] S220: Extract different centroids of projection points corresponding to small balls at different positions in the projection image, and use the coordinates of the centroids as reference coordinates of the projection points corresponding to the small balls.

[0063] S230: Number each ball, and obtain a point set of all balls according to the number and the reference coordinates.

[0064] Specifically, each projected image is binarized, that is, converted into a binary image with only two pixel values ​​(usually 0 and 255, i.e., black and white). First, the projected image is converted to a grayscale image to eliminate color interference. Then, a reasonable pixel segmentation threshold is calculated using the Otsu algorithm, the P-Tile algorithm, or any other suitable method or approach. Finally, pixel values ​​greater than or equal to the pixel segmentation threshold are set to the maximum pixel value of 255 (i.e., white), and pixel values ​​less than the pixel segmentation threshold are set to the minimum pixel value of 255 (i.e., black). This results in the binarized projected image (hereinafter referred to as the reference projected image).

[0065] In this embodiment, a connected domain analysis algorithm is used to perform connected domain analysis on the reference projection image, identify the connected domain in the reference projection image, and extract the centroid of the connected domain. The connected domain is the projection point, and the centroid of the connected domain is the centroid of the projection point, thereby obtaining multiple different centroids of the projection points corresponding to the small balls at all positions, and the coordinates of the centroid of the projection point corresponding to the small ball at each position are used as the reference coordinates of the projection point corresponding to the small ball.

[0066] Specifically, each ball is numbered, and based on the ball number and the reference coordinates of the projection point corresponding to the ball, a point set of projection points corresponding to all balls at all positions is obtained. That is, the reference coordinates of the projection points corresponding to each numbered ball are combined to obtain the point set of projection points corresponding to that numbered ball, thereby obtaining the point set of projection points corresponding to all balls at all positions.

[0067] For example, see Figure 5a and Figure 5b , the ball at position AD1 is numbered 1, and the reference coordinates of the projection points C1, D1, and E1 corresponding to ball 1 constitute the first point set CDE1 (i.e., the point set of the projection points corresponding to ball 1). The ball at position AD2 is numbered 2, and the reference coordinates of the projection points C2, D2, and E2 corresponding to ball 2 constitute the second point set CDE2 (i.e., the point set of the projection points corresponding to ball 2). The ball at position AD3 is numbered 3, and the reference coordinates of the projection points C3, D3, and E3 corresponding to ball 3 constitute the third point set CDE3 (i.e., the point set of the projection points corresponding to ball 3). The ball at position AD4 is numbered 4, and the reference coordinates of the projection points C4, D4, and E4 corresponding to ball 4 constitute the fourth point set CDE4 (i.e., the point set of the projection points corresponding to ball 4). The ball at position AD5 is numbered 5, and the reference coordinates of the projection points C5, D5, and E5 corresponding to ball 5 constitute the fifth point set CDE5 (i.e., the point set of the projection points corresponding to ball 5). The ball at position AD6 is numbered 6. The reference coordinates of the projection points C6, D6, and E6 corresponding to ball 6 constitute the sixth point set CDE6 (i.e., the point set of the projection points corresponding to ball 6). The ball at position AD7 is numbered 7. The reference coordinates of the projection points C7, D7, and E7 corresponding to ball 7 constitute the seventh point set CDE7 (i.e., the point set of the projection points corresponding to ball 7). The ball at position AD8 is numbered 8. The reference coordinates of the projection points C8, D8, and E8 corresponding to ball 8 constitute the eighth point set CDE8 (i.e., the point set of the projection points corresponding to ball 8).

[0068] S300: Determine a reference straight line based on a point set of projection points in the projection image.

[0069] In the embodiment of the present invention, for all projection images, the coordinates of the projection points corresponding to the balls at all positions are extracted and recorded as the point set , , For the The coordinates of the projection points corresponding to the balls at all positions in the projection image, is the number of projected images, The projected image The coordinates of the projection point corresponding to the ball at the position, is the number of balls, that is, the number of projection points, , The coordinates of the projection points corresponding to the balls at each position are connected to obtain a corresponding reference straight line. After connecting the coordinates of the projection points corresponding to the balls at all positions, multiple reference straight lines are obtained.

[0070] For example, see Figure 5c , Figure 5c Shows the connection Figure 5b The schematic diagram obtained by calculating the coordinates of the projection points corresponding to the balls at all positions in the image. Figure 5c It includes eight reference straight lines, namely reference straight line L1, reference straight line L2, reference straight line L3, reference straight line L4, reference straight line L5, reference straight line L6, reference straight line L7 and reference straight line L8. Reference straight line L1 is obtained by connecting the coordinates of projection points C1, D1 and E1 corresponding to ball 1 at position AD1. Reference straight line L2 is obtained by connecting the coordinates of projection points C2, D2 and E2 corresponding to ball 2 at position AD2. Reference straight line L3 is obtained by connecting the coordinates of projection points C3, D3 and E3 corresponding to ball 3 at position AD3. The reference straight line L4 is obtained by connecting the coordinates of the projection points C4, D4 and E4 corresponding to the ball 4 at position AD4, the reference straight line L5 is obtained by connecting the coordinates of the projection points C5, D5 and E5 corresponding to the ball 5 at position AD5, the reference straight line L6 is obtained by connecting the coordinates of the projection points C6, D6 and E6 corresponding to the ball 6 at position AD6, the reference straight line L7 is obtained by connecting the coordinates of the projection points C7, D7 and E7 corresponding to the ball 7 at position AD7, and the reference straight line L8 is obtained by connecting the coordinates of the projection points C8, D8 and E8 corresponding to the ball 8 at position AD8.

[0071] It should be understood that Figure 5c The marks of each projection point are omitted, and the balls and marks at the corresponding positions are the same as Figure 5b The balls and marks in corresponding positions are shown to be the same.

[0072] In some embodiments, determining a reference line based on a point set of projection points in a projection image includes but is not limited to the following steps S310-S330: S310: Select any one of the multiple projection points as a target projection point.

[0073] S320: Determine the reference coordinates of the target projection point in each projection image to obtain multiple target coordinates.

[0074] S330: Based on the multiple target coordinates, obtain a reference straight line corresponding to the target projection point.

[0075] For example, for any projection image, any one of the multiple projection points of the projection image is selected as the target projection point, the target projection point is the projection point corresponding to the target ball, and the target ball is any one of the multiple balls, for example, Figure 5a The ball 1 is shown.

[0076] Specifically, after determining the target projection point, the reference coordinates of the target projection point are determined in each projection image to obtain multiple target coordinates, that is, the reference coordinates of the target projection point corresponding to the target ball in each projection image are used as the target coordinates to obtain multiple target coordinates.

[0077] In this embodiment, multiple target coordinates are connected to obtain a reference line corresponding to the target projection point. That is, the reference coordinates (i.e., target coordinates) of the target projection point corresponding to each target ball are connected to obtain a corresponding reference line. After the reference coordinates (i.e., target coordinates) of the target projection points corresponding to all target balls are connected, multiple reference lines are obtained.

[0078] For example, see Figure 5a 、 Figure 5b and Figure 5c , select projection point C1 in projection image PP1 as the target projection point, projection point C1 as the projection point corresponding to ball 1, ball 1 as the target ball, determine the reference coordinates of the target projection point corresponding to ball 1 (i.e., projection point D1 and projection point E1) in projection image PP2 and projection image PP3, obtain multiple target coordinates (i.e., the reference coordinates of projection point C1, projection point D1, and projection point E1), connect the multiple target coordinates to obtain a corresponding reference straight line L1.

[0079] S400: Determine a target position based on a plurality of reference straight lines.

[0080] In this embodiment of the present invention, the target position is the position where the central ray of the radiation source is projected onto the plane where the detector is located. It will be appreciated that the multiple reference lines tend to point toward or surround the projection point of the central ray of the radiation source onto the plane where the detector is located. In other words, the projection position of the central ray of the radiation source onto the plane where the detector is located is located at or near the intersection of the multiple reference lines.

[0081] Specifically, select any two reference lines from multiple reference lines. and , and solve for the reference line and The intersection of intersection points, is the number of reference lines. Then determine whether all the intersections are concentrated in a certain area. If they are concentrated in a certain area, it means that the area is the projection point of the central ray of the ray source on the plane where the detector is located. Finally, determine the target position based on all the intersections, that is, take the mean of the horizontal coordinates and the mean of the vertical coordinates of all the intersections, and use the mean of the horizontal coordinates and the mean of the vertical coordinates as the target position. In some embodiments, the target position is calculated by the minimum distance, that is, minimize the total distance from the point to all reference lines, find a point so that the sum of its distances to all reference lines is minimized, and obtain the target point. The target point is the target position.

[0082] For example, see Figure 5c , point O1 is the target position, where point O1 is the intersection of multiple reference lines.

[0083] In some embodiments, determining the target position based on multiple reference lines includes but is not limited to the following steps S410-S420: S410: Constructing a straight line matrix equation based on the multiple reference straight lines.

[0084] S420: Solve the linear matrix equation to obtain the intersection point of the reference straight line.

[0085] In this step, the intersection point is the target position.

[0086] Specifically, for the point set of projection points corresponding to each ball, a fitting line is constructed , the fitting straight line is the reference straight line, is the direction vector, For the The point set of the projection points corresponding to the balls corresponds to the constructed fitting line. Let , , then the equation of each fitted line is:

[0087] According to all the fitted straight lines, construct the straight line matrix equation : in, , ,

[0088] Specifically, the least squares method or any other appropriate method is used to solve the above linear matrix equation to obtain , Coordinates in This is the intersection of the reference lines (i.e., the target position). It is understandable that in practice, the position of the ball's projection point may have errors. Therefore, the least squares method is needed to find the coordinates of the target point that is closest to the sum of the distances to all reference lines. The coordinates of the target point are the coordinates of the target position.

[0089] S500: Based on the target position, calculate the offset value between the target position and the reference position.

[0090] In this step, the reference position is the center of the plane where the detector is located, that is, the ideal position (or standard position) where the central ray of the ray source is projected onto the plane where the detector is located after the ray source and the detector are aligned.

[0091] Specifically, the center coordinates of the detector plane (i.e., the reference position) are obtained. These coordinates are fixed and known in the detector imaging coordinate system and are half the width and height of the projected image. Based on the coordinates of the reference and target positions, the offset between the target and reference positions is calculated using the distance calculation formula.

[0092] For example, in some embodiments, based on the target position, calculating the offset value between the target position and the reference position specifically includes but is not limited to the following steps S510-S530: S510: Acquire a reference position.

[0093] S520: Calculating a pixel offset distance between the target position and the reference position based on the target position and the reference position.

[0094] S530: Multiply the pixel offset distance by the resolution of the detector to obtain an offset value between the target position and the reference position.

[0095] Specifically, the center of the plane where the detector is located (i.e., the reference position) is obtained. It can be understood that after the detector is stably docked, the center of the plane where the detector is located can be determined, wherein the detector can send the center of the plane where it is located to the controller, or the controller can actively obtain the center of the plane where the detector is located from the detector.

[0096] Specifically, the coordinates of the target and reference locations are substituted into a distance calculation formula, such as the Euclidean distance formula, to calculate the pixel offset between the target and reference locations. The pixel offset is the distance in the detector's pixel coordinate system. The detector's resolution is then calculated, and the pixel offset is multiplied by the detector's resolution to obtain the offset between the target and reference locations. This offset is the distance in the real-world physical coordinate system.

[0097] S600: Based on the offset value, the detector is controlled to move to the target position to complete the alignment of the detector and the radiation source.

[0098] Specifically, after calculating the offset value, the detector is controlled to move along the X-axis / Y-axis to the target position so that the center of the detector plane coincides with the projection of the center ray of the radiation source on the detector plane, thereby achieving precise alignment between the detector and the radiation source. In some embodiments, after the movement is completed, the current position of the detector can be read using a position feedback sensor or encoder to verify whether it has reached the target position. If necessary, fine-tuning and compensation can be performed to ensure that the detector and radiation source are truly aligned.

[0099] For example, see Figure 6a as well as Figure 6b , Figure 6a shows a three-dimensional schematic diagram after the detector and the ray source are aligned, Figure 6b shows a top view of the detector and the ray source after alignment, Figure 6a The guide rails, correction phantoms and other components in the imaging system are omitted. After the detector and the radiation source are aligned, the center of the plane where the detector is located (i.e., the reference position / point O2) coincides with the projection position of the central ray 121 of the radiation source on the plane where the detector is located (i.e., the target position / point O1).

[0100] In some embodiments, based on the offset value, controlling the detector to move to the target position specifically includes but is not limited to the following steps S610-S620: S610: Determine a target orientation of the detector relative to the ray source based on the X-axis offset value and the Y-axis offset value.

[0101] In this embodiment, the offset value includes an X-axis offset value and a Y-axis offset value, and the target orientation represents the relative positional relationship between the center of the plane where the detector is located and the projection position of the central ray of the ray source on the plane where the detector is located.

[0102] In an embodiment of the present invention, a coordinate system is established with the reference position (i.e., the center of the plane where the detector is located) as the origin. The X-axis offset value is the horizontal offset of the target position (i.e., the projection position of the central ray of the ray source on the plane where the detector is located) relative to the reference position, and the Y-axis offset value is the vertical offset of the target position relative to the reference position.

[0103] Specifically, the direction quadrant in which the target position is located relative to the reference position is determined based on the signs of the X-axis offset value and the Y-axis offset value. Figure 7 and Figure 8 , Figure 7 and Figure 8 The schematic diagram of the positional relationship between the reference position and the target position of the coordinate system in a top-down perspective is schematically shown, where point O2 is the reference position and point O1 is the target position.

[0104] See Figure 7As shown in a in , if the X-axis offset value and the Y-axis offset value are both positive, the target orientation is that the detector is located at the lower left of the ray source, and the detector should be moved to the upper right.

[0105] See Figure 7 As shown in b, if the X-axis offset value is positive and the Y-axis offset value is negative, the target orientation is that the detector is located to the upper left of the ray source, and the detector should be moved to the lower right.

[0106] See Figure 7 As shown in c, if the X-axis offset value and the Y-axis offset value are both negative, the target orientation is that the detector is located to the upper right of the ray source, and the detector should be moved to the lower left.

[0107] See Figure 7 As shown in d, if the X-axis offset value is negative and the Y-axis offset value is positive, the target orientation is that the detector is located at the lower right of the ray source, and the detector should move to the upper left.

[0108] See Figure 8 As shown in a in , if the X-axis offset value is 0 and the Y-axis offset value is positive, the target orientation is that the detector is directly below the ray source, and the detector should move directly upward.

[0109] See Figure 8 As shown in b, if the X-axis offset value is 0 and the Y-axis offset value is negative, the target orientation is that the detector is directly above the ray source, and the detector should be moved directly downward.

[0110] See Figure 8 As shown in c, if the X-axis offset value is positive and the Y-axis offset value is 0, the target orientation is that the detector is located to the left of the ray source, and the detector should move to the right.

[0111] See Figure 8 As shown in d, if the X-axis offset value is negative and the Y-axis offset value is 0, the target orientation is that the detector is located to the right of the ray source, and the detector should move to the left.

[0112] S620: Based on the target orientation, control the detector to move by the X-axis offset value and the Y-axis offset value, so that the detector moves to the target position.

[0113] In this embodiment, when the target orientation is that the detector is located at the lower left of the ray source, the detector is controlled to move to the upper right, that is, the detector is controlled to move to the right by the absolute value of the X-axis offset value and to the upper part by the absolute value of the Y-axis offset value, so that the detector moves to the target position.

[0114] When the target orientation is that the detector is located to the upper left of the ray source, the detector is controlled to move to the lower right, that is, the detector is controlled to move to the right by the absolute value of the X-axis offset value and to the lower by the absolute value of the Y-axis offset value, so that the detector moves to the target position.

[0115] When the target orientation is that the detector is located to the upper right of the ray source, the detector is controlled to move to the lower left, that is, the detector is controlled to move to the absolute value of the X-axis offset value to the left and to the absolute value of the Y-axis offset value to the bottom, so that the detector moves to the target position.

[0116] When the target orientation is that the detector is located at the lower right of the ray source, the detector is controlled to move to the upper left, that is, the detector is controlled to move to the absolute value of the X-axis offset value to the left and to the absolute value of the Y-axis offset value to the upper part, so that the detector moves to the target position.

[0117] When the target orientation is that the detector is located directly below the ray source, the detector is controlled to move directly upward, that is, the detector is controlled to move directly upward by the absolute value of the Y-axis offset value, so that the detector moves to the target position.

[0118] When the target orientation is that the detector is located directly above the ray source, the detector is controlled to move directly downward, that is, the detector is controlled to move directly downward by the absolute value of the Y-axis offset value, so that the detector moves to the target position.

[0119] When the target orientation is that the detector is located to the left of the ray source, the detector is controlled to move to the right, that is, the detector is controlled to move to the right by the absolute value of the X-axis offset value, so that the detector moves to the target position.

[0120] When the target orientation is that the detector is located right to the ray source, the detector is controlled to move to the left, that is, the detector is controlled to move to the left by the absolute value of the X-axis offset value, so that the detector moves to the target position.

[0121] It can be understood that the embodiment of the present invention establishes a coordinate system with the reference position (i.e., the center of the plane where the detector is located) as the origin, and the coordinate system at a top-down perspective determines the target orientation of the detector relative to the radiation source and describes the moving direction of the detector. Those skilled in the art can also establish different coordinate systems according to actual needs, and determine the target orientation and describe the moving direction of the detector with coordinate systems at different perspectives. The embodiment of the present invention does not impose any limitations on this.

[0122] It should also be noted that the embodiment of the present invention is described by taking moving the detector to the target position to align the detector and the radiation source as an example. Those skilled in the art can also move the radiation source to a reference position to align the detector and the radiation source according to actual needs.

[0123] In summary, the alignment method of the detector and the radiation source provided in the embodiment of the present invention is applied to an imaging system, which includes a detector, a radiation source and a correction phantom, and the correction phantom includes multiple small balls. The method includes: controlling the movement of the correction phantom and obtaining multiple projection images taken by the detector, the projection images are images of multiple stages when the correction phantom moves, and each projection image has projection points formed by the projection of the small balls. Based on the projection image, a point set of the projection points in the projection image is extracted, based on the point set of the projection points in the projection image, a reference straight line is determined, and based on multiple reference straight lines, a target position is determined, the target position is the position where the center ray of the radiation source is projected to the plane where the detector is located, and based on the target position, an offset value between the target position and the reference position is calculated, and the reference position is the center of the plane where the detector is located. Based on the offset value, the detector is controlled to move to the target position to complete the alignment of the detector and the radiation source.

[0124] The embodiment of the present invention uses a detector to capture multiple projection images of the correction model when it moves, extracts a point set of projection points formed by the projection of the small ball of the correction model in the projection image, determines a reference straight line based on the point set of projection points, determines a target position based on multiple reference straight lines, and then calculates the offset value between the target position and the center of the plane where the detector is located. Based on the offset value, the detector is controlled to move to the target position, thereby completing the alignment of the detector and the radiation source. In this way, the offset value between the detector and the radiation source is calculated quickly and accurately, and the alignment is completed by only moving the detector according to the offset value. The operation is simple, time-saving and labor-saving, and the alignment efficiency is improved, thereby enhancing the user experience.

[0125] An embodiment of the present invention provides a computer-readable storage medium, which stores computer program instructions executable by a processor. When the computer program instructions are executed by the processor, the computer executes any one of the detector and ray source alignment methods provided by the embodiments of the present invention, or executes the steps in any one of the implementation methods of any one of the detector and ray source alignment methods provided by the embodiments of the present invention.

[0126] Those skilled in the art will understand that the embodiments provided by the present invention are merely illustrative, and the order in which the steps in the methods of the embodiments are written does not imply a strict order of execution and does not limit the implementation process. The order can be adjusted, merged, and deleted according to actual needs. The modules or submodules, units or subunits in the devices or systems of the embodiments can be merged, divided, and deleted according to actual needs. For example, the division of units is only a logical function division, and there can be other division methods in actual implementation. For another example, multiple units or components can be combined or integrated into another device, or some features can be ignored or not executed.

[0127] Through the description of the above embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a general hardware platform, or can also be implemented using hardware. Those skilled in the art will understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When executed, the computer program can include the processes of the above-mentioned method embodiments. The storage medium can be a magnetic disk, an optical disk, a read-only memory (ROM), or a random access memory (RAM).

[0128] It should be noted that the above embodiments are intended to illustrate the technical concepts and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the scope of protection of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments can be implemented according to the technical solutions recorded in the embodiments of the present invention, or some of the technical features can be equivalently replaced. It is understandable that these modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present invention, and should be regarded as equal changes and modifications based on the embodiments of the present invention, and should all fall within the scope of the claims of the present invention.

Claims

1. A method for aligning a detector and a radiation source, applied to an imaging system, characterized in that: The imaging system includes a detector, a radiation source and a calibration phantom, wherein the calibration phantom includes a plurality of small balls; The method comprises: Control the movement of the calibration phantom and obtain multiple projection images taken by the detector. The projection images are images of multiple stages when the calibration phantom moves. Each projection image contains a projection point formed by the projection of the ball. Based on the projection image, a point set of projection points in the projection image is extracted; Determine a reference straight line based on a point set of projection points in the projection image; Based on multiple reference lines, the target position is determined, where the central ray of the ray source is projected onto the plane where the detector is located; Based on the target position, the offset value between the target position and the reference position is calculated, and the reference position is the center of the plane where the detector is located; Based on the offset value, the detector is controlled to move to the target position to complete the alignment of the detector and the radiation source.

2. The method according to claim 1, characterized in that The step of extracting a point set of projection points in the projection image based on the projection image includes: Binarize the projected image; Extract the different centroids of the projection points corresponding to the balls at different positions in the projection image, and use the coordinates of the centroids as the reference coordinates of the projection points corresponding to the balls; Number each ball, and get the point set of all balls based on the number and reference coordinates.

3. The method according to claim 2, characterized in that The step of determining a reference line based on a point set of projection points in the projection image includes: Select any one of the multiple projection points as the target projection point; Determine the reference coordinates of the target projection point in each projection image to obtain multiple target coordinates; Based on multiple target coordinates, a reference straight line corresponding to the target projection point is obtained.

4. The method according to claim 1, wherein The method of determining a target position based on a plurality of reference straight lines includes: Based on multiple reference lines, construct a linear matrix equation; Solve the linear matrix equation to obtain the intersection point of the reference line, which is the target position.

5. The method according to claim 1, wherein The step of calculating the offset between the target position and the reference position based on the target position includes: Get the reference position; Based on the target position and the reference position, calculating the pixel offset distance between the target position and the reference position; Multiply the pixel offset distance by the detector resolution to obtain the offset value between the target position and the reference position.

6. The method according to claim 1, characterized in that The offset value includes an X-axis offset value and a Y-axis offset value, and controlling the detector to move to a target position based on the offset value includes: Determine the target orientation of the detector relative to the ray source based on the X-axis offset value and the Y-axis offset value; Based on the target position, the detector is controlled to move by the X-axis offset value and the Y-axis offset value so that the detector moves to the target position.

7. The method according to claim 1, characterized in that The imaging system also includes a guide rail provided between the detector and the radiation source, the correction phantom is passed through the guide rail, the guide rail is provided with a plurality of positioning points, and any two positioning points are separated by a preset distance; The control correction phantom movement and acquisition of multiple projection images captured by the detector include: Controlling the calibration phantom to move along the first direction on the guide rail to each positioning point; In response to detecting that the calibration phantom moves to the positioning point, the detector is controlled to capture a projection image to obtain a plurality of projection images.

8. The method according to claim 7, characterized in that Before the control correction phantom moves along the first direction on the guide rail to each positioning point, the method further includes: Control the movement of the ray source or detector so that the projection image is within the field of view of the detector. The projection image is the image formed by the rays from the ray source projected onto the calibration phantom.

9. An imaging system, characterized in that: include: A controller, a detector, a radiation source, a calibration phantom, and a guide rail, wherein the guide rail is vertically arranged between the detector and the radiation source, the calibration phantom is passed through the guide rail, the calibration phantom includes a plurality of small balls, and the guide rail is provided with a plurality of positioning points, with any two positioning points separated by a preset distance; The controller is communicatively connected to the detector, the ray source and the calibration phantom respectively; The controller includes: a processor and a memory communicatively connected to the processor; The memory stores computer program instructions executable by the processor, and when the computer program instructions are executed by the processor, the controller executes the method for aligning a detector and a ray source according to any one of claims 1 to 8.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer program instructions executable by a processor. When the computer program instructions are executed by the processor, the computer executes the method for aligning a detector and a ray source according to any one of claims 1 to 8.

Images