A flat panel detector positioning method, system, apparatus, and medium

Abstract

The application provides a flat panel detector positioning method, system, device and medium, comprising the following steps: acquiring a flat panel detector in a target environment, based on a time sequence collected positioning image sequence and magnetic field information sequence; extracting image coordinates of the flat panel detector in each positioning image; converting each image coordinate into a local space coordinate to obtain a local space position of the flat panel detector at each moving time; matching each local space position with each magnetic field information to obtain magnetic field information of the flat panel detector at each local space position as a magnetic field distribution in the target environment; acquiring current magnetic field information of the flat panel detector; and determining a current position of the flat panel detector based on the magnetic field distribution and the current magnetic field information. The flat panel detector positioning method, system, device and medium of the application can realize high-accuracy positioning of the flat panel detector when a low-frequency magnetic field distribution in the environment changes, greatly improving the positioning accuracy of the flat panel detector.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of positioning, and particularly relates to a flat panel detector positioning method, system, device and medium. BACKGROUND

[0002] The flat panel detector is one of the core components in a digital X-ray imaging system, has high sensitivity, can obtain a clear image under a lower radiation dose, thereby reducing radiation exposure to a patient, and is widely applied to various imaging examinations such as fluoroscopy, contrast and CT.

[0003] In the use process of the flat panel detector, the flat panel detector needs to be positioned to control the position of the flat panel detector relative to an X-ray source, so that the radiation dose distribution of the X-ray on the flat panel detector is more accurate, and the insufficient or excessive radiation dose received by the flat panel detector due to the position deviation is avoided. At present, since the low-frequency magnetic field is not affected by the human body shielding, the existing technology usually uses the low-frequency magnetic field to position the flat panel detector, obtains the low-frequency magnetic field information at the position of the flat panel detector, combines the low-frequency magnetic field distribution in the space which is measured in advance, to obtain the current position of the flat panel detector, and realizes the positioning of the flat panel detector. The existing flat panel detector positioning method usually pre-calibrates the magnetic field distribution in the space by manual operation, and applies the manually calibrated magnetic field distribution to the subsequent positioning of the flat panel detector. Since the low-frequency magnetic field is easily disturbed by the metal materials in the surrounding environment, when the distribution of the metal materials in the space changes, the current low-frequency magnetic field distribution in the space changes, that is, the low-frequency magnetic field information at the current position of the flat panel detector is different from the low-frequency magnetic field information measured in advance. Therefore, there is a large deviation between the position of the flat panel detector obtained based on the existing flat panel detector positioning method and the actual position of the flat panel detector, and the positioning accuracy of the flat panel detector is limited.

[0004] Therefore, how to reduce the influence of environmental changes on the positioning accuracy of the flat panel detector and realize high-accuracy positioning of the flat panel detector is an important problem to be solved at present. SUMMARY

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a flat panel detector positioning method for solving the problem that the current flat panel detector positioning method cannot accurately position the flat panel detector after the surrounding environment changes.

[0006] To achieve the above object and other related objects, the present application provides a flat panel detector positioning method, comprising the following steps:

[0007] Acquire a flat panel detector in a target environment, based on a sequence of positioning images and a sequence of magnetic field information collected in time sequence; the sequence of positioning images comprises: each positioning image containing the flat panel detector acquired in real time in the movement process of the flat panel detector; the sequence of magnetic field information comprises: the magnetic field information of the flat panel detector at each movement position acquired in real time in the movement process of the flat panel detector;

[0008] Extract the image coordinates of the flat panel detector in each positioning image; convert each image coordinate into a local space coordinate to obtain the local space position of the flat panel detector at each movement time;

[0009] Correspondingly match each space position and each magnetic field information to obtain the magnetic field information at each position of the flat panel detector as the magnetic field distribution in the target environment;

[0010] Acquire the current magnetic field information of the flat panel detector; based on the magnetic field distribution and the current magnetic field information, determine the current position of the flat panel detector;

[0011] Wherein, the local space coordinate is the coordinate of the flat panel detector in a pre-constructed local space coordinate system; the relative positions between the devices used to position the flat panel detector in the local space coordinate system remain unchanged.

[0012] In an embodiment of the present application, the acquisition method of the sequence of positioning images and the sequence of magnetic field information comprises:

[0013] In the movement process of the flat panel detector, the flat panel detector is photographed in real time, and the magnetic field of the flat panel detector at each movement position is sensed in real time;

[0014] Obtain the positioning image of the flat panel detector at each movement time as the sequence of positioning images; and obtain the magnetic field information of the flat panel detector at each movement time as the sequence of magnetic field information.

[0015] In an embodiment of the present application, the construction method of the local space coordinate system comprises:

[0016] Set a local coordinate origin; based on the local coordinate origin, construct the local space coordinate system; the local coordinate origin comprises: a magnetic field source, an X-ray source or a camera for photographing the positioning image; the relative positions between the magnetic field source, the X-ray source and the camera remain unchanged.

[0017] In an embodiment of the present application, when converting a single image coordinate into a local space coordinate, the conversion of each image coordinate into a local space coordinate comprises:

[0018] convert the image coordinates into camera coordinates in a three-dimensional camera coordinate system based on an intrinsic matrix of the camera; and convert the camera coordinates into local space coordinates based on a local extrinsic matrix of the camera.

[0019] The local extrinsic matrix is pre-constructed and contains rotation and translation information of the camera in the local coordinate system.

[0020] In an embodiment of the present application, the magnetic field distribution is obtained by:

[0021] The local space position and the magnetic field information at the same movement time are matched to obtain the magnetic field information at each local space position as the magnetic field distribution in the target environment.

[0022] In an embodiment of the present application, the current position of the flat panel detector is determined based on the magnetic field distribution and the current magnetic field information by:

[0023] The current position of the flat panel detector is obtained by searching the local space position corresponding to the current magnetic field information in the magnetic field distribution based on the current magnetic field information.

[0024] Correspondingly, the present application provides a flat panel detector positioning system, which comprises:

[0025] A obtaining module is configured to obtain a flat panel detector in a target environment based on a sequence of positioning images and a sequence of magnetic field information collected in time sequence; the sequence of positioning images comprises each positioning image containing the flat panel detector obtained in real time during movement of the flat panel detector; and the sequence of magnetic field information comprises magnetic field information of the flat panel detector at each movement position obtained in real time during movement of the flat panel detector.

[0026] A position extracting module is configured to extract image coordinates of the flat panel detector in each positioning image; and convert each image coordinate into a local space coordinate to obtain a local space position of the flat panel detector at each movement time; the local space coordinate is a coordinate of the flat panel detector in a pre-constructed local space coordinate system; and the relative positions between devices for positioning the flat panel detector in the local space coordinate system remain unchanged.

[0027] A magnetic field calibration module is configured to match each local space position and each magnetic field information one by one to obtain magnetic field information of the flat panel detector at each local space position as a magnetic field distribution in the target environment.

[0028] a detector positioning module, configured to acquire current magnetic field information of the flat panel detector; and determine a current position of the flat panel detector based on the magnetic field distribution and the current magnetic field information

[0029] Correspondingly, the present application provides a flat panel detector positioning device for positioning a flat panel detector, the device comprising:

[0030] a magnetic field source for generating a low-frequency magnetic field;

[0031] a camera for capturing a positioning image containing the flat panel detector;

[0032] a magnetic field sensor for sensing a magnetic field at a position where the flat panel detector is located to obtain magnetic field information;

[0033] a processing module connected to the camera and the magnetic field sensor respectively, configured to position the flat panel detector by using the flat panel detector positioning method as described above;

[0034] wherein the relative positions among the magnetic field source, the camera and the X-ray source remain unchanged.

[0035] In an embodiment of the present application, the device further comprises a positioning marker, which is arranged on a side of the flat panel detector facing the camera and does not block the radiation receiving surface of the flat panel detector.

[0036] Correspondingly, the present application provides a computer readable storage medium storing a computer program, which, when executed by a processor, implements the flat panel detector positioning method as described above.

[0037] As described above, the present application provides a flat panel detector positioning method, system, device and medium, which at least have the following advantages

[0038] Advantages:

[0039] The flat panel detector is acquired in a target environment, a positioning image sequence and a magnetic field information sequence are acquired, a local space position of the flat panel detector in a local coordinate system at each movement time is acquired based on the positioning image by using a visual positioning technology, the local space position at each movement time and the magnetic field information are matched to obtain a magnetic field distribution in the target environment, and the magnetic field distribution in the target environment is quickly calibrated; and the current magnetic field information of the flat panel detector in the target environment is acquired, the current position of the flat panel detector in the local coordinate system is quickly determined based on the magnetic field distribution and the current magnetic field information, the magnetic field distribution in the changed environment can be accurately acquired, the positioning accuracy of the flat panel detector relative to the X-ray source position is improved, and after the magnetic field distribution changes, manual recalibration of the magnetic field distribution in the space is not required, and the positioning efficiency of the flat panel detector relative to the X-ray source position is improved. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 A flowchart of a flat panel detector positioning method provided by the present application is shown in an embodiment.

[0041] Figure 2 A module diagram of a flat panel detector positioning system provided by the present application is shown in an embodiment.

[0042] Figure 3 A structural diagram of a flat panel detector positioning device provided by the present application is shown in an embodiment.

[0043] REFERENCE SIGNS

[0044] S1-S4, step; 200, flat panel detector positioning system; 201, acquisition module; 202, position extraction module; 203, magnetic field calibration module; 204, detector positioning module; A, flat panel detector; B, X-ray source; 1, magnetic field source; 2, camera; 3, magnetic field sensor; 4, processing module. DETAILED DESCRIPTION

[0045] The embodiments of the present application will be described in detail below with specific reference to the drawings. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the specification. The present application can also be implemented or applied by different specific embodiments, and the details in the specification can be modified or changed based on different views and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0046] It should be noted that the diagrams provided in the following embodiments only illustrate the basic concept of the present application in a schematic manner, and only the components related to the present application are shown in the diagrams, not the number, shape and size of the components when actually implemented. The actual implementation of each component can be a random change, and the component layout pattern can be more complex.

[0047] To facilitate the understanding of the technical solutions provided by the present application, the related terms in the present application are explained before the specific embodiments, as follows:

[0048] Intrinsic matrix: a matrix containing internal parameters of a camera, such as focal length, principal point coordinates (optical center), and physical size of pixels, used to map points in a three-dimensional camera coordinate system to points in a two-dimensional image coordinate system.

[0049] Extrinsic matrix: a transformation matrix from the world coordinate system to the camera coordinate system, usually containing two rotation matrices and a translation vector. The rotation matrix describes the rotation of the camera coordinate axis relative to the world coordinate axis, and the translation vector describes the position of the camera in the world coordinate system.

[0050] The embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the case of no conflict, the features in the following embodiments and implementation manners can be combined with each other.

[0051] The following embodiments of the present application provide a flat panel detector positioning method, which acquires a flat panel detector in a target environment, locates an image sequence and a magnetic field information sequence; based on the located image, the local space position of the flat panel detector in each moving moment in the pre-constructed local coordinate system is obtained by using visual positioning technology; the local space position and the magnetic field information at each moving moment are matched to obtain the magnetic field distribution in the target environment, realizing the rapid calibration of the magnetic field distribution in the target environment; and by acquiring the current magnetic field information of the flat panel detector in the target environment, based on the magnetic field distribution and the current magnetic field information, the current position of the flat panel detector in the local coordinate system is quickly determined, which not only can accurately obtain the magnetic field distribution in the changed environment, improve the positioning accuracy of the flat panel detector relative to the position of the X-ray source, and after the change of the magnetic field distribution, there is no need for manual recalibration of the magnetic field distribution in space, improving the positioning efficiency of the flat panel detector relative to the position of the X-ray source.

[0052] Please refer to Figure 1 , which shows a structure schematic diagram of a flat panel detector positioning method provided by the present application in an embodiment.

[0053] As Figure 1As shown, in the embodiment, the flat panel detector positioning method provided by the application comprises the following steps:

[0054] In step S1, a flat panel detector is acquired in a target environment, and a positioning image sequence and a magnetic field information sequence are acquired based on time sequence acquisition;

[0055] The positioning image sequence comprises real-time acquisition of each positioning image of the flat panel detector during movement of the flat panel detector; and the magnetic field information sequence comprises real-time acquisition of magnetic field information at each movement position of the flat panel detector during movement of the flat panel detector.

[0056] Specifically, the flat panel detector is moved in the target environment; during movement of the flat panel detector, the flat panel detector is photographed in real time, and the magnetic field at the position of the flat panel detector is sensed in real time, to obtain a positioning image of the flat panel detector at each movement time, as the positioning image sequence; and to obtain magnetic field information of the flat panel detector at each movement position, as the magnetic field information sequence.

[0057] Optionally, the magnetic field information comprises magnetic field strength and magnetic field direction.

[0058] In step S2, image coordinates of the flat panel detector in each positioning image are extracted; each image coordinate is converted into a local space coordinate, to obtain a local space position of the flat panel detector at each movement time.

[0059] The local space coordinate is a coordinate of the flat panel detector in a pre-constructed local space coordinate system; in the local space coordinate system, the relative positions between devices used for positioning the flat panel detector remain unchanged.

[0060] Specifically, each positioning image is input into a pre-constructed extraction model, to obtain each extraction result output by the extraction model; based on the extraction result, image coordinates of the flat panel detector in each positioning image are obtained; coordinate conversion is performed on each image coordinate, to obtain a local space coordinate corresponding to each image coordinate; based on the movement time corresponding to each positioning image, a local space position of the flat panel detector at each movement time is obtained.

[0061] Optionally, the extraction model is a pre-constructed neural network model used for extracting a target extraction object; the target extraction object comprises the flat panel detector.

[0062] Optionally, the construction method of the local space coordinate system comprises:

[0063] Setting a local coordinate origin; constructing the local space coordinate system based on the local coordinate origin; the local coordinate origin includes: a magnetic field source, an X-ray source or a camera for shooting the positioning image; the relative positions among the magnetic field source, the X-ray source and the camera remain unchanged.

[0064] Optionally, the conversion of each image coordinate into a local space coordinate includes:

[0065] Converting the image coordinate into a camera coordinate in a three-dimensional camera coordinate system based on an intrinsic matrix of the camera; converting the camera coordinate into a local space coordinate based on a local extrinsic matrix of the camera;

[0066] Wherein, the local extrinsic matrix contains rotation and translation information of the camera in the local coordinate system.

[0067] Optionally, the acquisition method of the local extrinsic matrix includes:

[0068] Calibrating the local space coordinate system to determine the geometric relationship between the camera and the local space coordinate system; constructing a local extrinsic matrix of the camera relative to the local space coordinate system based on the geometric relationship.

[0069] Optionally, the image coordinates of the upper left corner, the lower left corner, the upper right corner, the lower right corner or the center point of the extraction result are taken as the image coordinates of the flat panel detector in the positioning image.

[0070] Illustratively, the extraction result output by the extraction model is a recognition box, and the coordinates of the upper left corner, the lower left corner, the upper right corner, the lower right corner or the center point of the recognition box in the positioning image are taken as the image coordinates of the flat panel detector in the positioning image.

[0071] It should be noted that the acquisition method of the local extrinsic matrix is the same as the acquisition method of the extrinsic matrix of the camera relative to the world coordinate system, and the local extrinsic matrix can be acquired based on other existing acquisition methods of extrinsic matrix, which is not limited in the present application.

[0072] Step S3, respectively, one-to-one corresponding matching of each local space position and each magnetic field information is performed to obtain the magnetic field information of the flat panel detector at each local space position as the magnetic field distribution in the target environment;

[0073] Specifically, based on the correspondence between the local spatial position and the magnetic field information and the moving time, the local spatial position and the magnetic field information at the same moving time are matched as a group, and the local spatial position and the magnetic field information at each moving time are matched respectively, to obtain the magnetic field information at each local spatial position as the magnetic field distribution in the target environment.

[0074] Step S4, acquiring the current magnetic field information of the flat panel detector, determining the current position of the flat panel detector based on the magnetic field distribution and the current magnetic field information.

[0075] The current magnetic field information is the magnetic field information of the flat panel detector in the target environment at present.

[0076] Specifically, the magnetic field information of the flat panel detector at the current position in the target environment is acquired, and the local spatial position corresponding to the current magnetic field information in the magnetic field distribution is obtained as the current position of the flat panel detector based on the current magnetic field information.

[0077] The flat panel detector positioning method provided in the above embodiment can achieve the following effects. The flat panel detector positioning method can acquire the positioning image sequence and the magnetic field information sequence in the target environment, acquire the local spatial position of the flat panel detector in the local coordinate system at each moving time based on the positioning image by using the visual positioning technology, match the local spatial position and the magnetic field information at each moving time, obtain the magnetic field distribution in the target environment, and realize the rapid calibration of the magnetic field distribution in the target environment. In addition, the current position of the flat panel detector in the local coordinate system is quickly determined based on the magnetic field distribution and the current magnetic field information of the flat panel detector in the target environment. Therefore, the magnetic field distribution in the changed environment can be accurately acquired, the positioning accuracy of the flat panel detector relative to the X-ray source position is improved, and after the magnetic field distribution changes, the magnetic field distribution in space does not need to be recalibrated manually, and the positioning efficiency of the flat panel detector relative to the X-ray source position is improved.

[0078] As shown in FIG. 1, Figure 2 The flat panel detector positioning system provided in the embodiment of the present application comprises:

[0079] The acquisition module 201 is configured to acquire a flat panel detector in a target environment, based on a time-series acquired positioning image sequence and a magnetic field information sequence; the positioning image sequence comprises: each positioning image containing the flat panel detector acquired in real time during movement of the flat panel detector; and the magnetic field information sequence comprises: magnetic field information of the flat panel detector at each movement position acquired in real time during movement of the flat panel detector.

[0080] The position extraction module 202 is configured to extract image coordinates of the flat panel detector in each positioning image; and convert each image coordinate into a local space coordinate to obtain a local space position of the flat panel detector at each movement time; the local space coordinate is a coordinate of the flat panel detector in a pre-constructed local space coordinate system; in the local space coordinate system, relative positions between devices used for positioning the flat panel detector remain unchanged.

[0081] The magnetic field calibration module 203 is configured to perform one-to-one corresponding matching on each local space position and each magnetic field information to obtain magnetic field information of the flat panel detector at each local space position as a magnetic field distribution in the target environment.

[0082] The detector positioning module 204 is configured to acquire current magnetic field information of the flat panel detector; and determine a current position of the flat panel detector based on the magnetic field distribution and the current magnetic field information.

[0083] Referring to Figure 3 , a structure schematic diagram of a flat panel detector positioning device provided by the present application in an embodiment is shown.

[0084] As shown in Figure 3 , in the embodiment, the flat panel detector positioning device provided by the present application is used for positioning a flat panel detector A, and the flat panel detector positioning device comprises:

[0085] A magnetic field source 1 is configured to generate a low-frequency magnetic field.

[0086] A camera 2 is configured to shoot a positioning image containing the flat panel detector A.

[0087] A magnetic field sensor 3 is configured to sense a magnetic field at a position where the flat panel detector A is located to obtain magnetic field information.

[0088] The processing module 4 is connected with the camera 2 and the magnetic field sensor 3 respectively, and is configured to acquire the flat panel detector in the target environment based on the time-series collected positioning image sequence and magnetic field information sequence; extract image coordinates of the flat panel detector in each positioning image; convert each image coordinate into a local space coordinate to obtain a local space position of the flat panel detector at each movement time; match each local space position with each magnetic field information one by one to obtain magnetic field information of the flat panel detector at each local space position as a magnetic field distribution in the target environment; and acquire current magnetic field information of the flat panel detector; determine the current position of the flat panel detector based on the magnetic field distribution and the current magnetic field information.

[0089] The relative positions among the magnetic field source 1, the camera 2 and the X-ray source B remain unchanged.

[0090] Optionally, the magnetic field source 1 comprises a low-frequency magnetic field generating device such as an electromagnet.

[0091] Optionally, the magnetic field sensor 3 is an internal magnetic field sensing element in the flat panel detector A or an external magnetic field sensing device arranged on the flat panel detector A; when the magnetic field sensor 3 is the external magnetic field sensing device, the magnetic field sensor 3 is arranged at a position other than the radiation receiving surface of the flat panel detector A.

[0092] Optionally, the device further comprises a positioning marker; the positioning marker is arranged on a side of the flat panel detector A facing the camera and does not block the radiation receiving surface of the flat panel detector A, so that the camera 2 can capture the positioning marker without blocking the radiation receiving surface.

[0093] Optionally, the positioning marker comprises a sticker with a two-dimensional code printed on the surface.

[0094] The embodiments of the present application further provide a computer readable storage medium. A person of ordinary skill in the art can understand that all or part of the steps of the methods described in the above embodiments can be completed by a processor instructed by a program, and the program can be stored in a computer readable storage medium. The storage medium is a non-transitory medium, for example, a random access memory, a read only memory, a flash memory, a hard disk, a solid state disk, a magnetic tape, a floppy disk, an optical disc, and any combination thereof. The storage medium can be any available medium that can be accessed by a computer or a data storage device such as a server, a data center, and the like, which includes one or more available medium sets. The available medium can be a magnetic medium (for example, a floppy disk, a hard disk, a magnetic tape), an optical medium (for example, a digital video disc (DVD)), or a semiconductor medium (for example, a solid state disk (SSD)), and the like.

[0095] The embodiments of the present application can further provide a computer program product, which includes one or more computer instructions. When the computer instructions are loaded and executed on a computing device, all or part of the processes or functions described in the embodiments of the present application are generated. The computer instructions can be stored in a computer readable storage medium or transmitted from one computer readable storage medium to another, for example, the computer instructions can be transmitted from one website, computer or data center to another website, computer or data center through a wired (for example, coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (for example, infrared, wireless, microwave, etc.) manner.

[0096] When the computer program product is executed by a computer, the computer executes the method described in the foregoing method embodiments. The computer program product can be a software installation package, and when the foregoing method needs to be used, the computer program product can be downloaded and executed on the computer.

[0097] The description of the processes or structures corresponding to the above respective figures has different focuses, and the parts not described in detail in a certain process or structure can be referred to the related description of other processes or structures.

[0098] The above embodiments are only illustrative of the principles and effects of the present application, and are not used to limit the present application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the present application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical idea of the present application should be covered by the claims of the present application.

Claims

1. A flat panel detector positioning method, characterized by, The method comprises: acquiring a flat panel detector in a target environment, based on a time-series acquired positioning image sequence and a magnetic field information sequence; the positioning image sequence comprises: each positioning image containing the flat panel detector acquired in real time during movement of the flat panel detector; the magnetic field information sequence comprises: magnetic field information of the flat panel detector at each movement position acquired in real time during movement of the flat panel detector; extracting image coordinates of the flat panel detector in each positioning image; converting each image coordinate into a local space coordinate to obtain a local space position of the flat panel detector at each movement time; correspondingly matching each local space position and each magnetic field information to obtain magnetic field information of the flat panel detector at each local space position as a magnetic field distribution in the target environment; acquiring current magnetic field information of the flat panel detector; based on the magnetic field distribution and the current magnetic field information, determining a current position of the flat panel detector; wherein the local space coordinate is a coordinate of the flat panel detector in a pre-constructed local space coordinate system; in the local space coordinate system, the relative positions between a magnetic field source, an X-ray source and a camera for shooting the positioning image for positioning the flat panel detector remain unchanged.

2. The method of claim 1, wherein, The acquisition method of the positioning image sequence and the magnetic field information sequence comprises: during movement of the flat panel detector, shooting the flat panel detector in real time and sensing the magnetic field of the flat panel detector at each movement position in real time; obtaining a positioning image of the flat panel detector at each movement time as the positioning image sequence; and obtaining magnetic field information of the flat panel detector at each movement time as the magnetic field information sequence.

3. The method of claim 1, wherein, The construction method of the local space coordinate system comprises: setting a local coordinate origin; based on the local coordinate origin, constructing the local space coordinate system; the local coordinate origin comprises: a magnetic field source, an X-ray source or a camera for shooting the positioning image; the relative positions between the magnetic field source, the X-ray source and the camera remain unchanged.

4. The method of claim 1, wherein, The conversion of each image coordinate into a local space coordinate comprises, when converting a single image coordinate into a local space coordinate: based on an intrinsic matrix of the camera, converting the image coordinate into camera coordinates in a three-dimensional camera coordinate system; based on a local extrinsic matrix of the camera, converting the camera coordinates into local space coordinates; wherein the local extrinsic matrix is pre-constructed and contains rotation and translation information of the camera in the local space coordinate system.

5. The method of claim 1, wherein, The acquisition method of the magnetic field distribution comprises: matching the local space position and the magnetic field information at each movement time as a group to obtain the magnetic field information at each local space position as the magnetic field distribution in the target environment.

6. The method of claim 1, wherein, The determination of the current position of the flat panel detector based on the magnetic field distribution and the current magnetic field information comprises: Based on the current magnetic field information, the local spatial position corresponding to the current magnetic field information is obtained in the magnetic field distribution as the current position of the flat panel detector.

7. A flat panel detector positioning system, characterized by, Comprise: An acquisition module is configured to acquire a flat panel detector in a target environment based on a sequence of positioning images and a sequence of magnetic field information collected in time sequence. The sequence of positioning images comprises each positioning image containing the flat panel detector acquired in real time during the movement of the flat panel detector; and the sequence of magnetic field information comprises magnetic field information of the flat panel detector at each movement position acquired in real time during the movement of the flat panel detector. A position extraction module is configured to extract image coordinates of the flat panel detector in each positioning image; and convert each image coordinate into a local spatial coordinate to obtain a local spatial position of the flat panel detector at each movement time; the local spatial coordinate is a coordinate of the flat panel detector in a pre-constructed local spatial coordinate system; in the local spatial coordinate system, the relative positions among a magnetic field source, an X-ray source and a camera for shooting the positioning image for positioning the flat panel detector remain unchanged. A magnetic field calibration module is configured to respectively and correspondingly match each local spatial position and each magnetic field information to obtain magnetic field information of the flat panel detector at each local spatial position as a magnetic field distribution in the target environment. A detector positioning module is configured to acquire current magnetic field information of the flat panel detector; and determine a current position of the flat panel detector based on the magnetic field distribution and the current magnetic field information.

8. A flat panel detector positioning device, characterized by, The device for positioning a flat panel detector comprises: A magnetic field source is configured to generate a low-frequency magnetic field; A camera is configured to shoot a positioning image containing the flat panel detector; A magnetic field sensor is configured to sense a magnetic field at a position where the flat panel detector is located to obtain magnetic field information; A processing module is respectively connected to the camera and the magnetic field sensor, and is configured to position the flat panel detector by using a flat panel detector positioning method according to any one of claims 1 to 6. The relative positions among the magnetic field source, the camera and the X-ray source remain unchanged.

9. The apparatus of claim 8, wherein, The device further comprises a positioning marker; the positioning marker is arranged on a side of the flat panel detector facing the camera and does not shield a radiation receiving surface of the flat panel detector.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed to implement the flat panel detector positioning method according to any one of claims 1 to 6.

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