Three-dimensional camera calibration method and device in x-ray imaging and storage medium

Abstract

The embodiment of the present application discloses a three-dimensional camera calibration method, device and storage medium in X-ray imaging. The method comprises the following steps: obtaining a three-dimensional image of a calibration board photographed by a three-dimensional camera, wherein the calibration board contains a positioning mark, and the calibration board has a predetermined distance from an X-ray bulb; determining a first three-dimensional coordinate of the positioning mark in a three-dimensional camera coordinate system based on the three-dimensional image; determining a second three-dimensional coordinate of the positioning mark in an X-ray bulb coordinate system based on the distance; and determining a conversion matrix suitable for calibrating the three-dimensional camera based on the first three-dimensional coordinate and the second three-dimensional coordinate. The embodiment of the present application can overcome the system error caused by the difference between coordinate systems.

Description

Technical Field

[0001] This invention relates to the field of medical imaging technology, and in particular to a three-dimensional camera calibration method, apparatus, and storage medium for X-ray imaging. Background Technology

[0002] An X-ray imaging system typically includes an X-ray generator assembly, a chest frame (Bucky-Wall-Stand, BWS) assembly, an examination table assembly, a film cassette assembly containing a flat panel detector, and a remotely located control unit. The X-ray generator assembly uses high voltage provided by a high-voltage generator to emit X-rays that pass through and irradiate the target, forming a medical image of the target on the flat panel detector. The flat panel detector transmits the medical image information to the control unit. The target can stand near the chest frame assembly or lie on the examination table assembly to receive X-ray imaging of various parts of the body, such as the head, chest, abdomen, and joints.

[0003] Three-dimensional (3D) cameras are widely used in X-ray imaging systems to achieve various measurement-related functions (such as virtual collimation). The positioning information of 3D images captured by a 3D camera is usually referenced to the 3D camera coordinate system, while many parameters in X-ray imaging applications are referenced to the X-ray tube coordinate system. If the positioning information determined based on 3D images is directly applied to X-ray imaging applications, it may lead to systematic errors. Summary of the Invention

[0004] The present invention provides a method, apparatus and storage medium for calibrating a three-dimensional camera in X-ray imaging.

[0005] A method for calibrating a three-dimensional camera in X-ray imaging, comprising:

[0006] Acquire a 3D image of a calibration plate captured by a 3D camera, wherein the calibration plate includes positioning markers and is at a predetermined distance from the X-ray tube;

[0007] Based on the three-dimensional image, determine the first three-dimensional coordinates of the positioning mark in the three-dimensional camera coordinate system;

[0008] Based on the distance, determine the second three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system;

[0009] Based on the first three-dimensional coordinates and the second three-dimensional coordinates, a transformation matrix adapted to calibrate the three-dimensional camera is determined.

[0010] As can be seen, in the embodiments of the present invention, based on the transformation relationship between the three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system and the three-dimensional coordinates of the positioning mark in the three-dimensional camera coordinate system, the transformation matrix is ​​determined, thereby realizing the calibration of the three-dimensional camera and eliminating the systematic error caused by the coordinate system difference.

[0011] In one embodiment, the center of the calibration plate does not coincide with the center of the irradiation field of the X-ray tube; the calibration plate is arranged in an XY plane that includes the X-axis and the Y-axis.

[0012] The method also includes:

[0013] Move the calibration plate within the XY plane until the center of the calibration plate coincides with the center of the irradiation field of the X-ray tube.

[0014] Therefore, when the center of the calibration plate does not coincide with the center of the X-ray tube's irradiation field, the calibration plate can be moved to make its center coincide with the center of the X-ray tube's irradiation field. Thus, the three-dimensional coordinates of the calibration plate's center in the X-ray tube coordinate system can be simplified, thereby simplifying the calculation process of the transformation matrix.

[0015] In one implementation, determining the second three-dimensional coordinates of the positioning marker in the X-ray tube coordinate system based on the distance includes:

[0016] Determine the three-dimensional coordinates (0, 0, h) of the center of the calibration plate in the X-ray tube coordinate system, where h is the distance;

[0017] Determine the distance vector T between the positioning mark and the center of the calibration plate;

[0018] Determine the x-component of the distance vector T on the X-axis and the y-component on the Y-axis;

[0019] Determine the second three-dimensional coordinates (x, y, h).

[0020] As can be seen, the three-dimensional coordinates of the center of the calibration plate in the X-ray tube coordinate system have been simplified, enabling rapid calculation of the second three-dimensional coordinates.

[0021] In one embodiment, the center of the calibration plate does not coincide with the center of the irradiation field of the X-ray tube; the calibration plate is arranged in an XY plane that includes the X-axis and the Y-axis.

[0022] Determining the second three-dimensional coordinates of the positioning marker in the X-ray tube coordinate system based on the distance includes:

[0023] Determine the three-dimensional coordinates (Δx, Δy, h) of the center of the calibration plate in the X-ray tube coordinate system; where h is the distance; Δx is the X-axis component of the distance vector between the center point of the irradiation field and the center of the calibration plate; Δy is the Y-axis component of the distance vector between the center point of the irradiation field and the center of the calibration plate; determine the distance vector T between the positioning mark and the center of the calibration plate; determine the X-axis component x and the Y-axis component y of the distance vector T; determine the second three-dimensional coordinates (Δx+x, Δy+y, h) of the positioning mark.

[0024] Therefore, the process of moving the calibration plate to make its center coincide with the center of the X-ray tube's irradiation field can be omitted, simplifying the operation.

[0025] In one implementation, it further includes:

[0026] Determine the irradiation field setting range and the actual irradiation field range on the calibration plate corresponding to the irradiation field setting range; determine the irradiation field width calibration parameter γ. w and the calibration parameter γ of the irradiation field height h ;in H1 is the distance; SID is the preset source-image distance; w s Set the width of the illumination field; h s Set the height within the illumination field; w c h is the width of the actual irradiation field. c The height is the actual range of the irradiated field.

[0027] It can be seen that the width and height of the irradiation field can also be calibrated to eliminate systematic errors caused by the difference in irradiation fields.

[0028] In one embodiment, determining the irradiation field setting range and the actual irradiation field range on the calibration plate corresponding to the irradiation field setting range includes:

[0029] The actual range of the irradiation field is determined based on user input; the irradiation field setting range corresponding to the actual range of the irradiation field is adjusted; or

[0030] The irradiation field setting range is determined based on user input; the actual irradiation field range corresponding to the irradiation field setting range is measured.

[0031] Therefore, the irradiation field setting range and the actual irradiation field range can be determined in multiple ways, making it suitable for various implementation environments.

[0032] In one implementation, it further includes:

[0033] Adjust the distance m times, and determine the first three-dimensional coordinates and the second three-dimensional coordinates after each distance adjustment, where m is a positive integer of at least 1;

[0034] The step of determining the transformation matrix adapted for calibrating the 3D camera based on the first 3D coordinates and the second 3D coordinates includes:

[0035] Determine the translation vector T and the rotation matrix R, where:

[0036]

[0037]

[0038] in N is the number of positioning markers; i is the distance adjustment sequence number; det is the determinant function; U and V are... Singular value decomposition; q i It is the second three-dimensional coordinate determined in the i-th distance adjustment; P i It is the first three-dimensional coordinate determined in the i-th distance adjustment; the value of i ranges from [0, m];

[0039] The transformation matrix is ​​determined based on the translation vector T and the rotation matrix R.

[0040] Therefore, determining the transformation matrix through multiple distance adjustments improves accuracy.

[0041] A three-dimensional camera calibration device for X-ray imaging, comprising:

[0042] An acquisition module is used to acquire a three-dimensional image of a calibration plate captured by a three-dimensional camera, wherein the calibration plate includes positioning marks and the calibration plate is at a predetermined distance from the X-ray tube;

[0043] The first determining module is used to determine the first three-dimensional coordinates of the positioning mark in the three-dimensional camera coordinate system based on the three-dimensional image;

[0044] The second determining module is used to determine the second three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system based on the distance;

[0045] The third determining module is used to determine a transformation matrix adapted to calibrate the three-dimensional camera based on the first three-dimensional coordinates and the second three-dimensional coordinates.

[0046] As can be seen, in the embodiments of the present invention, based on the transformation relationship between the three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system and the three-dimensional coordinates of the positioning mark in the three-dimensional camera coordinate system, the transformation matrix is ​​determined, thereby realizing the calibration of the three-dimensional camera and eliminating the systematic error caused by the coordinate system difference.

[0047] In one embodiment, the center of the calibration plate does not coincide with the center of the irradiation field of the X-ray tube; the calibration plate is arranged in an XY plane that includes the X-axis and the Y-axis.

[0048] The acquisition module is also used to move the calibration plate in the XY plane until the center of the calibration plate coincides with the center of the irradiation field of the X-ray tube.

[0049] Therefore, when the center of the calibration plate does not coincide with the center of the X-ray tube's irradiation field, the calibration plate can be moved to make its center coincide with the center of the X-ray tube's irradiation field. Thus, the three-dimensional coordinates of the calibration plate's center in the X-ray tube coordinate system can be simplified, thereby simplifying the calculation process of the transformation matrix.

[0050] In one embodiment, the second determining module is configured to determine the three-dimensional coordinates (0, 0, h) of the center of the calibration plate in the X-ray tube coordinate system; where h is the distance; determine the distance vector T between the positioning mark and the center of the calibration plate; determine the component x of the distance vector T on the X-axis and the component y on the Y-axis; and determine the second three-dimensional coordinates (x, y, h).

[0051] As can be seen, the three-dimensional coordinates of the center of the calibration plate in the X-ray tube coordinate system have been simplified, enabling rapid calculation of the second three-dimensional coordinates.

[0052] In one embodiment, the center of the calibration plate does not coincide with the center of the irradiation field of the X-ray tube; the calibration plate is arranged in an XY plane that includes the X-axis and the Y-axis.

[0053] The second determining module is used to determine the three-dimensional coordinates (Δx, Δy, h) of the center of the calibration plate in the X-ray tube coordinate system; where h is the distance; Δx is the X-axis component of the distance vector between the center point of the irradiation field and the center of the calibration plate; Δy is the Y-axis component of the distance vector between the center point of the irradiation field and the center of the calibration plate; determine the distance vector T between the positioning mark and the center of the calibration plate; determine the X-axis component x and the Y-axis component y of the distance vector T; and determine the second three-dimensional coordinates (Δx+x, Δy+y, h) of the positioning mark.

[0054] Therefore, the process of moving the calibration plate to make its center coincide with the center of the X-ray tube's irradiation field can be omitted, simplifying the operation.

[0055] In one implementation, it further includes:

[0056] The fourth determining module is used to determine the irradiation field setting range and the actual irradiation field range on the calibration plate corresponding to the irradiation field setting range; and to determine the irradiation field width calibration parameter γ. w and the calibration parameter γ of the irradiation field height h ;in H1 is the distance; SID is the preset source-image distance; w s Set the width of the illumination field; h s Set the height within the illumination field; w c h is the width of the actual irradiation field. c The height is the actual range of the irradiated field.

[0057] It can be seen that the width and height of the irradiation field can also be calibrated to eliminate systematic errors caused by the difference in irradiation fields.

[0058] In one embodiment, the fourth determining module is used to determine the actual range of the irradiation field based on user input; adjust the irradiation field setting range corresponding to the actual range of the irradiation field; or, determine the irradiation field setting range based on user input; and measure the actual range of the irradiation field on the calibration plate corresponding to the irradiation field setting range.

[0059] Therefore, the irradiation field setting range and the actual irradiation field range can be determined in multiple ways, making it suitable for various implementation environments.

[0060] In one embodiment, the third determining module is further configured to adjust the distance m times and determine the first three-dimensional coordinates and the second three-dimensional coordinates after each distance adjustment, where m is a positive integer of at least 1; and determine the translation vector T and the rotation matrix R, wherein: in N is the number of positioning markers; i is the distance adjustment sequence number; det is the determinant function; U and V are... Singular value decomposition; q i It is the second three-dimensional coordinate determined in the i-th distance adjustment; P i It is the first three-dimensional coordinate determined in the i-th distance adjustment; the value of i ranges from [0, m].

[0061] Therefore, determining the transformation matrix through multiple distance adjustments improves accuracy.

[0062] A three-dimensional camera calibration device for X-ray imaging includes a processor and a memory;

[0063] The memory stores an application program that can be executed by the processor, which causes the processor to perform a three-dimensional camera calibration method in X-ray imaging as described above.

[0064] As can be seen, the embodiments of the present invention propose a three-dimensional camera calibration device with a processor-memory architecture. Based on the transformation relationship between the three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system and the three-dimensional coordinates of the positioning mark in the three-dimensional camera coordinate system, the transformation matrix is ​​determined, thereby realizing the calibration of the three-dimensional camera and eliminating the system error caused by the coordinate system difference.

[0065] A computer-readable storage medium storing computer-readable instructions for performing a three-dimensional camera calibration method in X-ray imaging as described in any of the preceding methods.

[0066] Therefore, embodiments of the present invention propose a computer-readable storage medium containing computer-readable instructions, which determines a transformation matrix based on the transformation relationship between the three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system and the three-dimensional coordinates of the positioning mark in the three-dimensional camera coordinate system, thereby achieving calibration for the three-dimensional camera and eliminating systematic errors caused by coordinate system differences. Attached Figure Description

[0067] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which will make the above and other features and advantages of the present invention more apparent to those skilled in the art. In the drawings:

[0068] Figure 1 This is a flowchart of a three-dimensional camera calibration method in X-ray imaging according to an embodiment of the present invention.

[0069] Figure 2 This is a schematic diagram of three-dimensional camera calibration in X-ray imaging according to an embodiment of the present invention.

[0070] Figure 3 This is a first schematic diagram illustrating the determination of the three-dimensional coordinates of the center of the calibration plate in the X-ray tube coordinate system according to an embodiment of the present invention.

[0071] Figure 4 This is a second schematic diagram illustrating the determination of the three-dimensional coordinates of the center of the calibration plate in the X-ray tube coordinate system according to an embodiment of the present invention.

[0072] Figure 5 This is a structural diagram of a three-dimensional camera calibration device in X-ray imaging according to an embodiment of the present invention.

[0073] Figure 6 This is a structural diagram of a three-dimensional camera calibration device for X-ray imaging with a processor-memory architecture according to an embodiment of the present invention.

[0074] The reference numerals in the attached figures are as follows:

[0075]

[0076] Detailed Implementation

[0077] To make the objectives, technical solutions, and advantages of the present invention clearer, the following embodiments are provided to further illustrate the present invention in detail.

[0078] For the sake of brevity and intuitiveness, the following description uses several representative embodiments to illustrate the solution of the present invention. Numerous details in the embodiments are only used to aid in understanding the solution of the present invention. However, it is obvious that the technical solution of the present invention can be implemented without being limited to these details. To avoid unnecessarily obscuring the solution of the present invention, some embodiments are not described in detail, but only a framework is given. In the following text, "comprising" means "including but not limited to," and "according to..." means "at least according to..., but not limited to only according to...". Due to Chinese language habits, unless the quantity of a component is specifically indicated below, it means that the component can be one or more, or can be understood as at least one.

[0079] The applicant discovered that the positioning information in 3D photographs taken by a 3D camera is usually referenced to the 3D camera coordinate system, while many parameters in X-ray imaging applications are referenced to the X-ray tube coordinate system. If the positioning information from the 3D photographs is directly applied to X-ray imaging applications, systematic errors may occur due to the coordinate system difference. The embodiments of this invention calibrate the 3D camera based on a transformation matrix to eliminate systematic errors caused by coordinate system differences.

[0080] Figure 1 This is a flowchart of a three-dimensional camera calibration method in X-ray imaging according to an embodiment of the present invention. Preferably, it can be executed by a controller. Figure 1 The method is illustrated. The controller can be implemented as or integrated into the control host of an X-ray imaging system, or it can be implemented as a control unit independent of the control host.

[0081] like Figure 1 As shown, the method 100 includes:

[0082] Step 101: Acquire a 3D image of the calibration plate taken by a 3D camera, wherein the calibration plate contains positioning marks and is at a predetermined distance from the X-ray tube.

[0083] 3D cameras are typically mounted on the X-ray tube housing of an X-ray generating assembly, or on the beam emitter housing of the X-ray generating assembly. For example, grooves for accommodating the 3D camera are arranged on the X-ray tube housing or the beam emitter housing, and the 3D camera is fixed to the groove by means of bolt connection, snap-fit ​​connection, wire rope loop, etc.

[0084] Here, a calibration plate is used to calibrate the 3D camera. The calibration plate is arranged with positioning markers for auxiliary positioning; the number of positioning markers can be one or more, preferably more. For example, the positioning markers can be multiple dots, where the distance between any two adjacent dots is the same. Alternatively, the positioning markers can be multiple concentric circles, where the radius difference between adjacent concentric circles is the same.

[0085] In one embodiment, a calibration plate is placed on the ground, and an X-ray tube (without rotation) is aligned with the calibration plate on the ground, with the X-ray direction of the X-ray tube perpendicular to the ground. In this case, the distance between the calibration plate and the X-ray tube is the vertical height at which the X-ray source in the X-ray tube reaches the calibration plate.

[0086] In one embodiment, a calibration plate is mounted on a wall, and the nozzle of an X-ray tube (not rotating) is aligned with the calibration plate on the wall, with the X-ray direction of the X-ray tube perpendicular to the wall. The distance between the calibration plate and the X-ray tube is then the horizontal distance from the X-ray source in the X-ray tube to the calibration plate.

[0087] The above exemplary descriptions of typical examples of calibration plates and positioning marks will be appreciated by those skilled in the art. Such descriptions are merely exemplary and are not intended to limit the scope of protection of the embodiments of the present invention.

[0088] Step 102: Based on the 3D image, determine the first 3D coordinates of the positioning marker in the 3D camera coordinate system.

[0089] The 3D camera coordinate system is a three-dimensional rectangular coordinate system established with the focal center of the 3D camera as the origin and the optical axis as the Z-axis. In the 3D camera coordinate system: (1) the origin is the focal center (i.e., the optical center) of the 3D camera; (2) the X-axis of the 3D camera coordinate system is parallel to the X-axis of the image plane; (3) the Y-axis of the 3D camera coordinate system is parallel to the Y-axis of the image plane; (4) the Z-axis of the 3D camera coordinate system is the camera optical axis, which is perpendicular to the image plane. The image plane is a two-dimensional rectangular coordinate system.

[0090] In one embodiment, step 102 specifically includes: converting the three-dimensional image obtained in step 101 into a two-dimensional image, and using an image recognition algorithm to determine the two-dimensional coordinates of the positioning mark in the image coordinate system from the two-dimensional image, and then converting the two-dimensional coordinates of the positioning mark in the image coordinate system into the three-dimensional coordinates of the positioning mark in the three-dimensional camera coordinate system (i.e., the first three-dimensional coordinates) based on the depth parameters of the three-dimensional camera.

[0091] In one implementation, step 102 specifically includes: determining the three-dimensional coordinates (i.e., the first three-dimensional coordinates) of the positioning marker in the three-dimensional image in the three-dimensional camera coordinate system based on a three-dimensional positioning algorithm.

[0092] Step 103: Determine the second three-dimensional coordinates of the positioning marker in the X-ray tube coordinate system based on the distance.

[0093] The X-ray tube coordinate system is a three-dimensional rectangular coordinate system established with the X-ray source as the origin and the X-ray axis as the Z-axis. In the X-ray tube coordinate system: (1) the origin is the X-ray source; (2) the X-axis of the X-ray tube coordinate system is parallel to the X-axis in the image plane; (3) the Y-axis of the X-ray tube coordinate system is parallel to the Y-axis in the image plane; (4) the Z-axis in the three-dimensional camera coordinate system is the X-ray axis, which is usually perpendicular to the calibration plate.

[0094] In one exemplary embodiment, the center of the calibration plate does not coincide with the center of the X-ray tube's irradiation field; the calibration plate is arranged in an XY plane including the X-axis and Y-axis, and the method further includes: moving the calibration plate in the XY plane until the center of the calibration plate coincides with the center of the X-ray tube's irradiation field.

[0095] The center of the X-ray tube's field of view is usually marked on the imaging target (e.g., a laser crosshair).

[0096] In one scenario, it can be discovered manually that the center of the calibration plate does not coincide with the imaging marker; that is, it is manually determined that the center of the calibration plate does not coincide with the center of the X-ray tube's irradiation field. Then, the calibration plate is moved manually or automatically within the XY plane where it is positioned until the center of the calibration plate coincides with the center of the X-ray tube's irradiation field.

[0097] In one scenario, an automatic optical recognition method is used to determine that the center of the calibration plate does not coincide with the imaging mark; that is, the center of the calibration plate is automatically determined to be different from the center of the X-ray tube's irradiation field. Then, the calibration plate is moved manually or automatically within the XY plane where it is positioned until the center of the calibration plate coincides with the center of the X-ray tube's irradiation field.

[0098] By aligning the center of the calibration plate with the center of the X-ray tube's irradiation field, the three-dimensional coordinates of the calibration plate's center in the X-ray tube coordinate system can be simplified, thereby simplifying the subsequent calculation process.

[0099] In one exemplary embodiment, determining the second three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system based on distance in step 103 includes: (1) determining the three-dimensional coordinates (0, 0, h) of the center of the calibration plate in the X-ray tube coordinate system, where h is the distance; (2) determining the distance vector T between the positioning mark and the center of the calibration plate; (3) determining the x component of the distance vector T on the X-axis and the y component on the Y-axis; and (4) determining the second three-dimensional coordinates (x, y, h).

[0100] As can be seen, by moving the calibration plate so that its center coincides with the center of the X-ray tube's irradiation field, the three-dimensional coordinates of the calibration plate's center in the X-ray tube coordinate system are simplified.

[0101] In one exemplary embodiment, the center of the calibration plate does not coincide with the center of the X-ray tube's irradiation field; the calibration plate is arranged in an XY plane containing the X and Y axes; step 103, based on distance, determines the second three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system, including:

[0102] (1) Determine the three-dimensional coordinates (Δx, Δy, h) of the center of the calibration plate in the X-ray tube coordinate system, where h is the distance; Δx is the component of the distance vector between the center point of the irradiation field and the center of the calibration plate on the X-axis; Δy is the component of the distance vector between the center point of the irradiation field and the center of the calibration plate on the Y-axis.

[0103] (2) Determine the distance vector T between the positioning mark and the center of the calibration plate;

[0104] (3) Determine the x-component of the distance vector T on the X-axis and the y-component of the distance vector T on the Y-axis;

[0105] (4) Determine the second three-dimensional coordinates (Δx+x, Δy+y, h) of the positioning mark.

[0106] Therefore, the process of moving the calibration plate to make its center coincide with the center of the X-ray tube's irradiation field can be omitted, simplifying the operation.

[0107] Step 104: Based on the first and second 3D coordinates, determine the transformation matrix adapted to calibrate the 3D camera.

[0108] Based on the first three-dimensional coordinates determined in step 102 and the second three-dimensional coordinates determined in step 103, the transformation matrix for calibrating the three-dimensional camera can be calculated using a matrix approach. To facilitate the calculation of the transformation matrix, the number of first three-dimensional coordinates is preferably six or more; correspondingly, the number of second three-dimensional coordinates is preferably six or more.

[0109] The distance between the calibration plate and the X-ray tube can be adjusted multiple times, and the first and second three-dimensional coordinates are determined accordingly after each distance adjustment. Using the first and second three-dimensional coordinates determined after multiple distance adjustments, the transformation matrix can be calculated more accurately. Preferably, the number of first three-dimensional coordinates determined after multiple distance adjustments is at least six; correspondingly, the number of second three-dimensional coordinates determined after multiple distance adjustments is also preferably at least six.

[0110] In one exemplary embodiment, the method further includes: adjusting the distance m times and determining the first three-dimensional coordinates and the second three-dimensional coordinates after each distance adjustment, where m is a positive integer of at least 1; and determining a transformation matrix (104) adapted for calibrating the three-dimensional camera based on the first three-dimensional coordinates and the second three-dimensional coordinates, including: determining a translation vector T and a rotation matrix R, where: in N is the number of positioning markers; i is the distance adjustment sequence number; det is the determinant function; U and V are... Singular value decomposition; q i It is the second three-dimensional coordinate determined in the i-th distance adjustment; P i It is the first three-dimensional coordinate determined in the i-th distance adjustment; the value range of i is [0, m]; the transformation matrix is ​​determined based on the translation vector T and the rotation matrix R.

[0111] Therefore, determining the transformation matrix through multiple distance adjustments improves accuracy.

[0112] For example, assuming there are k positioning markers in the calibration plate (where k is greater than 3), adjust the distance m times, and determine the first three-dimensional coordinates and the second three-dimensional coordinates after each distance adjustment.

[0113] Method (1): Select three corresponding 3D coordinate pairs from the first 3D coordinates before distance adjustment and the second 3D coordinates before distance adjustment. Then select three corresponding 3D coordinate pairs from the first 3D coordinates after distance adjustment and the second 3D coordinates after distance adjustment. Calculate the transformation matrix using these six 3D coordinate pairs.

[0114] Method (2): Select three corresponding 3D coordinate pairs from the first 3D coordinates before distance adjustment and the second 3D coordinates before distance adjustment. Then select three corresponding 3D coordinate pairs from the first 3D coordinates after distance adjustment and the second 3D coordinates after distance adjustment. Calculate the transformation matrix using these six 3D coordinate pairs.

[0115] Method (3): Select three corresponding 3D coordinate pairs from the first distance adjustment, the first 3D coordinate, and the second 3D coordinate after the first distance adjustment. Then select three corresponding 3D coordinate pairs from the second distance adjustment, the first 3D coordinate, and the second 3D coordinate after the second distance adjustment. Calculate the transformation matrix using these six 3D coordinate pairs.

[0116] The above illustrative description describes a specific implementation of calculating the transformation matrix. Those skilled in the art will recognize that this description is merely illustrative and is not intended to limit the implementation of the present invention.

[0117] As can be seen, in the embodiments of the present invention, based on the transformation relationship between the three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system and the three-dimensional coordinates of the positioning mark in the three-dimensional camera coordinate system, the transformation matrix is ​​determined, thereby realizing the calibration of the three-dimensional camera and eliminating the systematic error caused by the coordinate system difference.

[0118] In one exemplary embodiment, the method further includes: determining the irradiation field setting range and the actual irradiation field range on the calibration plate corresponding to the irradiation field setting range; and determining the irradiation field width calibration parameter γ. w and the calibration parameter γ of the irradiation field height h ;in H1 is the distance between the calibration plate and the X-ray tube; SID is the distance between the X-ray source and the imaging plane (Source to Image Distance), also known as source-image distance; w s Set the width of the illumination field; h s Set the height within the illumination field; w c h is the width of the actual irradiation field. c The height is the actual range of the irradiated field.

[0119] Irradiation field width calibration parameter γ w and the calibration parameter γ of the irradiation field height h This reflects the difference between the actual and the set collimator illumination field. It can be used to calibrate system errors, and also to calibrate the illumination field of a virtual collimator to make it consistent with the actual collimator illumination field. Therefore, the width and height of the illumination field can also be calibrated to ensure that the actual illumination field range matches the set illumination field range.

[0120] In one exemplary embodiment, determining the irradiation field setting range and the corresponding actual irradiation field range on the calibration plate includes the following methods:

[0121] Method (1): Determine the actual range of the irradiation field based on user input; adjust the irradiation field setting range to correspond to the actual range of the irradiation field.

[0122] For example, the user inputs that the actual range of the irradiation field is 10*10 square centimeters (cm). 2 Then, the irradiation field setting range in the X-ray imaging system was adjusted until manual observation of the calibration plate or image recognition of the 3D image of the calibration plate revealed that the actual irradiation field range on the calibration plate was 10*10 (cm). 2 When the X-ray imaging system is set to 11*11 (cm), record the field setting range at that moment. 2 This is the set range of the illumination field. At this point, the actual range of the illumination field is 10*10 (cm). 2); corresponding to 10*10 (cm) 2 The actual range of the irradiation field and the set range of the irradiation field are 11*11 (cm). 2 ).

[0123] Method (2): Determine the irradiation field setting range based on user input; measure the actual irradiation field range corresponding to the irradiation field setting range. Therefore, the irradiation field setting range and the actual irradiation field range can be determined in multiple ways, which is suitable for various implementation environments.

[0124] For example, the user inputs a field setting range of 10*10 (cm) in the X-ray imaging system. 2 Then, through manual observation of the calibration plate or image recognition of its 3D image, it was found that the actual irradiation field on the calibration plate was 9*9 cm. 2 Therefore, the actual range of the irradiation field is determined to be 9*9 (cm). 2 ), corresponding to 9*9 (cm) 2 The actual range of the irradiation field, and the set range of the irradiation field is 10*10 (cm). 2 ).

[0125] Figure 2 This is a schematic diagram of three-dimensional camera calibration in X-ray imaging according to an embodiment of the present invention.

[0126] exist Figure 2 The X-ray generating assembly, including an X-ray tube 71 and a beam 72, is connected to a telescopic sleeve 79 via a support member. The telescopic sleeve 79 is connected to the ceiling 70. A three-dimensional camera 81 is arranged on the housing of the beam 72. The control host 60 can be a control host located in a local control room or a remote control host, such as a control host located in the cloud.

[0127] A calibration plate 30 for calibrating the 3D camera 81 is arranged on the ground 20. Positioning marks for auxiliary positioning are arranged on the calibration plate 30; the number of positioning marks can be one or more. An X-ray tube 71 is aligned with the calibration plate 30 on the ground, with the X-ray direction of the X-ray tube 71 perpendicular to the calibration plate 30. The distance between the calibration plate 30 and the X-ray tube 71 is the vertical height at which the X-ray source 73 in the X-ray tube 71 reaches the calibration plate 30.

[0128] Figure 3 This is a first schematic diagram illustrating the determination of the three-dimensional coordinates of the center of the calibration plate in the X-ray tube coordinate system according to an embodiment of the present invention.

[0129] exist Figure 3 In the calibration plate 300, there are multiple dots that serve as positioning markers, such as... Figure 3The illustrated embodiment uses 28 dots as an example. These 28 dots are arranged in 7 rows, with 4 dots in each row. The dots in each row are evenly spaced with a known fixed spacing of D, and the spacing between adjacent dots in different rows is also D. For example, the first and second dots from the left in the first row are adjacent within the same row with a spacing of D; the second and third dots from the left in the first row are adjacent within the same row with a spacing of D; the first dots from the left in the first row and the first dots from the left in the second row are adjacent across different rows with a spacing of D; and the first dots from the left in the first row and the second dots from the left in the second row are adjacent across different rows with a spacing of D. Figure 3 In the diagram, the distance between any two adjacent circular points is a known constant value D.

[0130] The center of the calibration plate 300 is point O. The center of the X-ray tube's irradiation field, as presented on the calibration plate 300, is point M.

[0131] By examining the 3D image from the calibration plate 300, the 3D coordinates of each dot in the 3D camera coordinate system can be obtained. Correspondingly, the 3D coordinates of each dot in the X-ray tube coordinate system can be determined, thus facilitating the calculation of the 3D camera's transformation matrix.

[0132] Methods for determining the three-dimensional coordinates of each dot in the X-ray tube coordinate system include:

[0133] Case (1): When it is observed that point M on the calibration plate coincides with point O, the three-dimensional coordinates of the center point of the plate in the X-ray tube coordinate system can be determined as (0, 0, h), and the three-dimensional coordinates of each circle in the X-ray tube coordinate system can be conveniently determined.

[0134] For example, assuming the distance between the calibration plate 300 and the X-ray source of the X-ray tube is 180 cm, and the distance between any two adjacent dots is 5 cm, then the coordinates of the center point O of the calibration plate in the X-ray tube coordinate system can be determined as (0, 0, 180). Correspondingly, the coordinates of the first dot 301 to the left of the center point O in the X-ray tube coordinate system are (5, 0, 180); the coordinates of the first dot 302 to the right of the center point O are (-5, 0, 180). The coordinates of the first dot 303 above the center point O are (0, 5, 180), and the coordinates of the first dot 304 below the center point O are (0, -5, 180). Similarly, the coordinates of all the dots in the X-ray tube coordinate system can be determined.

[0135] Case (2): When Figure 3As shown, when point M on the calibration plate 300 does not coincide with point O, the distance vector between the center of the irradiation field (i.e., point M) and the center of the calibration plate (i.e., point O) is S. The component of the distance vector S on the X-axis is Δx, and the component of the distance vector S on the Y-axis is Δy. It can be seen that the magnitude of Δx is D, and the magnitude of Δy is D. Therefore, combined with the predetermined coordinate system direction, the three-dimensional coordinates (Δx, Δy, h) of the center of the calibration plate in the X-ray tube coordinate system can be determined, where h is the distance between the calibration plate 300 and the X-ray source of the X-ray tube. Then, the distance vector T between each point and the center of the calibration plate can be determined, as well as the component x on the X-axis and the component y on the Y-axis of the distance vector T, thereby determining the three-dimensional coordinates (Δx+x, Δy+y, h) of each point in the X-ray tube coordinate system.

[0136] Figure 4 This is a second schematic diagram illustrating the determination of the three-dimensional coordinates of the center of the calibration plate in the X-ray tube coordinate system according to an embodiment of the present invention.

[0137] exist Figure 4 In the calibration plate 400, positioning marks are provided as concentric circles 401, 402, 403, 404, and 405. The radius of concentric circle 401 is r; the radius difference between adjacent concentric circles is the same, assumed to be d. The center of the calibration plate 400 is point O. The center of the X-ray tube's irradiation field, as presented on the calibration plate 400, is point M.

[0138] By using the 3D image from the calibration plate 400, the 3D coordinates of each quadrant point (e.g., upper quadrant point, lower quadrant point, left quadrant point, and right quadrant point) in the 3D camera coordinate system can be obtained. The 3D coordinates of each quadrant point in the X-ray tube coordinate system can then be determined accordingly, facilitating the calculation of the 3D camera's transformation matrix.

[0139] Methods for determining the three-dimensional coordinates of each quadrant point of the concentric circles in the X-ray tube coordinate system include:

[0140] Case (1): When point M on calibration plate 400 coincides with point O, the three-dimensional coordinates of the plate center point in the X-ray tube coordinate system can be determined as (0, 0, h). Then, based on the geometric relationship between each concentric circle, the three-dimensional coordinates of the quadrant point of each concentric circle in the X-ray tube coordinate system are determined.

[0141] Case (2): When Figure 4As shown, when point M on the calibration plate 400 is located on the circumference of concentric circles 403 and does not coincide with point O, the distance vector between the center of the illumination field (i.e., point M) and the center of the calibration plate (i.e., point O) is S, and the magnitude of this distance vector is (r+2d). Based on the orientation of point M identified visually or by computer vision, the component of the distance vector S on the X-axis is determined to be Δx, and the component of the distance vector S on the Y-axis is determined to be Δy. For example, assuming the line connecting point M and point O is at a 45-degree angle to the X-axis, the magnitude of Δx is... The modulus of Δy is also Therefore, by combining this with a predetermined coordinate system orientation, the three-dimensional coordinates (Δx, Δy, h) of the calibration plate's center in the X-ray tube coordinate system can be determined, where h is the distance between the calibration plate 400 and the X-ray source of the X-ray tube. Then, the distance vector T between each pixel of each concentric circle and the center of the calibration plate can be determined, along with the x-axis component x and the y-axis component y of each distance vector T. Based on the geometric relationships between the concentric circles, the three-dimensional coordinates (Δx+x, Δy+y, h) of each pixel of each concentric circle in the X-ray tube coordinate system can be determined.

[0142] Figure 5 This is a structural diagram of a three-dimensional camera calibration device in X-ray imaging according to an embodiment of the present invention.

[0143] like Figure 5 As shown, the three-dimensional camera calibration device 500 in X-ray imaging includes:

[0144] The acquisition module 501 is used to acquire a three-dimensional image of the calibration plate captured by a three-dimensional camera, wherein the calibration plate includes positioning marks and the calibration plate is at a predetermined distance from the X-ray tube.

[0145] The first determining module 502 is used to determine the first three-dimensional coordinates of the positioning mark in the three-dimensional camera coordinate system based on the three-dimensional image;

[0146] The second determining module 503 is used to determine the second three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system based on the distance;

[0147] The third determining module 504 is used to determine a transformation matrix adapted to calibrate the 3D camera based on the first 3D coordinates and the second 3D coordinates.

[0148] In one embodiment, the center of the calibration plate does not coincide with the center of the X-ray tube's irradiation field; the calibration plate is arranged in an XY plane that includes the X-axis and Y-axis.

[0149] The acquisition module is also used to move the calibration plate in the XY plane until the center of the calibration plate coincides with the center of the X-ray tube's irradiation field.

[0150] In one embodiment, the second determining module 503 is used to determine the three-dimensional coordinates (0, 0, h) of the center of the calibration plate in the X-ray tube coordinate system; where h is the distance; determine the distance vector T between the positioning mark and the center of the calibration plate; determine the x component of the distance vector T on the X-axis and the y component on the Y-axis; and determine the second three-dimensional coordinates (x, y, h).

[0151] In one embodiment, the center of the calibration plate does not coincide with the center of the X-ray tube's irradiation field; the calibration plate is arranged in an XY plane containing the X-axis and Y-axis; the second determining module 503 is used to determine the three-dimensional coordinates (Δx, Δy, h) of the center of the calibration plate in the X-ray tube coordinate system; where h is the distance; Δx is the component of the distance vector between the center point of the irradiation field and the center of the calibration plate on the X-axis; Δy is the component of the distance vector between the center point of the irradiation field and the center of the calibration plate on the Y-axis; determine the distance vector T between the positioning mark and the center of the calibration plate; determine the component x of the distance vector T on the X-axis and the component y on the Y-axis; and determine the second three-dimensional coordinates (Δx+x, Δy+y, h) of the positioning mark.

[0152] In one embodiment, a fourth determining module 505 is further included, used to determine the irradiation field setting range and the actual irradiation field range on the calibration plate corresponding to the irradiation field setting range; and to determine the irradiation field width calibration parameter γ. w and the calibration parameter γ of the irradiation field height h ;in H1 represents the distance; SID represents the preset source-image distance; w s Set the width of the illumination field; h s Set the height within the illumination field; w c h is the width of the actual irradiation field. c The height is the actual range of the irradiated field.

[0153] In one embodiment, the fourth determining module 505 is used to determine the actual range of the irradiation field based on user input; adjust the irradiation field setting range corresponding to the actual range of the irradiation field; or, determine the irradiation field setting range based on user input; and measure the actual range of the irradiation field on the calibration plate corresponding to the irradiation field setting range.

[0154] In one embodiment, the third determining module 504 is further configured to adjust the distance m times and determine the first three-dimensional coordinates and the second three-dimensional coordinates after each distance adjustment, where m is a positive integer of at least 1; and determine the translation vector T and the rotation matrix R, wherein: in N is the number of positioning markers; i is the distance adjustment sequence number; det is the determinant function; U and V are... Singular value decomposition; qi It is the second three-dimensional coordinate determined in the i-th distance adjustment; p i It is the first three-dimensional coordinate determined in the i-th distance adjustment; the value of i ranges from [0, m].

[0155] The present invention also proposes a three-dimensional camera calibration device for X-ray imaging with a processor-memory architecture. Figure 6 This is a structural diagram of a three-dimensional camera calibration device for X-ray imaging with a processor-memory architecture according to an embodiment of the present invention.

[0156] like Figure 6 As shown, the device 600 for deploying industrial edge applications includes a processor 601, a memory 602, and a computer program stored on the memory 602 and executable on the processor 601. When executed by the processor 601, the computer program implements a three-dimensional camera calibration method in X-ray imaging as described above. Specifically, the memory 602 can be implemented as various storage media such as electrically erasable programmable read-only memory (EEPROM), flash memory, and programmable programmable read-only memory (PROM). The processor 601 can be implemented as including one or more central processing units (CPUs) or one or more field-programmable gate arrays (FPGAs), wherein the FPGA integrates one or more CPU cores. Specifically, the CPU or CPU core can be implemented as a CPU, MCU, DSP, etc.

[0157] It should be noted that not all steps and modules in the above processes and structural diagrams are mandatory; some steps or modules can be omitted as needed. The execution order of the steps is not fixed and can be adjusted as required. The division of modules is merely for the convenience of description and functional division. In actual implementation, a module can be implemented by multiple modules, and the functions of multiple modules can also be implemented by the same module. These modules can be located in the same device or in different devices.

[0158] The hardware modules in each embodiment can be implemented mechanically or electronically. For example, a hardware module may include specially designed permanent circuitry or logic devices (such as dedicated processors, such as FPGAs or ASICs) to perform specific operations. A hardware module may also include programmable logic devices or circuitry (such as general-purpose processors or other programmable processors) temporarily configured by software to perform specific operations. The choice between mechanical implementation, dedicated permanent circuitry, or temporarily configured circuitry (such as software-configured circuitry) can be made based on cost and time considerations.

[0159] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A three-dimensional camera calibration method (100) for X-ray imaging, characterized in that, include: Acquire a three-dimensional image of the calibration plate taken by a three-dimensional camera, wherein the calibration plate includes positioning marks and the calibration plate is at a predetermined distance (101) from the X-ray tube. Based on the three-dimensional image, the first three-dimensional coordinates (102) of the positioning mark in the three-dimensional camera coordinate system are determined. Based on the distance, the second three-dimensional coordinates (103) of the positioning mark in the X-ray tube coordinate system are determined. Based on the first three-dimensional coordinates and the second three-dimensional coordinates, a transformation matrix (104) adapted to calibrate the three-dimensional camera is determined. The calibration plate is placed on the ground or on a wall; The method further includes: Adjust the distance m times, and determine the first three-dimensional coordinates and the second three-dimensional coordinates after each distance adjustment, where m is a positive integer of at least 1; The step of determining the transformation matrix (104) adapted for calibrating the 3D camera based on the first 3D coordinates and the second 3D coordinates includes: Determine the translation vector T and the rotation matrix R, where: ； ； in , N is the number of positioning markers; i is the distance adjustment sequence number; det is the determinant function; U and V are... Singular value decomposition; q i It is the second three-dimensional coordinate determined in the i-th distance adjustment; p i It is the first three-dimensional coordinate determined in the i-th distance adjustment; the value of i ranges from [0, m]; The transformation matrix is ​​determined based on the translation vector T and the rotation matrix R.

2. The method (100) according to claim 1, characterized in that, The center of the calibration plate does not coincide with the center of the irradiation field of the X-ray tube; the calibration plate is arranged in the XY plane containing the X-axis and Y-axis. The method (100) further includes: Move the calibration plate within the XY plane until the center of the calibration plate coincides with the center of the irradiation field of the X-ray tube.

3. The method (100) according to claim 2, characterized in that, Determining the second three-dimensional coordinates (103) of the positioning mark in the X-ray tube coordinate system based on the distance includes: Determine the three-dimensional coordinates (0, 0, h) of the center of the calibration plate in the X-ray tube coordinate system, where h is the distance; Determine the distance vector T between the positioning mark and the center of the calibration plate; Determine the x-component of the distance vector T on the X-axis and the y-component on the Y-axis; Determine the second three-dimensional coordinates (x, y, h).

4. The method (100) according to claim 1, characterized in that, The center of the calibration plate does not coincide with the center of the irradiation field of the X-ray tube; the calibration plate is arranged in the XY plane that includes the X-axis and Y-axis; Determining the second three-dimensional coordinates (103) of the positioning mark in the X-ray tube coordinate system based on the distance includes: Determine the three-dimensional coordinates of the center of the calibration plate in the X-ray tube coordinate system. , (h), where h is the distance; The distance vector between the center point of the illumination field and the center of the calibration plate is represented on the X-axis. The distance vector between the center point of the illumination field and the center of the calibration plate is represented on the Y-axis. Determine the distance vector T between the positioning mark and the center of the calibration plate; Determine the x-component of the distance vector T on the X-axis and the y-component on the Y-axis; Determine the second three-dimensional coordinates of the positioning mark ( +x, +y,h).

5. The method (100) according to claim 1, characterized in that, Also includes: Determine the irradiation field setting range and the actual irradiation field range on the calibration plate corresponding to the irradiation field setting range; Determine the calibration parameters for the irradiation field width and irradiation field height calibration parameters ;in ; ; The distance is denoted as SID; SID is the preset source-image distance. Set the width of the illumination field; Set the height within the range of the illumination field; The width of the actual irradiated field; The height is the actual range of the irradiated field.

6. The method (100) according to claim 5, characterized in that, The determination of the irradiation field setting range and the actual irradiation field range on the calibration plate corresponding to the irradiation field setting range includes: The actual range of the irradiation field is determined based on user input; the irradiation field setting range corresponding to the actual range of the irradiation field is adjusted; or The irradiation field setting range is determined based on user input. Measure the actual range of the irradiation field corresponding to the set range of the irradiation field.

7. A three-dimensional camera calibration device (500) for X-ray imaging, characterized in that, include: The acquisition module (501) is used to acquire a three-dimensional image of the calibration plate captured by a three-dimensional camera, wherein the calibration plate includes positioning marks and the calibration plate is at a predetermined distance from the X-ray tube; The first determining module (502) is used to determine the first three-dimensional coordinates of the positioning mark in the three-dimensional camera coordinate system based on the three-dimensional image; The second determining module (503) is used to determine the second three-dimensional coordinates of the positioning mark in the X-ray tube coordinate system based on the distance; The third determining module (504) is used to determine a transformation matrix adapted to calibrate the three-dimensional camera based on the first three-dimensional coordinates and the second three-dimensional coordinates; The calibration plate is placed on the ground or on a wall; The third determining module (504) is further configured to adjust the distance m times and determine the first three-dimensional coordinates and the second three-dimensional coordinates after each distance adjustment, where m is a positive integer of at least 1; and determine the translation vector T and the rotation matrix R, wherein: ; ;in , N is the number of positioning markers; i is the distance adjustment sequence number; det is the determinant function; U and V are... Singular value decomposition; q i It is the second three-dimensional coordinate determined in the i-th distance adjustment; p i It is the first three-dimensional coordinate determined in the i-th distance adjustment; the value of i is in the range of [0, m].

8. The apparatus (500) according to claim 7, characterized in that, The center of the calibration plate does not coincide with the center of the irradiation field of the X-ray tube; the calibration plate is arranged in the XY plane that includes the X-axis and Y-axis; The acquisition module (501) is also used to move the calibration plate in the XY plane until the center of the calibration plate coincides with the center of the irradiation field of the X-ray tube.

9. The apparatus (500) according to claim 8, characterized in that, The second determining module (503) is used to determine the three-dimensional coordinates (0, 0, h) of the center of the calibration plate in the X-ray tube coordinate system; where h is the distance; determine the distance vector T between the positioning mark and the center of the calibration plate; determine the component x of the distance vector T on the X-axis and the component y on the Y-axis; and determine the second three-dimensional coordinates (x, y, h).

10. The apparatus (500) according to claim 7, characterized in that, The center of the calibration plate does not coincide with the center of the irradiation field of the X-ray tube; the calibration plate is arranged in the XY plane that includes the X-axis and Y-axis; The second determining module (503) is used to determine the three-dimensional coordinates of the center of the calibration plate in the X-ray tube coordinate system. , (h), where h is the distance; The distance vector between the center point of the illumination field and the center of the calibration plate is represented on the X-axis. The distance vector between the center point of the irradiation field and the center of the calibration plate is defined on the Y-axis; the distance vector T between the positioning mark and the center of the calibration plate is determined; the x-component of the distance vector T on the X-axis and the y-component on the Y-axis are determined; the second three-dimensional coordinates of the positioning mark are determined. +x, +y,h).

11. The apparatus (500) according to claim 7, characterized in that, Also includes: The fourth determining module (505) is used to determine the irradiation field setting range and the actual irradiation field range on the calibration plate corresponding to the irradiation field setting range; and to determine the irradiation field width calibration parameter. and irradiation field height calibration parameters ;in ; ; The distance is denoted as SID; SID is the preset source-image distance. Set the width of the illumination field; Set the height within the range of the illumination field; The width of the actual irradiated field; The height is the actual range of the irradiated field.

12. The apparatus (500) according to claim 11, characterized in that, The fourth determining module (505) is used to determine the actual range of the irradiation field based on user input; adjust the irradiation field setting range corresponding to the actual range of the irradiation field; or, determine the irradiation field setting range based on user input. The actual range of the irradiation field on the measurement calibration plate, corresponding to the set range of the irradiation field.

13. A three-dimensional camera calibration device (600) for X-ray imaging, characterized in that, Includes a processor (601) and a memory (602); The memory (602) stores an application program that can be executed by the processor (601) to cause the processor (601) to execute the three-dimensional camera calibration method (100) in X-ray imaging as claimed in any one of claims 1 to 6.

14. A computer-readable storage medium, characterized in that, It contains computer-readable instructions for performing a three-dimensional camera calibration method (100) in X-ray imaging as described in any one of claims 1 to 6.

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