3D reconstruction method, 3D reconstruction systems, and readable storage medium and c-arm

Abstract

The present application is applied to the technical field of computer imaging. Provided are a 3D reconstruction method, 3D reconstruction systems, and a readable storage medium and a C-arm. The 3D reconstruction method comprises: establishing a space coordinate system; selecting a three-dimensional point from the space coordinate system, and acquiring the coordinates of the three-dimensional point; determining a plane coordinate expression of a detector; determining the focal-spot coordinates of an X-ray tube; on the basis of the focal-spot coordinates, determining the projection of the three-dimensional point on a plane image; acquiring a linear expression of a boundary of the plane image; on the basis of the linear expression and projection coordinates, obtaining the two-dimensional coordinates of the three-dimensional point on the plane image; and establishing a 3D reconstruction model on the basis of the two-dimensional coordinates on the plane image and a correspondence between the two-dimensional coordinates and the three-dimensional coordinates. In the method, a conventional 2D C-arm can be used to perform 3D reconstruction, so that the operation convenience and flexibility can be improved; in addition, the 3D model can be correspondingly generated on the basis of pixels of a 2D image, so that the accuracy of the 3D reconstruction model is improved, the replicability is high, and high practical value is achieved.

Description

3D reconstruction method, system, readable storage medium and C-arm

[0001] The present application claims priority to the Chinese patent application No. 202410684927.5, filed on May 30, 2024, with the Chinese Patent Office, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the technical field of computer imaging, in particular to a 3D reconstruction method, system, readable storage medium and C-arm. BACKGROUND

[0003] The operating room uses a 3D C-arm to perform 3D scanning imaging before / during / after surgery, and the 3D image can make the doctor more intuitive and effective in performing various activities of surgery. Most 3D C-arms have high requirements for imaging consistency, accuracy, mechanical precision, process, and electric control precision.

[0004] Most 3D imaging adopts an isocenter mechanical structure, resulting in a large size of the C-arm device, and the need for periodic geometric correction and high mechanical repeatability. If a conventional 2D C-arm can be used for 3D reconstruction, the convenience and flexibility of surgery will be improved.

[0005] Therefore, how to propose a 3D reconstruction method using a conventional 2D C-arm for 3D reconstruction has become a problem to be solved at present. SUMMARY

[0006] The present application proposes a 3D reconstruction method, system, readable storage medium and C-arm, which solves the problem in the related art that a 3D imaging device needs to be used and a conventional 2D C-arm cannot be used for 3D imaging.

[0007] To this end, a first object of the present application is to provide a 3D reconstruction method.

[0008] A second object of the present application is to provide a 3D reconstruction system.

[0009] A third object of the present application is to provide another 3D reconstruction system.

[0010] A fourth object of the present application is to provide a readable storage medium.

[0011] A fifth object of the present application is to provide a C-arm.

[0012] Therefore, the embodiment of the first aspect of the present application provides a 3D reconstruction method for a C-arm, the C-arm comprising a detector and a ball tube, the 3D reconstruction method comprising: establishing a space coordinate system; selecting a three-dimensional point on the space coordinate system and obtaining a coordinate of the three-dimensional point; determining a planar coordinate expression of a planar image formed by the detector at each working position in the space coordinate system; determining a focal point coordinate of the ball tube at each working position; determining a projection of the three-dimensional point on the planar image according to the focal point coordinate, to obtain a projection coordinate in the space coordinate system; obtaining a straight line expression of a boundary of each planar image in the space coordinate system; obtaining a two-dimensional coordinate of the three-dimensional point on the planar image according to the straight line expression and the projection coordinate; obtaining a corresponding relationship between the two-dimensional coordinate and the three-dimensional coordinate based on the two-dimensional coordinate of any three-dimensional point on the planar image and the three-dimensional coordinate of any three-dimensional point; and establishing a 3D reconstruction model according to the two-dimensional coordinate on the planar image and the corresponding relationship.

[0013] In this embodiment, the 3D reconstruction method is used for a C-arm. The 3D reconstruction method first needs to establish a space coordinate system, and all subsequent coordinate data is processed based on the space coordinate system, which plays a role of unifying data standards. Further, a three-dimensional coordinate in the space coordinate system is obtained, that is, a coordinate point is needed. Then, a planar coordinate expression of a planar image formed by the detector at a certain position of the C-arm in the space coordinate system is determined. The planar coordinate expression can represent that the planar image formed by the detector at the current position exists in the space coordinate system, and the focal point coordinate of the ball tube at the current position in the space coordinate system. In actual use, any working position of the C-arm corresponds to a planar coordinate expression and a focal point coordinate. Then, according to the focal point coordinate, the planar coordinate expression and the required coordinate point, the projection of the coordinate point on the planar coordinate expression relative to the focal point can be obtained, and then the projection of the coordinate point on the planar image is obtained. This process simulates the projection of an object on the coordinate point on the planar image, so the projection point of the coordinate point on the planar coordinate expression is the imaging of the object on the coordinate point on the actual planar image. Then, the boundary of the planar image is determined, the two-dimensional coordinate of the projection coordinate on the planar image is determined according to the straight line expression of the boundary on the three-dimensional coordinate system, that is, the distance between the projection coordinate and the boundary is determined. In this way, a corresponding relationship between the three-dimensional coordinate of the coordinate point and the two-dimensional coordinate on the planar image can be formed, and a 3D reconstruction model based on the planar image can be established according to the corresponding relationship. The 3D reconstruction model obtained by the scheme in the present application can be obtained by using a conventional 2D C-arm for 3D reconstruction, which improves the convenience and flexibility of the operation, and can generate a 3D model according to the pixels of the 2D image, improves the accuracy of the 3D reconstruction model, has strong reproducibility, and has great practical value.

[0014] In actual use, since the focal point of the ball tube and the projection plane are different in each use of the C-shaped arm, the focal point of the ball tube and the projection plane need to be measured each time projection is performed, thereby improving the accuracy of the correspondence between the two-dimensional coordinates and the three-dimensional coordinates. The generated 3D model is more accurate.

[0015] A second aspect of the present application provides a 3D reconstruction system for a C-shaped arm, the C-shaped arm comprising a detector and a ball tube, the 3D reconstruction system comprising: a coordinate establishing module for establishing a spatial coordinate system; a data selecting module for selecting a three-dimensional point on the spatial coordinate system and obtaining the coordinates of the three-dimensional point; a plane data obtaining module for determining the plane coordinate expression of the planar image formed by the detector at each working position in the spatial coordinate system and determining the focal point coordinates of the ball tube at each working position; a projection determining module for determining the projection of the three-dimensional point on the planar image according to the focal point coordinates, obtaining the projection coordinates in the spatial coordinate system; a boundary determining module for obtaining the straight line expression of the boundary of each planar image in the spatial coordinate system; a projection two-dimensional coordinate calculating module for obtaining the two-dimensional coordinates of the three-dimensional point on the planar image according to the straight line expression and the projection coordinates; and a model establishing module for obtaining the correspondence between the two-dimensional coordinates and the three-dimensional coordinates based on the two-dimensional coordinates of any three-dimensional point on the planar image and the three-dimensional coordinates of any three-dimensional point, and establishing a 3D reconstruction model according to the two-dimensional coordinates on the planar image and the correspondence.

[0016] A third aspect of the present application provides a 3D reconstruction system comprising a memory and a processor, the memory storing a program or instructions executable on the processor, the program or instructions being executed by the processor to implement the steps of the 3D reconstruction method provided in the first aspect.

[0017] A fourth aspect of the present application provides a readable storage medium having a program and / or instructions stored thereon, the program and / or instructions being executed by a processor to implement the steps of the 3D reconstruction method provided in the first aspect.

[0018] A fifth aspect of the present application provides a C-shaped arm comprising: the 3D reconstruction system provided in the second aspect, and / or the 3D reconstruction system provided in the third aspect, and / or the readable storage medium provided in the fourth aspect.

[0019] Additional aspects and advantages of the present application will become apparent in the description that follows, or will be learned by practice of the application. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present application or the embodiments in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the drawings shown.

[0021] Fig. 1 is a flowchart of a 3D reconstruction method according to an embodiment of the present application;

[0022] Fig. 2 is a block diagram of a 3D reconstruction system according to an embodiment of the present application;

[0023] Fig. 3 is a block diagram of a 3D reconstruction system according to an embodiment of the present application;

[0024] Fig. 4 is a schematic diagram of a C-arm, a navigation camera and a spatial coordinate system according to an embodiment of the present application;

[0025] Fig. 5 is a schematic diagram of a C-arm, a navigation camera and a spatial coordinate system according to an embodiment of the present application;

[0026] Fig. 6 is a schematic diagram of the changes of a focal point, a planar image and a projection point during rotation according to an embodiment of the present application;

[0027] Fig. 7 is a schematic diagram of the changes of a focal point, a planar image and a projection point during rotation according to an embodiment of the present application.

[0028] In Fig. 4 and Fig. 5, the correspondence between the reference signs and the component names is as follows:

[0029] 1 C-arm, 2 navigation camera, 3 tube, 4 detector. DETAILED DESCRIPTION

[0030] The embodiments in the present application will be described clearly and completely in the following with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0031] The 3D reconstruction method, system, readable storage medium and C-arm according to some embodiments of the present application will be described below with reference to Fig. 1 to Fig. 7.

[0032] The embodiments of the first aspect of the present application provide a 3D reconstruction method for a C-arm, the C-arm comprising a detector and a tube, as shown in Fig. 1, the 3D reconstruction method comprising:

[0033] S101: Establish a spatial coordinate system;

[0034] S102: Select a three-dimensional point on the spatial coordinate system and obtain the coordinates of the three-dimensional point;

[0035] S103: Determine the planar coordinate expression of the planar image formed by the detector at each working position in the spatial coordinate system;

[0036] S104: Determine the focal point coordinates of the ball tube at each working position;

[0037] S105: Determine the projection of the three-dimensional point on the planar image according to the focal point coordinates to obtain the projection coordinates in the spatial coordinate system;

[0038] S106: Obtain the straight line expression of the boundary of each planar image in the spatial coordinate system;

[0039] S107: Obtain the two-dimensional coordinates of the three-dimensional point on the planar image according to the straight line expression and the projection coordinates;

[0040] S108: Obtain the corresponding relationship between the two-dimensional coordinates and the three-dimensional coordinates based on the two-dimensional coordinates of any three-dimensional point on the planar image and the three-dimensional coordinates of any three-dimensional point;

[0041] S109: Establish a 3D reconstruction model according to the two-dimensional coordinates on the planar image and the corresponding relationship.

[0042] In this embodiment, the 3D reconstruction method is used for a C-arm. The 3D reconstruction method first needs to establish a spatial coordinate system, and all subsequent coordinate data is processed based on the spatial coordinate system, which plays a role in unifying data standards. Further, a three-dimensional coordinate in the spatial coordinate system is obtained, that is, the required coordinate point. Then, the planar coordinate expression of the planar image formed by the detector at a certain position of the C-arm in the spatial coordinate system is determined. The planar coordinate expression can represent the existence of the plane in which the planar image formed by the detector at the current position in the spatial coordinate system, and the focal point coordinate of the ball tube at the current position in the spatial coordinate system, that is, the focal point coordinate. In actual use, any working position of the C-arm corresponds to a planar coordinate expression and a focal point coordinate. Then, according to the focal point coordinate, the planar coordinate expression, and the required coordinate point, the projection of the coordinate point on the planar coordinate expression with respect to the focal point can be obtained, and then the projection of the coordinate point on the planar image is obtained. This process simulates the projection of the object at the coordinate point on the planar image, so the projection point of the coordinate point on the planar coordinate expression is the imaging of the object at the coordinate point on the actual planar image. Then the boundary of the planar image is determined, and the two-dimensional coordinate of the projection coordinate on the planar image is determined according to the straight line expression of the boundary on the three-dimensional coordinate system, that is, the distance between the projection coordinate and the boundary is determined. In this way, a corresponding relationship between the three-dimensional coordinate of the coordinate point and the two-dimensional coordinate on the planar image can be formed, and a 3D reconstruction model based on the planar image can be established according to the corresponding relationship. The 3D reconstruction model obtained by the scheme in the present application can be used for 3D reconstruction using a conventional 2D C-arm, which improves the convenience and flexibility of the operation. At the same time, the 3D model can be generated according to the pixels of the 2D image, which improves the accuracy of the 3D reconstruction model and has strong reproducibility and great practical value.

[0043] In some embodiments, the step of establishing a spatial coordinate system includes: taking any point on the axis of the C-arm as the origin, taking the axis of the C-arm as the X axis, and taking the initial position of the ball tube from the origin as the Z axis to establish the spatial coordinate system.

[0044] In this embodiment, as shown in FIGS. 4 and 5, a spatial coordinate system is established with any point on the axis of the C-arm as the origin, the axis of the C-arm as the X axis, and the initial position of the ball tube from the origin as the Z axis. All subsequent coordinate data is processed based on the spatial coordinate system, which plays a role in unifying data standards.

[0045] In some embodiments, the step of determining the planar coordinate expression of the planar image formed by the detector at each working position in the spatial coordinate system and determining the focal point coordinate of the ball tube at each working position includes: obtaining the initial position of the detector and the initial position of the focal point, the first planar coordinate expression of the planar image formed by the detector, the first coordinate of the focal point and the first direction angle of the detector in the spatial coordinate system; obtaining the transformation matrix Md of the detector and the transformation matrix Ms of the focal point; obtaining the second direction angle of the detector at any working position, and determining the second planar coordinate expression of the planar image formed by the detector at any working position and the second coordinate of the focal point according to the first direction angle of the detector, the second direction angle of the detector, the transformation matrix Md of the detector and the transformation matrix Ms of the focal point.

[0046] In some embodiments, the step of determining the projection of the three-dimensional coordinate of any point in the planar coordinate expression according to the focal point coordinate to obtain the projection coordinate includes: determining a first straight line according to the three-dimensional coordinate of any point and the second coordinate; and obtaining the projection coordinate of any point on the second planar coordinate expression of the planar image formed by the detector according to the first straight line and the second planar coordinate expression.

[0047] In some embodiments, the step of obtaining the straight line expression of the boundary of the planar image at any working position includes: obtaining the boundary coordinate of the detector at the initial position; and obtaining the straight line expression of the boundary of the planar image at any working position according to the transformation matrix Md of the detector and the boundary coordinate of the detector at the initial position.

[0048] The step of obtaining the first expression of the planar image of the detector, the first coordinate of the focal point and the first direction angle of the detector in the spatial coordinate system according to the present application includes: obtaining the foot point P of the focal point to the detector platform represented as (Px, Py, Pz), the first azimuth angle n of the detector represented as and the first coordinate S represented as (Sx, Sy, Sz) by using a calibration algorithm, determining the first expression of the planar image of the detector based on the foot point P and the first coordinate S:

[0049] wherein x, y, z represent unknown numbers, Px represents the X-axis coordinate of the P point, Py represents the Y-axis coordinate of the P point, Pz represents the Z-axis coordinate of the P point, a represents the included angle between the detector and the X-axis, β represents the included angle between the detector and the Y-axis, represents the included angle between the detector and the Z-axis, Sx represents the X-axis coordinate of the first coordinate, Sy represents the Y-axis coordinate of the first coordinate, Sz represents the Z-axis coordinate of the first coordinate, and cos represents the cosine function.

[0050] Using Zhang's camera calibration algorithm, the internal and external parameters of the C-arm can be obtained, including the spatial positions of the detector and the focal point in the reconstruction space coordinate system: P(Px, Py, Pz) is the foot point of the focal point to the detector plane, is the first direction angle of the detector, and S(Sx, Sy, Sz) is the focal point position.

[0051] In some embodiments, exemplarily, the step of obtaining the second direction angle of the detector, and determining the second expression of the detector plane and the second coordinate of the focal point of the detector at the second direction angle according to the first direction angle of the detector, the transformation matrix Md of the detector and the transformation matrix Ms of the focal point comprises: obtaining the second direction angle n' expressed as calculating the foot point P' of the detector at the second direction angle expressed as (P'x, P'y, P'z) = Md x P; and determining the second expression of the detector plane based on the foot point P' at the second direction angle and the second direction angle n':

[0052] the second coordinate S' of the focal point expressed as (S'x, S'y, S'z) = Ms x S;

[0053] wherein x, y, z represent unknown numbers, n'α represents the included angle between the second direction angle n' and the X-axis, n'β represents the included angle between the second direction angle n' and the Y-axis, n'γ represents the included angle between the second direction angle n' and the Z-axis, P'x represents the X-axis coordinate of the P' point, P'y represents the Y-axis coordinate of the P' point, P'z represents the Z-axis coordinate of the P' point, S'x represents the X-axis coordinate of the S' point, S'y represents the Y-axis coordinate of the S' point, and S'z represents the Z-axis coordinate of the S' point.

[0054] In some embodiments, exemplarily, the step of obtaining a point R expressed as (Rx, Ry, Rz) on the spatial coordinate system, and determining the first straight line according to the coordinates of the point R and the second coordinate comprises: the first straight line is expressed as:

[0055] wherein x, y, z represent unknown numbers, S'x represents the X-axis coordinate of the S' point, S'y represents the Y-axis coordinate of the S' point, S'z represents the Z-axis coordinate of the S' point, Rx represents the X-axis coordinate of the R point, Ry represents the Y-axis coordinate of the R point, Rz represents the Z-axis coordinate of the R point, and t represents the slope of the straight line.

[0056] In some embodiments, exemplarily, the step of calculating the projection point coordinate of the point R on the second expression of the detector plane according to the first straight line and the second expression comprises: obtaining the coordinate RP of the point R on the detector plane expressed as (RPx, RPy, RPz) by bringing the first straight line into the second expression; and the calculation method of the coordinate RP is as follows:

[0057] wherein RPx represents the X-axis coordinate of the RP point, RPy represents the Y-axis coordinate of the RP point, RPz represents the Z-axis coordinate of the RP point, t represents the slope of the straight line, n'α represents the included angle between the second direction angle n' and the X-axis, n'β represents the included angle between the second direction angle n' and the Y-axis, n'γ represents the included angle between the second direction angle n' and the Z-axis, S'x represents the X-axis coordinate of the S' point, S'y represents the Y-axis coordinate of the S' point, S'z represents the Z-axis coordinate of the S' point, Rx represents the X-axis coordinate of the R point, Ry represents the Y-axis coordinate of the R point, and Rz represents the Z-axis coordinate of the R point.

[0058] In some embodiments, as shown in FIG. 6, when the second direction angle is acquired, the step of determining the index of the projection point at the second direction angle according to the projection point coordinate and the boundary equation of the detector includes: determining the corner point coordinates CLU(CLUx, CLUy, CLUz), CLD(CLDx, CLDy, CLDz), CRU(CRUx, CRUy, CRUz), and CRD(CRDx, CRDy, CRDz) of the detector at the first direction angle; determining the corner point coordinates CLU'(CLU'x, CLU'y, CLU'z), CLD'(CLD'x, CLD'y, CLD'z), CRU'(CRU'x, CRU'y, CRU'z), and CRD'(CRD'x, CRD'y, CRD'z) of the detector at the second direction angle based on the second direction angle; determining the expressions of the straight lines CLU'-CRU' and CLU'-CLD' based on the corner point coordinates at the second direction angle as follows:

[0059] calculating the distance from the coordinate RP to the straight lines CLU'-CRU' and CLU'-CLD' to determine the index (dx, dy) of the projection point at the second direction angle;

[0060] ​Wherein, CLUx represents the X-axis coordinate of the CLU point, CLUy represents the Y-axis coordinate of the CLU point, CLUz represents the Z-axis coordinate of the CLU point, CLDx represents the X-axis coordinate of the CLD point, CLDy represents the Y-axis coordinate of the CLD point, CLDz represents the Z-axis coordinate of the CLD point, CRUx represents the X-axis coordinate of the CRU point, CRUy represents the Y-axis coordinate of the CRU point, CRUz represents the Z-axis coordinate of the CRU point, CRDx represents the X-axis coordinate of the CRD point, CRDy represents the Y-axis coordinate of the CRD point, CRDz represents the Z-axis coordinate of the CRD point, CLU'x represents the X-axis coordinate of the CLU' point, CLU'y represents the Y-axis coordinate of the CLU' point, CLU'z represents the Z-axis coordinate of the CLU' point, CLD'x represents the X-axis coordinate of the CLD' point, CLD'y represents the Y-axis coordinate of the CLD' point, CLD'z represents the Z-axis coordinate of the CLD' point, CRU'x represents the X-axis coordinate of the CRU' point, CRU'y represents the Y-axis coordinate of the CRU' point, CRU'z represents the Z-axis coordinate of the CRU' point, CRD'x represents the X-axis coordinate of the CRD' point, CRD'y represents the Y-axis coordinate of the CRD' point, CRD'z represents the Z-axis coordinate of the CRD' point, dx represents the x-axis coordinate of the projection point on the planar image, dy represents the y-axis of the projection point on the planar image, and ps represents the pixel of the planar image.

[0061] In some embodiments, as shown in FIG. 7, for a point R(Rx, Ry, Rz) to be reconstructed at a new angle of the C-shaped arm, its corresponding projection point RP(dx, dy) on the image can be obtained, so that interpolation reconstruction can be performed according to the 3D reconstruction formula, and the specific reconstruction formula is as follows:

[0062] Wherein, the spatial point coordinates R(Rx, Ry, Rz) and the projection point coordinates RP(dx, dy) have been obtained in the above calculation, g(l, z, β) is the filtered projection of the point R passing through the detector RP, β is the projection angle, l is the projection path, DSO represents the distance of the focal point and the x-axis in the y direction, and DSD represents the distance of the focal point and the planar image in the y direction.

[0063] The second aspect of the present application provides a 3D reconstruction system 200 for a C-arm, the C-arm comprising a detector and a tube, as shown in FIG. 2, the 3D reconstruction system 200 comprising: a coordinate establishing module 202 configured to establish a spatial coordinate system; a data selecting module 204 configured to select a three-dimensional point in the spatial coordinate system and obtain a coordinate of the three-dimensional point; a plane data obtaining module 206 configured to determine a plane coordinate expression of a plane image formed by the detector at each working position in the spatial coordinate system and determine a focal point coordinate of the tube at each working position; a projection determining module 208 configured to determine a projection of the three-dimensional point on the plane image according to the focal point to obtain a projection coordinate of the projection in the spatial coordinate system; a boundary determining module 210 configured to obtain a straight line expression of a boundary of each plane image in the spatial coordinate system; a projection two-dimensional coordinate calculating module 212 configured to obtain a two-dimensional coordinate of the three-dimensional point on the plane image according to the straight line expression and the projection coordinate; and a model establishing module 214 configured to establish a 3D reconstruction model based on a corresponding relationship between a two-dimensional coordinate of any point on the plane image and a three-dimensional coordinate of the any point and the two-dimensional coordinate on the plane image and the corresponding relationship.

[0064] Exemplarily, as shown in FIG. 4 and FIG. 5, the plane data obtaining module comprises a navigation camera 2. The navigation camera 2 can be fixed on the C-arm 1, and the navigation camera 2 is used to provide positions of the tube 3 and the detector 4, and thus a transformation matrix Md of the detector and a transformation matrix Ms of the focal point are calculated.

[0065] The third aspect of the present application provides a 3D reconstruction system 300, as shown in FIG. 3, comprising a memory 302 and a processor 304, the memory 302 storing a program or instructions executable on the processor 304, and the program or instructions are executed by the processor 304 to implement the steps of the 3D reconstruction method provided in the first aspect.

[0066] The fourth aspect of the present application provides a readable storage medium, and the readable storage medium stores a program and / or instructions, and the program and / or instructions are executed by a processor to implement the steps of the 3D reconstruction method provided in the first aspect.

[0067] The fifth aspect of the present application provides a C-arm 1, comprising: the 3D reconstruction system 200 provided in the second aspect, and / or the 3D reconstruction system 300 provided in the third aspect, and / or the readable storage medium provided in the fourth aspect.

[0068] In addition, the descriptions in the present application such as "first", "second", etc. are only for the purpose of description and should not be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0069] In the present application, unless otherwise specifically defined and limited, the terms "connection", "fixing" and the like should be understood broadly, for example, "fixing" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through intermediate medium; can be internal communication of two elements or interaction relationship of two elements, unless otherwise specifically limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0070] In addition, the embodiments of various embodiments of the present application can be combined with each other, but it must be based on the fact that the person skilled in the art can realize it, when the combination of the embodiments appears contradictory or unachievable, it should be considered that the combination of the embodiments does not exist, nor within the protection scope claimed by the present application.

[0071] The above is only the preferred embodiment of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A 3D reconstruction method, wherein, For a C-arm, the C-arm comprising a detector and an X-ray tube, the 3D reconstruction method includes: Establish a spatial coordinate system; Select a three-dimensional point on the spatial coordinate system and obtain the coordinates of the three-dimensional point; Determine the planar coordinate expression of the planar image formed by the detector at each working position in the spatial coordinate system; Determine the focal coordinates of the X-ray tube at each working position; The projection of the three-dimensional point onto the planar image is determined based on the focal coordinates, and the projection coordinates of the projection in the spatial coordinate system are obtained. Obtain the linear expression of the boundary of each of the planar images in the spatial coordinate system; Based on the linear expression and the projected coordinates, the two-dimensional coordinates of the three-dimensional point on the planar image are obtained; The correspondence between the two-dimensional coordinates and the three-dimensional coordinates is obtained based on the two-dimensional coordinates of any three-dimensional point on the planar image and the three-dimensional coordinates of any three-dimensional point. A 3D reconstruction model is established based on the two-dimensional coordinates on the planar image and the corresponding relationship.

2. The 3D reconstruction method according to claim 1, wherein, The steps for establishing a spatial coordinate system include: A spatial coordinate system is established with any point on the axis of the C-shaped arm as the origin, the axis of the C-shaped arm as the X-axis, and the distance from the origin to the initial position of the X-ray tube as the Z-axis.

3. The 3D reconstruction method according to claim 1, wherein, The planar coordinate expression of the planar image formed by the detector at each working position in the spatial coordinate system is determined; The steps for determining the focal coordinates of the X-ray tube at each working position include: Based on the initial position of the detector and the initial position of the focus, obtain the first planar coordinate expression of the planar image formed by the detector, the first coordinate of the focus, and the first orientation angle of the detector in the spatial coordinate system; Obtain the transformation matrix Md of the detector and the transformation matrix Ms of the focal spot; Obtain the second orientation angle of the detector and the focus at any working position. Based on the first orientation angle of the detector, the second orientation angle of the detector, the transformation matrix Md of the detector, and the transformation matrix Ms of the focus, determine the second planar coordinate expression of the planar image formed by the detector at any working position and the second coordinate of the focus.

4. The 3D reconstruction method according to claim 3, wherein, The step of determining the projection of the three-dimensional point onto the planar image based on the focal coordinates, and obtaining the projection coordinates of the projection in the spatial coordinate system, includes: The first straight line is determined based on the three-dimensional coordinates of any of the three-dimensional points and the second coordinates; Based on the first straight line and the second plane coordinate expression, the projected coordinates of any three-dimensional point on the second plane coordinate expression are obtained.

5. The 3D reconstruction method according to claim 3 or 4, wherein, The step of obtaining the linear expression of the boundary of each planar image in the spatial coordinate system includes: Obtain the boundary coordinates of the detector at its initial position; Based on the transformation matrix Md of the detector and the boundary coordinates of the detector at the initial position, the linear expression of the boundary of the planar image at any working position is obtained.

6. A 3D reconstruction system, wherein, For use with a C-arm, the C-arm including a detector and an X-ray tube, the 3D reconstruction system includes: The coordinate establishment module is used to establish a spatial coordinate system; The data selection module is used to select a three-dimensional point on the spatial coordinate system and obtain the coordinates of the three-dimensional point; The planar data acquisition module is used to determine the planar coordinate expression of the planar image formed by the detector at each working position in the spatial coordinate system and to determine the focal coordinates of the X-ray tube at each working position. The projection determination module is used to determine the projection of the three-dimensional point on the planar image based on the focal coordinates, and to obtain the projection coordinates of the projection in the spatial coordinate system. A boundary determination module is used to obtain the linear expression of the boundary of each planar image in the spatial coordinate system; The two-dimensional coordinate calculation module is used to obtain the two-dimensional coordinates of the three-dimensional point on the planar image based on the line expression and the projected coordinates. The model building module is used to obtain the correspondence between the two-dimensional coordinates and the three-dimensional coordinates based on the two-dimensional coordinates of any three-dimensional point on the planar image and the three-dimensional coordinates of any three-dimensional point, and to build a 3D reconstruction model based on the two-dimensional coordinates on the planar image and the correspondence.

7. The 3D reconstruction system according to claim 6, wherein, The planar data acquisition module includes a navigation camera.

8. A 3D reconstruction system, wherein, It includes a memory and a processor, the memory storing a program or instructions that can run on the processor, the program or instructions being executed by the processor to implement the steps of the 3D reconstruction method as described in any one of claims 1 to 5.

9. A readable storage medium, wherein, It stores programs and / or instructions that, when executed by a processor, implement the steps of the 3D reconstruction method as described in any one of claims 1 to 5.

10. A C-shaped arm, wherein, include: The 3D reconstruction system as described in claim 6 or 7; and / or The 3D reconstruction system as described in claim 8; and / or The readable storage medium as described in claim 9.

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