Dynamic real-time construction method and equipment for digital model of concentric sheathing canal

Abstract

The invention discloses a concentric sheathing canal digital model dynamic real-time construction method, which comprises the following steps: S1, reading control values in real time, the control values comprising a large sheathing bending control value, a large sheathing rotation value, a large sheathing feed value, a small sheathing bending control value, a small sheathing rotation value and a small sheathing feed value, S2, retrieving the large sheathing bending control value in a large sheathing retrieval table to obtain a retrieval table two-dimensional coordinate of a large sheathing anchor point, calculating and processing the large sheath anchor point space coordinates to obtain a large sheath path; s3, rendering a large sheath canal grid according to the large sheath path; s4, retrieving the small sheath bending control value and the length of the small sheath extending out of the large sheath in the small sheath retrieval table to obtain a retrieval table two-dimensional coordinate of the small sheath anchor point, performing calculation processing on the retrieval table two-dimensional coordinate to obtain a small sheath anchor point space coordinate, and performing calculation processing on the small sheath anchor point space coordinate to obtain a small sheath path; and S5, rendering a sheath canal grid according to the sheath path. According to the method, dynamic real-time modeling of the concentric sheathing canal can be realized by utilizing the pre-established retrieval table.

Description

Technical Field

[0001] The present invention relates to the field of digital modeling, and in particular to a method and device for dynamically and real-time constructing a concentric sheath tube digital model. Background Art

[0002] In the field of cardiac surgery, interventional surgery has superior postoperative effects to surgical surgery in terms of both sustainability and effectiveness. Cardiac interventional surgery is complex, difficult to operate, and requires viewing medical images during the procedure. This requires doctors to have extensive operational experience and places high demands on their surgical training. At the same time, interventional treatment relies on digital subtraction angiography (DSA) to observe the patient's physiological condition and the progress of the operation. This can result in doctors being exposed to high radiation doses at close range, posing a health hazard to them. Furthermore, the time and financial costs of using animals or clinics for surgical training are high, so the number of animal and human surgical exercises should be minimized during surgical training. Therefore, the design of surgical simulators plays an important role in training for interventional surgery.

[0003] Since most interventional surgical instruments are sheath structures, it is very important to design a dynamic real-time construction scheme for the sheath structure.

[0004] There are several technologies for digital modeling of sheath structures with complex shapes:

[0005] Static modeling solution: This involves building a model in modeling software and importing it into a game engine for use. The problem with this solution is that the model cannot be deformed after modeling. Forcibly bending the mesh to deform it will result in obvious defects.

[0006] Dynamic modeling solution 1: Modeling the sheath based on the Cosserat rod model, constructing an analytical model, and calculating the mechanical morphology in real time. However, the problem is that the solution time is long, and the sheath (mainly various medical devices) is generally divided into multiple segments with different stiffness, which makes parameter measurement and modeling very difficult.

[0007] Dynamic modeling solution 2: Build a sheath model based on the game engine's skeletal system. The disadvantage is that the deformation is too rigid and the model is severely deformed.

[0008] No relevant work has been found on the coordinated motion and digital model construction of concentric sheath mechanisms.

[0009] Therefore, those skilled in the art are committed to developing a method for dynamically and real-time constructing a concentric sheath digital model. Summary of the Invention

[0010] In view of the above-mentioned defects of the prior art, the technical problems to be solved by the present invention are:

[0011] 1) There is currently a lack of a real-time rendering solution that can adjust the sheath shape according to input changes in real time during simulator operation;

[0012] 2) Since most interventional surgical instruments are multi-segment concentric sheath structures, it is necessary to design double sheaths to ensure overall coordinated movement when the concentric tube structures are nested.

[0013] To achieve the above objectives, the present invention provides a method for dynamically and real-time constructing a concentric sheath tube digital model, comprising:

[0014] Establish a spatial coordinate system, wherein the spatial coordinate system takes the initial position of the starting endpoint of the large sheath as the origin, the axis direction of the starting endpoint of the large sheath as the X axis, and the initial path plane of the large sheath as the XZ plane,

[0015] S1: Read control values ​​in real time, including the large sheath bending control value, large sheath rotation value, large sheath feed value, small sheath bending control value, small sheath rotation value, and small sheath feed value. The bending control value describes the degree of sheath bending, the rotation value describes the rotation angle of the path plane where the sheath is located, and the feed value describes the linear movement distance of the starting endpoint of the sheath in the direction of the starting endpoint axis.

[0016] S2: Retrieve the large sheath bending control value from the large sheath retrieval table to obtain the two-dimensional coordinates of the large sheath anchor point, calculate and process the two-dimensional coordinates to obtain the large sheath anchor point spatial coordinates, and calculate and process the large sheath anchor point spatial coordinates to obtain the large sheath path;

[0017] S3: Rendering the sheath mesh according to the sheath path;

[0018] S4: Retrieving the small sheath bending control value and the length of the small sheath extending outside the large sheath from the small sheath retrieval table to obtain the retrieval table two-dimensional coordinates of the small sheath anchor point, calculating and processing the two-dimensional coordinates to obtain the small sheath anchor point spatial coordinates, and calculating and processing the small sheath anchor point spatial coordinates to obtain the small sheath path;

[0019] S5: Rendering the sheath mesh according to the sheath path;

[0020] The sheath retrieval table establishes a mapping relationship between different sheath bending control values ​​and the retrieval table two-dimensional coordinates of the sheath anchor points. The retrieval table two-dimensional coordinates of the sheath anchor points are the two-dimensional coordinates of multiple anchor points on the sheath tube relative to the starting end point of the sheath in the sheath path plane.

[0021] The small sheath retrieval table establishes a mapping relationship between different small sheath bending control values, the length of the small sheath extending outside the large sheath and the two-dimensional coordinates of the small sheath anchor point in the retrieval table. The length of the small sheath extending outside the large sheath is the small sheath feed value minus the large sheath feed value. The two-dimensional coordinates of the small sheath anchor point in the retrieval table are the two-dimensional coordinates of multiple anchor points on the small sheath sheath tube relative to the starting end point of the small sheath in the small sheath path plane.

[0022] Further, the step S2 includes:

[0023] S201: Calculating the coordinates of the starting endpoint of the large sheath according to the large sheath feed value;

[0024] S202: Calculating the large sheath path plane according to the large sheath rotation value;

[0025] S203: searching the large sheath retrieval table for the large sheath bending control value to obtain the retrieval table two-dimensional coordinates of the large sheath anchor point;

[0026] S204: Calculating and processing the two-dimensional coordinates of the sheath anchor point in the retrieval table, the coordinates of the starting end point of the sheath, and the sheath path plane to obtain the spatial coordinates of the sheath anchor point;

[0027] S205: According to the spatial coordinates of the anchor point of the large sheath, a large sheath path is obtained using a multi-segment continuous cubic Bezier curve method.

[0028] Furthermore, the step S205 includes:

[0029] S2051: Set two large sheath control points between each two adjacent large sheath anchor points;

[0030] S2052: Using any two adjacent large sheath anchor points and the two large sheath control points therebetween, a corresponding large sheath Bezier curve path is obtained according to a cubic Bezier formula, and the large sheath Bezier curve paths are connected to obtain a large sheath path.

[0031] Further, the step S4 includes:

[0032] S401: The final anchor point of the large sheath is used as the starting endpoint of the small sheath, and the vector from the penultimate anchor point of the large sheath to the final anchor point of the large sheath is used as the axis direction of the starting endpoint of the small sheath;

[0033] S402: The small sheath path plane is a plane including the axis of the starting endpoint of the small sheath, the small sheath path initial plane coincides with the large sheath path plane, and the small sheath path plane is calculated based on the small sheath rotation value;

[0034] S403: searching the small sheath bending control value and the length of the small sheath extending outside the large sheath in the small sheath search table to obtain the two-dimensional coordinates of the small sheath anchor point;

[0035] S404: Calculate and process the two-dimensional coordinates of the small sheath anchor point in the retrieval table, the coordinates of the starting end point of the small sheath, and the small sheath path plane to obtain the spatial coordinates of the small sheath anchor point;

[0036] S405: According to the spatial coordinates of the small sheath anchor point, a small sheath path is obtained using a multi-segment continuous cubic Bezier curve method.

[0037] Furthermore, the step S405 includes:

[0038] S4051: Set two small sheath control points between every two adjacent small sheath anchor points;

[0039] S4052: using any two adjacent small sheath anchor points and the two small sheath control points therebetween to obtain a corresponding small sheath Bezier curve path according to a cubic Bezier formula, and connecting the small sheath Bezier curve paths to obtain a small sheath path.

[0040] Further, the step S3 includes:

[0041] S301: Arrange large sheath surrounding points around the large sheath path;

[0042] S302: performing triangle coding on the large sheath surrounding points, and constructing a large sheath surrounding point coordinate set and a triangle connection relationship between the large sheath surrounding points;

[0043] S303: Rendering the large sheath mesh;

[0044] The step S5 comprises:

[0045] S501: arranging small sheath surrounding points around the small sheath path;

[0046] S502: performing triangle coding on the small sheath surrounding points, and constructing a small sheath surrounding point coordinate set and a triangle connection relationship between the small sheath surrounding points;

[0047] S503: Rendering the mesh of the small sheath tube.

[0048] Further, the method may further include step S6:

[0049] S6: performing collision detection on the large sheath path and the small sheath path to determine whether the large sheath path and the small sheath path collide with the environment.

[0050] Furthermore, the method for reading the control value in real time is to read it from an external analog controller in real time.

[0051] Furthermore, the large sheath retrieval table and the small sheath retrieval table can be established by any method including physical experiment, simulation, and calculation.

[0052] In a second aspect, the present invention further provides a computer device, comprising:

[0053] Memory;

[0054] one or more processors coupled to the memory;

[0055] One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by one or more processors, and the one or more applications are configured to execute the construction method according to any one of claims 1 to 9.

[0056] By providing the above method and device, the present invention can achieve the following technical effects:

[0057] 1) The present invention uses a data-based method to construct multiple continuous Bezier curves through anchor points for trajectory approximation. The automation of grid construction is achieved. Collision detection based on spatial grids is achieved, and it can run independently without relying on the game engine. The present invention is based on data and uses multiple continuous Bezier curves to set anchor points to model the sheath trajectory. Interpolation is performed based on the anchor points to smooth the trajectory. The grid point position calculation is automatically completed based on the anchor points, and the grid rendering can be automatically completed, thereby achieving dynamic modeling. The surgical environment model is stored in the spatial grid, and collision detection is achieved by detecting whether there are environmental model points within the sheath radius around the anchor point. The present invention can dynamically adjust the shape of the entire sheath during program operation by changing the anchor point position, with low latency. After the environmental information is stored in the spatial grid before the program runs, dynamic detection of the sheath and the environment can be performed in real time.

[0058] 2) Small Sheath Design: The small sheath's actual posture is determined by two-dimensional variables, namely, its extension length and degree of bending control. Coordination of the small and large sheaths: The small sheath uses the anchor point at the end of the large sheath as the starting point for sheath generation, allowing the bending and rotation of the large sheath to influence the starting position of the small sheath. Advancing the large sheath simultaneously reduces the length of the small sheath by the same amount, while retracting the large sheath causes the small sheath to lengthen synchronously. Small sheath Independence: The small sheath has independent advancement, rotation, and bending control, and its shape in the local coordinate system is unaffected by the bending and rotation of the large sheath. Quaternion assignment is used to ensure that the local coordinate system positions and axis orientations of the small and large sheath connection points are identical, thus ensuring the consistent orientation of the small and large sheath connection points. Rotation is applied by rotating the small sheath connection point in the local coordinate system by a specified angle along the direction of the large sheath. Coordinate assignment is performed in the local coordinate system, allowing the entire model to be rotated by rotating the local coordinate system, eliminating the need to recalculate world coordinates based on the rotation angle. Retracting the large sheath increases the extension of the small sheath by the same amount, achieving a simulated effect. This invention achieves excellent coordinated motion when concentrically nesting two sheaths. The movement of the large sheath affects the movement of the small sheath by changing the position of the large sheath's end, which is the starting point of the small sheath. The small sheath has independent feeding, bending, and rotation functions, which conforms to the movement mode of most concentric sheath instruments in interventional surgeries.

[0059] 3) A dataset is constructed using experimental data, and anchor point locations are determined through retrieval and interpolation to achieve control bending posture determination. (Large sheath control bending uses one-dimensional retrieval, while small sheath control bending uses two-dimensional retrieval.) Based on real experimental data, a mapping table is determined for control variables in the simulated sheath to anchor point locations, thereby achieving the mapping of control variables to sheath posture. The specific bending shape of the sheath can be achieved by modifying the reference data, making it very easy to customize.

[0060] The concept, specific structure and technical effects of the present invention will be further described below in conjunction with the accompanying drawings to fully understand the purpose, characteristics and effects of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] Figure 1 This is a flow chart of a method for dynamically and real-time constructing a concentric sheath tube digital model according to a preferred embodiment of the present invention;

[0062] Figure 2 This is a diagram showing the setting of anchor points and control points of a multi-segment continuous Bezier curve according to a preferred embodiment of the present invention;

[0063] Figure 3 This is an example of a grid coding process and an algorithm diagram of a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0064] The following describes several preferred embodiments of the present invention with reference to the accompanying drawings to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms of embodiments, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0065] In the drawings, components with the same structure are denoted by the same numerical numerals, and components with similar structure or function are denoted by similar numerical numerals.

[0066] like Figure 1 As shown, the present invention provides a solution for dynamically and real-time construction of a concentric sheath tube digital model. Figure 1The process of building and updating a concentric sheath model in real time is demonstrated in the following text. First, a data retrieval table is constructed; its contents and functions are described in detail later. Next, control values ​​are read from an external controller. These control values ​​consist of six degrees of freedom (DOFs), including bending, rotation, and feed control for the outer sheath (hereafter referred to as the "large sheath") and the inner sheath (hereafter referred to as the "small sheath"). In the modeling environment, the large sheath is initially straight, with its starting endpoint initially positioned at the spatial origin. The starting endpoint axis is fixed and contained within the path plane (e.g., the starting endpoint axis is typically chosen to coincide with the x-axis, so the path plane is initially the xz plane passing through the origin). The length of the small sheath extending beyond the large sheath is determined by subtracting the large sheath feed value from the small sheath feed value, initially set to 0. The small sheath starting endpoint axis is the direction of the large sheath's final endpoint and initially coincides with the large sheath starting endpoint axis. The detailed determination process is described later. The small sheath path plane is the plane containing the small sheath starting endpoint axis and is initially set to coincide with the large sheath path plane. Among the control values, the rotation value refers to the rotation angle of the path plane where the trajectory (anchor point) is located relative to the initial position around the axis of the starting endpoint; the large sheath feed value refers to the translation distance of the large sheath starting endpoint relative to the initial position along the axis of the starting endpoint, and the small sheath feed value is combined with the large sheath feed value to calculate the length of the small sheath extending out of the large sheath; the bending control value is used to describe the path of the sheath tube on the path plane. In the present invention, the sheath tube path is mainly determined by determining the positions of several anchor points on the path plane, and the specific shape path of the sheath tube is determined by path fitting between the anchor points, and the bending control value is the control value that describes the degree of bending of the sheath tube. The mapping relationship between the bending control value and the coordinates of the anchor point on the path plane is established through the data retrieval table mentioned in the first step. The retrieval data table is composed of a large sheath retrieval table and a small sheath retrieval table. The mapping relationship between the two-dimensional coordinates of multiple anchor points on the large sheath tube relative to the starting endpoint in the path plane corresponding to different large sheath bending control values ​​is established in the large sheath retrieval table. There are many ways to set up the distribution of multiple anchor points, such as: equal division, fewer initial ends and more final ends, more initial ends and fewer final ends, etc. The specific setting method depends on the deformation requirements of the sheath: for the part of the sheath with a larger degree of bending, the anchor point distribution should be more dense to better fit the sheath path; for the part of the sheath with a smaller degree of bending, the anchor point distribution should be reduced to reduce the amount of calculation. When the anchor point distribution with fewer initial ends and more final ends is adopted, the larger bending capacity of the final end of the sheath can be better marked. The specific scheme can be set as follows: from the final end anchor point to the initial end anchor point, the distances between adjacent anchor points are arranged in an arithmetic progression. This scheme optimizes the marking effect while reducing the amount of calculation in the later stage. For the large sheath control bending value input by the controller, through a one-dimensional line search, the two-dimensional coordinates of the anchor points set on the large sheath in the corresponding control bending state in the path plane relative to the starting end point of the large sheath can be obtained (the two-dimensional coordinates of the large sheath anchor point in the retrieval table). The small sheath retrieval table is a two-dimensional search. The small sheath bending control value and the length of the small sheath extending outside the large sheath in the current state are used as two independent variables to retrieve the two-dimensional coordinates of the anchor point on the small sheath relative to the starting end point of the small sheath (the two-dimensional coordinates of the small sheath anchor point in the retrieval table).The large sheath retrieval table and the small sheath retrieval table can be obtained through physical experiments, simulations, calculations, etc. The number of anchor points set on the sheath tube can be set by the user, and the bending control value can be set by the user. The coordinates of the anchor points under different states are measured and recorded to obtain a table.

[0067] In each frame, the paths of the large and small sheaths need to be recalculated, and new paths are obtained and rendered to achieve dynamic real-time construction. The entire construction process is as follows Figure 1 shown.

[0068] After obtaining the control value, the sheath must first be fed. This involves confirming the coordinates of the large sheath's starting endpoint using the large sheath's feed value and determining the extension length of the small sheath by subtracting the large and small sheath feed values. For the large sheath's feeding process, the starting endpoint coordinates are fed along the starting endpoint axis. Since the coordinates of the sheath's path points are in a local coordinate system with the starting endpoint as the origin, the entire sheath moves along with the starting point to achieve feeding. For the small sheath, its starting endpoint is the large sheath's final endpoint, and the starting endpoint axis is the normal to the plane formed by the large sheath's final endpoint and the surrounding points around it. The direction of the small sheath's starting endpoint axis can be approximated by the vector from the second final endpoint on the large sheath's path point to the final endpoint.

[0069] Subsequently, the large sheath path plane needs to be rotated according to the control value, and the path plane is rotated along the starting endpoint axis by a specific angle according to the large sheath rotation value.

[0070] Next, confirm the distribution of the sheath path relative to the starting endpoint on the path plane. According to the construction and retrieval method of the data table described above, the two-dimensional coordinates of the sheath anchor point can be retrieved in the data table through the input control value. The coordinates are the coordinate values ​​in the local coordinate system with the starting endpoint of the sheath as the origin and the sheath path plane as the xz plane. The two-dimensional coordinates of the sheath anchor point can be transformed by combining the coordinates of the starting endpoint of the sheath and the sheath path plane to obtain the spatial coordinates of the sheath anchor point. After arranging the sheath anchor point, use the following method: Figure 2The control points of the sheath are determined by the following method. In the figure, 100-102 are anchor points, and 103-106 are control points. The three anchor points drawn in the figure represent three anchor point situations: 100 is the starting anchor point, 102 is the final anchor point, and 101 is the intermediate anchor point. In actual practice, there are usually several anchor points between the starting anchor point and the final anchor point, but their subsequent processing methods are exactly the same as the 101 anchor point. Therefore, the 101 anchor point is used here as a representative. The motion fitting of the sheath tube is performed using a multi-segment continuous cubic Bezier curve method. That is, a sheath Bezier curve path is calculated between every two sheath anchor points. The paths between all the sheath anchor points are connected end to end to obtain the overall path of the sheath tube (the sheath path). This ensures that the overall path of the sheath tube passes through all anchor points, ensuring the accuracy of the posture of the constructed sheath tube. According to the cubic Bezier formula, to complete the above operation, two sheath control points must be set between every two adjacent sheath anchor points. The sheath control points are recorded as 103-106. Since the overall sheath path is composed of several smaller paths connected end-to-end between anchor points, ensuring the overall continuity and smoothness of the sheath path requires that the two connected curves have the same slope at the connection point. Therefore, the following sheath control point setting method is used to ensure that adjacent Bezier curves connect with the same curvature: For the middle anchor point 101, the two control points before and after it are determined as follows: Take the angle bisector 107 of the angle 100-101-102, and draw a perpendicular line 108 through 101. Control points 104 and 105 are located on 108, near 100 and 102, respectively, and their distance from 101 is half the distance from 101 to 100 and 102, respectively. For the starting point 100, only the position of the first control point 103 is determined. Similarly, the end point 102 only contributes to the position of the last control point 106. 103 is located midway between 100 and 104, and 106 is located midway between 102 and 105. After determining the coordinates of all control points, according to the cubic Bezier curve formula

[0071] B(t)=P0(1-t) 3 +3P1t(1-t) 2 +3P2t 2 (1--t)+P3t 3,t∈[0,1], for example, the coordinates 100, 103, 104, and 101 are substituted into P0-P3 in sequence to obtain the Bezier curve equation between 100-101. Repeating the above operation can obtain the equation of the Bezier curve between any two anchor points (large sheath Bezier curve path). Connecting the above large sheath Bezier curve paths can obtain the path fitting equation of the entire sheath (large sheath path). Since triangular meshes are used for imaging in computer graphics, to establish a sheath model based on the large sheath path, it is necessary to arrange large sheath surrounding points around the large sheath path, and build a grid code through the large sheath surrounding points to realize sheath imaging. In order to make the modeled sheath continuous and smooth, it is necessary to arrange sufficiently dense large sheath surrounding points. First, it is necessary to interpolate on the obtained large sheath Bezier curve path to obtain enough path points, and then arrange surrounding points around it based on the path points. According to the large sheath Bezier curve path equation that has been obtained, t is uniformly valued between 0-1 to obtain enough path points. After interpolation, large sheath surrounding points are arranged around each interpolation point and anchor point. As Figure 3 As shown, E is the path point obtained after interpolation, S is the sheath surrounding point arranged around the path point, with the path point as the center, on the normal plane of the vector from the next path point to the current path point, a circle with the sheath radius as the radius is drawn, and the circle is divided into n equal parts, and each equal part is a sheath surrounding point. Figure 3 The method shown above is to encode the front and rear sheath surrounding points into triangles, construct the sheath surrounding point coordinate set used to build the mesh, and the triangle connection relationship between these sheath surrounding points, so as to render the sheath tube mesh in the engine. At this point, the sheath model has been fully confirmed.

[0072] Next, the small sheath model needs to be determined. By using the position and orientation of the large sheath's final endpoint (approximated using the vector direction of the large sheath's second final endpoint pointing to the large sheath's final endpoint), the small sheath's starting endpoint position is determined to be identical to the large sheath's final endpoint, and the small sheath's starting endpoint axis direction is identical to the large sheath's final endpoint direction. The small sheath path plane is set to be the plane containing the small sheath's starting endpoint axis, initially set to coincide with the large sheath path plane. Based on the small sheath rotation value in the control value, the small sheath path plane is rotated around the small sheath's starting endpoint axis. Based on the small sheath's bending control value and the previously calculated length of the small sheath extending beyond the large sheath, the coordinates of the small sheath anchor point on the path plane relative to the small sheath's starting endpoint (the retrieval table two-dimensional coordinates of the small sheath anchor point) are determined using the small sheath retrieval data table. The small sheath path is determined by confirming the same method as the large sheath path, and the small sheath's surrounding points are arranged and triangle encoding and rendering are performed in the same manner as the large sheath. At this point, the large and small sheath models have been fully confirmed. After the grid points are automatically updated, the rendering sheath tube also automatically completes real-time construction.

[0073] Finally, collision detection is performed on the sheath. First, the 3D bounding box of the environment model is obtained. The space within the bounding box is divided into small 3D grids, with the grid side length set to the radius of the large sheath. A corresponding 3D matrix is ​​created based on the number of grid cells corresponding to the length, width, and height of the bounding box. Each spatial grid corresponds to a grid coordinate in this grid matrix. All nodes in the environment model are numbered and stored in the corresponding position of the matrix according to their spatial coordinates. During collision detection, all path points of the large and small sheaths are sequentially traversed. For each path point, its coordinates are first determined to determine whether it is within the bounding box. If it is outside the bounding box, it is skipped. If it is inside the bounding box, its coordinates are used to determine which 3D grid it belongs to and obtain its grid coordinates. The distance from the grid coordinate value and all nodes stored in the 27 surrounding grid coordinates to the current path point is then sequentially checked. If this distance is less than the radius of the large sheath, the sheath and the environment model have collided at this node. If all path points do not collide with the environment model, then the sheath and the environment have not collided.

[0074] The dynamic modeling method for sheaths described above allows for extensive customization, such as the specific bending control position information of the sheath, the sheath radius, the number of interpolated path points, and the number of surrounding points. While the modeling of two concentric sheaths is used as an example, this method can be expanded to include dynamic modeling of multiple concentric sheaths.

[0075] The preferred embodiments of the present invention have been described in detail above. It should be understood that numerous modifications and variations based on the concepts of the present invention are possible without inventive effort by those skilled in the art. Therefore, any technical solution that can be derived by one skilled in the art through logical analysis, reasoning, or limited experimentation based on the concepts of the present invention and the prior art should be within the scope of protection defined by the claims.

Claims

1. A method for dynamically constructing a concentric sheath digital model in real time, characterized in that: include: Establish a spatial coordinate system, wherein the spatial coordinate system takes the initial position of the starting endpoint of the large sheath as the origin, the axis direction of the starting endpoint of the large sheath as the X axis, and the initial path plane of the large sheath as the XZ plane, S1: Read control values ​​in real time, including the large sheath bending control value, large sheath rotation value, large sheath feed value, small sheath bending control value, small sheath rotation value, and small sheath feed value. The bending control value describes the degree of sheath bending, the rotation value describes the rotation angle of the path plane where the sheath is located, and the feed value describes the linear movement distance of the starting endpoint of the sheath in the direction of the starting endpoint axis. S2: Retrieve the large sheath bending control value from the large sheath retrieval table to obtain the two-dimensional coordinates of the large sheath anchor point, calculate and process the two-dimensional coordinates to obtain the large sheath anchor point spatial coordinates, and calculate and process the large sheath anchor point spatial coordinates to obtain the large sheath path; S3: Rendering the sheath mesh according to the sheath path; S4: Retrieving the small sheath bending control value and the length of the small sheath extending outside the large sheath from the small sheath retrieval table to obtain the retrieval table two-dimensional coordinates of the small sheath anchor point, calculating and processing the two-dimensional coordinates to obtain the small sheath anchor point spatial coordinates, and calculating and processing the small sheath anchor point spatial coordinates to obtain the small sheath path; S5: Rendering the sheath mesh according to the sheath path; The sheath retrieval table establishes a mapping relationship between different sheath bending control values ​​and the retrieval table two-dimensional coordinates of the sheath anchor points. The retrieval table two-dimensional coordinates of the sheath anchor points are the two-dimensional coordinates of multiple anchor points on the sheath tube relative to the starting end point of the sheath in the sheath path plane. The small sheath retrieval table establishes a mapping relationship between different small sheath bending control values, the length of the small sheath extending outside the large sheath and the two-dimensional coordinates of the small sheath anchor point in the retrieval table. The length of the small sheath extending outside the large sheath is the small sheath feed value minus the large sheath feed value. The two-dimensional coordinates of the small sheath anchor point in the retrieval table are the two-dimensional coordinates of multiple anchor points on the small sheath sheath tube relative to the starting end point of the small sheath in the small sheath path plane.

2. The method for dynamically constructing a digital model of a concentric sheath tube in real time according to claim 1, wherein: The step S2 comprises: S201: Calculating the coordinates of the starting endpoint of the large sheath according to the large sheath feed value; S202: Calculating the large sheath path plane according to the large sheath rotation value; S203: searching the large sheath retrieval table for the large sheath bending control value to obtain the retrieval table two-dimensional coordinates of the large sheath anchor point; S204: Calculating and processing the two-dimensional coordinates of the sheath anchor point in the retrieval table, the coordinates of the starting end point of the sheath, and the sheath path plane to obtain the spatial coordinates of the sheath anchor point; S205: According to the spatial coordinates of the anchor point of the large sheath, a large sheath path is obtained using a multi-segment continuous cubic Bezier curve method.

3. The method for dynamically constructing a digital model of a concentric sheath tube in real time according to claim 2, wherein: The step S205 includes: S2051: Set two large sheath control points between each two adjacent large sheath anchor points; S2052: Using any two adjacent large sheath anchor points and the two large sheath control points therebetween, a corresponding large sheath Bezier curve path is obtained according to a cubic Bezier formula, and the large sheath Bezier curve paths are connected to obtain a large sheath path.

4. The method for dynamically constructing a digital model of a concentric sheath tube in real time according to claim 1, wherein: The step S4 comprises: S401: The final anchor point of the large sheath is used as the starting endpoint of the small sheath, and the vector from the penultimate anchor point of the large sheath to the final anchor point of the large sheath is used as the axis direction of the starting endpoint of the small sheath; S402: The small sheath path plane is a plane including the axis of the starting endpoint of the small sheath, the small sheath path initial plane coincides with the large sheath path plane, and the small sheath path plane is calculated based on the small sheath rotation value; S403: searching the small sheath bending control value and the length of the small sheath extending outside the large sheath in the small sheath search table to obtain the two-dimensional coordinates of the small sheath anchor point; S404: Calculate and process the two-dimensional coordinates of the small sheath anchor point in the retrieval table, the coordinates of the starting end point of the small sheath, and the small sheath path plane to obtain the spatial coordinates of the small sheath anchor point; S405: According to the spatial coordinates of the small sheath anchor point, a small sheath path is obtained using a multi-segment continuous cubic Bezier curve method.

5. The method for dynamically constructing a digital model of a concentric sheath tube in real time according to claim 4, wherein: The step S405 includes: S4051: Set two small sheath control points between every two adjacent small sheath anchor points; S4052: using any two adjacent small sheath anchor points and the two small sheath control points therebetween to obtain a corresponding small sheath Bezier curve path according to a cubic Bezier formula, and connecting the small sheath Bezier curve paths to obtain a small sheath path.

6. The method for dynamically constructing a concentric sheath tube digital model in real time according to claim 1, wherein: The step S3 comprises: S301: Arrange large sheath surrounding points around the large sheath path; S302: performing triangle coding on the large sheath surrounding points, and constructing a large sheath surrounding point coordinate set and a triangle connection relationship between the large sheath surrounding points; S303: Rendering the large sheath mesh; The step S5 comprises: S501: arranging small sheath surrounding points around the small sheath path; S502: performing triangle coding on the small sheath surrounding points, and constructing a small sheath surrounding point coordinate set and a triangle connection relationship between the small sheath surrounding points; S503: Rendering the mesh of the small sheath tube.

7. The method for dynamically constructing a digital model of a concentric sheath tube in real time according to claim 1, wherein: Also includes step S6, S6: performing collision detection on the large sheath path and the small sheath path to determine whether the large sheath path and the small sheath path collide with the environment.

8. The method for dynamically constructing a digital model of a concentric sheath tube in real time according to claim 1, wherein: The method for reading the control value in real time is to read it from an external analog controller in real time.

9. The method for dynamically constructing a digital model of a concentric sheath tube in real time according to claim 1, wherein: The large sheath retrieval table and the small sheath retrieval table can be established by any method of physical experiment, simulation, or calculation.

10. A computer device, characterized in that: include: Memory; one or more processors coupled to the memory; One or more applications, wherein the one or more applications are stored in the memory and configured to be executed by one or more processors, and the one or more applications are configured to execute the construction method according to any one of claims 1 to 9.

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