A ligament dynamic simulation and isometric analysis method and system

Abstract

The present invention relates to the technical field of ligament simulation analysis, and provides a ligament dynamic simulation and isometric analysis method, including: S1: selecting a ligament starting point and a ligament ending point on the surface of the starting bone and the ending bone to which the current ligament is connected respectively; S2: connecting the ligament starting point and the ligament ending point to form a rotation axis, and obtaining a plurality of section planes passing through the rotation axis; S3: obtaining passable areas that can establish three-dimensional lines of the current ligament for the section planes respectively, calculating the set of connected lines that the current ligament can pass through in the passable area, and calculating the shortest three-dimensional path based on the set of connected lines; S4: constructing a ligament length set based on the shortest three-dimensional paths calculated on all section planes, and taking the shortest path in the length set as the three-dimensional space path of the current ligament at the current moment. The ligament length in the motion process can be quickly calculated to realize the simulation of the ligament, and the three-dimensional ligament length information can be obtained without a large amount of simulation analysis.

Description

Technical Field

[0001] The present invention relates to the technical field of ligament simulation analysis, and in particular to a ligament dynamic simulation and isometric analysis method and system. Background Art

[0002] Ligaments are important structures that maintain the stability of human bone joints. They are connective tissues that connect bones and are essential for the stability and function of human bone joints. Here are some key information about the importance of ligaments in maintaining joint stability:

[0003] Connecting Bones: Ligaments are connective tissues composed of fibers that connect one bone to another. They are located around joints, forming the capsule of the joint and providing structural support between the bones through bundles of fibers.

[0004] Maintain joint stability: One of the main functions of ligaments is to maintain the stability of bone joints. Ligaments prevent joints from moving excessively or dislocating during exercise by resisting the tensile and torsional forces around the joints.

[0005] Transmitting force: Ligaments transmit force during movement and activity. They help share the body's load, allowing the body to maintain balance and coordination during movement and activity.

[0006] Sensing joint position: Ligaments also work with the nervous system to help the body sense and adjust its position in space by sensing signals about joint position and range of motion.

[0007] Injury and Rehabilitation: Due to their importance, injuries to ligaments can affect joint stability and function. Rehabilitation and treatment often include an emphasis on restoring and strengthening the ligaments.

[0008] Analyzing the length of ligaments during movement can help evaluate the biomechanical behavior of ligaments during movement, which is helpful for clinical surgery planning and risk assessment. Dynamic X-rays can be used to analyze joint movement, however, traditional X-rays cannot see ligaments and other tissues. If ligament simulation can be achieved, it will further expand the clinical application of X-rays in ligaments and other soft tissues.

[0009] In the prior art, in order to achieve ligament measurement, the following methods are usually used:

[0010] (1) In the article "Dynamic Study of the Anterior Cruciate Ligament of the Knee Using Open MRI" published in the Journal of Surgical and Radiologic Anatomy in 2017, Guenoun et al. used the method of capturing magnetic resonance information from multiple positions, reconstructing the ligament model, and mapping its three-dimensional condition. This method is extremely accurate and can reflect the morphological information of the ligament. However, although capturing magnetic resonance information from multiple positions and reconstructing the ligament model is accurate, three-dimensional magnetic resonance takes a long time and cannot be generalized. In addition, it cannot reflect the stress of the joint under load.

[0011] (2) Hang Xu published an article titled "An Improved OpenSim Gait Model with Multi-DOF Knee Joint and Ligaments" in the journal "Application of Computational Methods in Biomechanics and Biomedical Engineering" in 2015. The article used a linear model to measure the straight-line distance between ligaments based on the human body motion captured by light. This is a functional motion under load-bearing position and can measure ligament information under different motions. However, the linear model cannot reflect the ligament distance under the actual knee joint geometry and the accuracy cannot be guaranteed. Summary of the invention

[0012] In view of the above problems, the purpose of the present invention is to provide a ligament dynamic simulation and isometric analysis method and system, which can quickly calculate the ligament length during movement to achieve ligament simulation, and obtain three-dimensional ligament length information without a large amount of simulation analysis.

[0013] The above-mentioned object of the present invention is achieved through the following technical solutions:

[0014] A ligament dynamic simulation and isometric analysis method, comprising:

[0015] S1: Based on the three-dimensional model of the bone joint, the starting point and the ending point of the ligament at the current moment are respectively selected on the surface of the starting bone and the ending bone to which the current ligament that needs to be dynamically simulated is connected;

[0016] S2: connecting the starting point of the ligament and the ending point of the ligament to form a rotation axis, and obtaining a plurality of section planes passing through the rotation axis;

[0017] S3: for any of the cutting planes, respectively obtaining a passable area through which a three-dimensional connection line of the current ligament can be established, calculating a set of connected lines through which the current ligament can pass within the passable area, and calculating the shortest three-dimensional path from the starting point of the ligament to the ending point of the ligament based on the set of connected lines;

[0018] S4: constructing a ligament length set based on the shortest three-dimensional paths calculated on all the cutting planes, and taking the shortest shortest three-dimensional path in the ligament length set as the three-dimensional spatial path of the current ligament at the current moment.

[0019] S5: selecting a plurality of ligament termination points on the surface of the termination bone, repeatedly executing steps S2-S4 to calculate the three-dimensional space path based on different ligament termination points, and finding all the ligament termination points whose three-dimensional space path is less than a preset length to draw contour lines, wherein the range corresponding to the contour lines is the equal length interval required to construct the current ligament;

[0020] S6: Different weights are set for all the three-dimensional space paths in the equal-length interval respectively, and the weighted center point in the equal-length interval is calculated based on the weights, the three-dimensional space path corresponding to the weighted center point is the most equal-length point of the current ligament, and the most equal-length point is the final space path of the current ligament.

[0021] Further, in step S1, based on the three-dimensional model of the bone joint, the ligament starting point and the ligament ending point at the current moment are respectively selected on the surface of the starting bone and the ending bone to which the current ligament that needs to be dynamically simulated is connected, specifically:

[0022] S11: Establishing three-dimensional surface models of the starting bone and the ending bone connected to the current ligament, respectively, wherein the point set formed by the three-dimensional surface model of the starting bone is recorded as a three-dimensional point set P start The point set formed by the three-dimensional patch model of the termination bone is recorded as a three-dimensional point set P end ;

[0023] S12: The starting point of the ligament at the initial moment is recorded as L start , the termination point of the ligament is recorded as L end , respectively obtain the motion transformation matrix T of the starting bone and the ending bone from the initial time to the current time T start and the motion transformation matrix T end , using the motion transformation matrix T start and the motion transformation matrix T end The ligament starting point L start and the ligament termination point L end Transform to the starting point of the ligament at the current time T and the ligament termination point

[0024] Further, in step S2, the ligament starting point and the ligament ending point are connected to form the rotation axis, and a plurality of section planes passing through the rotation axis are obtained, specifically:

[0025] S21: connecting the starting point of the ligament and the ending point of the ligament to form a line segment V;

[0026] S22: Taking the line segment V as the rotation axis, rotate the angle α multiple times to generate a plurality of the section planes passing through the rotation axis, until the section planes evenly cover the rotation range of 0-180 degrees, wherein the angle α is set according to the accuracy of simulating the current ligament.

[0027] Further, in step S3, the passable area capable of establishing the three-dimensional connection line of the current ligament is obtained for any of the section planes, specifically:

[0028] The number of the cutting planes is recorded as n. For any of the cutting planes, the set of intersections of the cutting plane with the three-dimensional surface model of the starting bone and the ending bone is recorded as and Where i ranges from 1 to n;

[0029] At this time, define the collection range of the intersection and The bone tissue portion inside is the impassable area, and the area other than the bone tissue portion is the permissible area;

[0030] The calculated three-dimensional connection line of the current ligament is the curve connection line in the passable area.

[0031] Further, in step S3, the set of connected lines through which the current ligament can pass is calculated in the passable area, specifically:

[0032] Using a plurality of polygons on the section plane to divide the bones around the bone joint, each of the polygons is composed of a set of nodes and edges;

[0033] For each of the nodes in all of the polygons, each of the nodes in all of the polygons is connected to form a plurality of node lines;

[0034] A plurality of node lines are judged respectively. If the node line intersects with any of the polygons, it does not constitute the connected line; otherwise, it is added to the set of connected lines.

[0035] Further, in step S3, the shortest three-dimensional path from the ligament starting point to the ligament ending point is calculated based on the set of connected lines, specifically:

[0036] S31: Initializing an open list for storing the path that the current ligament is about to take and a closed list for storing the path that the current ligament has already taken;

[0037] S32: adding the ligament starting point to the open list;

[0038] S33: when the open list is not empty, take out the last node on the path with the minimum cost of the adjacent points that has been calculated from the open list as the current node and add it to the closed list, wherein when step S33 is executed for the first time, the current node is the starting point of the ligament, and when step S33 is not executed for the first time, the current node is the last node on the path with the minimum cost of the adjacent points that has been calculated;

[0039] S34: Determine whether the current node is the ligament termination point. If it is the ligament termination point, the algorithm ends and jumps directly to step S37;

[0040] S35: Obtain all the next nodes adjacent to the current node according to the connected lines in the set, and respectively calculate the adjacent point costs from the ligament starting point to all the next nodes, and if the adjacent next node is not in the open list and the closed list, add the adjacent next node to the open list;

[0041] S36: in the open list, update the adjacent point costs from the ligament starting point to all the next nodes, and determine whether the current node is the ligament ending point. If it is the ligament ending point, the algorithm ends and directly jumps to step S37; otherwise, jumps to step S33 to continue executing the current algorithm;

[0042] S37: Output all the nodes from the starting point of the ligament to the ending point of the ligament from the closed list, and record them as the shortest three-dimensional path.

[0043] Furthermore, the adjacent point cost F 韧带 The Euclidean distance formula is used for calculation, which is:

[0044] F 韧带 =G+H

[0045] Among them, G is the actual cost, that is, the path that has been traveled from the starting point of the ligament to the current node, and H is the estimated cost and the estimated path that needs to be traveled from the current node to the next node adjacent to the current node.

[0046] A ligament dynamic simulation and isometric analysis system for performing the above-mentioned ligament dynamic simulation and isometric analysis method comprises:

[0047] A ligament starting and ending point selection module is used to select the ligament starting point and ligament ending point at the current moment on the starting bone and ending bone surfaces to which the current ligament that needs to be dynamically simulated is connected, based on the three-dimensional model of the bone joint;

[0048] A ligament section plane acquisition module, used to connect the ligament starting point and the ligament ending point to form a rotation axis, and acquire a plurality of section planes passing through the rotation axis;

[0049] A cross-sectional path calculation module, for obtaining, for any of the section planes, a passable area capable of establishing a three-dimensional connection line of the current ligament, calculating a set of connected lines through which the current ligament can pass within the passable area, and calculating the shortest three-dimensional path from the starting point of the ligament to the ending point of the ligament based on the set of connected lines;

[0050] A spatial path acquisition module is used to construct a ligament length set based on the shortest three-dimensional paths calculated on all the cutting planes, and take the shortest three-dimensional path in the ligament length set as the three-dimensional spatial path of the current ligament at the current moment.

[0051] A computer-readable storage medium stores computer codes. When the computer codes are executed, the above method is executed.

[0052] Compared with the prior art, the present invention has at least one of the following beneficial effects:

[0053] (1) A ligament dynamic simulation and isometric analysis method is provided, comprising: S1: based on a three-dimensional model of a bone joint, selecting a ligament starting point and a ligament ending point at the current moment on the surface of a starting bone and an ending bone to which a current ligament that needs to be dynamically simulated is connected; S2: connecting the ligament starting point and the ligament ending point to form a rotation axis, and obtaining a plurality of section planes passing through the rotation axis;

[0054] S3: For any of the cutting planes, obtain the passable area that can establish the three-dimensional connection line of the current ligament, calculate the set of connected lines that the current ligament can pass through in the passable area, and calculate the shortest three-dimensional path from the starting point of the ligament to the ending point of the ligament based on the set of connected lines; S4: Construct a ligament length set based on the shortest three-dimensional paths calculated on all the cutting planes, and take the shortest shortest three-dimensional path in the ligament length set as the three-dimensional space path of the current ligament at the current moment. The above technical solution has fast calculation and does not require a large amount of simulation analysis to obtain three-dimensional ligament length information. Based on the set of connected lines of the constructed nodes, the problem of excessive calculation caused by too many nodes in the three-dimensional patch model is reduced, and three-dimensional calculation can be realized.

[0055] (2) The present invention simplifies the construction process of the three-dimensional visual map, further reduces the amount of calculation of the three-dimensional visual map, optimizes the calculation process, and can realize the three-dimensional analysis of multiple ligaments. At the same time, it can perform calculations based on any input three-dimensional joint motion to realize the analysis of the dynamic length of the ligament under load.

[0056] (3) The present invention is universal in all scenarios. Regardless of the individualized model, the joint motion data acquired by magnetic resonance or optical capture can calculate the three-dimensional path of the ligament based on the three-dimensional bone information. It has wide versatility and can analyze the load-bearing position data. The data is accurate, and the calculated ligament length is a non-linear ligament distance, which can comprehensively consider the joint geometry.

[0057] (4) The present invention can calculate the equal length area of ​​the ligament through multiple points within a preset range. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 It is an overall flow chart of the ligament dynamic simulation and isometric analysis method of the present invention;

[0059] Figure 2 A three-dimensional schematic diagram of a cross-section plane of the present invention;

[0060] Figure 3 A schematic diagram of the skeleton division into two polygons according to the present invention;

[0061] Figure 4 It is a two-dimensional schematic diagram of the cross-section plane of the present invention;

[0062] Figure 5 This is a schematic diagram showing an example of the Euclid algorithm of the present invention;

[0063] Figure 6 A schematic diagram of the shortest three-dimensional path found by the present invention;

[0064] Figure 7 A schematic diagram of calculating the shortest three-dimensional path of the current cutting plane for each cutting plane according to the present invention;

[0065] Figure 8 A schematic diagram of selecting a plurality of ligament termination points on the termination bone surface according to the present invention;

[0066] Fig. 9 A schematic diagram of the equal-length interval arrangement of the present invention;

[0067] Fig.10 It is the overall structure diagram of the ligament dynamic simulation and isometric analysis system of the present invention. DETAILED DESCRIPTION

[0068] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0069] Those skilled in the art will appreciate that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0070] First embodiment

[0071] like Figure 1 As shown, this embodiment provides a ligament dynamic simulation and isometric analysis method, including:

[0072] S1: Based on the three-dimensional model of the bone joint, the starting point and the ending point of the ligament at the current moment are respectively selected on the surface of the starting bone and the ending bone to which the current ligament that needs to be dynamically simulated is connected.

[0073] Ligaments are tissues that connect two bones, including the starting bone and the ending bone, to form a joint. Before performing ligament dynamic simulation, you need to do the following:

[0074] S11: Establishing three-dimensional surface models of the starting bone and the ending bone connected to the current ligament, respectively, wherein the point set formed by the three-dimensional surface model of the starting bone is recorded as a three-dimensional point set P start The point set formed by the three-dimensional patch model of the termination bone is recorded as a three-dimensional point set P end .

[0075] S12: The starting point of the ligament at the initial moment is recorded as L start , the termination point of the ligament is recorded as L end , respectively obtain the motion transformation matrix T of the starting bone and the ending bone from the initial time to the current time T start and the motion transformation matrix T end , using the motion transformation matrix T start and the motion transformation matrix T end The ligament starting point L start and the ligament termination point Lend Transform to the starting point of the ligament at the current time T and the ligament termination point

[0076] The conversion formula of the ligament starting point and ligament ending point through the motion conversion matrix is:

[0077]

[0078]

[0079] For the motion transformation matrix T start and the motion transformation matrix T end For the two motion transformation matrices, it is necessary to rely on the pre-established coordinate system for transformation. The starting point of the ligament at the initial moment is recorded as L start , the termination point of the ligament is recorded as L end and the starting point of the ligament at the current time T and the ligament termination point All are represented by coordinates, but it should be noted that this embodiment does not limit the specific way of establishing the coordinate system. It only requires that the established coordinate system can mark the coordinates of all points and complete the coordinate transformation according to the motion transformation matrix.

[0080] S2: Connect the ligament starting point and the ligament ending point to form a rotation axis, and obtain a plurality of section planes passing through the rotation axis.

[0081] In this embodiment, several cross-sectional planes passing through the rotation axis are obtained, specifically:

[0082] S21: Connect the starting point of the ligament and the ending point of the ligament to form a line segment V.

[0083] S22: Taking the line segment V as the rotation axis, rotate the line segment V multiple times by an angle α to generate a plurality of section planes passing through the rotation axis, until the section planes evenly cover the rotation range of 0-180 degrees.

[0084] The angle α is set according to the accuracy of the simulation of the current ligament. When the simulation accuracy is high and the calculation speed is low, the value of the rotation angle α is set to be small, such as 0.1 degrees, etc. When the simulation accuracy is low but the calculation speed is fast, the value of the rotation angle α is set to be large, such as 2 degrees, etc. Figure 2 The above is a three-dimensional schematic diagram of one of the cross-section planes.

[0085] S3: For any one of the cutting planes, respectively obtain a passable area that can establish a three-dimensional connection line of the current ligament, calculate a set of connected lines through which the current ligament can pass within the passable area, and calculate the shortest three-dimensional path from the starting point of the ligament to the ending point of the ligament based on the set of connected lines.

[0086] In this embodiment, the passable area capable of establishing the three-dimensional connection line of the current ligament is obtained for any of the cutting planes, specifically:

[0087] The number of the cutting planes is recorded as n. For any of the cutting planes, when intersecting with the three-dimensional surface model, the set of intersection points of the cutting plane and the three-dimensional surface model of the starting bone and the ending bone is recorded as and Where i ranges from 1 to n;

[0088] At this time, define the collection range of the intersection and The bone tissue portion inside is the impassable area, and the area other than the bone tissue portion is the permissible area;

[0089] The three-dimensional line of the current ligament that is expected to be calculated is the starting point of the ligament. and ligament termination points The curve lines within the passable region are connected.

[0090] Furthermore, the set of connected lines through which the current ligament can pass is calculated in the passable region, specifically:

[0091] Calculate from the starting point of the ligament Starting from the visible area in any section plane, such as Figure 4 As shown in the two-dimensional schematic diagram of the cutting plane, the black line is the bone cross section, and the gray line is the passable area of ​​each node. The construction process of the visible area is: the bones around the bone joints are divided by using a number of polygons on the cutting plane, and the divided polygons are recorded as {Poly1, Poly2...Poly n},like Figure 3 As shown in the figure, it is a schematic diagram of the skeleton division into two polygons. Each polygon is composed of a set of nodes and edges {V, E}; for each node in all the polygons, each node in all the polygons is connected to form a number of node lines; the node lines are judged separately, if the node line intersects with any of the polygons, it does not constitute the connected line, otherwise it is added to the set of connected lines. The set of all connected lines constitutes the visible image area.

[0092] Furthermore, the shortest three-dimensional path from the ligament starting point to the ligament ending point is calculated based on the set of connected lines, specifically:

[0093] Calculate from the starting point of the ligament To the end point of the ligament The shortest three-dimensional path on each cutting plane, that is, to obtain the shortest path from the starting point of the ligament on the current cutting plane To the end point of the ligament The ligament path on the ligament, its three-dimensional length is recorded as Len i , where i is 1 to n and is the number of the cutting plane. In this embodiment, the shortest three-dimensional path is obtained by using the adjacent point cost F in the Euclidean distance formula. 韧带 Perform calculations.

[0094] The neighboring point cost F 韧带 The Euclidean distance formula is used for calculation, which is:

[0095] F 韧带 =G+H

[0096] Among them, G is the actual cost, that is, the path that has been traveled from the starting point of the ligament to the current node, and H is the estimated cost and the estimated path that needs to be traveled from the current node to the next node adjacent to the current node.

[0097] For example, Figure 5 As shown in the schematic diagram of the Euclidean algorithm example, from the starting point of the ligament To the end point of the ligament The nodes on the connected line that can be passed are n1, n2a, n2b, and n2c. If the current node that has been calculated is point n1, it is the starting point of the ligament that has been passed. The path to n1 is denoted as G. The next three different paths from n1 to n2a, n2b, and n2c are the estimated walking paths H. n1 to n2a is denoted as H1, n1 to n2b is denoted as H2, and n1 to n2c is denoted as H3. The adjacent point cost F calculated in G+{H1, H2, H3} 韧带 The smallest path is the shortest path from the current node n1 to all the next nodes. Figure 5 It can be concluded that F = G + H2 is the shortest path. In addition, from Figure 5 It can be seen that the next node of n2b is only the ligament termination point One, that is Figure 5 The shortest three-dimensional path calculated in is the starting point of the ligament To n1 to n2b to the end point of the ligament

[0098] In addition, the Euclidean distance between adjacent points on the path is calculated as:

[0099]

[0100] Among them, p1 and P2 are two points on the path, p1.x and p2.x, p1.y and p2.y are their corresponding X and Y coordinate values. The sum of the distances between all two points on the path is recorded as the distance d.

[0101] The overall calculation process of the shortest three-dimensional path is:

[0102] S31: Initializing an open list for storing the path that the current ligament is about to take and a closed list for storing the path that the current ligament has already taken;

[0103] S32: The starting point of the ligament Add to the open list;

[0104] S33: When the open list is not empty, take out the calculated adjacent point cost F from the open list. 韧带 The last node on the smallest path is added to the closed list as the current node, wherein when step S33 is executed for the first time, the current node is the starting point of the ligament. When step S33 is not performed for the first time, the current node is the last node on the currently calculated path with the minimum cost of the adjacent points;

[0105] S34: Determine whether the current node is the ligament termination point If the ligament ends at Then the algorithm ends and jumps directly to step S37;

[0106] S35: Obtain all the next nodes adjacent to the current node according to the connected lines in the set, and calculate the ligament starting points respectively. The cost F of the adjacent points to all the next nodes 韧带 , if the next adjacent node is not in the open list and the closed list, add the next adjacent node to the open list;

[0107] S36: updating the ligament starting point in the open list The cost F of the adjacent points to all the next nodes 韧带 , and determine whether the current node is the ligament termination point If the ligament ends at If yes, the algorithm ends and jumps directly to step S37, otherwise jumps to step S33 to continue executing the current algorithm;

[0108] S37: Outputting from the closed list the number of cells starting from the ligament starting point To the end point of the ligament All the nodes are recorded as the shortest three-dimensional path, such as Figure 6 Schematic diagram of the shortest three-dimensional path found.

[0109] S4: constructing a ligament length set based on the shortest three-dimensional paths calculated on all the cutting planes, and taking the shortest shortest three-dimensional path in the ligament length set as the three-dimensional spatial path of the current ligament at the current moment.

[0110] Specifically, in this embodiment, step S3 is repeatedly performed, such as Figure 7 As shown, for each cutting plane, the shortest three-dimensional path of the current cutting plane is calculated and recorded as Len 1 ,Len 2 ...Len n , construct the ligament length set Len N .

[0111] Take the ligament length set Len N The shortest three-dimensional path Len shortest , which is the starting point of the ligament To the end point of the ligament The three-dimensional space path at the current time T.

[0112] S5: Figure 8 As shown, multiple ligament termination points are selected on the termination bone surface to construct a ligament termination point set. Repeat steps S2-S4 to calculate the three-dimensional space path based on different ligament termination points, find all the ligament termination points whose three-dimensional space path is less than the preset length to draw contour lines, and the range corresponding to the contour lines is the equal length interval required to construct the current ligament. The setting of the equal length interval is as follows: Fig. 9 Shown in medium grey area.

[0113] Specifically, the purpose of drawing contour lines and establishing the equal length intervals required for the current ligament based on the contour lines is to find a set of points with the smallest change in ligament length during movement, so that the ligament established later is optimal.

[0114] S6: Different weights are set for all the three-dimensional space paths in the equal-length interval respectively, and the weighted center point in the equal-length interval is calculated based on the weights, the three-dimensional space path corresponding to the weighted center point is the most equal-length point of the current ligament, and the most equal-length point is the final space path of the current ligament.

[0115] The basis for setting different weights for all three-dimensional space paths in the equal-length interval is to set a higher weight for the point where the ligament length changes the least during the movement, so that the weighted center point finally calculated based on the weight will be closer to the point where the ligament length changes the least during the movement.

[0116] Second embodiment

[0117] like Fig.10 As shown, this embodiment provides a ligament dynamic simulation and isometric analysis system for executing the ligament dynamic simulation and isometric analysis method as in the first embodiment, comprising:

[0118] The ligament starting and ending point selection module 1 is used to select the ligament starting point and ligament ending point at the current moment on the starting bone and ending bone surfaces connected to the current ligament that needs to be dynamically simulated based on the three-dimensional model of the bone joint.

[0119] The ligament section plane acquisition module 2 is used to connect the ligament starting point and the ligament ending point to form a rotation axis, and acquire a plurality of section planes passing through the rotation axis.

[0120] The cross-sectional path calculation module 3 is used to obtain, for any one of the cutting planes, a passable area that can establish a three-dimensional connection line of the current ligament, calculate a set of connected lines through which the current ligament can pass within the passable area, and calculate the shortest three-dimensional path from the starting point of the ligament to the ending point of the ligament based on the set of connected lines.

[0121] The spatial path acquisition module 4 is used to construct a ligament length set based on the shortest three-dimensional paths calculated on all the cutting planes, and take the shortest three-dimensional path in the ligament length set as the three-dimensional spatial path of the current ligament at the current moment.

[0122] An equal length interval acquisition module 5 is used to select a plurality of ligament termination points on the termination bone surface, repeatedly execute steps S2-S4 to calculate the three-dimensional space path based on different ligament termination points, and find all the ligament termination points whose three-dimensional space path is less than a preset length to draw contour lines, and the range corresponding to the contour lines is the equal length interval required to construct the current ligament;

[0123] The most isometric point acquisition module 6 is used to set different weights for all the three-dimensional space paths in the isometric interval, and calculate the weighted center point in the isometric interval based on the weights. The three-dimensional space path corresponding to the weighted center point is the most isometric point of the current ligament, and the most isometric point is the final spatial path of the current ligament.

[0124] A computer-readable storage medium stores a computer code. When the computer code is executed, the above method is executed. A person skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program. The program can be stored in a computer-readable storage medium. The storage medium can include: a read-only memory (ROM), a random access memory (RAM), a disk or an optical disk, etc.

[0125] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

[0126] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0127] It should be noted that the above embodiments can be freely combined as needed. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered as the protection scope of the present invention.

Claims

1. A ligament dynamic simulation and isometric analysis method, characterized in that: include: S1: Based on the three-dimensional model of the bone joint, the starting point and the ending point of the ligament at the current moment are respectively selected on the surface of the starting bone and the ending bone to which the current ligament that needs to be dynamically simulated is connected; S2: connecting the starting point of the ligament and the ending point of the ligament to form a rotation axis, and obtaining a plurality of section planes passing through the rotation axis; S3: for any of the cutting planes, respectively obtaining a passable area through which a three-dimensional connection line of the current ligament can be established, calculating a set of connected lines through which the current ligament can pass within the passable area, and calculating the shortest three-dimensional path from the starting point of the ligament to the ending point of the ligament based on the set of connected lines; S4: constructing a ligament length set based on the shortest three-dimensional paths calculated on all the cutting planes, and taking the shortest three-dimensional path in the ligament length set as the three-dimensional space path of the current ligament at the current moment; S5: selecting a plurality of ligament termination points on the surface of the termination bone, repeatedly executing steps S2-S4 to calculate the three-dimensional space path based on different ligament termination points, and finding all the ligament termination points whose three-dimensional space path is less than a preset length to draw contour lines, wherein the range corresponding to the contour lines is the equal length interval required to construct the current ligament; S6: Different weights are set for all the three-dimensional space paths in the equal-length interval respectively, and the weighted center point in the equal-length interval is calculated based on the weights, the three-dimensional space path corresponding to the weighted center point is the most equal-length point of the current ligament, and the most equal-length point is the final space path of the current ligament.

2. The ligament dynamic simulation and isometric analysis method according to claim 1, characterized in that: In step S1, based on the three-dimensional model of the bone joint, the ligament starting point and the ligament ending point at the current moment are respectively selected on the surfaces of the starting bone and the ending bone to which the current ligament to be dynamically simulated is connected, specifically: S11: Establishing three-dimensional surface models of the starting bone and the ending bone connected to the current ligament, respectively, wherein the point set formed by the three-dimensional surface model of the starting bone is recorded as a three-dimensional point set P start The point set formed by the three-dimensional patch model of the termination bone is recorded as a three-dimensional point set P end ; S12: The starting point of the ligament at the initial moment is recorded as L start , the termination point of the ligament is recorded as L end , respectively obtain the motion transformation matrix T of the starting bone and the ending bone from the initial time to the current time T start and the motion transformation matrix T end , using the motion transformation matrix T start and the motion transformation matrix T end The ligament starting point L start and the ligament termination point L end Transform to the starting point of the ligament at the current time T and the ligament termination point .

3. The ligament dynamic simulation and isometric analysis method according to claim 1, characterized in that: In step S2, the ligament starting point and the ligament ending point are connected to form the rotation axis, and a plurality of section planes passing through the rotation axis are obtained, specifically: S21: connecting the starting point of the ligament and the ending point of the ligament to form a line segment V; S22: Taking the line segment V as the rotation axis, rotate the angle α multiple times to generate a plurality of the section planes passing through the rotation axis, until the section planes evenly cover the rotation range of 0-180 degrees, wherein the angle α is set according to the accuracy of simulating the current ligament.

4. The ligament dynamic simulation and isometric analysis method according to claim 2, characterized in that: In step S3, the passable area capable of establishing the three-dimensional connection line of the current ligament is obtained for any of the section planes, specifically: The number of the cutting planes is recorded as n. For any of the cutting planes, the set of intersections of the cutting plane with the three-dimensional surface model of the starting bone and the ending bone is recorded as and , where i ranges from 1 to n; At this time, define the collection range of the intersection and The bone tissue portion inside is the impassable area, and the area other than the bone tissue portion is the permissible area; The calculated three-dimensional connection line of the current ligament is the curve connection line in the passable area.

5. The ligament dynamic simulation and isometric analysis method according to claim 1, characterized in that: In step S3, the set of connected lines through which the current ligament can pass is calculated in the passable area, specifically: Using a plurality of polygons on the section plane to divide the bones around the bone joint, each of the polygons is composed of a set of nodes and edges; For each of the nodes in all of the polygons, each of the nodes in all of the polygons is connected to form a plurality of node lines; A plurality of node lines are judged respectively. If the node line intersects with any of the polygons, it does not constitute the connected line; otherwise, it is added to the set of connected lines.

6. The ligament dynamic simulation and isometric analysis method according to claim 5, characterized in that: In step S3, the shortest three-dimensional path from the ligament starting point to the ligament ending point is calculated based on the set of connected lines, specifically: S31: Initializing an open list for storing the path that the current ligament is about to take and a closed list for storing the path that the current ligament has already taken; S32: adding the ligament starting point to the open list; S33: when the open list is not empty, take out the last node on the path with the minimum cost of adjacent points that has been calculated from the open list as the current node and add it to the closed list, wherein when step S33 is executed for the first time, the current node is the starting point of the ligament, and when step S33 is not executed for the first time, the current node is the last node on the path with the minimum cost of adjacent points that has been calculated; S34: Determine whether the current node is the ligament termination point. If it is the ligament termination point, the algorithm ends and jumps directly to step S37; S35: Obtain all the next nodes adjacent to the current node according to the connected lines in the set, and respectively calculate the adjacent point costs from the ligament starting point to all the next nodes, and if the adjacent next node is not in the open list and the closed list, add the adjacent next node to the open list; S36: in the open list, update the adjacent point costs from the ligament starting point to all the next nodes, and determine whether the current node is the ligament ending point. If it is the ligament ending point, the algorithm ends and directly jumps to step S37; otherwise, jumps to step S33 to continue executing the current algorithm; S37: Output all the nodes from the starting point of the ligament to the ending point of the ligament from the closed list, and record them as the shortest three-dimensional path.

7. The ligament dynamic simulation and isometric analysis method according to claim 6, characterized in that: The neighboring point cost F 韧带 The Euclidean distance formula is used for calculation, which is: F 韧带 =G+H, Among them, G is the actual cost, that is, the path that has been traveled from the starting point of the ligament to the current node, and H is the estimated cost and the estimated path that needs to be traveled from the current node to the next node adjacent to the current node.

8. A ligament dynamic simulation and isometric analysis system for executing the ligament dynamic simulation and isometric analysis method according to any one of claims 1 to 7, characterized in that: include: A ligament starting and ending point selection module is used to select the ligament starting point and ligament ending point at the current moment on the starting bone and ending bone surfaces to which the current ligament that needs to be dynamically simulated is connected, based on the three-dimensional model of the bone joint; A ligament section plane acquisition module, used to connect the ligament starting point and the ligament ending point to form a rotation axis, and acquire a plurality of section planes passing through the rotation axis; A cross-sectional path calculation module, for obtaining, for any of the section planes, a passable area capable of establishing a three-dimensional connection line of the current ligament, calculating a set of connected lines through which the current ligament can pass within the passable area, and calculating the shortest three-dimensional path from the starting point of the ligament to the ending point of the ligament based on the set of connected lines; A spatial path acquisition module is used to construct a ligament length set based on the shortest three-dimensional paths calculated on all the cutting planes, and take the shortest three-dimensional path in the ligament length set as the three-dimensional spatial path of the current ligament at the current moment.

9. A computer-readable storage medium storing computer codes, wherein when the computer codes are executed, the method according to any one of claims 1 to 7 is executed.

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