Bending method and system for body surface model

Abstract

A bending method and system for a body surface model, relating to the technical field of three-dimensional modeling. The method comprises: acquiring a body surface model and bending parameters; determining a first reference plane and a second reference plane on the body surface model; on the basis of the first reference plane and the second reference plane, determining several bending modes, and determining, with respect to each bending mode, mesh vertices for bending in the body surface model and a bending method therefor; in each different bending mode, on the basis of the bending parameters and the bending method, performing bending with respect to the mesh vertices for bending, so as to obtain mesh vertices after bending; and connecting all the mesh vertices after bending to obtain a body surface model after bending. The present invention achieves a high automation level and a high degree of freedom, and ensures that body surface models generated after bending have high accuracy and conform to the real contour of human bodies, thus further improving the efficiency of generating design schemes for orthopaedic appliances.

Description

A bending method and system for a body surface model TECHNICAL FIELD

[0001] The present application relates to the technical field of three-dimensional modeling, and more particularly, to a bending method and system for a body surface model. BACKGROUND

[0002] Scoliosis is a common spinal deformity, mainly manifested as abnormal lateral curvature of the spine in the coronal plane. Scoliosis usually develops during childhood and adolescence, and can be caused by genetic factors, neuromuscular diseases, poor posture, and other factors. Traditional scoliosis orthosis manufacturing requires multiple complex procedures: preparing the patient's torso negative mold, casting the positive plaster mold, modifying the positive plaster mold, hot forming and modifying the orthosis plate, etc., so that the correction effect often depends on the experience of the orthotist, and there are also disadvantages such as low accuracy, serious material consumption, low automation, long design cycle, and difficulty in achieving personalized customization.

[0003] With the development of computer-aided design (CAD) technology, more and more rehabilitation medical device designs begin to use CAD software. Through optical or laser technology to obtain the geometric data of the object surface, a three-dimensional scanner is used to scan the patient's body surface to obtain three-dimensional point cloud data containing the shape and curve details of the body, and then CAD software is used to process and analyze these data to generate a body surface model of the patient.

[0004] For the method of generating a body surface model by scanning the body to obtain three-dimensional point cloud data, it is extremely dependent on the real body surface data of the patient; in the early stage of orthosis design, it is difficult to design multiple schemes for a body surface model obtained. And the human body as a typical elastic connection rigid body, linearly changing the body surface data will cause the adjusted human body model to not conform to the real three-dimensional contour and details of the human body, and then affect the accuracy of the orthosis design method. Therefore, it is urgent to design a bending method for a human body model with high automation and high degree of freedom, to generate multiple orthosis design schemes according to the geometric shape and curve characteristics of the patient's body surface, and to evaluate the correction effect of different design schemes, reduce the trial and adjustment time, and select the best scheme to improve the efficiency of the treatment process. SUMMARY

[0005] One of the purposes of the present application is to provide a bending method for a body surface model to overcome the defects of the prior art that the automation degree is low when bending the human body model, and the bent human body model does not conform to the real situation of the human body; the second purpose is to provide a bending system for a body surface model.

[0006] To solve the above technical problems, the technical scheme of the present application is as follows:

[0007] The application discloses a bending method for a body surface model, comprising:

[0008] obtaining a body surface model and bending parameters for bending the body surface model;

[0009] determining a first reference surface and a second reference surface on the body surface model;

[0010] based on the first reference surface and the second reference surface, dividing several bending modes and determining grid vertices to be bent in the body surface model and bending modes thereof in each bending mode;

[0011] based on the bending parameters and the bending modes, bending the grid vertices to be bent in different bending modes to obtain bent grid vertices;

[0012] connecting all the bent grid vertices to obtain a bent body surface model.

[0013] Preferably, the bending parameters comprise a bending direction and a bending amplitude.

[0014] Preferably, determining the first reference surface and the second reference surface on the body surface model comprises:

[0015] according to a type of scoliosis corresponding to the body surface model, constructing two horizontal planes penetrating the body surface model as the first reference surface and the second reference surface respectively by using a ray casting method;

[0016] taking a longitudinal coordinate of any intersection point of the first reference surface and the body surface model as a first reference surface height value;

[0017] taking a longitudinal coordinate of any intersection point of the second reference surface and the body surface model as a second reference surface height value;

[0018] the second reference surface height value is less than the first reference surface height value.

[0019] Preferably, the several bending modes comprise a top bending mode, a bottom bending mode and an overall bending mode.

[0020] Preferably, determining the grid vertices to be bent in the body surface model in each bending mode comprises:

[0021] determining all the grid vertices and three-dimensional coordinates thereof constituting the body surface model and comparing sizes of a longitudinal coordinate of each grid vertex and the second reference surface height value or the first reference surface height value;

[0022] when in the top bending mode, taking the grid vertex with the longitudinal coordinate greater than the second reference surface height value as the grid vertex to be bent;

[0023] When in the top bending mode, grid vertices with a vertical coordinate less than the first reference plane height value are taken as the grid vertices to be bent;

[0024] When in the overall bending mode, all grid vertices are taken as the grid vertices to be bent.

[0025] Preferably, the bending manner of the grid vertices to be bent in the body surface model under each bending mode is determined, comprising:

[0026] The vertical coordinates of the grid vertices to be bent are compared with the first reference plane height value and the second reference plane height value respectively:

[0027] When in the top bending mode, the transition bending manner is adopted for the grid vertices to be bent with a vertical coordinate greater than the second reference plane height value and less than or equal to the first reference plane height value, and the direct bending manner is adopted for the grid vertices to be bent with a vertical coordinate greater than the first reference plane height value;

[0028] When in the bottom bending mode, the transition bending manner is adopted for the grid vertices to be bent with a vertical coordinate greater than or equal to the second reference plane height value and less than the first reference plane height value, and the direct bending manner is adopted for the grid vertices to be bent with a vertical coordinate less than the second reference plane height value;

[0029] When in the overall bending mode, the transition bending manner is adopted for the grid vertices to be bent with a vertical coordinate greater than or equal to the second reference plane height value and less than or equal to the first reference plane height value, and the direct bending manner is adopted for the remaining grid vertices to be bent.

[0030] Preferably, under different bending modes, the grid vertices to be bent are bent based on the bending parameters and the bending manner to obtain the bent grid vertices, comprising:

[0031] Under any bending mode, for the grid vertices to be bent adopting the direct bending manner:

[0032] A rotation axis is constructed according to the bending direction: rotateAxis(a, b, c) = [cos(direction×π÷180°) sin(direction×π÷180°) 0]

[0033] In the formula, rotateAxis represents the rotation axis, a represents the angle of rotation around the x-axis, b represents the angle of rotation around the y-axis, c represents the angle of rotation around the z-axis, and direction represents the bending direction;

[0034] The bending amplitude is converted into radian form to obtain the bending amplitude in radian form;

[0035] Based on the bending amplitude in the form of rotation axis and radian, a first rotation matrix is constructed:

[0036] In the formula, M represents the first rotation matrix, and θ represents the bending amplitude in the form of radian.

[0037] The three-dimensional coordinates of the grid vertex to be bent in the direct bending mode are multiplied by the first rotation matrix to obtain the three-dimensional coordinates of the bent grid vertex.

[0038] Preferably, in different bending modes, the grid vertex to be bent is bent based on the bending parameter and the bending mode to obtain the bent grid vertex, and the method further comprises:

[0039] In any bending mode, for the grid vertex to be bent in the transition bending mode:

[0040] The distance between the first reference surface and the second reference surface is calculated, denoted as the first distance: H = Z1-Z2

[0041] In the formula, H represents the first distance, Z1 represents the first reference surface height value, and Z2 represents the second reference surface height value.

[0042] Based on the longitudinal coordinate of each grid vertex to be bent, the first reference surface height value and the second reference surface height value, the second distance of each grid vertex to be bent is calculated.

[0043] Based on the first distance and the second distance, the bending proportion coefficient is calculated:

[0044] In the formula, β i represents the bending proportion coefficient of the i-th grid vertex to be bent, h i represents the second distance of the i-th grid vertex to be bent.

[0045] According to the bending direction, a rotation axis is constructed: rotateAxis(a,b,c) = [cos(direction×π÷180°)sin(direction×π÷180°)0]

[0046] In the formula, rotateAxis represents the rotation axis, a represents the angle of rotation around the x-axis, b represents the angle of rotation around the y-axis, c represents the angle of rotation around the z-axis, and direction represents the bending direction.

[0047] The bending proportion coefficient is multiplied by the bending amplitude to obtain a proportional bending amplitude.

[0048] The proportional bending amplitude is converted into the form of radian to obtain the proportional bending amplitude in the form of radian.

[0049] Based on the rotation axis and the proportional bending amplitude in radian form, a second rotation matrix is constructed:

[0050] In the formula, M' represents the second rotation matrix, and θ' represents the proportional bending amplitude in radian form.

[0051] The three-dimensional coordinates of the grid vertices to be bent in the transition bending mode are multiplied by the second rotation matrix to obtain the three-dimensional coordinates of the corresponding bent grid vertices.

[0052] Preferably, the second distance of each grid vertex to be bent is calculated based on the longitudinal coordinate of each grid vertex to be bent, the first reference plane height value, and the second reference plane height value, including:

[0053] When the top bending mode is selected, the difference between the longitudinal coordinate of each grid vertex to be transition-bent and the second reference plane height value is calculated respectively, which corresponds to the second distance of each grid vertex to be bent.

[0054] When the bottom bending mode is selected, the difference between the longitudinal coordinate of each grid vertex to be transition-bent and the first reference plane height value is calculated respectively, which corresponds to the second distance of each grid vertex to be bent.

[0055] When the overall bending mode is selected, the median value of the height values of the first reference plane and the second reference plane is calculated, and the difference between the longitudinal coordinate of each grid vertex to be transition-bent and the median value of the height values is calculated respectively, which corresponds to the second distance of each grid vertex to be bent.

[0056] The application further discloses a bending system for a body surface model, which is used to implement the bending method and comprises:

[0057] A model and parameter acquisition module is configured to acquire a body surface model and bending parameters for bending the body surface model.

[0058] A reference plane determination module is configured to determine a first reference plane and a second reference plane on the body surface model.

[0059] A bending mode determination module is configured to divide a plurality of bending modes based on the first reference plane and the second reference plane, and determine grid vertices to be bent in the body surface model and their bending modes in each bending mode.

[0060] A grid vertex bending module is configured to bend the grid vertices to be bent based on the bending parameters and the bending modes in different bending modes, and obtain bent grid vertices.

[0061] A bent model acquisition module is configured to connect all the bent grid vertices to obtain a bent body surface model.

[0062] Compared with the prior art, the present application has the beneficial effects that:

[0063] The present application obtains a body surface model, determines a first reference surface and a second reference surface on the body surface model, divides several bending modes to meet the orthopedic requirements of different types of scoliosis with the first reference surface and the second reference surface, determines the grid vertexes to be bent and the bending mode of the grid vertexes in the body surface model for each bending mode, bends the grid vertexes to be bent based on the bending parameters and the bending mode under different bending modes, obtains the bent grid vertexes, connects all the bent grid vertexes, and obtains the bent body surface model. The application of different bending modes to the grid vertexes to be bent can improve the accuracy and rationality of the bending of the body surface model and better meet the real contour of the human body. The present application has high automation and high degree of freedom, can generate multiple bent body surface models by fine-tuning the bending parameters, the generated bent body surface models have high accuracy and meet the real contour of the human body, further improve the efficiency of generating the orthosis design scheme, reduce the trial and error and adjustment time, and improve the efficiency of the treatment process. BRIEF DESCRIPTION OF DRAWINGS

[0064] Fig. 1 is a flowchart of a bending method for a body surface model according to embodiment 1;

[0065] Fig. 2 is a front view of the bending of the body surface model in the top bending mode according to embodiment 2;

[0066] Fig. 3 is a left view of the bending of the body surface model in the top bending mode according to embodiment 2;

[0067] Fig. 4 is a front view of the bending of the body surface model in the left-right bending mode according to embodiment 2;

[0068] Fig. 5 is a left view of the bending of the body surface model in the left-right bending mode according to embodiment 2;

[0069] Fig. 6 is a front view of the bending of the body surface model in the bottom bending mode according to embodiment 2;

[0070] Fig. 7 is a left view of the bending of the body surface model in the bottom bending mode according to embodiment 2;

[0071] Fig. 8 is a front view of the bending of the body surface model in the left-right bending mode according to embodiment 2;

[0072] Fig. 9 is a left view of the bending of the body surface model in the left-right bending mode according to embodiment 2;

[0073] Fig. 10 is a front view of the bending of the body surface model in the overall bending mode according to embodiment 2;

[0074] Fig. 11 is a left view of the front and back bending of the body surface model under the overall bending mode described in Embodiment 2;

[0075] Fig. 12 is a front view of the left and right bending of the body surface model under the overall bending mode described in Embodiment 2;

[0076] Fig. 13 is a left view of the left and right bending of the body surface model under the overall bending mode described in Embodiment 2;

[0077] Fig. 14 is a structural schematic diagram of a bending system for a body surface model described in Embodiment 3. DETAILED DESCRIPTION

[0078] The accompanying drawings are only for illustrative purposes and should not be construed as limiting the patent;

[0079] In order to better illustrate the embodiments, some components in the drawings may be omitted, enlarged or reduced, and do not represent the actual size of the product;

[0080] For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0081] The technical solutions of the present application will be further described below in combination with the drawings and embodiments.

[0082] Embodiment 1

[0083] The present embodiment discloses a bending method for a body surface model, as shown in Fig. 1, comprising:

[0084] S1: obtaining a body surface model and bending parameters for bending the body surface model;

[0085] S2: determining a first reference surface and a second reference surface on the body surface model;

[0086] S3: based on the first reference surface and the second reference surface, dividing a plurality of bending modes, and determining the grid vertex to be bent in the body surface model and its bending mode under each bending mode;

[0087] S4: under different bending modes, based on the bending parameters and the bending mode, bending the grid vertex to be bent to obtain the bent grid vertex;

[0088] S5: connecting all the bent grid vertices to obtain the bent body surface model.

[0089] In the implementation process, the embodiment acquires a body surface model, determines a first reference surface and a second reference surface on the body surface model, divides several bending modes to meet the orthopedic requirements of different types of scoliosis based on the first reference surface and the second reference surface, determines, for each bending mode, a grid vertex to be bent in the body surface model in the mode and a bending mode of the grid vertex, bends the grid vertex to be bent based on the bending parameter and the bending mode in different bending modes, obtains a bent grid vertex, connects all the bent grid vertices to obtain a bent body surface model, and applies different bending modes to the grid vertex to be bent, which can improve the accuracy and rationality of bending of the body surface model and be more consistent with the real contour of the human body. The embodiment has high automation and high degree of freedom, can generate a plurality of bent body surface models by fine-tuning the bending parameter, the generated bent body surface model has high accuracy and is consistent with the real contour of the human body, further improves the efficiency of generating an orthosis design scheme, reduces trial and error and adjustment time, and improves the efficiency of the treatment process.

[0090] Embodiment 2

[0091] The embodiment discloses a bending method for a body surface model, comprising:

[0092] S1: acquiring a body surface model and a bending parameter for bending the body surface model;

[0093] The bending parameter comprises a bending direction and a bending amplitude;

[0094] S2: determining a first reference surface and a second reference surface on the body surface model;

[0095] According to the type of the scoliosis corresponding to the body surface model, two horizontal planes penetrating the body surface model are constructed as the first reference surface and the second reference surface by using a ray casting method;

[0096] The longitudinal coordinate of any intersection point of the first reference surface and the body surface model is taken as a first reference surface height value;

[0097] The longitudinal coordinate of any intersection point of the second reference surface and the body surface model is taken as a second reference surface height value;

[0098] The second reference surface height value is less than the first reference surface height value.

[0099] In the specific implementation process, in the patient with single waist bending in the coronal plane, the pelvis appears to be tilted, and the upper and lower iliac crests can be selected as the first reference surface and the second reference surface to adjust the height of the pelvis through the bending in the medial and lateral directions and restore the normal physiological curvature; in the patient with double bending in the coronal plane, the thoracic segment also needs to be laterally bent to exert a lateral flexion effect, and the axillary region of the patient can be selected as the first reference surface and the second reference surface; in the patient with excessive lordosis or insufficient lordosis of the lumbar vertebrae in the sagittal plane, the first lumbar vertebra to the fifth lumbar vertebra can be selected as the first reference surface and the second reference surface to adjust the lumbar vertebrae to the normal physiological curvature; in the patient with insufficient thoracic kyphosis (flat back) or excessive thoracic kyphosis (humpback) in the sagittal plane, the thoracic vertebrae above and below can be selected as the first reference surface and the second reference surface to adjust the thoracic vertebrae to the normal physiological curvature.

[0100] S3: based on the first reference surface and the second reference surface, dividing a plurality of bending modes, and determining the mesh vertices to be bent and the bending mode thereof in the body surface model in each bending mode;

[0101] In the specific implementation process, based on the first reference surface and the second reference surface, a top bending mode, a bottom bending mode and an overall bending mode are divided;

[0102] When the top bending mode is selected, the mesh vertices above the second reference surface need to be bent; when the bottom bending mode is selected, the mesh vertices below the first reference surface need to be bent; when the overall bending mode is selected, all mesh vertices in the body surface model need to be bent; and the implementation is specifically achieved by comparing the longitudinal coordinates of all mesh vertices of the body surface model with the height value of the second reference surface or the height value of the first reference surface:

[0103] When in the top bending mode, the mesh vertices with longitudinal coordinates greater than the height value of the second reference surface are taken as the mesh vertices to be bent;

[0104] When in the bottom bending mode, the mesh vertices with longitudinal coordinates less than the height value of the first reference surface are taken as the mesh vertices to be bent;

[0105] When in the overall bending mode, all mesh vertices are taken as the mesh vertices to be bent.

[0106] Further, in order to make the bending effect more consistent with the real nonlinear change of human body, the bending mode of the grid vertex to be bent is further distinguished: in the top bending mode, the grid vertices above the second reference surface need to be bent, the grid vertices between the first reference surface and the second reference surface and on the first reference surface need to be bent with a transition, so as to achieve the purpose of model smoothing, and the grid vertices above the first reference surface can be directly bent with the pre-set bending amplitude; similarly, in the bottom bending mode, the grid vertices below the first reference surface need to be bent, the grid vertices between the first reference surface and the second reference surface and on the second reference surface need to be bent with a transition, so as to achieve the purpose of model smoothing, and the grid vertices below the second reference surface can be directly bent with the pre-set bending amplitude; in the overall bending mode, all the grid vertices need to be bent, the grid vertices between the first reference surface and the second reference surface and on the first reference surface and the second reference surface need to be bent with a transition, so as to achieve the purpose of model smoothing, and the grid vertices above the first reference surface and below the second reference surface can be directly bent with the pre-set bending amplitude; specifically, the comparison of the longitudinal coordinate of the grid vertex to be bent with the second reference surface height value and the first reference surface height value is realized, that is:

[0107] When in the top bending mode, the grid vertex to be bent with the longitudinal coordinate greater than the second reference surface height value and less than or equal to the first reference surface height value is bent with a transition, and the grid vertex to be bent with the longitudinal coordinate greater than the first reference surface height value is bent directly;

[0108] When in the bottom bending mode, the grid vertex to be bent with the longitudinal coordinate greater than or equal to the second reference surface height value and less than the first reference surface height value is bent with a transition, and the grid vertex to be bent with the longitudinal coordinate less than the second reference surface height value is bent directly;

[0109] When in the overall bending mode, the grid vertex to be bent with the longitudinal coordinate greater than or equal to the second reference surface height value and less than or equal to the first reference surface height value is bent with a transition, and the remaining grid vertex to be bent is bent directly.

[0110] S4: in different bending modes, based on the bending parameters and the bending mode, the grid vertex to be bent is bent to obtain the bent grid vertex;

[0111] In the specific implementation process, when the top bending mode is selected, for the grid vertex to be bent above the first reference surface which is bent directly, a rotation axis is first constructed according to the pre-set bending direction: rotateAxis(a,b,c) =[cos(direction×π÷180°)sin(direction×π÷180°)0]

[0112] In the formula, rotateAxis represents a rotation axis, a represents an angle of rotation around the x-axis, b represents an angle of rotation around the y-axis, c represents an angle of rotation around the z-axis, and direction represents a bending direction.

[0113] The pre-set bending amplitude is then converted into radian form to obtain a radian form bending amplitude.

[0114] A first rotation matrix is then constructed according to the rotation axis and the radian form bending amplitude:

[0115] In the formula, M represents the first rotation matrix, and θ represents the radian form bending amplitude.

[0116] Finally, the three-dimensional coordinates of the grid vertices to be bent above the first reference surface are multiplied by the first rotation matrix to obtain the three-dimensional coordinates of the corresponding bent grid vertices.

[0117] For the grid vertices to be bent using the transition bending mode, the bending proportion coefficient of each grid vertex to be bent is first calculated, including:

[0118] The distance between the first reference surface and the second reference surface is calculated, denoted as a first distance: H = Z1 - Z2

[0119] In the formula, H represents the first distance, Z1 represents the first reference surface height value, and Z2 represents the second reference surface height value.

[0120] The distance between the grid vertex to be bent and the second reference surface is calculated as a second distance: h i = z i -Z2

[0121] In the formula, h i represents the second distance of the i-th grid vertex to be bent, z i represents the vertical coordinate of the i-th grid vertex to be bent.

[0122] The bending proportion coefficient of the grid vertex to be bent is calculated:

[0123] In the formula, β i represents the bending proportion coefficient of the i-th grid vertex to be bent.

[0124] The corresponding proportion bending amplitude is then obtained by multiplying the corresponding bending proportion coefficient of each grid vertex to be bent by the pre-set bending amplitude.

[0125] The corresponding proportion bending amplitude is then obtained by multiplying the corresponding bending proportion coefficient of each grid vertex to be bent by the pre-set bending amplitude.

[0126] Then, based on the rotation axis and the proportional bending amplitude in radian form, a second rotation matrix is constructed:

[0127] In the formula, M' represents the second rotation matrix, and θ' represents the proportional bending amplitude in radian form.

[0128] Finally, the three-dimensional coordinates of the grid vertex to be bent in the transition bending mode are multiplied by the second rotation matrix to obtain the three-dimensional coordinates of the corresponding bent grid vertex.

[0129] As shown in FIGS. 2 and 3, the front and rear views of the body surface model in the top bending mode are shown; as shown in FIGS. 4 and 5, the front and rear views of the body surface model in the top bending mode are shown; in the figures, the two dark lines represent the first reference surface and the second reference surface; the bending direction determines whether the body surface model is bent front and rear or left and right, at this time, the grid vertices above the second reference surface need to be bent, the grid vertices between the first reference surface and the second reference surface and on the first reference surface need to be transitionally bent to achieve the purpose of model smoothing, and the grid vertices above the first reference surface can be directly bent by the pre-set bending amplitude.

[0130] When the bottom bending mode is selected, for the grid vertex to be bent below the second reference surface in the direct bending mode, the bending method is the same as that of the top bending mode; for the grid vertex to be bent in the transition bending mode, the bending method is basically the same as that of the top bending mode, the difference lies in the method of calculating the second distance, in the bottom bending mode, the distance between the grid vertex to be bent and the first reference surface is calculated as the second distance: i = z i - Z1

[0131] In the formula, h i represents the second distance of the i-th grid vertex to be bent, z i represents the vertical coordinate of the i-th grid vertex to be bent.

[0132] As shown in FIGS. 6 and 7, the front and rear views of the body surface model in the bottom bending mode are shown; as shown in FIGS. 8 and 9, the front and rear views of the body surface model in the bottom bending mode are shown; in the figures, the two dark lines represent the first reference surface and the second reference surface; the bending direction determines whether the body surface model is bent front and rear or left and right, at this time, the grid vertices below the first reference surface need to be bent, the grid vertices between the first reference surface and the second reference surface and on the second reference surface need to be transitionally bent to achieve the purpose of model smoothing, and the grid vertices below the second reference surface can be directly bent by the pre-set bending amplitude.

[0133] When the overall bending mode is selected, for the grid vertices to be bent below the second reference plane and above the first reference plane using the direct bending mode, the bending method is the same as that of the top bending mode; for the grid vertices to be bent using the transition bending mode, the bending method is basically the same as that of the top bending mode, the difference lies in the method of calculating the second distance, in the overall bending mode, the height value median of the first reference plane and the second reference plane is calculated, and then the difference between the vertical coordinate of each grid vertex to be transition-bent and the height value median is calculated as the second distance of each grid vertex to be bent:

[0134] In the formula, h i represents the second distance of the i-th grid vertex to be bent, z i represents the vertical coordinate of the i-th grid vertex to be bent.

[0135] As shown in FIGS. 10 and 11, which are the front view and the left view of the body surface model bent front and back in the overall bending mode, respectively; as shown in FIGS. 12 and 13, which are the front view and the left view of the body surface model bent left and right in the overall bending mode, respectively; in the figures, the two dark lines represent the first reference plane and the second reference plane, respectively; the bending direction determines whether the body surface model is bent front and back or bent left and right, at this time, all the grid vertices need to be bent, the grid vertices between the first reference plane and the second reference plane and on the first reference plane and the second reference plane need to be transition-bent to achieve the purpose of smooth model, and the grid vertices above the first reference plane and below the second reference plane can be directly bent to the pre-set bending amplitude.

[0136] In addition, when constructing the rotation matrix, if the second distance corresponding to the grid vertex to be bent is positive, the rotation matrix needs to be constructed counterclockwise; if the second distance corresponding to the grid vertex to be bent is negative, the rotation matrix needs to be constructed clockwise to achieve the correct bending effect.

[0137] S5: connecting all the bent grid vertices according to the original topological relationship of the body surface model to obtain the bent body surface model.

[0138] In actual use, after importing the body surface model of the patient, the bending direction, the bending amplitude, the first reference plane and the second reference plane can be freely set, and the corresponding bent body surface model can be obtained by using the bending method provided in the embodiment; then a plurality of design schemes of orthoses are generated according to the bent body surface model, the correction effects of different design schemes are evaluated, the trial and error and adjustment time are reduced, so as to select the best scheme and improve the efficiency of the treatment process.

[0139] Embodiment 3

[0140] The embodiment discloses a bending system for a body surface model, and is used for implementing the bending method in the embodiments 1 or 2, as shown in Fig. 14, comprising:

[0141] a model and parameter acquisition module, configured to acquire a body surface model and bending parameters for bending the body surface model;

[0142] a reference surface determination module, configured to determine a first reference surface and a second reference surface on the body surface model;

[0143] a bending mode determination module, configured to divide a plurality of bending modes based on the first reference surface and the second reference surface, and determine a grid vertex to be bent and a bending mode thereof in the body surface model in each bending mode;

[0144] a grid vertex bending module, configured to bend the grid vertex to be bent based on the bending parameters and the bending mode in different bending modes, and obtain a bent grid vertex;

[0145] a bent model acquisition module, configured to connect all the bent grid vertices, and obtain a bent body surface model.

[0146] the same or similar reference numerals correspond to the same or similar components;

[0147] the terms describing the positional relationship in the drawings are only used for illustrative description, and should not be understood as a limitation to the patent;

[0148] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the implementation modes of the present application. Any modification, equivalent replacement and improvement made on the basis of the above description for those skilled in the art should be included in the protection scope of the claims of the present application.

Claims

1. A method of bending for a body surface model, characterized by, The method comprises the following steps: acquiring a body surface model and a bending parameter for bending the body surface model; determining a first reference surface and a second reference surface on the body surface model; dividing several bending modes based on the first reference surface and the second reference surface, and determining the grid vertexes to be bent in the body surface model and the bending mode of each bending mode; bending the grid vertexes to be bent based on the bending parameter and the bending mode in different bending modes to obtain the bent grid vertexes; connecting all the bent grid vertexes to obtain the bent body surface model.

2. The bending method for a body surface model according to claim 1, characterized by, The bending parameter comprises a bending direction and a bending amplitude.

3. The bending method for a body surface model according to claim 1, wherein The method for determining the first reference surface and the second reference surface on the body surface model comprises the following steps: constructing two horizontal planes penetrating through the body surface model as the first reference surface and the second reference surface respectively by using a ray casting method according to the type of the scoliosis corresponding to the body surface model; taking the longitudinal coordinate of any intersection point of the first reference surface and the body surface model as the first reference surface height value; taking the longitudinal coordinate of any intersection point of the second reference surface and the body surface model as the second reference surface height value; The second reference surface height value is smaller than the first reference surface height value.

4. The bending method for a body surface model according to any one of claims 1 to 3, characterized by, The several bending modes comprise a top bending mode, a bottom bending mode and an overall bending mode.

5. The bending method for a body surface model according to claim 4, wherein The method for determining the grid vertexes to be bent in the body surface model in each bending mode comprises the following steps: determining all the grid vertexes and their three-dimensional coordinates constituting the body surface model, and comparing the longitudinal coordinate of each grid vertex with the second reference surface height value or the first reference surface height value: when in the top bending mode, taking the grid vertexes with the longitudinal coordinate greater than the second reference surface height value as the grid vertexes to be bent; when in the bottom bending mode, taking the grid vertexes with the longitudinal coordinate smaller than the first reference surface height value as the grid vertexes to be bent; when in the overall bending mode, taking all the grid vertexes as the grid vertexes to be bent.

6. The bending method for a body surface model according to claim 5, wherein The method for determining the bending mode of the grid vertexes to be bent in the body surface model in each bending mode comprises the following steps: respectively comparing the longitudinal coordinate of the grid vertexes to be bent with the first reference surface height value and the second reference surface height value: when in the top bending mode, adopting a transition bending mode for the grid vertexes to be bent with the longitudinal coordinate greater than the second reference surface height value and smaller than or equal to the first reference surface height value, and adopting a direct bending mode for the grid vertexes to be bent with the longitudinal coordinate greater than the first reference surface height value; when in the bottom bending mode, adopting a transition bending mode for the grid vertexes to be bent with the longitudinal coordinate greater than or equal to the second reference surface height value and smaller than the first reference surface height value, and adopting a direct bending mode for the grid vertexes to be bent with the longitudinal coordinate smaller than the second reference surface height value; when in the overall bending mode, adopting a transition bending mode for the grid vertexes to be bent with the longitudinal coordinate greater than or equal to the second reference surface height value and smaller than or equal to the first reference surface height value, and adopting a direct bending mode for the remaining grid vertexes to be bent.

7. The bending method for a body surface model according to claim 6, wherein The method for bending the grid vertexes to be bent based on the bending parameter and the bending mode in different bending modes to obtain the bent grid vertexes comprises the following steps: In any bending mode, for the grid vertex to be bent in the direct bending mode: According to the bending direction, a rotation axis is constructed: rotateAxis(a, b, c) =[cos(direction×π÷180°)sin(direction×π÷180°)0] In the formula, rotateAxis represents the rotation axis, a represents the angle of rotation around the x-axis, b represents the angle of rotation around the y-axis, c represents the angle of rotation around the z-axis, and direction represents the bending direction; The bending amplitude is converted into radian form to obtain the bending amplitude in radian form; Based on the bending amplitude of the rotation axis and the radian form, a first rotation matrix is constructed: In the formula, M represents the first rotation matrix, and θ represents the bending amplitude in radian form; The three-dimensional coordinates of the grid vertex to be bent in the direct bending mode are multiplied by the first rotation matrix to obtain the three-dimensional coordinates of the corresponding bent grid vertex.

8. The bending method for a body surface model according to claim 6, wherein In different bending modes, based on the bending parameters and bending mode, the grid vertex to be bent is bent to obtain the bent grid vertex, and the method further comprises: In any bending mode, for the grid vertex to be bent in the direct bending mode: The distance between the first reference surface and the second reference surface is calculated, denoted as the first distance: H=Z1-Z2 In the formula, H represents the first distance, Z1 represents the first reference surface height value, and Z2 represents the second reference surface height value; Based on the longitudinal coordinate of each grid vertex to be bent, the first reference surface height value and the second reference surface height value, the second distance of each grid vertex to be bent is calculated; based on the first and second distances, a bending ratio coefficient is calculated: In the formula, β i represents the bending ratio coefficient of the i-th mesh vertex to be bent, h i represents the second distance of the i-th mesh vertex to be bent; According to the bending direction, a rotation axis is constructed: rotateAxis(a, b, c) =[cos(direction×π÷180°)sin(direction×π÷180°)0] In the formula, rotateAxis represents the rotation axis, a represents the angle of rotation around the x-axis, b represents the angle of rotation around the y-axis, c represents the angle of rotation around the z-axis, and direction represents the bending direction; The bending amplitude is converted into radian form to obtain the bending amplitude in radian form; In the formula, M represents the first rotation matrix, and θ represents the bending amplitude in radian form; Based on the proportional bending amplitude of the rotation axis and the radian form, a second rotation matrix is constructed: The three-dimensional coordinates of the grid vertex to be bent in the direct bending mode are multiplied by the first rotation matrix to obtain the three-dimensional coordinates of the corresponding bent grid vertex. Based on the longitudinal coordinate of each grid vertex to be bent, the first reference surface height value and the second reference surface height value, the second distance of each grid vertex to be bent is calculated, comprising:

9. The bending method for a body surface model according to claim 8, wherein, When the top bending mode is selected, the difference between the longitudinal coordinate of each grid vertex to be bent and the second reference surface height value is calculated respectively, which corresponds to the second distance of each grid vertex to be bent; When the bottom bending mode is selected, the difference between the longitudinal coordinate of each grid vertex to be bent and the first reference surface height value is calculated respectively, which corresponds to the second distance of each grid vertex to be bent; ​ When the overall bending mode is selected, a height value median of the first reference surface and the second reference surface is calculated; a difference between a longitudinal coordinate of each mesh vertex to be bent and the height value median is calculated respectively, and the difference corresponds to a second distance of each mesh vertex to be bent.

10. A bending system for a body surface model for implementing the bending method of any one of claims 1 to 9, characterized by The method comprises the following steps: a model and parameter acquisition module is configured to acquire a body surface model and bending parameters for bending the body surface model; a reference surface determination module is configured to determine a first reference surface and a second reference surface on the body surface model; a bending mode determination module is configured to divide a plurality of bending modes based on the first reference surface and the second reference surface, and determine mesh vertices to be bent in the body surface model and bending manners of the mesh vertices in each bending mode; a mesh vertex bending module is configured to bend the mesh vertices to be bent based on the bending parameters and the bending manners in different bending modes, and obtain bent mesh vertices; a bent model acquisition module is configured to connect all the bent mesh vertices, and obtain a bent body surface model.

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