A method, medium and device for generating a three-dimensional gingival mesh model

Abstract

The present invention provides a method, medium and device for generating a three-dimensional gingival mesh model. The method obtains the edge points of a three-dimensional crown model, and projects the edge points of the three-dimensional crown model to the specified upper and lower jaw directions by a first preset distance and then performs polynomial fitting to obtain the bottom contour line of the three-dimensional gingival mesh model, and obtains the gingival bottom mesh model based on the bottom contour line; interpolates the edge points with the points on the projected bottom contour line, and connects the interpolated points to form a gingival side mesh model; connects the edge points of the crown model with the center point of the crown model to construct a gingival top mesh model; and merges the gingival top mesh model, the gingival bottom mesh model and the gingival side mesh model to obtain a complete gingival mesh model. The above scheme fully considers the detailed characteristics of the crown edge points when generating the gingival mesh model, so that the generated gingival details are richer and the accuracy is higher.

Description

Technical Field

[0001] The present invention relates to the field of tooth model processing, and in particular to a method, medium and device for generating a three-dimensional gingival mesh model. Background Art

[0002] Virtual gingiva is a three-dimensional gingival model generated through oral scanning data and computer technology. It aims to accurately simulate the actual morphology of the gingiva in the patient's mouth and can help doctors design tooth correction or restoration. However, due to the complex and diverse gingival surface morphology, existing systems often find it difficult to accurately reproduce its detailed surface features when generating gingival models, and the flexibility of further editing the generated surface morphology is also limited. Summary of the invention

[0003] Therefore, it is necessary to provide a technical solution for generating a three-dimensional gingival mesh model to solve the technical problem that the existing gingival model generation method cannot accurately retain the gingival surface characteristics.

[0004] To solve the above problems, this application proposes the following solutions:

[0005] In a first aspect, the present application provides a method for generating a three-dimensional gingival mesh model, the method comprising the following steps:

[0006] Load the maxillary dentition model or the mandibular dentition model;

[0007] Using the MeshSegNet algorithm to segment the maxillary dentition model or the mandibular dentition model into an independent three-dimensional crown model;

[0008] Constructing a three-dimensional coordinate system, obtaining the edge point coordinates of each of the three-dimensional crown models, and obtaining a first point coordinate set;

[0009] Calculating the center point coordinates corresponding to the first point coordinate set of each three-dimensional crown model, sequentially connecting the coordinate points in the first point coordinate set of each three-dimensional crown model with the corresponding center point coordinates, and constructing a gingival top mesh model according to the first topological rule;

[0010] Projecting the edge point coordinates in the first point coordinate set by a first preset distance along the Z-axis direction of the three-dimensional coordinate system to obtain a second point coordinate set, performing polynomial fitting on the coordinate points in the second point coordinate set to obtain a bottom contour line of the three-dimensional gingival mesh model, and connecting the bottom contour lines according to a second topological rule to obtain a gingival bottom mesh model;

[0011] interpolating between the first point coordinate set and the second point coordinate set to obtain a plurality of interpolation point coordinate sets, and connecting the interpolation point coordinate sets according to a third topological rule to obtain a gingival side mesh model;

[0012] The gum top mesh model, the gum bottom mesh model and the gum side mesh model are merged to obtain a complete gum mesh model.

[0013] Furthermore, constructing a three-dimensional coordinate system includes:

[0014] The geometric mean center of all crown three-dimensional models is taken as the origin of the three-dimensional coordinate system, the direction of the occlusal plane perpendicular to the maxillary dentition or the mandibular dentition is taken as the Z axis of the three-dimensional coordinate system, the occlusal direction is taken as the Y axis of the three-dimensional coordinate system, and the direction of the plane formed by the perpendicular Y axis and Z axis is taken as the X axis of the three-dimensional coordinate system.

[0015] Furthermore, the edge point coordinates of each of the three-dimensional crown models are obtained to obtain a first point coordinate set including:

[0016] Performing edge smoothing processing on each of the three-dimensional crown models, obtaining edge points of the smoothed three-dimensional crown models, and obtaining the first point coordinate set;

[0017] The first point coordinate set of each of the three-dimensional crown models includes a labial point, a buccal point, a mesial point and a distal point, which are defined as follows:

[0018] For a 3D crown model with adjacent teeth on both sides, obtain edge points within a first preset range between the current 3D crown model and the 3D crown models of the adjacent teeth on both sides, and according to the different distances to the midline of the teeth, record the edge point on the side farther from the midline as the distal point, and record the edge point on the side closer to the midline as the mesial point.

[0019] The remaining edge points except the distal point and the mesial point are divided into labial points and buccal points according to the vector angle between them and the labiolingual axis of the tooth, wherein the labiolingual axis of the tooth represents a vector with its origin at the center of the three-dimensional crown model and its direction pointing from the buccal side to the labial side. If the vector angle θ between the remaining edge points and the labiolingual axis is less than π, it indicates that the edge point is a labial point; if the vector angle θ between the remaining edge points and the labiolingual axis is greater than π, it indicates a buccal point.

[0020] Furthermore, the edge point coordinates in the first point coordinate set are projected along the Z-axis direction of the three-dimensional coordinate system by a first preset distance to obtain a second point coordinate set, and polynomial fitting is performed on the coordinate points in the second point coordinate set to obtain the bottom contour line of the three-dimensional gingival mesh model, including:

[0021] For a three-dimensional crown model with adjacent teeth on both sides of the mandibular dentition model, the labial points and buccal points in the first point coordinate set are projected by a first preset distance along the direction of decreasing Z coordinates, and the projection points of the buccal points and the labial points are fitted with a fourth-order polynomial respectively, and the projection points are approximated to the nearest point on the fitted polynomial, so as to fit the projection points into smooth curve points;

[0022] Alternatively, for a three-dimensional crown model with adjacent teeth on both sides in the maxillary dentition model, the labial points and buccal points in the first point coordinate set are projected a first preset distance along the direction of increasing Z coordinate, and the projection points of the buccal points and the labial points are fitted with fourth-order polynomials, and the projection points are approximated to the nearest points on the fitted polynomials to fit the projection points into smooth curve points.

[0023] Furthermore, the method further comprises:

[0024] For a terminal three-dimensional crown model having adjacent teeth on only one side of the maxillary dentition model or the mandibular dentition model, two endpoints of the edge points of the terminal three-dimensional crown model are obtained, the two endpoints are the two edge points with the largest distance, a circle is fitted to the two endpoints using the least squares method, and the fitted circle is projected onto the plane where the bottom contour line is located to obtain the terminal contour line;

[0025] Connecting the bottom contour lines according to the second topological rule to obtain a mesh model of the gingival bottom includes:

[0026] The bottom contour line and the end contour line are connected in sequence, and the minimum angle method is used as the second topological rule to form the gingival bottom mesh model.

[0027] Furthermore, interpolation is performed between the first point coordinate set and the second point coordinate set to obtain a plurality of interpolation point coordinate sets, and each of the interpolation point coordinate sets is connected according to a third topological rule to obtain a gingival side mesh model, including:

[0028] Constructing a point pair according to the edge points in the first point coordinate set and the coordinate points on the bottom contour line, calculating the normal vector of the coordinate point on the bottom contour line, extending the coordinate point on the bottom contour line along the direction of the normal vector corresponding to it by a second preset distance to obtain a first extended coordinate point, starting from the first extended coordinate point, sequentially extending the preset unit distance upward along the Z-axis direction of the three-dimensional coordinate system to obtain a second extended coordinate point, interpolating a plurality of interpolation points based on the point pair, the first extended coordinate point and the second extended coordinate point to generate a third-order Bezier curve;

[0029] Traverse all point pairs between edge points in the first point coordinate set and coordinate points on the bottom contour line, construct multiple Bezier curves, and generate the gingival side mesh model based on the multiple Bezier curves.

[0030] Furthermore, the method further comprises:

[0031] The mesh model of the gingival side surface is subdivided by using the Loop algorithm, and smoothed by using the Laplace algorithm to obtain the mesh model of the gingival side surface after subdivision and smoothing;

[0032] The gum top mesh model, the gum bottom mesh model and the gum side mesh model are merged to obtain a complete gum mesh model including:

[0033] The gum top mesh model, the gum bottom mesh model and the gum side mesh model after subdivision and smoothing are merged to obtain a complete gum mesh model.

[0034] Furthermore, the method further comprises:

[0035] The complete gingival mesh model is meshed by using a Loop algorithm and smoothed by using a Laplace algorithm to obtain the complete gingival mesh model after meshing and smoothing.

[0036] In a second aspect, the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for generating a three-dimensional gingival mesh model as described in the first aspect of the present application.

[0037] In a third aspect, the present application provides an electronic device having a computer program stored thereon, comprising a processor and a storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by the processor, the method for generating a three-dimensional gingival mesh model as described in the first aspect of the present application is implemented.

[0038] Different from the prior art, the present invention provides a method, medium and device for generating a three-dimensional gingival mesh model. The method obtains the edge points of the three-dimensional crown model, and projects the edge points of the three-dimensional crown model to the specified upper and lower jaw directions by a first preset distance to obtain a second point coordinate set, performs polynomial fitting on the coordinate points in the second point coordinate set to obtain the bottom contour line of the three-dimensional gingival mesh model, connects the bottom contour line according to the second topological rule to obtain the gingival bottom mesh model; interpolates the edge points with the points on the projected bottom contour line, connects the interpolated points according to the topological rule to form a gingival side mesh model; and after connecting the edge points of the crown model with the center point of the crown model, constructs a gingival top mesh model according to the first topological rule; and then merges the gingival top mesh model, the gingival bottom mesh model and the gingival side mesh model to obtain a complete gingival mesh model. The above scheme fully considers the detailed characteristics of the crown edge points when generating the gingival mesh model, which can make the generated gingival details richer and more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a flow chart of a method for generating a three-dimensional gingival mesh model according to a first embodiment of the present invention;

[0040] Figure 2 is a flow chart of a method for generating a three-dimensional gingival mesh model according to a second embodiment of the present invention;

[0041] Figure 3 is a flow chart of a method for generating a three-dimensional gingival mesh model according to a third embodiment of the present invention;

[0042] Figure 4 A schematic diagram of an electronic device according to an embodiment of the present invention;

[0043] Figure 5 is a schematic diagram of a three-dimensional coordinate system involved in one embodiment of the present invention;

[0044] Figure 6 A schematic diagram of the edge point distribution of a three-dimensional crown model according to an embodiment of the present invention;

[0045] Figure 7 It is a schematic diagram of the principle of dividing the labial points and the buccal points involved in one embodiment of the present invention;

[0046] Figure 8 A schematic diagram of the distribution of edge points in a first point coordinate set corresponding to each three-dimensional crown model involved in an embodiment of the present invention;

[0047] Fig. 9 It is a schematic diagram of obtaining a bottom contour line by projecting a labial point and a buccal point onto a bottom plane according to an embodiment of the present invention;

[0048] Fig.10 It is a schematic diagram of obtaining a terminal contour line by projecting a fitting circle onto the plane where the bottom contour line is located according to an embodiment of the present invention;

[0049] Fig.11 A schematic diagram of a curve obtained by merging a bottom contour line and an end contour line obtained by projection according to an embodiment of the present invention;

[0050] FIG. 12 ( a ) is a schematic diagram of a curve obtained by merging a bottom contour line and an end contour line according to an embodiment of the present invention;

[0051] FIG12( b ) is a schematic diagram of a mesh model of the gum bottom according to an embodiment of the present invention;

[0052] Fig.13 A distribution diagram of interpolation points for constructing a Bezier curve according to an embodiment of the present invention;

[0053] FIG. 14 ( a ) is a schematic diagram of a plurality of constructed Bezier curves according to an embodiment of the present invention;

[0054] FIG. 14( b ) is a schematic diagram of a mesh model of the gingival side surface according to an embodiment of the present invention;

[0055] Fig.15 A schematic diagram of a mesh model of the top of the gums according to an embodiment of the present invention;

[0056] Fig.16 is a schematic diagram of a complete gingival mesh model according to an embodiment of the present invention;

[0057] Fig.17 A schematic diagram of a complete gingival mesh model after subdivision and smoothing according to an embodiment of the present invention;

[0058] Fig.18 This is a schematic diagram of the principle of the third topology rule involved in one embodiment of the present invention;

[0059] Reference numerals:

[0060] 10. Electronic equipment;

[0061] 101. Processor;

[0062] 102. Storage medium. DETAILED DESCRIPTION

[0063] In order to explain in detail the possible application scenarios, technical principles, specific schemes that can be implemented, and the purposes and effects that can be achieved, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0064] Reference to "embodiment" herein means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present application. The term "embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or association with other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the various technical features mentioned in the embodiments can be combined in any way to form a corresponding implementable technical solution.

[0065] Unless otherwise defined, the technical terms used in this document have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms in this document is only for describing specific embodiments and is not intended to limit this application.

[0066] In the description of this application, the term "and / or" is an expression used to describe the logical relationship between objects, indicating that three relationships may exist, for example, A and / or B, which means: A exists, B exists, and A and B exist at the same time. In addition, the character " / " in this article generally indicates that the objects before and after are in an "or" logical relationship.

[0067] In the present application, terms such as “first” and “second” are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship of quantity, priority or sequence between these entities or operations.

[0068] Without further limitations, in this application, the words "include", "comprises", "has" or other similar expressions used in sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product including the elements, so that the process, method or product including a series of elements may include not only those limited elements, but also other elements not explicitly listed, or also include elements inherent to such process, method or product.

[0069] In this application, expressions such as "greater than", "less than", "exceed" and the like are understood to exclude the number itself; expressions such as "above", "below", "within" and the like are understood to include the number itself. In addition, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this way, such as "multiple groups", "multiple times", etc., unless otherwise clearly and specifically limited.

[0070] In the first aspect, Figure 1 As shown, the present application provides a method for generating a three-dimensional gingival mesh model, the method comprising the following steps:

[0071] Step S1: loading the maxillary dentition model or the mandibular dentition model;

[0072] Step S2: using the MeshSegNet algorithm to segment the maxillary dentition model or the mandibular dentition model into an independent three-dimensional crown model;

[0073] Step S3: constructing a three-dimensional coordinate system, obtaining the edge point coordinates of each of the three-dimensional crown models, and obtaining a first point coordinate set;

[0074] Step S4: calculating the center point coordinates corresponding to the first point coordinate set of each three-dimensional crown model, connecting the coordinate points in the first point coordinate set of each three-dimensional crown model with the corresponding center point coordinates in sequence, and constructing a gingival top mesh model according to the first topological rule;

[0075] Step S5: projecting the edge point coordinates in the first point coordinate set by a first preset distance along the Z-axis direction of the three-dimensional coordinate system to obtain a second point coordinate set, performing polynomial fitting on the coordinate points in the second point coordinate set to obtain a bottom contour line of the three-dimensional gingival mesh model, and connecting the bottom contour lines according to a second topological rule to obtain a gingival bottom mesh model;

[0076] Step S6: interpolating between the first point coordinate set and the second point coordinate set to obtain a plurality of interpolation point coordinate sets, and connecting the interpolation point coordinate sets according to a third topological rule to obtain a gingival side mesh model;

[0077] Step S7: merging the gum top mesh model, the gum bottom mesh model and the gum side mesh model to obtain a complete gum mesh model.

[0078] In steps S1 and S2, a three-dimensional digital model of teeth can be obtained first. The three-dimensional digital model of teeth includes a maxillary dentition model or a mandibular dentition model. The three-dimensional digital model of teeth is obtained by scanning with a mouth scanner. For the original three-dimensional digital model of teeth, the MeshSegNet algorithm can be used to segment independent crown three-dimensional models, and each crown three-dimensional model corresponds to one tooth.

[0079] In step S3, constructing a three-dimensional coordinate system includes: taking the geometric mean center of all crown three-dimensional models as the origin of the three-dimensional coordinate system, taking the direction of the occlusal plane perpendicular to the maxillary dentition or mandibular dentition as the Z axis of the three-dimensional coordinate system, taking the occlusal direction as the Y axis of the three-dimensional coordinate system, and taking the direction of the plane formed by the vertical Y axis and Z axis as the X axis of the three-dimensional coordinate system. The distribution of the X axis, Y axis and Z axis of the three-dimensional coordinate system is as follows: Figure 5 shown.

[0080] The three-dimensional crown model usually includes a base part and a crown part. In this application, the edge point of the three-dimensional crown model refers to the bottom edge contour of the crown part of the three-dimensional crown model, and its distribution is as follows: Figure 6 shown.

[0081] In step S4, the coordinates of the center point of a 3D crown model are the coordinates of all the coordinate points of the crown part of the 3D crown model. The first topological rule is to connect the edge points of a 3D crown model with their corresponding center points in sequence, and fill the connection area with triangular facets to obtain a mesh model of the top of the gums. The constructed mesh model of the top of the gums is as follows: Fig.15 shown.

[0082] In step S5, the size of the first preset distance can be set according to actual needs, and can usually be set to the distance from the three-dimensional crown model to be displayed to the base.

[0083] In step S6, the number of interpolation points can be set according to actual needs. Generally, the vertical distances between adjacent interpolation points can be set to be the same. For example, three points need to be interpolated between point A and point E. The three interpolated points are recorded as point B, point C, and point D according to their distance from point A. When point B to point D are projected to the vertical height, the distance between point B and point C, and the distance between point C and point D can be set to be the same.

[0084] It should be noted that steps S4, S5, and S6 can be executed sequentially or in parallel, that is, how to generate the gingival top mesh model, the gingival bottom mesh model, and the gingival side mesh model are independent of each other.

[0085] In step S7, the complete gingival mesh model is as follows: Fig.16 shown.

[0086] The above scheme fully considers the detailed features of the crown edge points when generating the gingival mesh model, which can make the generated gingival details richer and more accurate.

[0087] In some embodiments, obtaining the edge point coordinates of each of the three-dimensional crown models to obtain a first point coordinate set includes:

[0088] Perform edge smoothing on each of the three-dimensional crown models, obtain edge points of the smoothed three-dimensional crown models, and obtain the first point coordinate set.

[0089] In this embodiment, the smoothing algorithm can be selected from Laplace smoothing algorithm, curvature-based smoothing algorithm, Taubin smoothing algorithm, and HC Laplace smoothing algorithm. Preferably, the smoothing algorithm is selected from Laplace smoothing algorithm. By performing edge smoothing on the three-dimensional crown model, the edge details of the three-dimensional crown model can be better presented.

[0090] In some embodiments, the first point coordinate set of each of the three-dimensional crown models includes a labial point, a buccal point, a mesial point, and a distal point, which are defined as follows:

[0091] For a three-dimensional crown model with adjacent teeth on both sides, edge points within a first preset range between the current three-dimensional crown model and the three-dimensional crown models of the adjacent teeth on both sides are obtained, and according to the different distances to the midline of the teeth, the edge point on the side farther from the midline is recorded as the distal point, and the edge point on the side closer to the midline is recorded as the mesial point, and the remaining edge points except the distal point and the mesial point are divided into labial points and buccal points according to their vector angles with the labiolingual axis of the teeth.

[0092] like Figure 7 As shown in the figure, the labial-lingual axis of the tooth represents a vector with its origin at the center of the 3D crown model and its direction from the buccal side to the lip side. If the angle θ between the remaining edge points and the labial-lingual axis is less than π, then the edge point is a lip point. If the angle θ between the remaining edge points and the labial-lingual axis is greater than π, then the edge point is a buccal point. The distribution of edge points in the first point coordinate set corresponding to each 3D crown model is shown in the figure below. Figure 8 shown.

[0093] In some embodiments, projecting the edge point coordinates in the first point coordinate set by a first preset distance along the Z-axis direction of the three-dimensional coordinate system to obtain a second point coordinate set, and performing polynomial fitting on the coordinate points in the second point coordinate set to obtain the bottom contour line of the three-dimensional gingival mesh model includes:

[0094] For a three-dimensional crown model with adjacent teeth on both sides of the mandibular dentition model, the labial points and buccal points in the first point coordinate set are projected by a first preset distance along the direction of decreasing Z coordinates, and the projection points of the buccal points and the labial points are fitted with a fourth-order polynomial respectively, and the projection points are approximated to the nearest point on the fitted polynomial, so as to fit the projection points into smooth curve points;

[0095] Alternatively, for a three-dimensional crown model with adjacent teeth on both sides in the maxillary dentition model, the labial points and buccal points in the first point coordinate set are projected a first preset distance along the direction of increasing Z coordinate, and the projection points of the buccal points and the labial points are fitted with fourth-order polynomials, and the projection points are approximated to the nearest points on the fitted polynomials to fit the projection points into smooth curve points.

[0096] The expression of the 4th order polynomial fit is as follows:

[0097] ;

[0098] in, Indicates the coefficients that need to be determined during the fitting process; Represents the projection point coordinate; Represents the projection point after fitting The goal of the 4th-order polynomial fit is to adjust the coefficients , so that the error between the polynomial and the given point is minimized, and the error is defined as and the fitting function difference.

[0099] The least squares method is used to determine the polynomial coefficients. The error sum of squares is constructed as follows:

[0100] ;

[0101] In order to minimize the total sum of squared errors (i.e., least squares method), we define the sum of squared errors as follows:

[0102] ;

[0103] In order to find the coefficient with the smallest sum of squared errors S , we need to differentiate each coefficient of S, set the derivative to 0, and get the linear equation system:

[0104] ;

[0105] If expressed in matrix form, it can be expressed as:

[0106] ;

[0107] By solving this linear system of equations, the polynomial coefficients can be calculated .

[0108] Project the labial and buccal points onto the bottom plane to obtain the bottom contour line as shown below: Fig. 9 shown.

[0109] In some embodiments, Figure 2 As shown, the method also includes:

[0110] Step S201: For the end three-dimensional crown model of the maxillary dentition model or the mandibular dentition model with adjacent teeth on only one side, obtain two endpoints of the edge points of the end three-dimensional crown model, where the two endpoints are the two edge points with the largest distance, fit a circle to the two endpoints using the least squares method, project the fitted circle to the plane where the bottom contour line is located, and obtain the end contour line.

[0111] In this embodiment, the radius of the fitting circle is half the distance between the two end points, and the fitting circle uses the center point of the two end points. The fitting result is as follows: Fig.10 shown.

[0112] Furthermore, the bottom contour lines are connected according to the second topological rule to obtain the gingival bottom mesh model, including:

[0113] Step S202: Connect the bottom contour line and the end contour line in sequence to obtain a merged contour curve, adopt the minimum angle method as the second topological rule, and form the gingival bottom mesh model based on the merged contour curve.

[0114] The minimum angle method is described as follows: for each point on the merged contour curve, first calculate the angle between the two adjacent sides of each adjacent point. Then find the point with the minimum angle and determine the number of digitized triangles to be added. Next, update the point information and find the next boundary point with the minimum angle until the gingival bottom mesh model is formed based on the merged contour curve. The projection process of the merged contour curve is as follows: Fig.11 As shown, the merged contour curve is shown in Figure 12 (a), and the constructed gingival bottom mesh model is shown in Figure 12 (b).

[0115] In some embodiments, Figure 3 As shown, interpolation is performed between the first point coordinate set and the second point coordinate set to obtain a plurality of interpolation point coordinate sets, and each of the interpolation point coordinate sets is connected according to a third topological rule to obtain a gingival side mesh model, including:

[0116] Step S301: constructing a point pair according to the edge points in the first point coordinate set and the coordinate points on the bottom contour line, calculating the normal vector of the coordinate point on the bottom contour line, extending the coordinate point on the bottom contour line along the direction of its corresponding normal vector by a second preset distance to obtain a first extended coordinate point, starting from the first extended coordinate point, sequentially extending the preset unit distance upward along the Z-axis direction of the three-dimensional coordinate system to obtain a second extended coordinate point, interpolating a number of interpolation points based on the point pair, the first extended coordinate point and the second extended coordinate point to generate a third-order Bezier curve;

[0117] Step S302: traverse all point pairs between edge points in the first point coordinate set and coordinate points on the bottom contour line, construct multiple Bezier curves, and generate the gingival side mesh model based on the multiple Bezier curves.

[0118] In this embodiment, the second preset distance is generally a small distance, and the specific value can be set according to actual needs, such as 0-0.2mm, preferably 0.1mm. The preset unit distance can be set according to actual needs. For example, if the first preset distance is recorded as L, the preset unit distance can be set to L / 4, and then the corresponding number of coordinate points set can be interpolated based on the first extended coordinate point, the two coordinate points in the point pair, and the second extended coordinate point to generate a third-order Bezier curve. The number of second extended coordinate points can be 1 or more. The distribution of the two coordinate points in the point pair, the first extended coordinate point, and the second extended coordinate point is as follows: Fig.13 As shown, the distribution of interpolation points of the constructed Bezier curve is shown in Figure 14 (a), and the gingival side mesh model is shown in Figure 14 (b).

[0119] In this embodiment, if Fig.18 As shown, the third topological rule involved in this application is explained below: the black font serial number represents the vertex distribution of the constructed triangular face, and the red font represents the triangular face information constructed according to the vertex serial number, wherein the three coordinate vertices with serial numbers 1, 2, and 11 constitute a triangular face 1, the three coordinate vertices with serial numbers 2, 11, and 12 constitute a triangular face 2, and the three coordinate vertices with serial numbers 2, 3, and 12 constitute a triangular face 3, and so on. Since the points on the side are arranged in order on multiple Bezier curves, it can be used as follows Fig.18 The triangular facets are filled according to the rules shown to obtain the mesh model of the gingival side.

[0120] In some embodiments, the method further comprises:

[0121] The mesh model of the gingival side surface is subdivided by using the Loop algorithm, and smoothed by using the Laplace algorithm to obtain the mesh model of the gingival side surface after subdivision and smoothing;

[0122] The gum top mesh model, the gum bottom mesh model and the gum side mesh model are merged to obtain a complete gum mesh model including:

[0123] The gum top mesh model, the gum bottom mesh model and the gum side mesh model after subdivision and smoothing are merged to obtain a complete gum mesh model.

[0124] In some other embodiments, the method further comprises:

[0125] The complete gingival mesh model is meshed by using a Loop algorithm and smoothed by using a Laplace algorithm to obtain the complete gingival mesh model after meshing and smoothing.

[0126] In short, the gingival side mesh model can be subdivided and smoothed first, and then the subdivided and smoothed gingival side mesh model, gingival top mesh model and gingival bottom mesh model can be merged to obtain a complete subdivided and smoothed gingival mesh model. Alternatively, the gingival side mesh model, gingival top mesh model and gingival bottom mesh model can be merged first, and then the obtained gingival mesh model can be subdivided and smoothed to obtain the following: Fig.17 The complete gingival mesh model after subdivision and smoothing is shown.

[0127] In a second aspect, the present invention further provides a computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the method for generating a three-dimensional gingival mesh model as described in the first aspect of the present invention is implemented.

[0128] The computer-readable storage medium may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories.

[0129] The non-volatile memory can be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a ferromagnetic random access memory (FRAM), a flash memory, a magnetic surface memory, an optical disc, or a compact disc read-only memory (CD ROM); the magnetic surface memory can be a disk memory or a tape memory.

[0130] The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of RAM are available, such as static random access memory (SRAM), synchronous static random access memory (SSRAM), dynamic random access memory (DRAM), synchronous dynamic random access memory (SDRAM), double data rate synchronous dynamic random access memory (DDRSDRAM), enhanced synchronous dynamic random access memory (ESDRAM), synchronous link dynamic random access memory (SLDRAM), direct memory bus random access memory (DRRAM). The computer-readable storage medium described in the embodiments of the present invention is intended to include these and any other suitable types of memory.

[0131] like Figure 4 As shown, in a third aspect, the present invention provides an electronic device 10, comprising a processor 101 and a storage medium 102, wherein a computer program is stored on the storage medium, and when the computer program is executed by the processor, the method for generating a three-dimensional gingival mesh model as described in the first aspect of the present invention is implemented.

[0132] In some embodiments, the processor can be implemented by software, hardware, firmware or a combination thereof, and can use circuits, single or multiple application specific integrated circuits (Application Specific Integrated Circuit, ASIC), digital signal processors (Digital Signal Processor, DSP), digital signal processing devices (Digital Signal Processing Device, DSPD), programmable logic devices (Programmable Logic Device, PLD), field programmable gate arrays (Field Programmable Gate Array, FPGA), central processing units (Central Processing Unit, CPU), controllers, microcontrollers, microprocessors, at least one of which, so that the processor can execute some or all of the steps in the method for generating a three-dimensional gingival mesh model in the various embodiments of the present application, or any combination of the steps therein.

[0133] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concept of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A method for generating a three-dimensional gingival mesh model, characterized in that: The method comprises the following steps: Load the maxillary dentition model or the mandibular dentition model; Using the MeshSegNet algorithm to segment the maxillary dentition model or the mandibular dentition model into an independent three-dimensional crown model; Constructing a three-dimensional coordinate system, obtaining the edge point coordinates of each of the three-dimensional crown models, and obtaining a first point coordinate set; Calculating the center point coordinates corresponding to the first point coordinate set of each three-dimensional crown model, sequentially connecting the coordinate points in the first point coordinate set of each three-dimensional crown model with the corresponding center point coordinates, and constructing a gingival top mesh model according to a first topological rule, wherein the first topological rule is to sequentially connect the edge points of a certain three-dimensional crown model with the corresponding center points, and fill the connection area with triangular facets; The edge point coordinates in the first point coordinate set are projected along the Z-axis direction of the three-dimensional coordinate system by a first preset distance to obtain a second point coordinate set, and the coordinate points in the second point coordinate set are fitted with a polynomial to obtain the bottom contour line of the three-dimensional gingival mesh model; the bottom contour lines are connected according to a second topological rule to obtain a gingival bottom mesh model, specifically including: for a terminal three-dimensional crown model with adjacent teeth on only one side of the maxillary dentition model or the mandibular dentition model, two endpoints of the edge points of the terminal three-dimensional crown model are obtained, the two endpoints are the two edge points with the largest distance, a circle is fitted to the two endpoints using the least squares method, and the fitted circle is projected to the plane where the bottom contour line is located to obtain the terminal contour line; the bottom contour line and the terminal contour line are connected in sequence, and the minimum angle method is used as the second topological rule to form the gingival bottom mesh model; interpolating between the first point coordinate set and the second point coordinate set to obtain a plurality of interpolation point coordinate sets, and connecting the interpolation point coordinate sets according to a third topological rule to obtain a gingival side mesh model; The gum top mesh model, the gum bottom mesh model and the gum side mesh model are merged to obtain a complete gum mesh model.

2. The method for generating a three-dimensional gingival mesh model according to claim 1, characterized in that: Constructing a three-dimensional coordinate system includes: The geometric mean center of all crown three-dimensional models is taken as the origin of the three-dimensional coordinate system, the direction of the occlusal plane perpendicular to the maxillary dentition or the mandibular dentition is taken as the Z axis of the three-dimensional coordinate system, the occlusal direction is taken as the Y axis of the three-dimensional coordinate system, and the direction of the plane formed by the perpendicular Y axis and Z axis is taken as the X axis of the three-dimensional coordinate system.

3. The method for generating a three-dimensional gingival mesh model according to claim 1, characterized in that: Obtaining the edge point coordinates of each of the three-dimensional crown models to obtain a first point coordinate set includes: Performing edge smoothing processing on each of the three-dimensional crown models, obtaining edge points of the smoothed three-dimensional crown models, and obtaining the first point coordinate set; The first point coordinate set of each of the three-dimensional crown models includes a labial point, a buccal point, a mesial point and a distal point, which are defined as follows: For a 3D crown model with adjacent teeth on both sides, obtain edge points within a first preset range between the current 3D crown model and the 3D crown models of the adjacent teeth on both sides, and according to the different distances to the midline of the teeth, record the edge point on the side farther from the midline as the distal point, and record the edge point on the side farther from the midline as the mesial point. The remaining edge points except the distal point and the mesial point are divided into labial points and buccal points according to the vector angle between them and the labiolingual axis of the tooth, wherein the labiolingual axis of the tooth represents a vector with its origin at the center of the three-dimensional crown model and its direction pointing from the buccal side to the labial side of the tooth. If the vector angle θ between the remaining edge points and the labiolingual axis is less than π, it indicates that the edge point is a labial point; if the vector angle θ between the remaining edge points and the labiolingual axis is greater than π, it indicates a buccal point.

4. The method for generating a three-dimensional gingival mesh model according to claim 3, characterized in that: The step of projecting the edge point coordinates in the first point coordinate set by a first preset distance along the Z-axis direction of the three-dimensional coordinate system to obtain a second point coordinate set, and performing polynomial fitting on the coordinate points in the second point coordinate set to obtain the bottom contour line of the three-dimensional gingival mesh model includes: For a three-dimensional crown model with adjacent teeth on both sides of the mandibular dentition model, the labial points and buccal points in the first point coordinate set are projected by a first preset distance along the direction of decreasing Z coordinates, and the projection points of the buccal points and the labial points are fitted with a fourth-order polynomial respectively, and the projection points are approximated to the nearest point on the fitted polynomial, so as to fit the projection points into smooth curve points; Alternatively, for a three-dimensional crown model with adjacent teeth on both sides in the maxillary dentition model, the labial points and buccal points in the first point coordinate set are projected a first preset distance along the direction of increasing Z coordinate, and the projection points of the buccal points and the labial points are fitted with fourth-order polynomials, and the projection points are approximated to the nearest points on the fitted polynomials to fit the projection points into smooth curve points.

5. The method for generating a three-dimensional gingival mesh model according to claim 1, characterized in that: Interpolating between the first point coordinate set and the second point coordinate set to obtain a plurality of interpolation point coordinate sets, and connecting the interpolation point coordinate sets according to a third topological rule to obtain a gingival side mesh model includes: Constructing a point pair according to the edge points in the first point coordinate set and the coordinate points on the bottom contour line, calculating the normal vector of the coordinate point on the bottom contour line, extending the coordinate point on the bottom contour line along the direction of the normal vector corresponding to it by a second preset distance to obtain a first extended coordinate point, starting from the first extended coordinate point, sequentially extending the preset unit distance upward along the Z-axis direction of the three-dimensional coordinate system to obtain a second extended coordinate point, interpolating a plurality of interpolation points based on the point pair, the first extended coordinate point and the second extended coordinate point to generate a third-order Bezier curve; Traverse all point pairs between edge points in the first point coordinate set and coordinate points on the bottom contour line, construct multiple Bezier curves, and generate the gingival side mesh model based on the multiple Bezier curves.

6. The method for generating a three-dimensional gingival mesh model according to claim 1 or 5, characterized in that: The method further comprises: The mesh model of the gingival side surface is subdivided by using the Loop algorithm, and smoothed by using the Laplace algorithm to obtain the mesh model of the gingival side surface after subdivision and smoothing; The gum top mesh model, the gum bottom mesh model and the gum side mesh model are merged to obtain a complete gum mesh model including: The gum top mesh model, the gum bottom mesh model and the gum side mesh model after subdivision and smoothing are merged to obtain a complete gum mesh model.

7. The method for generating a three-dimensional gingival mesh model according to claim 1, characterized in that: The method further comprises: The complete gingival mesh model is meshed by using a Loop algorithm and smoothed by using a Laplace algorithm to obtain the complete gingival mesh model after meshing and smoothing.

8. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method for generating a three-dimensional gingival mesh model according to any one of claims 1 to 7 is implemented.

9. An electronic device having a computer program stored thereon, characterized in that: It comprises a processor and a storage medium, wherein the storage medium stores a computer program, and when the computer program is executed by the processor, the method for generating a three-dimensional gingival mesh model according to any one of claims 1 to 7 is implemented.

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