Method and device for obtaining characteristic direction information, and computer program product

Abstract

The present disclosure provides a method and device for acquiring characteristic direction information, and a computer program product for use in dental restorations. The acquisition method includes: acquiring a pre-constructed interface mesh model; identifying the inner region of the interface mesh model, removing the mesh corresponding to the inner region, and using the remaining mesh as the outer region of the interface mesh model; traversing the outer region of the interface mesh model to generate a bottom standard circle; using the bottom standard circle as a reference, and along the normal direction of the bottom standard circle, determining the characteristic direction information of the interface mesh model, wherein the characteristic direction information includes at least one of a spiral region, an interface line, and a top edge line. After removing the mesh corresponding to the inner region, the present application can automatically acquire the characteristic direction information by using the bottom standard circle as a reference, without the need for manual processing, thereby improving the matching accuracy between the gingival interface and the finished restoration.

Description

Technical Field

[0001] The present disclosure relates to the field of dental restoration technology, and in particular to a method and device for acquiring characteristic direction information, and a computer program product. Background Art

[0002] In dental restoration, it is necessary to ensure a perfect fit between the finished restoration and the gums. The key to this process is to achieve precise matching between the interface located on the gums and the finished restoration.

[0003] Currently, restorations are typically manufactured by hand-polishing, which is inefficient, results in inconsistent quality, and prevents precise matching between the gum interface and the finished restoration. Therefore, finding a technical solution to improve the matching accuracy between the gum interface and the finished restoration has become an urgent issue. Summary of the Invention

[0004] In view of this, the present disclosure provides a method and apparatus for acquiring characteristic direction information, and a computer program product, which can improve the matching accuracy between the gingival interface and the finished restoration.

[0005] The present disclosure provides a method for acquiring characteristic direction information, which is applied to dental restoration, comprising:

[0006] Get pre-built interface mesh models;

[0007] Identifying an inner region of the interface grid model, removing grids corresponding to the inner region, and using the remaining grids as an outer region of the interface grid model;

[0008] Traversing the outer region of the interface grid model to generate a bottom standard circle;

[0009] Taking the bottom standard circle as a reference, characteristic direction information of the interface grid model is determined along the normal direction of the bottom standard circle, where the characteristic direction information includes at least one of a spiral area, an interface line, and a top edge line.

[0010] Optionally, identifying the inner region of the interface grid model includes:

[0011] Traversing all the facets of the interface mesh model and determining the center of gravity and normal vector of each facet;

[0012] Taking the centroid of each facet as the starting point, generate the first ray along the normal vector of each facet;

[0013] When the first ray intersects the second patch on the interface mesh model, taking the patch corresponding to the first ray as the first patch;

[0014] Taking the center of gravity of the second face patch as a starting point and along the normal vector of the second face patch, generating a second ray;

[0015] When determining that the second ray intersects the interface mesh model, the area where the first facet is located is used as the inner area of the interface mesh model.

[0016] Optionally, traversing the outer region of the interface grid model to generate a bottom standard circle includes:

[0017] Traversing the patch area corresponding to the outer area of the interface grid model to obtain at least two sets of boundary point sets;

[0018] Select three points from each set of boundary points and fit them to generate at least two reference planes;

[0019] Removing points from each set of boundary points whose distances from their corresponding reference planes are greater than a preset distance threshold, to obtain at least two sets of circle point sets;

[0020] Converting the at least two groups of circle point sets into at least two image matrices respectively, and converting the at least two image matrices into corresponding at least two fitting circles;

[0021] According to the actual point positions and the preset point positions of the fitting circles, the fitting circle with the smallest radius is selected as the bottom standard circle.

[0022] Optionally, after converting the at least two image matrices into corresponding at least two fitting circles, the method further includes:

[0023] Divide each fitting circle into quadrants;

[0024] Traverse the points in each quadrant on each fitting circle, and use the fitting circle with points in each quadrant as the target fitting circle.

[0025] Optionally, the characteristic direction information includes a spiral area;

[0026] The determining of characteristic direction information of the interface grid model along the normal direction of the bottom standard circle based on the bottom standard circle includes:

[0027] Performing a cross-section operation on the interface grid model along the normal direction of the bottom standard circle according to a preset first interval;

[0028] When it is determined that the figure obtained by the cross-section operation is not a standard circle, performing a plurality of cross-section operations on the interface mesh model along the normal direction of the bottom standard circle according to a preset second interval;

[0029] Project the cross-section points obtained from each cross-section operation onto the middle plane as the spiral boundary reference point, where the middle plane refers to the plane obtained from the cross-section operation at the middle position when multiple cross-section operations are performed;

[0030] A deduplication operation is performed on the spiral boundary reference points to generate the spiral area.

[0031] Optionally, after generating the spiral area, it also includes: determining the symmetry axis of the spiral area, including: selecting the point with the shortest distance between the point set of the spiral area and the center point; wherein the center point is the projection point of the bottom standard circle on the spiral area; according to the set angle, the selected points are symmetrically changed to obtain the symmetric points corresponding to each angle; the symmetric point with the shortest distance to the point set of the spiral area among the multiple symmetric points and the line between the center point are used as the symmetry axis of the spiral area.

[0032] Optionally, the characteristic direction information includes an interface line;

[0033] The determining of characteristic direction information of the interface grid model along the normal direction of the bottom standard circle based on the bottom standard circle includes:

[0034] Determine the circumference corresponding to the cross section at each position along the normal direction of the bottom standard circle and in the axial direction of the interface grid model;

[0035] Determine a circumference whose radius ratio to the bottom standard circle is not 1 and whose point set contains the most points, and use the position of the circumference as a reference position;

[0036] Along the normal direction of the bottom standard circle, with the reference position as the reference, within a preset range, traverse the axial direction of the interface grid model until a circumference with a ratio of 1 to the bottom standard circle is obtained, and the position of the circumference is used as the interface line.

[0037] Optionally, the characteristic direction information includes a top edge line;

[0038] The determining of characteristic direction information of the interface grid model along the normal direction of the bottom standard circle based on the bottom standard circle includes:

[0039] The top boundary area of the interface grid model is traversed along the normal direction of the bottom standard circle, and the top boundary area opposite to the bottom standard circle is used as the top hole area.

[0040] The present disclosure also provides a characteristic direction information acquisition device for use in dental restoration, the characteristic direction information acquisition device comprising:

[0041] an acquisition unit, adapted to acquire a pre-built interface grid model;

[0042] A generating unit, adapted to traverse the outer region of the interface grid model and generate a bottom standard circle;

[0043] A processing unit is adapted to identify the inner region of the interface grid model, remove the grid corresponding to the inner region, and use the remaining grid as the outer region of the interface grid model; and, based on the bottom standard circle, determine the characteristic direction information of the interface grid model along the normal direction of the bottom standard circle, wherein the characteristic direction information includes at least one of: a spiral region, an interface line, and a top edge line.

[0044] The present disclosure also provides a computer program product, comprising a computer program / instruction, which implements the steps of the method described in any of the above examples when executed by a processor.

[0045] By adopting the characteristic direction information acquisition method provided by the embodiment of the present disclosure, after removing the grid corresponding to the inner layer area of the interface grid model, the remaining grid is the outer layer area of the interface grid model. In this way, the interference of the inner layer area can be avoided, which is conducive to reducing the difficulty of feature recognition; in the feature recognition process, taking the bottom standard circle as the reference, along the normal direction of the bottom standard circle, the accuracy of the characteristic direction information of the interface grid model can be improved, and then the location of the special diagnostic information of the finished restoration can be accurately determined; and the entire process does not require manual processing, which can avoid the errors caused by manual processing, improve the formation quality and efficiency of the finished restoration, and thus improve the matching accuracy between the gingival interface and the finished restoration. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0047] Figure 1 This is a flow chart of a method for acquiring characteristic direction information in an embodiment of the present disclosure;

[0048] Figure 2 This is a flow chart of identifying an inner region of an interface grid model according to an embodiment of the present disclosure;

[0049] Figure 3A and 3B A schematic diagram of a method for identifying and removing inner regions of an interface mesh model according to an embodiment of the present disclosure;

[0050] Figure 4 A schematic diagram of a principle for determining a boundary point set in an embodiment of the present disclosure;

[0051] Figure 5 This is a flow chart for selecting a bottom standard circle in an embodiment of the present disclosure;

[0052] Figure 6 This is a flow chart of a method for generating a spiral region according to an embodiment of the present disclosure;

[0053] Figure 7 Schematic diagram of the spiral region on the interface mesh model;

[0054] Figure 8 This is a flow chart of a method for generating an interface line according to an embodiment of the present disclosure;

[0055] Figure 9 It is a schematic diagram of the interface line on the interface grid model;

[0056] Figure 10 A schematic diagram of the top edge line on the interface mesh model;

[0057] Figure 11 Schematic diagram of the structure of a characteristic direction information acquisition system in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0058] As described in the background art, the existing method of forming a repair product by manual polishing has problems such as complicated operation, low precision, time and labor consumption, and unstable quality.

[0059] In order to solve the above technical problems, the present disclosure provides a method for obtaining characteristic direction information. After removing the grid corresponding to the inner layer area of the interface grid model, the remaining grid is the outer layer area of the interface grid model. In this way, the interference of the inner layer area can be avoided, which is conducive to reducing the difficulty of feature recognition; in the feature recognition process, taking the bottom standard circle as the reference, along the normal direction of the bottom standard circle, the accuracy of the characteristic direction information of the interface grid model can be improved, and then the location of the special diagnostic information of the finished restoration can be accurately determined; and the entire process does not require manual processing, which can avoid the errors caused by manual processing, improve the formation quality and efficiency of the finished restoration, and thus improve the matching accuracy between the gingival interface and the finished restoration.

[0060] In order to enable those skilled in the art to better understand and implement the present disclosure, the specific schemes, principles, advantages and effects of the present disclosure are described in detail below through specific embodiments with reference to the accompanying drawings.

[0061] In this disclosure, see Figure 1 The flowchart of a method for obtaining characteristic direction information in an embodiment of the present disclosure is shown in FIG. Figure 1As shown, you can perform the following steps:

[0062] S11, obtaining a pre-built interface grid model.

[0063] The interface mesh model is used to generate finished restorations, which are products that use various materials and techniques to restore natural teeth or old dentures into a new, complete tooth structure to restore oral function and aesthetics. These products include crowns, bridges, dentures, and trays.

[0064] In some embodiments of the present disclosure, the interface mesh model can be obtained by manually uploading the user, or by obtaining a pre-stored interface mesh model from a local or cloud server, or by directly scanning the patient's oral cavity and performing modeling to obtain the interface mesh model.

[0065] S12, identifying an inner region of the interface grid model, removing grids corresponding to the inner region, and using the remaining grids as an outer region of the interface grid model.

[0066] In some embodiments of the present disclosure, the interface mesh model typically has a hollow channel. The inner region can be considered the area within the channel. By removing the mesh corresponding to the inner region, the hollow channel can be opened up. The remaining mesh then becomes the outer region of the interface mesh model. Since feature direction information originates from the outer region, removing the inner region can eliminate or reduce its influence on the feature direction information recognition process, thereby reducing the difficulty of feature recognition.

[0067] For example, if the mesh corresponding to the inner region is not removed, when performing cross-section operations later, the inner region data and the outer region data will be obtained for the same cross-section operation. In this case, other methods will be needed to identify the inner region data and the outer region data, or even the inner region data and the outer region data cannot be effectively distinguished, which will increase the difficulty of feature recognition.

[0068] S13, traversing the outer region of the interface grid model to generate a bottom standard circle.

[0069] In some embodiments of the present disclosure, the outer region is generally the axial outer region of the interface grid model. By traversing the outer region of the interface grid model, the shape of the outer region at each position can be determined, for example, whether the outer region is circular or other shapes, etc., and then by processing the outer region at each position, the bottom standard circle can be obtained.

[0070] The standard circle can be understood as a circle in which the distances from the center to each edge are the same or tend to be the same.

[0071] S14, taking the bottom standard circle as a reference, and determining characteristic direction information of the interface grid model along the normal direction of the bottom standard circle.

[0072] In some embodiments of the present disclosure, when determining the bottom standard circle, the normal direction of the bottom standard circle (for example, the normal direction pointing to the top) can be determined, and then along the normal direction of the bottom standard circle, according to the parameters at different positions of the interface grid model, the characteristic direction information of the interface grid model can be determined.

[0073] In some examples, the characteristic direction information includes at least one of a spiral area, an interface line, and a top edge line.

[0074] Among them, the spiral area refers to the spiral part in the finished tooth restoration, which is used to connect with the gums or tooth roots to achieve fixation and stability between the finished tooth restoration and the gums or tooth roots; the interface line refers to the interface between the finished tooth restoration and the teeth, which is used to connect the finished tooth restoration and the teeth, which determines the stability, firmness and biocompatibility of the restoration; the top edge line refers to the interface between the edge area of the finished tooth restoration and the teeth, which is used to connect the edge part of the finished tooth restoration and the teeth.

[0075] Therefore, on the one hand, in the feature recognition process, taking the bottom standard circle as the reference, along the normal direction of the bottom standard circle, the accuracy of the feature direction information of the interface grid model can be improved, and then the location of the special diagnostic information of the finished restoration can be accurately determined; on the other hand, the entire process does not require manual processing, which can avoid the errors caused by manual processing, improve the formation quality and efficiency of the finished restoration, and thus improve the matching accuracy between the gingival interface and the finished restoration.

[0076] In some embodiments of the present disclosure, in certain areas of the interface mesh model, it is not clear whether the area is an inner area or an outer area. If the outer area is removed, it will result in the inability to obtain correct feature direction information.

[0077] Based on this, in order to improve the accuracy of feature direction information, combined with Figures 2 to 3B ,in, Figure 2 3A and 3B are schematic diagrams of identifying and removing inner areas of an interface mesh model according to an embodiment of the present disclosure, for illustrative purposes.

[0078] It is understandable that Figure 3A and Figure 3B The shape of the interface grid model shown is merely an example, used to indicate that the inner region can be determined by traversing the interface grid model, and is not to be construed as a limitation to the present invention.

[0079] like Figures 2 to 3BAs shown, you can perform the following steps:

[0080] S21, traversing all the facets of the interface mesh model, and determining the center of gravity and normal vector of each facet.

[0081] In some embodiments of the present disclosure, see Figure 3A By traversing all regions of the interface mesh model S, the corresponding patches of each region can be obtained (i.e., the front or facial edge region of the repaired product), and then the center of gravity and normal vector of each patch can be determined.

[0082] The center of gravity and normal vector of the patch can be determined according to the coordinates of each vertex of the patch.

[0083] S22 , taking the centroid of each facet as a starting point and along the normal vector of each facet, generate a first ray.

[0084] The first ray represents the location of the mesh within the interface mesh. For example, if the mesh is located within the inner region of the interface mesh, the first ray will intersect the interface mesh. If the mesh is located outside the interface mesh, the first ray will not intersect the interface mesh.

[0085] S23: When the first ray intersects with the second patch on the interface mesh model, use the patch corresponding to the first ray as the first patch.

[0086] In some embodiments of the present disclosure, the number of first rays is the same as the number of facets, and there is a one-to-one correspondence. When it is determined that the first ray can intersect with the second facet on the interface mesh model, it means that the facet corresponding to the first ray may be located in the inner area of the interface mesh model. Therefore, the facet can be regarded as the alternative facet and recorded as the first facet.

[0087] S24 , taking the center of gravity of the second face patch as a starting point and generating a second ray along the normal vector of the second face patch.

[0088] In some embodiments of the present disclosure, multiple first facets may be obtained by using steps S21 to S23. To improve the judgment accuracy, a second facet corresponding to the first facet can be searched (for example, the second facet is located directly opposite the first facet), and then a second ray is generated along the normal vectors of each facet with the center of gravity of the second facet as the starting point to determine the position of the second facet.

[0089] S25 , when determining that the second ray intersects the interface mesh model, taking the area where the first facet is located as the inner area of the interface mesh model.

[0090] In some embodiments of the present disclosure, when it is determined that the second ray intersects the interface mesh model, it indicates that the second facet is located in the inner region of the interface mesh model. In the case where the first ray is also located in the inner region of the interface mesh model, as shown in FIG. Figure 3A As shown, the inner area SA of the interface grid model S can be determined.

[0091] The reason why the inner area can be determined by using the above example is that if the patch is located in the inner area, the first ray and the second ray must be able to intersect with the interface grid model. If it is a patch in the outer area, the ray is directed outward, and there is no intersection between this ray and the interface grid model itself, so no intersecting patch can be detected. Therefore, all inner areas can be determined, and then as shown in the following example: Figure 3B As shown, all the marked inner area grids can be removed to form area SO.

[0092] In some embodiments of the present disclosure, after the mesh in the inner region is removed, the outer region of the interface mesh model may be processed.

[0093] See also Figure 4 The schematic diagram of the principle of determining a boundary point set in an embodiment of the present disclosure is shown in FIG. Figure 4 As shown, first, the patch area corresponding to the outer area SB of the interface grid model S is traversed to obtain at least two boundaries D1 and D2, and the morphologies of the boundaries D1 and D2 tend to be circular; then all the identification points on the boundaries D1 and D2 are obtained respectively, and the boundary point set of the boundary D1 and the boundary point set of the boundary D2 can be determined.

[0094] In some embodiments of the present disclosure, the outer region SB has multiple patch regions, and each patch region is located at a different position, so that the position of the identification point of each patch region is also different. To facilitate the acquisition of feature direction information, the identification point at a specific position can be used as a candidate bottom point.

[0095] It is understandable that Figure 4 The illustrated boundary point set is merely an example, and is used to indicate that boundary points at different locations can be obtained by traversing the outer region of the interface grid model, and is not to be construed as a limitation to the present invention.

[0096] Depend on Figure 4 It can be seen that the candidate bottom circle set may include multiple distant points in different locations and shapes. In this case, one of the regions can be used as a reference to obtain feature information of the interface grid model.

[0097] See also Figure 5 A flowchart of selecting a bottom standard circle in an embodiment of the present disclosure is shown in FIG. Figure 5 As shown, the main steps are as follows:

[0098] S31, traversing the patch area corresponding to the outer area of the interface grid model to obtain at least two groups of boundary point sets.

[0099] The process of obtaining two sets of boundary points can be found in the parameter example.

[0100] S32: Select at least three points from each set of boundary points, and generate a reference plane corresponding to each set of boundary points by fitting.

[0101] The selection of the at least three points may be arbitrary, as long as at least three points can be obtained. The reference plane corresponding to each group of boundary point sets can be determined by obtaining the at least three points.

[0102] S33 , removing points in each group of boundary point sets whose distances from the corresponding reference planes are greater than a preset distance threshold, to obtain at least two groups of circle point sets.

[0103] In some embodiments of the present disclosure, a reference plane is generated by fitting and selecting at least three points. Consequently, the reference plane's shape and position vary for different selection combinations, and consequently, the distances from the reference plane to each boundary point set are not identical. Therefore, the number of boundary points removed under different selection combinations can be compared as a reference, and the point set containing the most boundary points can be selected.

[0104] In short, the vast majority of boundary points in each set of boundary points are covered by the reference plane.

[0105] As an optional example, a random sampling consensus (RANSAC) algorithm is used to fit the reference plane to obtain an initial bottom point set.

[0106] Specifically, it includes: initializing parameters, including the maximum number of initialization iterations, the point threshold of the boundary point set, and the minimum point value contained in the boundary point set; randomly selecting at least three points in the boundary point set, and using these at least three points to fit the plane model; then, calculating the distance from each point in the boundary point set to the plane, and determining the boundary points with an error less than the threshold; if the bottom circle point set is greater than the set minimum value and exceeds the previous best set, updating the best model; repeating the above process until the maximum number of iterations is reached to obtain the circle point set containing the most boundary points.

[0107] S34, converting the at least two groups of circle point sets into at least two image matrices respectively, and converting the at least two image matrices into corresponding at least two fitting circles.

[0108] As an optional example, multiple fitted circles can be obtained in the following way: preprocess the image matrix, for example, use Gaussian blur and Canny edge detection to extract edge information; use OpenCV's HoughCircles function to perform Hough circle transform to detect circles in the image matrix; traverse the detected circles, draw the circles and their centers on the original image, and display the resulting image to obtain the corresponding fitted circles.

[0109] S35 , selecting a fitting circle with the smallest radius as the bottom standard circle according to the actual point positions and the preset point positions of the fitting circles.

[0110] In some embodiments of the present disclosure, during the above steps, two fitting circles at different positions may be obtained. At this time, it can be determined that the actual point position of the fitting circle coincides or nearly coincides with the preset point position, and the fitting circle with the smallest radius is used as the bottom standard circle. The bottom standard circle can be considered as a circle with the same distance from the center to each edge.

[0111] Through the above operation, by removing points that do not meet the requirements (ie, outliers) in the candidate bottom circle point set, the accuracy of the obtained bottom standard circle can be improved.

[0112] For ease of understanding, an example is given in which an interface model has two sets of boundary point sets, wherein the first set of boundary point sets is the points on the boundary D1; the second set of boundary point sets is the points on the boundary D2.

[0113] At least three points are selected from the first set of boundary points, and a first reference plane corresponding to the first set of boundary points is generated by fitting; and at least three points are selected from the second set of boundary points, and a second reference plane corresponding to the second set of boundary points is generated by fitting.

[0114] Then, the distance between each boundary point in the first set of boundary points and the reference plane is calculated respectively, and points with distance values greater than a preset distance threshold are removed to obtain a first circle point set, wherein the first circle point set should satisfy the requirement of containing the vast majority of boundary points in the first set of boundary points.

[0115] Similarly, a second set of circle points is obtained, wherein the second set of circle points should satisfy the requirement of including the vast majority of boundary points in the second set of boundary points.

[0116] Next, a first fitting circle is formed based on the first set of points; and a second fitting circle is formed based on the second set of points.

[0117] Finally, the fitted circle with the smallest radius is used as the bottom standard circle. For example, the second fitted circle is used as the bottom standard circle, that is, the area where the boundary D2 is located is the bottom standard circle.

[0118] The process of selecting the bottom standard circle uses a fitting method, which reads the contour of the circle. In specific applications, some parts of the fitted circle may be missing. However, using the above fitting method, the missing fitted circle may be mistakenly used as the bottom standard circle.

[0119] In order to avoid the occurrence of the above problems, after converting at least two image matrices into corresponding at least two fitting circles, it also includes: dividing each fitting circle into quadrants; traversing the points in each quadrant on each fitting circle, and taking the fitting circle with points in each quadrant as the target fitting circle.

[0120] Specifically, if the fitted circle is a complete circle, then when dividing the quadrants, each quadrant should be continuous and contain boundary points. If there is no boundary point in a quadrant, it means that the fitted circle is not a perfect circle.

[0121] In this case, the selected bottom standard circle is the target fitting circle.

[0122] In some optional examples, after determining the bottom standard circle, the center and radius of the bottom standard circle, as well as the normal vector, can be calculated. Furthermore, along the normal direction of the bottom standard circle, characteristic direction information of the interface mesh model can be determined. A random sampling consensus algorithm can be used to determine the center and radius of the bottom standard circle.

[0123] In some embodiments of the present disclosure, the characteristic direction information includes a spiral area. In this case, see Figure 6 and Figure 7 ,in, Figure 6 is a flow chart of a method for generating a spiral region in an embodiment of the present disclosure. Figure 7 Schematic diagram of the spiral region on the interface mesh model.

[0124] like Figure 6 As shown, you can perform the following steps:

[0125] S41 , performing a cross-section operation on the interface mesh model along the normal direction of the bottom standard circle according to a preset first interval.

[0126] The first interval may refer to the distance between the cross section formed and the bottom standard circle when performing a cross section operation (which may be understood as the first cross section operation), or the distance between each cross section.

[0127] In some examples, the first interval may refer to 0.3f, where f may refer to a distance value between adjacent section operations.

[0128] S42: When it is determined that the figure obtained by the cross-section operation is not a standard circle, perform a plurality of cross-section operations on the interface mesh model along the normal direction of the bottom standard circle according to a preset second interval.

[0129] In some embodiments of the present disclosure, when the figure obtained by the section operation is not a standard circle, it indicates that the spiral area has begun to be entered. At this time, the interval of the section operation can be changed. For example, a second interval smaller than the first interval (for example, 0.1f) is used, and multiple section operations (which can be understood as second section operations) are performed on the interface mesh model along the normal direction of the bottom standard circle to obtain multiple sections.

[0130] The method for determining whether the figure obtained by the cross-section operation is a standard circle can be referred to the above example.

[0131] S43, projecting the section points obtained from each section operation onto the middle plane as the spiral boundary reference points.

[0132] In some embodiments of the present disclosure, since each section operation is performed when it is determined that the figure obtained by the section operation is not a standard circle, the area of the subsequent section operation can be determined to be a spiral area. At this time, the section point can be projected to the middle plane to obtain the spiral boundary reference point.

[0133] In some embodiments, the middle plane refers to a plane obtained by a cross-section operation in the middle when multiple cross-section operations are performed.

[0134] For example, according to the preset second interval, five cross-section operations are performed on the interface mesh model along the normal direction of the bottom standard circle, and the plane obtained by the third cross-section operation is the middle plane.

[0135] S44: performing a deduplication operation on the spiral boundary reference points to generate the spiral area.

[0136] like Figure 7 As shown, the spiral boundary reference points are deduplicated to generate a spiral area as indicated by the arrow.

[0137] The reason why the spiral area can be determined by using the above method is that the spiral area is the area where the non-standard circle is located which is closer to the bottom standard circle. When the section operation is performed according to the preset first interval and it is determined that the figure obtained by the section operation is not a standard circle, it means that the spiral area is about to be entered; then, a preset second interval which is smaller than the preset first interval is used to accurately determine the spiral area.

[0138] In some optional examples, after determining the spiral region, the symmetry axis of the spiral region may also be determined.

[0139] For example, the point with the shortest distance between the point set of the spiral area and the center point is selected; wherein the center point is the projection point of the bottom standard circle on the spiral area; according to the set angle, the selected points are symmetrically changed to obtain the symmetrical points corresponding to each angle; the symmetrical point with the shortest distance to the point set of the spiral area among the multiple symmetrical points and the line between it and the center point are used as the symmetry axis of the spiral area.

[0140] Among them, "the symmetrical point with the closest distance to the point set of the spiral area among multiple symmetrical points" refers to "the symmetrical point with the smallest sum of distances to each point set of the spiral area among multiple symmetrical points". As an example, when determining the point with the shortest distance between the point set of the spiral area and the center point, the angle step size can be set, such as 15 degrees on both sides, divided into 30 parts, and a symmetrical transformation is performed on the selected points along each degree. After the symmetrical change, the symmetrical point with the closest distance to the point set of the spiral area is determined, so that the angle information and the corresponding line segment can be determined, that is, the symmetry axis of the spiral area is obtained. By determining the symmetry axis of the spiral area, it is convenient to control the rotation direction and amount of the interface mesh model, which helps to reduce the difficulty of alignment.

[0141] In some embodiments of the present disclosure, the characteristic direction information includes an interface line. In this case, see Figure 8 and Figure 9 ,in, Figure 8 This is a flow chart of a method for generating an interface line according to an embodiment of the present disclosure. Figure 9 Schematic diagram of the interface line on the interface grid model.

[0142] like Figure 8 and Figure 9 As shown, you can perform the following steps:

[0143] S51 , determining the circumference corresponding to the cross section at each position along the normal direction of the bottom standard circle and in the axial direction of the interface grid model.

[0144] In some embodiments of the present disclosure, the bottom standard circle may be used as a base, and cross-section processing may be performed on the interface mesh model on the bottom standard circle, so as to obtain the circumference at the corresponding position.

[0145] S52, determining a circumference whose radius ratio to the bottom standard circle is not 1 and whose point set contains the most points, and taking the position of the circumference as a reference position.

[0146] In some embodiments of the present disclosure, the corresponding sizes of circles at different positions are different. Within the reference ratio range, if the circles grow at the same proportion, it means that this position may be an interface part.

[0147] For example, there is a circle whose ratio to the bottom standard circle is not 1. At this time, the point sets contained in the circle at each position are traversed. The more point sets there are, the richer the information contained in the circle, which means that the probability that the circle is an interface part is greater. Therefore, the position of the circle can be used as a reference position.

[0148] S53, along the normal direction of the bottom standard circle, with the reference position as the reference, within a preset range, traverse the axial direction of the interface grid model until a circumference with a ratio of 1 to the bottom standard circle is obtained, and the position of the circumference is used as the interface line.

[0149] In some embodiments of the present disclosure, when a circumference with a ratio of 1 to the bottom standard circle is found, it means that the location of the circumference is the interface position, wherein the interface position refers to the location of the interface between the finished tooth restoration and the tooth; the standard circle can refer to a circle with the same or similar distance from the circumference to the edge.

[0150] In short, using the above-mentioned search method, after roughly finding the interface position, a detailed search is performed by exploring up or down at that position until a standard circle is found near that position. Because the interface position must be a standard circle, this rule can be used to find the interface position very precisely and accurately.

[0151] In some embodiments of the present disclosure, the reference position can be used as a reference to move up and down along the reference position to traverse the axial direction of the interface grid model on both sides of the reference position, so as to obtain a circumference with a ratio of 1 to the bottom standard circle, such as Figure 9 As shown, the location of the circle is the interface line.

[0152] In some embodiments of the present disclosure, the feature direction information includes the top edge line. In this case, see Figure 10 The schematic diagram of the top edge line on the interface grid model is shown, wherein the top boundary area of the interface grid model can be determined along the normal direction of the bottom standard circle, and the top boundary area set opposite to the bottom standard circle is used as the top hole area, and the curve corresponding to the top hole area is the top edge line.

[0153] Specifically, the interface grid model usually has two boundary opening areas that are set opposite to each other. In the process of generating the bottom standard circle, one of the boundary opening areas can be determined, and then the other boundary opening area can be used as the top hole area.

[0154] Combine Figures 1 to 10 By using the characteristic direction information acquisition method in the embodiment of the present disclosure, information such as the spiral area, interface line, and top edge line can be determined, thereby improving the matching accuracy between the gingival interface and the finished restoration.

[0155] The method for acquiring characteristic direction information is described in detail above through some embodiments. To enable those skilled in the art to better understand and implement it, the corresponding products are also described in detail below through some embodiments.

[0156] See also Figure 11 FIG. 1 is a structural diagram of a device for acquiring characteristic direction information. In the embodiment of the present disclosure, the device 100 for acquiring characteristic direction information includes:

[0157] An acquisition unit 110 is adapted to acquire a pre-built interface grid model;

[0158] A generating unit 120 is adapted to traverse the outer region of the interface grid model and generate a bottom standard circle;

[0159] The processing unit 130 is adapted to identify the inner region of the interface grid model, remove the grid corresponding to the inner region, and use the remaining grid as the outer region of the interface grid model; and, based on the bottom standard circle, determine the characteristic direction information of the interface grid model along the normal direction of the bottom standard circle, wherein the characteristic direction information includes at least one of: a spiral region, an interface line, and a top edge line.

[0160] It is understandable that the division of the above units is only a division of logical functions, and in actual implementation, they can be fully or partially integrated into one physical entity, or physically separated. In addition, the above units can be implemented in the form of a processor calling software.

[0161] For example, a system may include a processor connected to a memory storing instructions. The memory may call the instructions stored in the memory to implement any of the methods or functions of each unit in the above embodiments. The processor may be a general-purpose processor, such as a central processing unit (CPU), and the memory may be internal or external to the device. Alternatively, each of the above units may be implemented as a hardware circuit, with some or all of the functions of the units being implemented through the design of the hardware circuit. The hardware circuit may be understood as one or more processors. For example, in one implementation, the hardware circuit may be an application-specific integrated circuit (ASIC), which implements some or all of the functions of the above units through the design of the logical relationships between the components within the circuit. In another implementation, the hardware circuit may be implemented as a programmable logic device (PLD), which may include a large number of logic gates. The logical relationships between the logic gates are configured using a configuration file to implement some or all of the functions of the above units. All units of the above system may be implemented entirely by the processor calling a program, entirely by the hardware circuit, or partially by the processor calling a program, with the remainder implemented in the hardware circuit.

[0162] The embodiment of the present disclosure also provides a computer system suitable for implementing the method for acquiring feature direction information.

[0163] It should be noted that the computer system of the electronic device shown below is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present application.

[0164] The computer system includes a central processing unit (CPU), which can perform various appropriate actions and processes based on programs stored in read-only memory (ROM) or programs loaded from storage into random access memory (RAM), such as the methods described in the above embodiments. RAM also stores various programs and data required for system operation. The CPU, ROM, and RAM are interconnected via bus 304. Input / output (I / O) interfaces are also connected to the bus.

[0165] The following components are connected to the I / O interface: an input section including a keyboard and mouse; an output section including cathode ray tubes (CRTs), liquid crystal displays (LCDs), and speakers; a storage section including a hard disk; and a communication section including network interface cards such as LAN (Local Area Network) cards and modems. The communication section performs communication processing via a network such as the Internet. Drives are also connected to the I / O interface as needed. Removable media such as magnetic disks, optical disks, magneto-optical disks, and semiconductor memories are installed in the drive as needed, allowing computer programs read from these media to be installed in the storage section as needed.

[0166] In particular, according to embodiments of the present application, the processes described above with reference to the flowcharts can be implemented as computer software programs. For example, embodiments of the present application include a computer program product comprising a computer program carried on a computer-readable medium, the computer program including a computer program for executing the methods illustrated in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network via a communication component and / or installed from removable media. When executed by a central processing unit (CPU), the computer program performs the various functions defined in the system of the present application.

[0167] It should be noted that the computer-readable medium shown in the embodiments of the present application may be a computer-readable signal medium or a computer-readable storage medium or any combination of the above. The computer-readable storage medium may be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or component, or any combination of the above. More specific examples of computer-readable storage media may include, but are not limited to: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above.

[0168] In this application, a computer-readable storage medium may be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device. In this application, a computer-readable signal medium may include a data signal propagated in baseband or as part of a carrier wave, which carries a computer-readable computer program. This propagated data signal may take a variety of forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination of the foregoing. A computer-readable signal medium may also be any computer-readable medium other than a computer-readable storage medium that can send, propagate, or transmit a program for use by or in conjunction with an instruction execution system, apparatus, or device. The computer program contained on the computer-readable medium may be transmitted using any suitable medium, including but not limited to wireless, wired, etc., or any suitable combination of the foregoing.

[0169] The flowcharts and block diagrams in the accompanying drawings illustrate the possible implementation architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present application. Among them, each box in the flowchart or block diagram can represent a module, program segment, or part of the code, and the above-mentioned module, program segment, or part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box can also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0170] The units involved in the embodiments described in this application may be implemented by software or hardware, and the units described may also be set in a processor. In some cases, the names of these units do not constitute limitations on the units themselves.

[0171] According to one aspect of the present application, a computer program product or computer program is provided, the computer program product or computer program including computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the methods provided in the various optional implementations described above.

[0172] As another aspect, the present application further provides a computer-readable medium, which may be included in the electronic device described in the above embodiments, or may exist independently without being incorporated into the electronic device. The computer-readable medium carries one or more programs, and when the one or more programs are executed by the electronic device, the electronic device implements the method described in the above embodiments.

[0173] It should be noted that, although several modules or units of the device for action execution are mentioned in the above detailed description, this division is not mandatory. In fact, according to the embodiment of the application, the features and functions of two or more modules or units described above can be concretized in one module or unit. On the contrary, the features and functions of one module or unit described above can be further divided into multiple modules or units to be concretized.

[0174] Through the description of the above embodiments, it is easy for those skilled in the art to understand that the example embodiments described herein can be implemented by software or by combining software with necessary hardware. Therefore, the technical solution according to the embodiments of the present application can be embodied in the form of a software product, which can be stored in a non-volatile storage medium (which can be a CD-ROM, a USB flash drive, a mobile hard disk, etc.) or on a network, and includes a number of instructions to enable a computing device (which can be a personal computer, a server, a touch terminal, or a network device, etc.) to execute the method according to the embodiments of the present application.

[0175] Although the embodiments of this specification are disclosed above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A method for acquiring characteristic direction information, applied to dental restoration, characterized in that: The characteristic direction information method includes: Get pre-built interface mesh models; Identifying an inner region of the interface grid model, removing grids corresponding to the inner region, and using the remaining grids as an outer region of the interface grid model, wherein the interface grid model has a hollow channel, and the inner region is a region located within the channel; Traversing the outer region of the interface grid model to generate a bottom standard circle; Taking the bottom standard circle as a reference, determining characteristic direction information of the interface grid model along the normal direction of the bottom standard circle, wherein the characteristic direction information includes at least one of a spiral area, an interface line, and a top edge line; Among them, the spiral area refers to the spiral part in the finished tooth restoration, which is used to connect with the gums or tooth roots; the interface line refers to the interface between the finished tooth restoration and the teeth, which is used to connect the finished tooth restoration and the teeth; the top edge line refers to the interface between the edge area of the finished tooth restoration and the teeth, which is used to connect the edge part of the finished tooth restoration and the teeth.

2. The method for acquiring characteristic direction information according to claim 1, wherein: The identifying the inner region of the interface grid model includes: Traversing all the facets of the interface mesh model and determining the center of gravity and normal vector of each facet; Taking the centroid of each facet as the starting point, generate the first ray along the normal vector of each facet; When the first ray intersects the second patch on the interface mesh model, taking the patch corresponding to the first ray as the first patch; Taking the center of gravity of the second face patch as a starting point and along the normal vector of the second face patch, generating a second ray; When determining that the second ray intersects the interface mesh model, the area where the first facet is located is used as the inner area of the interface mesh model.

3. The method for acquiring characteristic direction information according to claim 1, wherein: The traversing the outer region of the interface grid model to generate a bottom standard circle includes: Traversing the patch area corresponding to the outer area of the interface grid model to obtain at least two sets of boundary point sets; Select at least three points from each set of boundary points, and fit the reference plane corresponding to each set of boundary points; Removing points from each set of boundary points whose distances from their corresponding reference planes are greater than a preset distance threshold, to obtain at least two sets of circle point sets; Converting the at least two groups of circle point sets into at least two image matrices respectively, and converting the at least two image matrices into corresponding at least two fitting circles; According to the actual point positions and the preset point positions of the fitting circles, the fitting circle with the smallest radius is selected as the bottom standard circle.

4. The method for acquiring characteristic direction information according to claim 3, wherein: After converting the at least two image matrices into the corresponding at least two fitting circles, the method further includes: Divide each fitting circle into quadrants; Traverse the points in each quadrant on each fitting circle, and use the fitting circle with points in each quadrant as the target fitting circle.

5. The method for acquiring characteristic direction information according to claim 1, wherein: The characteristic direction information includes a spiral area; The determining of characteristic direction information of the interface grid model along the normal direction of the bottom standard circle based on the bottom standard circle includes: Performing a cross-section operation on the interface grid model along the normal direction of the bottom standard circle according to a preset first interval; When it is determined that the figure obtained by the cross-section operation is not a standard circle, performing a plurality of cross-section operations on the interface mesh model along the normal direction of the bottom standard circle according to a preset second interval; Project the cross-section points obtained from each cross-section operation onto the middle plane as the spiral boundary reference point, where the middle plane refers to the plane obtained from the cross-section operation at the middle position when multiple cross-section operations are performed; A deduplication operation is performed on the spiral boundary reference points to generate the spiral area.

6. The method for acquiring characteristic direction information according to claim 5, wherein: After generating the spiral region, the method further includes: Determining the axis of symmetry of the spiral area includes: selecting a point with the shortest distance between the point set of the spiral area and the center point; wherein the center point is the projection point of the bottom standard circle on the spiral area; symmetrically changing the selected points according to set angles to obtain symmetrical points corresponding to each angle; and taking the symmetrical point with the shortest distance to the point set of the spiral area among multiple symmetrical points and the line between the symmetrical point and the center point as the axis of symmetry of the spiral area.

7. The method for acquiring characteristic direction information according to claim 1, wherein: The characteristic direction information includes an interface line; The determining of characteristic direction information of the interface grid model along the normal direction of the bottom standard circle based on the bottom standard circle includes: Determine the circumference corresponding to the cross section at each position along the normal direction of the bottom standard circle and in the axial direction of the interface grid model; Determine a circumference whose radius ratio to the bottom standard circle is not 1 and whose point set contains the most points, and use the position of the circumference as a reference position; Along the normal direction of the bottom standard circle, with the reference position as the reference, within a preset range, traverse the axial direction of the interface grid model until a circumference with a ratio of 1 to the bottom standard circle is obtained, and the position of the circumference is used as the interface line.

8. The method for acquiring characteristic direction information according to claim 1, wherein: The characteristic direction information includes a top edge line; The determining of characteristic direction information of the interface grid model along the normal direction of the bottom standard circle based on the bottom standard circle includes: The top boundary area of the interface grid model is traversed along the normal direction of the bottom standard circle, and the top boundary area set opposite to the bottom standard circle is used as the top hole area, and the curve corresponding to the top hole area is the top edge line.

9. A characteristic direction information acquisition device, used in dental restoration, characterized in that: The characteristic direction information acquisition device includes: an acquisition unit, adapted to acquire a pre-built interface grid model; A generating unit, adapted to traverse the outer region of the interface grid model and generate a bottom standard circle; a processing unit adapted to identify an inner region of the interface grid model, remove grids corresponding to the inner region, and use the remaining grids as an outer region of the interface grid model, wherein the interface grid model has a hollow channel, and the inner region is an area located within the channel; and determine characteristic direction information of the interface grid model along a normal direction of the bottom standard circle with a reference to the bottom standard circle, wherein the characteristic direction information includes at least one of a spiral region, an interface line, and a top edge line; Among them, the spiral area refers to the spiral part in the finished tooth restoration, which is used to connect with the gums or tooth roots; the interface line refers to the interface between the finished tooth restoration and the teeth, which is used to connect the finished tooth restoration and the teeth; the top edge line refers to the interface between the edge area of the finished tooth restoration and the teeth, which is used to connect the edge part of the finished tooth restoration and the teeth.

10. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the method according to any one of claims 1 to 8 are implemented.

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