Three-dimensional tooth model display method and device, oral cavity scanner and storage medium

Abstract

The invention provides a three-dimensional tooth model display method and device, an oral cavity scanner and a storage medium, and relates to the technical field of oral cavity scanning. The method comprises the following steps: acquiring a first point cloud of a standard dental cast and a second point cloud of a to-be-corrected display dental cast, and establishing a global coordinate system of the first point cloud and a global coordinate system of the second point cloud; using the first point cloud, the second point cloud, the global coordinate system of the first point cloud and the global coordinate system of the second point cloud to establish a shape curve of the to-be-corrected display dental cast; based on the shape curve of the to-be-straightened display dental cast, determining a focus, a viewpoint and an upward direction when the to-be-straightened display dental cast is straightened under a display visual angle set by a user; according to the method, the to-be-adjusted display dental cast is displayed according to the focus, the viewpoint and the upper direction of the to-be-adjusted display dental cast during adjustment, so that the dental cast is displayed quickly and objectively, and a user can master details of teeth more accurately.

Description

Technical Field

[0001] The present invention relates to the technical field of oral scanning, and in particular to a three-dimensional tooth model display method, device, oral scanner and storage medium. Background Art

[0002] As people's living standards continue to improve, their attention to dental problems is also increasing. Intraoral scanners, as digital products that allow people to more intuitively understand the condition of their teeth, are widely favored by users due to their ease of operation and user experience, which is superior to traditional forehead impression taking methods.

[0003] However, the perspective and position of the scanned model are unknown. Only by accurately, quickly, and objectively presenting the model to clients and doctors can they more accurately grasp the details of the pathological tooth and better guide treatment. This requires the model to be aligned from multiple perspectives. Current scanners suffer from slow alignment speed and low accuracy, which undoubtedly hinders market acceptance of this product. Summary of the Invention

[0004] In view of this, an object of the present invention is to provide a three-dimensional tooth model display method, device, oral scanner and storage medium.

[0005] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present invention are as follows: In a first aspect, the present invention provides a method for displaying a three-dimensional tooth model, the method comprising: Acquire a first point cloud of the standard dental cast and a second point cloud of the dental cast to be displayed and straightened, and establish a global coordinate system of the first point cloud and a global coordinate system of the second point cloud; Using the first point cloud, the second point cloud, the global coordinate system of the first point cloud, and the global coordinate system of the second point cloud, a shape curve of the dental cast to be straightened and displayed is established; Determining, based on the shape curve of the displayed dental model to be straightened, the focus, the viewpoint, and the upward direction of the displayed dental model to be straightened when straightening the dental model at a display viewing angle set by the user; The dental model to be corrected is displayed according to the focus, viewpoint and upward direction of the dental model to be corrected when corrected.

[0006] Optionally, the step of establishing the global coordinate system of the first point cloud and the global coordinate system of the second point cloud includes: Obtaining the centroids of the first point cloud and the second point cloud respectively, and decentralizing the first point cloud and the second point cloud respectively to obtain decentralized first point cloud and second point cloud; Construct the covariance matrices of the decentralized first point cloud and the second point cloud respectively; Establishing a global coordinate system of the first point cloud based on the centroid of the first point cloud and the covariance matrix of the decentralized first point cloud; A global coordinate system of the second point cloud is established based on the centroid of the second point cloud and the covariance matrix of the decentralized second point cloud.

[0007] Optionally, the step of establishing the shape curve of the dental cast to be straightened and displayed using the first point cloud, the second point cloud, the global coordinate system of the first point cloud, and the global coordinate system of the second point cloud includes: Correcting the decentralized first point cloud to be symmetrical about a first target axis in a global coordinate system of the first point cloud to obtain a corrected first point cloud; Projecting the corrected first point cloud along a second target axis in the global coordinate system of the first point cloud to obtain a first planar point cloud; Correcting the decentralized second point cloud to be symmetrical about the first target axis in the global coordinate system of the second point cloud to obtain a corrected second point cloud; Projecting the corrected second point cloud along a second target axis in the global coordinate system of the second point cloud to obtain a second planar point cloud; wherein the first target axis and the second target axis are perpendicular to each other; The shape curve of the dental cast to be straightened is obtained by using the first plane point cloud and the second plane point cloud.

[0008] Optionally, the step of establishing the shape curve of the dental cast to be straightened and displayed using the first plane point cloud and the second plane point cloud includes: Performing joint Gaussian distribution modeling using the first plane point cloud and the second plane point cloud to obtain a predicted mean of the second plane point cloud; A shape curve of the dental cast to be straightened and displayed is obtained according to the second plane point cloud and the predicted mean value.

[0009] Optionally, obtaining the shape curve of the dental cast to be straightened and displayed according to the second plane point cloud and the predicted mean value includes: A quadratic polynomial is fitted using the second plane point cloud and the predicted mean to obtain a shape curve of the dental cast to be straightened and displayed.

[0010] Optionally, the second plane point cloud includes first coordinate axis data and second coordinate axis data, and the step of determining, based on the shape curve of the dental cast to be straightened, the focus, viewpoint, and upward direction of the dental cast to be straightened at a display viewing angle set by the user when the dental cast to be straightened is straightened comprises: Substituting the first coordinate axis data into the equation of the shape curve of the dental model to be straightened and displayed to obtain a first standard deviation; Substituting the second coordinate axis data into the equation of the shape curve of the dental model to be straightened and displayed to obtain a second standard deviation; Determining the symmetry axis of the shape curve of the dental cast to be straightened based on a comparison result of the first standard deviation and the second standard deviation; Using the mass point of the second plane point cloud as the focus of the dental cast to be aligned when being aligned; Based on the symmetry axis of the shape curve of the dental cast to be straightened and the normal vector of the second plane point cloud, the viewpoint and the upward direction when the dental cast to be straightened is straightened at the display viewing angle set by the user are determined.

[0011] Optionally, the step of determining the viewpoint and the upward direction when the dental cast to be straightened is straightened at a display viewing angle set by the user based on the symmetry axis of the shape curve of the dental cast to be straightened and the normal vector of the second plane point cloud comprises: Determining a viewpoint when aligning the dental model to be aligned based on a display viewing angle set by a user, an axis of symmetry of a shape curve of the dental model to be aligned, and an extreme point of the shape curve of the dental model to be aligned; The upward direction of the aligning display dental model is determined according to the display viewing angle set by the user and the normal vector of the second plane point cloud.

[0012] In a second aspect, the present invention provides a three-dimensional tooth model display device, comprising: An acquisition module, used for acquiring a first point cloud of a standard dental cast and a second point cloud of a dental cast to be oriented and displayed; An establishment module is used to establish a global coordinate system of the first point cloud and a global coordinate system of the second point cloud; and to establish a shape curve of the dental cast to be straightened and displayed using the first point cloud, the second point cloud, the global coordinate system of the first point cloud, and the global coordinate system of the second point cloud; a determination module, configured to determine, based on the shape curve of the dental model to be straightened, a focus, a viewpoint, and an upward direction when the dental model to be straightened is straightened at a display viewing angle set by a user; The display module is used to display the dental model to be straightened according to the focus, viewpoint and upward direction of the dental model to be straightened when it is straightened.

[0013] In a third aspect, the present invention provides an oral scanner comprising a processor and a memory, wherein the memory stores machine-executable instructions that can be executed by the processor, and the processor can execute the machine-executable instructions to implement the three-dimensional tooth model display method described in the first aspect.

[0014] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the three-dimensional tooth model display method as described in the first aspect above.

[0015] The three-dimensional tooth model display method, device, oral scanner, and storage medium provided by the embodiments of the present invention obtain a first point cloud of a standard dental model and a second point cloud of a dental model to be calibrated and displayed, and establish a global coordinate system of the first point cloud and a global coordinate system of the second point cloud; use the first point cloud, the second point cloud, the global coordinate system of the first point cloud, and the global coordinate system of the second point cloud to establish a shape curve of the dental model to be calibrated and displayed; based on the shape curve of the dental model to be calibrated and displayed, determine the focus, viewpoint, and upward direction of the dental model to be calibrated and displayed when calibrated at a display viewing angle set by the user; and display the dental model to be calibrated and displayed according to the focus, viewpoint, and upward direction of the dental model to be calibrated when calibrated. Because the embodiments of the present invention determine the shape curve of the dental model to be calibrated and displayed based on the point cloud and its global coordinate system of the standard dental model and the point cloud and its global coordinate system of the dental model to be calibrated and displayed, and determine the focus, viewpoint, and upward direction of the dental model to be calibrated and displayed when calibrated based on the shape curve of the dental model to be calibrated, the dental model can be displayed quickly and objectively, allowing the user to more accurately grasp the details of the teeth.

[0016] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are given below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0018] Figure 1 A schematic diagram showing a flow chart of a method for displaying a three-dimensional tooth model provided by an embodiment of the present invention; Figure 2 An example diagram of a three-dimensional tooth model provided by an embodiment of the present invention is shown; Figure 3 An example diagram showing a point cloud and a plane point cloud of a three-dimensional tooth model provided by an embodiment of the present invention is shown; Figure 4 An example diagram of a tooth model shape curve provided by an embodiment of the present invention is shown; Figure 5 A posture diagram of a three-dimensional mandibular tooth model after being straightened is shown in an embodiment of the present invention; Figure 6 A functional module block diagram of a three-dimensional tooth model display device provided by an embodiment of the present invention is shown; Figure 7 A schematic structural block diagram of an oral scanner provided by an embodiment of the present invention is shown.

[0019] Icons: 100 - 3D tooth model display device; 101 - acquisition module; 102 - establishment module; 103 - determination module; 104 - display module; 200 - oral scanner; 210 - memory; 220 - processor; 230 - communication module. DETAILED DESCRIPTION

[0020] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely intended to represent selected embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative work are within the scope of protection of the present invention.

[0022] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0023] In order to overcome the deficiencies of the prior art, an embodiment of the present invention provides a three-dimensional tooth model display method, which will be described in detail below.

[0024] Please refer to Figure 1 The three-dimensional tooth model display method includes steps S101 to S104.

[0025] S101, obtaining a first point cloud of a standard dental cast and a second point cloud of a dental cast to be rectified and displayed, and establishing a global coordinate system of the first point cloud and a global coordinate system of the second point cloud.

[0026] The point cloud of the three-dimensional tooth model is as follows Figure 2 As shown, in a possible implementation, the implementation process of "establishing a global coordinate system for the first point cloud" can be: obtaining the center of mass of the first point cloud and decentralizing the first point cloud to obtain the decentralized first point cloud, constructing the covariance matrix of the decentralized first point cloud, and establishing the global coordinate system of the first point cloud based on the center of mass of the first point cloud and the covariance matrix of the decentralized first point cloud.

[0027] Similarly, the implementation process of "establishing a global coordinate system for the second point cloud" can be: obtaining the center of mass of the second point cloud and decentralizing the second point cloud to obtain the decentralized second point cloud, constructing the covariance matrix of the second point cloud, and establishing the global coordinate system of the second point cloud based on the center of mass of the second point cloud and the covariance matrix of the decentralized first point cloud.

[0028] In the embodiment of the present invention, the first point cloud is recorded as , and record the second point cloud as , respectively calculated 、 The center of mass of 、 The center of mass of is aligned with the origin of the world coordinate system.

[0029] First point cloud The centroid satisfies the formula: ,in, for The center of mass, For the first point cloud The data, the first point cloud Include data.

[0030] The first point cloud after decentralization The covariance matrix satisfies the formula: , according to theorem , use the eigenvalue decomposition method to solve the covariance matrix The eigenvalues ​​and eigenvectors of for The eigenvalues ​​of ; The three eigenvectors corresponding to the eigenvalues ​​are the first point cloud. The main direction of the point cloud is perpendicular to each other, so that the first point cloud is obtained. The global coordinate system of .

[0031] Second point cloud The centroid satisfies the formula: ,in, for The center of mass, For the second point cloud The data, the second point cloud Include data.

[0032] The second point cloud after decentralization The covariance matrix satisfies the formula: , according to theorem , use the eigenvalue decomposition method to solve the covariance matrix The eigenvalues ​​and eigenvectors of for The eigenvalues ​​of ; The three eigenvectors corresponding to the eigenvalues ​​are the second point cloud. The main direction of the point cloud is perpendicular to each other, so that the second point cloud is obtained. The global coordinate system of .

[0033] S102 , establishing a shape curve of the dental cast to be straightened and displayed using the first point cloud, the second point cloud, the global coordinate system of the first point cloud, and the global coordinate system of the second point cloud.

[0034] In a possible implementation, the implementation process of step S102 may include sub-steps S102 - 1 to S102 - 3 .

[0035] S102-1, correct the decentralized first point cloud to be symmetrical about the first target axis in the global coordinate system of the first point cloud, to obtain a corrected first point cloud; project the corrected first point cloud along the second target axis in the global coordinate system of the first point cloud, to obtain a first planar point cloud.

[0036] Among them, the first target axis can be the Y-axis of the global coordinate system. By correcting the decentralized first point cloud of the standard dental mold to make it symmetrical about the Y-axis, the first plane point cloud of the standard dental mold can be used as training data for joint Gaussian distribution modeling when the dental mold to be centered and displayed is subsequently centered.

[0037] The second target axis can be the Z axis of the global coordinate system, and the corrected first point cloud Project along the Z axis onto the XY plane to obtain the first plane point cloud .

[0038] S102-2, correcting the decentralized second point cloud to be symmetrical about the first target axis in the global coordinate system of the second point cloud to obtain a corrected second point cloud; projecting the corrected second point cloud along the second target axis in the global coordinate system of the second point cloud to obtain a second planar point cloud.

[0039] Likewise, the first target axis may be the Y axis of the global coordinate system, and the second target axis may be the Z axis of the global coordinate system.

[0040] The corrected second point cloud Project along the Z axis onto the XY plane to obtain the second plane point cloud .

[0041] like Figure 3 As shown, the yellow part is the point cloud of the three-dimensional tooth model, and the green part is the planar point cloud obtained by projecting the point cloud onto the XY plane.

[0042] S102-3, using the first plane point cloud and the second plane point cloud, obtain a shape curve of the dental model to be rectified and displayed.

[0043] Optionally, the implementation process of step S102-3 may be: S102-3-1, use the first plane point cloud and the second plane point cloud to perform joint Gaussian distribution modeling to obtain the predicted mean of the second plane point cloud.

[0044] In an embodiment of the present invention, the polynomial of the shape curve of the three-dimensional tooth model is as follows: The kernel function determined according to the point cloud distribution can be expressed as:

[0045] Where, Control function output amplitude, Control the smoothness, you can adjust 、 Set to 0.8 and 1.0 respectively.

[0046] The first plane point cloud As training data, the second plane point cloud As test data, joint Gaussian distribution modeling is performed, which can be expressed as:

[0047] in: is the kernel matrix between training data ， is the kernel matrix between training data and test data, is the kernel matrix between the test data and the training data, is the kernel matrix between the test data, is the variance of the observation noise. According to the conditional distribution properties of the multivariate Gaussian, the predicted distribution of the second plane point cloud is obtained:

[0048] Among them, the pseudo code for calculating the kernel matrix and the kernel function are as follows: Pseudocode for calculating the kernel matrix:

[0049] Kernel function:

[0050] Gaussian process regression prediction function:

[0051] In the embodiment of the present invention, the predicted distribution can be used to obtain the predicted mean of the second plane point cloud.

[0052] S102-3-2, obtaining the shape curve of the dental cast to be straightened and displayed based on the second plane point cloud and the predicted mean.

[0053] In the embodiment of the present invention, the second plane point cloud and the predicted mean value can be used to fit a quadratic polynomial to obtain the shape curve of the dental model to be straightened and displayed.

[0054] Using test data (i.e. second plane point cloud) and the predicted mean By fitting a quadratic polynomial, the polynomial coefficients of the shape curve of the dental model to be straightened and displayed can be obtained, thereby obtaining the equation of the shape curve of the dental model to be straightened and displayed.

[0055] S103 , based on the shape curve of the displayed dental model to be aligned, determining the focus, viewpoint, and upward direction of the displayed dental model to be aligned at a display viewing angle set by the user.

[0056] In 3D visualization, the "viewpoint" refers to the location of the camera (or observer), and is typically used together with the "focal point" and "up vector" to define a complete camera pose. The focal point refers to where the camera (or observer) is looking, and the up vector refers to the direction the camera (or observer) is looking.

[0057] The second plane point cloud includes first coordinate axis data and second coordinate axis data. For example, the first coordinate axis data may be the second plane point cloud The X coordinate of the second coordinate axis data can be the second plane point cloud The Y coordinate of

[0058] In a possible implementation, the implementation process of step S103 may include: S103-1, substituting the first coordinate axis data into the equation of the shape curve of the dental model to be straightened and displayed, to obtain a first standard deviation.

[0059] S103-2, substituting the second coordinate axis data into the equation of the shape curve of the dental model to be straightened and displayed, to obtain a second standard deviation.

[0060] For example, the second plane point cloud The X coordinate is Substitute the equation of the shape curve of the dental model to be corrected and calculate it. Compare the obtained plane point cloud with the second plane point cloud. Calculate the standard deviation and get the first sign difference , which is the standard deviation in the X direction.

[0061] The second plane point cloud The Y coordinate is Substitute the equation of the shape curve of the dental model to be corrected and calculate it. Compare the obtained plane point cloud with the second plane point cloud. Calculate the standard deviation and get the second standard deviation , which is the standard deviation in the Y direction.

[0062] S103-3, determining the symmetry axis of the shape curve of the dental cast to be corrected based on the comparison result of the first standard deviation and the second standard deviation.

[0063] In the embodiment of the present invention, if < , then the second plane point cloud If the X direction is more concentrated, the symmetry axis of the shape curve of the dental model to be corrected is the Y axis (i.e. the vertical direction); if > , then the second plane point cloud If the shape curve of the dental model to be corrected is more concentrated in the Y direction, the symmetry axis is the X axis (ie, the horizontal direction).

[0064] The symmetry axis of the shape curve of the dental model to be displayed determines the main direction and symmetry relationship of the dental model to be displayed on the two-dimensional projection plane. In the subsequent alignment process, the symmetry axis serves as a geometric reference benchmark in determining the focus, viewpoint and upward direction of each view.

[0065] S103-3, taking the mass point of the second plane point cloud as the focus of the dental cast to be aligned.

[0066] S103-5, based on the symmetry axis of the shape curve of the dental model to be straightened and the normal vector of the second plane point cloud, determine the viewpoint and the upward direction when straightening the dental model to be straightened at the user-set viewing angle.

[0067] In a possible implementation, the implementation process of step S103-5 can be to determine the viewpoint when the dental model to be straightened is corrected based on the display viewing angle set by the user, the axis of symmetry of the shape curve of the dental model to be straightened, and the extreme point of the shape curve of the dental model to be straightened; and determine the upward direction when the dental model to be straightened is corrected based on the display viewing angle set by the user and the normal vector of the second plane point cloud.

[0068] The second-order derivative of the equation of the shape curve of the dental cast to be rectified is calculated, and the point where the second-order derivative is 0 is used as the extreme point of the shape curve of the dental cast to be rectified. Different regions in the second plane point cloud have different normal vectors.

[0069] When the user sets the display perspective to be normal, the viewpoint can be set to the extreme point in the direction of the symmetry axis of the shape curve of the dental model to be straightened, the resultant vector of the normal vectors of different areas in the second plane point cloud can be obtained, and the upward direction can be set as the direction of the resultant vector.

[0070] When the user sets the display perspective to a side view, the viewpoint can be set at an extreme point in the direction perpendicular to the axis of symmetry of the shape curve of the dental model to be straightened and displayed. That is, when the axis of symmetry is the X-axis, the viewpoint is set at an extreme point in the Y-axis direction of the shape curve of the dental model to be straightened and displayed; when the axis of symmetry is the Y-axis, the viewpoint is set at an extreme point in the Z-axis direction of the shape curve of the dental model to be straightened and displayed. The upward direction is set as the direction of the normal vector corresponding to the side surface of the dental model to be straightened and displayed in the second plane point cloud. S104: Display the dental model to be straightened and displayed according to the focus, viewpoint, and upward direction during straightening.

[0071] In the embodiment of the present invention, the minimum bounding box of the second planar point cloud is constructed by using the maximum value and the minimum value of the first coordinate axis data and the maximum value and the minimum value of the second coordinate axis data.

[0072] Among them, the minimum bounding box refers to the smallest rectangular box that can completely contain the second plane point cloud, which can be used to determine the spatial range distribution, that is, to determine the distribution range of the current tooth model in the entire field of view, providing a basis for view scaling.

[0073] The minimum bounding box can also be used to assist in centering the view. That is, when displaying the tooth model in the 3D view, the entire tooth model can be displayed in the center based on the bounding box.

[0074] The minimum bounding box can also be used to determine the orientation, that is, the bounding box can be used to further determine whether the tooth model is tilted and whether it needs to be rotated and adjusted.

[0075] For example, assuming that the second plane point cloud represents a mandibular dental arch, these points are roughly U-shaped, and the minimum bounding box will be a rectangle that can just cover all the points. The coordinates of the upper left, upper right, lower right, and lower left corners of this rectangle are the four vertices of the minimum bounding box. According to the four vertices of the minimum bounding box, we can get the approximate size of the dental arch, and then set the appropriate camera focal length to ensure that the entire dental arch is in the field of view, and we can determine whether the dental arch needs to be rotated so that it faces the user "frontally" based on the direction of the bounding box.

[0076] In the embodiment of the present invention, the opening direction of the shape curve of the dental cast to be straightened can be determined according to the positive or negative value of the coefficient in the equation of the shape curve of the dental cast to be straightened.

[0077] The equation for the shape curve of the dental model to be corrected can be expressed as ,like , then the shape curve of the dental model will be opened upwards. , then the shape curve of the dental model to be corrected will open downwards.

[0078] According to the opening direction of the shape curve of the dental model to be corrected, it can be determined whether the dental model to be corrected is the maxillary dental arch or the mandibular dental arch.

[0079] Generally speaking, the maxillary dental arch opens upwards, and the corresponding shape curve is U-shaped, while the mandibular dental arch opens downwards, and the corresponding shape curve is an inverted U-shaped (see Figure 4 ).

[0080] In an embodiment of the present invention, the distribution range of the tooth model in the field of view is determined based on the minimum bounding box, and whether the tooth model is the maxillary dental arch or the mandibular dental arch is determined based on the opening direction. Then, the tooth model is displayed according to the determined focus, viewpoint, and upward direction. For example, when the user sets the view angle to emmetropia, the normal mandibular dental arch is displayed according to the determined focus, viewpoint, and upward direction when it is aligned, and the following is obtained: Figure 5 Frontal view of the mandibular dental arch shown.

[0081] In order to execute the corresponding steps in the above embodiments and various possible methods, a method for implementing the three-dimensional tooth model display device 100 is given below. Figure 6 , Figure 6 This is a functional block diagram of a 3D tooth model display device 100 provided in an embodiment of the present invention. It should be noted that the basic principles and technical effects of the 3D tooth model display device 100 provided in this embodiment are the same as those of the above-mentioned embodiments. For the sake of brevity, any details not mentioned in this embodiment can be referred to the corresponding contents of the above-mentioned embodiments. The 3D tooth model display device 100 includes: The acquisition module 101 is used to acquire a first point cloud of a standard dental cast and a second point cloud of a dental cast to be oriented and displayed.

[0082] The establishment module 102 is used to establish the global coordinate system of the first point cloud and the global coordinate system of the second point cloud; and to establish the shape curve of the dental model to be straightened and displayed using the first point cloud, the second point cloud, the global coordinate system of the first point cloud and the global coordinate system of the second point cloud.

[0083] The determination module 103 is configured to determine, based on the shape curve of the dental model to be aligned, the focus, viewpoint, and upward direction of the dental model to be aligned at a display viewing angle set by the user.

[0084] The display module 104 is used to display the dental model to be aligned according to the focus, viewpoint and upward direction of the dental model to be aligned when aligned.

[0085] In the several embodiments provided in this application, it should be understood that the disclosed devices and methods can also be implemented in other ways. The device embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings show the possible architectures, functions and operations of the devices, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flowchart or block diagram can represent a module, a program segment or a portion of code, and the module, program segment or a portion of 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 consecutive boxes 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 and / or flowchart, and the combination of boxes in the block diagram and / or flowchart, can be implemented using a dedicated hardware-based system that performs the specified function or action, or can be implemented using a combination of dedicated hardware and computer instructions.

[0086] In addition, the functional modules in the various embodiments of the present invention may be integrated together to form an independent part, or each module may exist independently, or two or more modules may be integrated to form an independent part.

[0087] If the functions are implemented as software modules and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or the portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage media include various media capable of storing program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0088] Please refer to Figure 7 is a block diagram of an oral scanner 200 provided in an embodiment of the present invention. The oral scanner 200 includes a memory 210, a processor 220, and a communication module 230. The memory 210, processor 220, and communication module 230 are electrically connected to each other, either directly or indirectly, to enable data transmission or exchange. For example, these components may be electrically connected via one or more communication buses or signal lines.

[0089] The memory 210 is used to store programs or data. The memory 210 may be, but is not limited to, random access memory (RAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.

[0090] The processor 220 is used to read / write data or programs stored in the memory 210 and execute corresponding functions.

[0091] The communication module 230 is used to establish a communication connection between the oral scanner 200 and other communication terminals through the network, and to send and receive data through the network.

[0092] It should be understood that Figure 7The structure shown is only a schematic diagram of the structure of the oral scanner 200. The oral scanner 200 may also include Figure 7 More or fewer components than shown, or with Figure 1 Different configurations shown. Figure 7 Each component shown in the figure can be implemented by hardware, software or a combination thereof.

[0093] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A three-dimensional tooth model display method, characterized in that: The method comprises: Acquire a first point cloud of the standard dental cast and a second point cloud of the dental cast to be displayed and straightened, and establish a global coordinate system of the first point cloud and a global coordinate system of the second point cloud; Using the first point cloud, the second point cloud, the global coordinate system of the first point cloud, and the global coordinate system of the second point cloud, a shape curve of the dental cast to be straightened and displayed is established; Determining, based on the shape curve of the displayed dental model to be straightened, the focus, the viewpoint, and the upward direction of the displayed dental model to be straightened when straightening the dental model at a display viewing angle set by the user; The dental model to be corrected is displayed according to the focus, viewpoint and upward direction of the dental model to be corrected when corrected.

2. The three-dimensional tooth model display method according to claim 1, wherein: The step of establishing the global coordinate system of the first point cloud and the global coordinate system of the second point cloud comprises: Obtaining the centroids of the first point cloud and the second point cloud respectively, and decentralizing the first point cloud and the second point cloud respectively to obtain decentralized first point cloud and second point cloud; Construct the covariance matrices of the decentralized first point cloud and the second point cloud respectively; Establishing a global coordinate system of the first point cloud based on the centroid of the first point cloud and the covariance matrix of the decentralized first point cloud; A global coordinate system of the second point cloud is established based on the centroid of the second point cloud and the covariance matrix of the decentralized second point cloud.

3. The three-dimensional tooth model display method according to claim 2, wherein: The step of establishing the shape curve of the dental cast to be straightened and displayed using the first point cloud, the second point cloud, the global coordinate system of the first point cloud, and the global coordinate system of the second point cloud comprises: Correcting the decentralized first point cloud to be symmetrical about a first target axis in a global coordinate system of the first point cloud to obtain a corrected first point cloud; Projecting the corrected first point cloud along a second target axis in the global coordinate system of the first point cloud to obtain a first planar point cloud; Correcting the decentralized second point cloud to be symmetrical about the first target axis in the global coordinate system of the second point cloud to obtain a corrected second point cloud; Projecting the corrected second point cloud along a second target axis in the global coordinate system of the second point cloud to obtain a second planar point cloud; wherein the first target axis and the second target axis are perpendicular to each other; The shape curve of the dental cast to be straightened is obtained by using the first plane point cloud and the second plane point cloud.

4. The three-dimensional tooth model display method according to claim 3, wherein: The step of establishing the shape curve of the dental cast to be corrected and displayed using the first plane point cloud and the second plane point cloud comprises: Performing joint Gaussian distribution modeling using the first plane point cloud and the second plane point cloud to obtain a predicted mean of the second plane point cloud; A shape curve of the dental cast to be straightened and displayed is obtained according to the second plane point cloud and the predicted mean value.

5. The three-dimensional tooth model display method according to claim 4, wherein: The step of obtaining the shape curve of the dental cast to be straightened and displayed according to the second plane point cloud and the predicted mean value comprises: A quadratic polynomial is fitted using the second plane point cloud and the predicted mean to obtain a shape curve of the dental cast to be straightened and displayed.

6. The three-dimensional tooth model display method according to claim 3, wherein: The second plane point cloud includes first coordinate axis data and second coordinate axis data, and the step of determining, based on the shape curve of the dental cast to be straightened, the focus, the viewpoint, and the upward direction of the dental cast to be straightened at a display viewing angle set by the user when the dental cast to be straightened is straightened includes: Substituting the first coordinate axis data into the equation of the shape curve of the dental model to be straightened and displayed to obtain a first standard deviation; Substituting the second coordinate axis data into the equation of the shape curve of the dental model to be straightened and displayed to obtain a second standard deviation; Determining the symmetry axis of the shape curve of the dental cast to be straightened based on a comparison result of the first standard deviation and the second standard deviation; Using the mass point of the second plane point cloud as the focus of the dental cast to be aligned when being aligned; Based on the symmetry axis of the shape curve of the dental cast to be straightened and the normal vector of the second plane point cloud, the viewpoint and the upward direction when the dental cast to be straightened is straightened at the display viewing angle set by the user are determined.

7. The three-dimensional tooth model display method according to claim 6, wherein: The step of determining the viewpoint and the upward direction of the dental model to be straightened at the display viewing angle set by the user based on the symmetry axis of the shape curve of the dental model to be straightened and the normal vector of the second plane point cloud comprises: Determining a viewpoint when aligning the dental model to be aligned based on a display viewing angle set by a user, an axis of symmetry of a shape curve of the dental model to be aligned, and an extreme point of the shape curve of the dental model to be aligned; The upward direction of the aligning display dental model is determined according to the display viewing angle set by the user and the normal vector of the second plane point cloud.

8. A three-dimensional tooth model display device, characterized in that: The device comprises: An acquisition module, used for acquiring a first point cloud of a standard dental cast and a second point cloud of a dental cast to be oriented and displayed; An establishment module is used to establish a global coordinate system of the first point cloud and a global coordinate system of the second point cloud; and to establish a shape curve of the dental cast to be straightened and displayed using the first point cloud, the second point cloud, the global coordinate system of the first point cloud, and the global coordinate system of the second point cloud; a determination module, configured to determine, based on the shape curve of the dental model to be straightened, a focus, a viewpoint, and an upward direction when the dental model to be straightened is straightened at a display viewing angle set by a user; The display module is used to display the dental model to be straightened according to the focus, viewpoint and upward direction of the dental model to be straightened when it is straightened.

9. An oral scanner, characterized in that: The device comprises a processor and a memory, wherein the memory stores machine executable instructions that can be executed by the processor, and the processor can execute the machine executable instructions to implement the three-dimensional tooth model display method according to any one of claims 1 to 7.

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

Images