KR102493440B1 - Method for determining region of object from three dimensional model and apparatus for processing three dimensional model - Google Patents

Abstract

An aspect of the present disclosure is a method of determining a region corresponding to an object from a 3D model of an oral cavity, comprising: acquiring the 3D model; determining a seed point on the 3D model; determining a reference point on the 3D model based on the seed point; determining an area corresponding to the object by gradually expanding a selection area based on the reference point; and displaying the determined area on the 3D model.

Description

Method for determining object region from 3D model and apparatus for processing 3D model

The present disclosure relates to a method and apparatus for processing a 3D model, and more particularly, to a method and apparatus for determining a region corresponding to an object from a 3D model of the oral cavity.

Dental CAD/CAM (Dental Computer Aided Design/Computer Aided Manufacturing) technology is widely used in dental treatment, particularly prosthetic treatment. The most important thing in dental treatment using CAD/CAM is to acquire precise 3D data about the shape of an object such as a patient's teeth, gums, and jawbone. In performing dental treatment, there is an advantage in that accurate calculation can be performed by a computer by using 3D data obtained from an object.

For example, methods such as computed tomography (CT), magnetic resonance imaging (MRI), and optical scanning may be used to obtain 3D data of an object during dental CAD/CAM treatment.

In the dental CAD/CAM field, 3D scanning devices are widely used. The 3D scanning device may obtain 3D surface shape information by using light reflected from an object. For example, an impression of a tooth, a plaster model obtained for the impression, or a 3D model of the surface of a tooth may be acquired. can do. The surface data may be recorded in the form of a polygon mesh, and may include location information of vertices of the surface of the object and connection relationship information between the respective vertices. Alternatively, the surface data may be recorded in the form of a point cloud and include location information of vertices of the surface of the object.

When a 3D model is acquired from scan data of the oral cavity and gypsum model, a prosthesis can be virtually designed or an orthodontic plan can be established using the acquired model.

In order to design a virtual prosthesis and an orthodontic plan, information on an object (eg, individual teeth, gingiva, etc.) is required, and thus, information such as setting an object region may be added to the 3D model.

However, conventionally, a method of manually selecting an area corresponding to an object from a 3D model has been used to select an object area. Accordingly, there are problems in that a lot of time is taken in the process of manually selecting an object region or an unnecessary region is set.

An aspect of the present disclosure is a method of determining a region corresponding to an object from a 3D model of an oral cavity, comprising: acquiring the 3D model; determining a seed point on the 3D model; determining a reference point on the 3D model based on the seed point; determining an area corresponding to the object by gradually expanding a selection area based on the reference point; and displaying the determined area on the 3D model.

In addition, according to an embodiment of the present disclosure, the determining of the reference point may include determining the reference point based on a curvature value of the seed point.

In addition, in one embodiment of the present disclosure, the 3D model is acquired by a 3D scanning device, includes shape information of a plurality of teeth in the oral cavity and the surface of the gingiva, and the object is teeth or gingiva. Characteristically, a region determination method can be provided.

In addition, in an embodiment of the present disclosure, the determining of the seed point may include displaying the 3D model; and determining the seed point based on a user input for the displayed 3D model.

In addition, in an embodiment of the present disclosure, the determining of the reference point includes determining the reference point based on the curvature value of the seed point determined on the 3D model, and the curvature of the seed point The value is a curvature value k1 having the largest absolute value among curvature values formed by a curve where normal planes including the normal of the seed point and the curved surface of the object intersect, and a curvature value k1 that is orthogonal to the normal plane and is perpendicular to the normal of the seed point. It is possible to provide a region determination method that includes at least one of curvature values (k2) formed by a curve where an orthogonal normal plane including a crosses the curved surface of the object.

In addition, in one embodiment of the present disclosure, the determining of the reference point may include determining the seed point as a reference point when the curvature value of the seed point determined on the 3D model has a value within a predetermined range; and if the curvature value of the seed point does not have a value within the predetermined range, determining another point having a curvature value within the predetermined range as a reference point.

In addition, in an embodiment of the present disclosure, the determining of the region corresponding to the object may include a first region having a curvature value within a threshold range based on the curvature value of the reference point by gradually extending a selection region from the reference point. It is possible to provide a method for determining a region, including the step of determining.

In addition, in one embodiment of the present disclosure, the determining of the region corresponding to the object further comprises determining a second region corresponding to the object by repeating region expansion and contraction processing from the determined first region. , a region determination method can be provided.

In addition, in an embodiment of the present disclosure, the determining of the region corresponding to the object may include a first region having a curvature value within a threshold range based on the curvature value of the reference point by gradually extending a selection region from the reference point. and determining a region, wherein the region determination method includes: changing the threshold range based on a user's drag input; and determining a second area based on the changed threshold range.

Also, in one embodiment of the present disclosure, the determining of the seed point may include performing segmentation to divide the 3D model into regions corresponding to a plurality of objects; and determining the seed point on one of the plurality of regions.

In addition, displaying an image displaying a plurality of teeth and a tooth number corresponding to each tooth on the 3D model in one embodiment of the present disclosure; and receiving a user input for selecting a first tooth among the plurality of teeth as the object, wherein the determining of the reference point includes determining the reference point on the first tooth. It is possible to provide a method for determining a region.

Another aspect of the present disclosure is an apparatus for processing a three-dimensional model of the oral cavity,

a display for displaying an image rendered from the 3D model; and determining a region corresponding to the object by determining a seed point on the 3D model, determining a reference point on the 3D model based on the seed point, and gradually expanding a selection region based on the reference point. and at least one processor controlling the display to display the determined region on the 3D model.

Also, in one embodiment of the present disclosure, the display displays the 3D model, and the at least one processor determines the seed point based on a user input for the displayed 3D model. It is possible to provide a 3D model processing device that does.

In addition, in one embodiment of the present disclosure, the at least one processor determines a first region having a curvature value within a threshold range based on the curvature value of the reference point by gradually extending a selection region from the reference point, and It is possible to provide a 3D model processing apparatus characterized by determining a second region corresponding to the object by repeating region expansion and contraction processing from the determined first region.

In addition, in one embodiment of the present disclosure, the display displays an image in which a plurality of teeth and a tooth number corresponding to each tooth are displayed on the 3D model, and the at least one processor, among the plurality of teeth It is possible to provide a 3D model processing apparatus characterized by receiving a user input for selecting a first tooth as the object and determining the reference point on the first tooth.

Another aspect of the present disclosure is a method for determining a region from a 3-dimensional model, comprising: acquiring a 3-dimensional model for the oral cavity; determining at least a partial region of the region to be selected in the oral cavity; determining a first region corresponding to the region to be selected from the 3D model based on the determined at least some region; and displaying the determined first area.

In addition, according to an embodiment of the present disclosure, the determining of the at least partial area may include determining the at least partial area based on a user input.

In addition, in one embodiment of the present disclosure, a region determination method may be provided in which the user input includes at least one gesture among click, hover, and drag.

In addition, in one embodiment of the present disclosure, further comprising performing segmentation to divide the 3D model into a plurality of regions corresponding to each of a plurality of teeth, wherein the determining of at least some regions comprises the segmentation Based on the three-dimensional model, selecting one of the plurality of teeth; and determining the at least partial area based on the seed point on the selected tooth.

According to the disclosed embodiments, the accuracy of selecting an object region can be increased and the required time can be reduced.

The present disclosure may be readily understood from the combination of the following detailed description and accompanying drawings, where reference numerals may denote structural elements.
1 is a diagram for explaining a 3D model processing system according to an exemplary embodiment.
2 is a view for explaining a method of manually selecting an outer line of an individual tooth.
3 shows a block diagram of a 3D model processing system according to an embodiment.
4 is a flowchart of a method of determining an object region from a 3D model by a 3D model processing apparatus according to an exemplary embodiment.
5 is a diagram for explaining curvature values calculated from seed points according to an exemplary embodiment.
6A is a diagram in which k1 values of teeth are displayed in color.
6B shows a graph showing the distribution of k1 values of the tooth surface.
7 illustrates seed points and reference points selected on a tooth according to an embodiment.
8 is a diagram for explaining a reference point determined for selecting a tooth region according to an exemplary embodiment.
9A is a diagram illustrating a region having curvature values within a critical range on a 3D model of a plurality of teeth according to an embodiment.
9B is a diagram illustrating sporadically selected tooth regions according to an exemplary embodiment.
10A is a diagram for explaining a method of expanding a tooth selection area according to an exemplary embodiment.
10B is a diagram illustrating an extended tooth area according to an exemplary embodiment.
10C is a diagram for explaining a method of shrinking an extended tooth area according to an exemplary embodiment.
10D is a diagram showing a tooth area finally determined through a process of area expansion and contraction according to an embodiment.
11A is a diagram for explaining a method of expanding a tooth selection area based on a user's drag input according to an embodiment.
11B is a diagram for explaining a method of expanding a tooth selection area based on a user's drag input according to an embodiment.
11C is a diagram for explaining a method of expanding a tooth selection area based on a user's drag input according to an embodiment.
12 illustrates an example of a driving screen of a program to which a tooth region selection method according to an embodiment is applied.
13A illustrates an example of a driving screen of a program to which a tooth region selection method according to an embodiment is applied.
13B illustrates an example of a driving screen of a program to which a tooth region selection method according to an embodiment is applied.
13C illustrates an example of a driving screen of a program to which a tooth region selection method according to an embodiment is applied.
14 illustrates an example of a driving screen of a program to which a tooth region selection method according to an exemplary embodiment is applied.
15 is a block diagram of a 3D model processing apparatus according to an embodiment.

This specification clarifies the scope of the present invention, explains the principles of the present invention, and discloses embodiments so that those skilled in the art can practice the present invention. The disclosed embodiments may be implemented in various forms.

Like reference numbers designate like elements throughout the specification. This specification does not describe all elements of the embodiments, and general content or overlapping content between the embodiments in the technical field to which the present invention pertains will be omitted. The term 'part' (portion) used in the specification may be implemented in software or hardware, and according to embodiments, a plurality of 'units' may be implemented as one element (unit, element), or a single 'unit' It is also possible that ' contains a plurality of elements. Hereinafter, the working principle and embodiments of the present invention will be described with reference to the accompanying drawings.

In the present disclosure, an 'object' is an object to be photographed, and may include a human, an animal, or a part thereof. For example, the object may include a body part (organ or organ, etc.), an artificial structure attachable on or insertable into the object, or a phantom. For example, the object may include teeth, gingiva, at least a portion of the oral cavity, and/or artificial structures (eg, orthodontic devices including brackets and wires, implants, artificial teeth, inlays, and onlays) that can be inserted into the oral cavity. dental restorations including, orthodontic aids inserted into the oral cavity, etc.), teeth or gingiva to which artificial structures are attached, and the like.

In the present disclosure, an 'image' may be a 2D image of an object or a 3D model or 3D image representing the object in three dimensions. In the present disclosure, an image may include both a 2D frame and a 3D frame. For example, the image may include a 2D frame including 2D images acquired at different viewpoints of the object, or a 3D frame expressed in the form of a point cloud or polygon mesh.

Also, in the present disclosure, 'data' may refer to information required to represent an object in 2D or 3D, eg, raw data obtained from at least one image sensor. Specifically, the raw data may be 2D images acquired to create a 3D model of the object. The raw data may be 2D images of different viewpoints acquired by a plurality of image sensors when an object is scanned using a 3D scanner (eg, an intraoral scanner). Also, in the present disclosure, 'data' may refer to a 3D model representing three-dimensional characteristics of an object including at least one of teeth, gingiva, and an artificial structure attached to the teeth or gingiva.

Hereinafter, embodiments will be described in detail with reference to the drawings.

1 is a diagram for explaining a 3D model processing system according to an exemplary embodiment.

As shown in FIG. 1 , a 3D model processing system according to an embodiment of the present disclosure may include a 3D scanning device 100 and a 3D model processing device 300 .

A 3D model processing system according to an embodiment projects pattern light to an object using the 3D scanning device 100 and scans the object to which the pattern light is irradiated, thereby performing triangulation measurement by deformation of the pattern. A 3D model representing the shape of an object may be acquired using the principle. However, the method of acquiring the 3D model using the 3D scanning device 100 is not limited thereto, and the 3D model may be acquired in various ways depending on the implementation method.

The 3D scanning device 100 according to an embodiment may transmit raw data obtained from an object to the 3D model processing device 300 . The 3D model processing apparatus 300 may generate a 3D model representing the shape of the surface of the object in 3D, based on the received raw data. The 3D model may be point cloud data or polygon mesh data. The 3D scanning device 100 according to another embodiment may generate a 3D frame by reconstructing raw data obtained from an object, and transmit the generated 3D frame to the 3D model processing device 300 .

The 3D scanning device 100 according to an embodiment may include a medical device for obtaining a 3D model of the oral cavity. Specifically, the 3D scanning device 100 may be a device for generating a 3D model of the oral cavity including at least one tooth by being inserted into the oral cavity and scanning teeth in a non-contact manner. In addition, the 3D scanning device 100 may have a shape capable of being drawn in and out of the oral cavity, and may scan the inside of the patient's oral cavity using at least one image sensor (eg, an optical camera). Also, the 3D scanning device 100 may be a table scanner.

The 3D scanning device 100 is an object of the oral cavity, such as teeth, gingiva, and artificial structures that can be inserted into the oral cavity (eg, orthodontic devices including brackets and wires, implants, artificial teeth, orthodontic aid tools inserted into the oral cavity, etc.) ), surface information of the object may be obtained as raw data in order to image at least one surface of the target object. The 3D model processing apparatus 300 obtains a 3D model by performing a 3D operation such as merge based on raw data, and displays an image obtained by rendering the 3D model on a display on a screen. there is.

The 3D model processing device 300 according to an embodiment is connected to the 3D scanning device 100 through a wired or wireless communication network, and raw data obtained by scanning an object from the 3D scanning device 100 or 3 A dimensional frame may be received.

The 3D model processing device 300 may be any electronic device capable of generating, processing, displaying, and/or transmitting a 3D model or image of an object based on received raw data or 3D frames. For example, the 3D model processing device 300 may be a computing device such as a smart phone, a laptop computer, a desktop computer, a PDA, or a tablet PC, but is not limited thereto.

The 3D model processing device 300 generates at least one of information necessary for diagnosing an object and an object image based on the data received from the 3D scan device 100, and displays the generated information and/or image ( 320) can be displayed.

The 3D model processing apparatus 300 according to an embodiment may analyze a 3D model or image of an object, process, display, and/or transmit the analysis result.

Also, the 3D model processing device 300 according to an embodiment may store and execute dedicated software linked to the 3D scanning device 100 . Dedicated software may be referred to as a dedicated program or a dedicated application. When the 3D model processing device 300 operates in conjunction with the 3D scanning device 100, dedicated software stored in the 3D model processing device 300 is connected to the 3D scanning device 100 to scan an object. Data obtained through can be received in real time. For example, there is dedicated software for processing data obtained through intraoral scan in the i500 corresponding to the company's intraoral scanner i500 product. The 3D model processing device 300 may store and execute dedicated software corresponding to the i500 product. Dedicated software may perform at least one operation for acquiring, processing, storing, and/or transmitting the 3D model.

Dedicated software may be stored in the processor or memory of the 3D model processing device 300 . Also, the dedicated software may provide a user interface for using data obtained from the 3D scanning device 100 . A user interface screen provided by dedicated software may include a 3D model of an object created according to the disclosed embodiments. For example, in the disclosed embodiment, a user interface screen provided by dedicated software may be any one of user interface screens shown in the following drawings.

Meanwhile, in order to design a virtual prosthesis and an orthodontic plan, for example, information on individual teeth may be required. In order to select a region corresponding to an individual tooth, a method of manually selecting a tooth shape from a 3D model of a plurality of teeth in a 3D model has conventionally been used.

2 is a view for explaining a method of manually selecting an outer line of an individual tooth.

As shown in FIG. 2 , conventionally, a user manually selects a boundary area of a tooth 210 on a 3D model image 200 . When the user selects points on the boundary of the tooth 210, the 3D model processing apparatus determines the individual tooth area by connecting the points selected by the user to obtain an outline 205. Therefore, according to the prior art, there is a problem in that a lot of time is taken or an unnecessary area is set in the process of manually selecting individual teeth.

In order to solve this problem, the 3D model processing apparatus 300 according to various embodiments of the present disclosure proposes a method of automatically selecting an object region with high speed and high accuracy.

3 shows a block diagram of a 3D model processing system according to an embodiment.

As shown in FIG. 3 , the 3D model processing apparatus 300 according to an embodiment may be connected to an external device or an external server through a wired or wireless communication network. The 3D model processing device 300 according to an embodiment includes a 3D scanning device 31, a data acquisition device 32 (eg, a medical diagnosis device such as CT or MRI), and a server 33. Data on the object may be acquired and processed from at least one. Alternatively, the 3D model processing apparatus 300 according to an embodiment may acquire and process data previously stored in an internal memory.

According to various embodiments of the present disclosure, the 3D model processing apparatus 300 may determine a region corresponding to at least one object from the 3D model of the oral cavity. The 3D model processing apparatus 300 according to an embodiment may obtain a 3D model of the oral cavity and determine at least a partial region of the region to be selected in the oral cavity. The 3D model processing apparatus 300 according to an embodiment may determine at least a partial region based on a user input. For example, the user input may include at least one gesture among click, hover, and drag.

For example, the 3D model processing apparatus 300 may perform segmentation to divide the 3D model into a plurality of regions corresponding to each of a plurality of teeth. The 3D model processing apparatus 300 may select one tooth from among a plurality of teeth based on the segmented 3D model. The 3D model processing apparatus 300 may determine at least a partial region based on the seed point on the selected tooth.

The 3D model processing apparatus 300 may determine a first region corresponding to a region to be selected from the 3D model, based on the determined at least some region. The 3D model processing apparatus 300 may display the determined first region.

A specific method of selecting an object region by the 3D model processing apparatus 300 according to various embodiments will be described in more detail with reference to FIGS. 4 to 14 hereinafter.

4 is a flowchart of a method of determining an object region from a 3D model by a 3D model processing apparatus according to an exemplary embodiment.

In step S401, the 3D model processing apparatus 300 according to an embodiment may obtain a 3D model of the oral cavity. For example, a 3D model including surface shape information of a plurality of teeth, gingiva, and/or artificial structures in the oral cavity may be obtained. For example, the 3D model may be scan data acquired by a 3D scanning device. The 3D model processing device 300 may obtain a 3D model from an external device such as a 3D scanning device or an external server. Alternatively, the 3D model processing device 300 may acquire a 3D model previously stored in an internal memory.

The 3D model processing apparatus 300 according to an embodiment may select a seed point on a region estimated to correspond to an object on the 3D model. A seed point may refer to a point selected to determine a region corresponding to an object. For example, the 3D model processing apparatus 300 may select a seed point on a first tooth from among a plurality of teeth indicated by the 3D model.

As an example, the 3D model processing apparatus 300 may select a seed point based on a user input.

To receive a user input for selecting a seed point, first, the 3D model processing apparatus 300 may display an image rendered from the 3D model on the screen. The 3D model processing apparatus 300 may display a 3D model, receive a user input for selecting a point on the displayed 3D model, and determine a seed point on the 3D model based on the location of the selected point. there is.

7 shows a part of a 3D model displayed by the 3D model processing device 300 . The 3D model processing apparatus 300 may receive a user input for selecting a seed point 701 on the 3D model.

In order to select a seed point in the 3D space based on a user input for an image displayed on a 2D screen, the 3D model processing apparatus 300 determines a 3D coordinate value corresponding to a location at which the user input is received. can For example, a user input for selecting a seed point may include a tap gesture on a touch screen, a gesture to place a mouse pointer on the screen (Hover), a gesture to place a mouse pointer on the screen and click, or a gesture to drag after clicking. can include

For example, the 3D model processing apparatus 300 may obtain x-axis and y-axis coordinate values of a displayed image on the screen coordinate system based on a location at which a user's mouse click input is received. The 3D model processing apparatus 300 may convert the obtained x-axis and y-axis coordinate values into a coordinate system of a 3D model and determine a seed point within the 3D model represented by triangle meshes. The 3D model processing apparatus 300 may determine a vertex corresponding to the transformed coordinate value as a seed point.

As another example, the 3D model processing apparatus 300 may automatically select a seed point by analyzing the 3D model.

As another example, the 3D model processing apparatus 300 may select a segmentation area as a seed point.

The 3D model processing apparatus 300 according to an embodiment may perform segmentation to divide the 3D model into regions corresponding to a plurality of objects. The 3D model processing apparatus 300 may determine a seed point on one area among a plurality of areas identified by segmentation.

Specifically, the 3D model processing apparatus 300 may segment the 3D model. For example, the 3D model processing device 300 may separate the 3D model into a region corresponding to at least one tooth and a region corresponding to the gingiva by using a template or artificial intelligence, and may use a plurality of teeth. The area for the teeth can be separated into areas corresponding to individual teeth.

However, in the case of an existing method of selecting an area corresponding to a predetermined object (eg, tooth or gingiva) by segmenting a 3D model, there is a limit to accurately selecting an area corresponding to the object. Depending on the noise or resolution of the scanner, the tooth area determined through segmentation may include only a part of the actual tooth area or may include an area outside the actual tooth area. Therefore, according to the existing method, there is a limit to accurately identifying the region of each individual tooth. Therefore, the 3D model processing apparatus 300 according to an embodiment may select a seed point on a region estimated as a region corresponding to an object through segmentation after primarily performing segmentation. Such an embodiment may be executed without user input.

In step S402, the 3D model processing apparatus 300 according to an embodiment may determine a reference point on the 3D model. The 3D model processing apparatus 300 according to an embodiment may determine a reference point on the 3D model based on the curvature value of the seed point.

Curvature is an indicator indicating the degree of curvature of a curved surface and can be expressed as the reciprocal of the radius of a curved surface. The curvature value of a predetermined point on the surface of the object may represent the degree of curvature of at least one curve passing through the predetermined point, determined on the surface of the object. In this case, curves passing through a predetermined point may have different degrees of bending depending on the direction. Therefore, the 3D model processing apparatus 300 according to an embodiment may determine the largest curvature value as the curvature value of a predetermined point, but the present disclosure is not limited thereto.

The 3D model processing apparatus 300 according to an embodiment may determine the seed point as a reference point when the curvature value of the seed point determined on the 3D model has a value within a predetermined range. On the other hand, if the curvature value of the seed point does not have a value within a predetermined range, the 3D model processing apparatus 300 may determine another point having a curvature value within a predetermined range as a reference point.

As another example, when the seed point is a certain area (eg, a segmentation area), the 3D model processing apparatus 300 may determine at least one reference point within the corresponding area. When there are more than one reference point, selection areas selected from each reference point may be combined to determine the area corresponding to the object.

In step S403, the 3D model processing apparatus 300 according to an embodiment may determine a region corresponding to the object by gradually expanding the selection region based on the reference point. The 3D model processing apparatus 300 may determine a region corresponding to the object by gradually expanding the selection region based on the curvature value of the reference point.

The 3D model processing apparatus 300 may determine a region corresponding to the object having a curvature value within a threshold range based on the curvature value of the reference point.

The 3D model processing apparatus 300 may use the k1 value of the reference point, both the k1 value and the k2 value, or a smaller value between the k1 value and the k2 value as a reference value for selecting the object region.

Also, the 3D model processing apparatus 300 according to an embodiment may determine a first region corresponding to an object having a curvature value within a threshold range based on the curvature value of the reference point. The 3D model processing apparatus 300 may determine a second region corresponding to the object by repeating region expansion and contraction processing from the determined first region. The 3D model processing apparatus 300 may determine the second area as the final area corresponding to the object.

In this case, the 3D model processing apparatus 300 may change a threshold range of curvature values for determining the object region based on the user's drag input. The 3D model processing apparatus 300 may determine a region corresponding to the object based on the changed threshold range.

In step S404, the 3D model processing apparatus 300 according to an embodiment may display the region determined as the region corresponding to the object on the 3D model. The 3D model processing apparatus 300 may display the area determined as the area corresponding to the object to be distinguished from other areas using color, contrast, line, or texture.

Hereinafter, a case of determining a region corresponding to a first tooth from a 3D model of a plurality of teeth will be described as an example, and a detailed operation method according to the present disclosure. However, various embodiments of the present disclosure are not limited to determining a tooth region on a 3D model, and as described above, the method of the present disclosure is also used to determine a region corresponding to at least one of teeth, gingiva, and artificial structures. this may apply. Redundant descriptions are omitted.

5 is a diagram for explaining curvature values calculated from seed points according to an exemplary embodiment.

The 3D model processing apparatus 300 according to an embodiment may calculate a curvature value of the seed point 501 .

The 3D model processing apparatus 300 may calculate curvature values of curves where the normal planes including the normal vector 531 (or normal) of the seed point 501 and the curved surface 520 of the tooth intersect. . The 3D model processing apparatus 300 may determine that the absolute value of the curvature value k1 of the curve where the first normal plane 542 and the curved surface 520 of the tooth intersect is the greatest among the calculated curvature values. In addition, the 3D model processing apparatus 300 is a curve in which the orthogonal normal plane 544, which is orthogonal to the first normal plane 542 and includes the normal vector of the seed point 501, intersects the curved surface 520 of the tooth. The curvature value k2 formed by this can be calculated. The 3D model processing apparatus 300 may use at least one of a k1 value and a k2 value as a curvature value of the seed point 501 .

6A is a diagram in which k1 values of points on a tooth are displayed in color.

As shown in FIG. 6A , points on a cusp region, which is a protruding portion of a tooth, may be displayed in red because they have a relatively large k1 value. On the other hand, points on a groove area formed by a tooth and points on a boundary area between a tooth and the gingiva have a relatively small k1 value and may be displayed in blue.

6B shows a graph showing the distribution of k1 values of the tooth surface. More specifically, FIG. 6B may be a graph showing a frequency distribution for each section of k1 values of points on the tooth surface.

Referring to FIG. 6B , it can be seen that the points on the tooth surface have a similar distribution to the left and right with the average value as the center, and most of the points have k1 values within a predetermined range. Accordingly, the 3D model processing apparatus 300 according to an embodiment may identify, as a tooth region, a region including points having curvature values (eg, a k1 value) within a predetermined range.

At this time, accuracy may vary depending on which point is used to select the tooth region. For example, if the user-selected seed point is located in the cusp of a tooth, the tooth region is selected relatively accurately, whereas if the user-selected seed point is located in the groove of a tooth, the tooth region is relatively inaccurate. can be chosen appropriately.

Therefore, the 3D model processing apparatus 300 may increase region selection accuracy by determining a reference point for tooth region selection based on the curvature value of the seed point. The 3D model processing apparatus 300 according to an embodiment may determine the seed point as a reference point when the curvature value of the seed point is within a predetermined range. On the other hand, if the curvature value of the seed point is not within a predetermined range, the 3D model processing apparatus 300 may determine another point having a curvature value within a predetermined range as a reference point. The 3D model processing apparatus 300 may determine, as a reference point, a point closest to the seed point among points having a curvature value within a predetermined range.

When the curvature value of the selected seed point is not within a predetermined range, the 3D model processing apparatus 300 may search for a point closest to the seed point among points having a curvature value within the predetermined range. For example, the predetermined range may be a range of curvature values represented by a cusp region of a tooth. The 3D model processing apparatus 300 searches for points in a region within a certain distance (eg, 0.01 to 0.02 mm) from the seed point and gradually expands the search target region, and finds that the curvature value is within a certain range. A point may be determined as a reference point.

7 illustrates seed points and reference points selected on a tooth according to an embodiment.

As shown in FIG. 7 , when the seed point 701 selected by the user is located in the tooth groove, the k1 value of the seed point 701 is calculated to be very low. The 3D model processing apparatus 300 may determine another point as a reference point when it is determined that the k1 value of the seed point 701 is out of a predetermined range. That is, since the selected seed point 701 is not a point on the cusp, the 3D model processing apparatus 300 may determine that the tooth region should be selected using another point as a reference point. Accordingly, the 3D model processing apparatus 300 may determine a point having a curvature value within a predetermined range and closest to the seed point 701 as the reference point 703 by searching for a region around the seed point 701 .

The reason why the seed point selected by the user is not used as a reference point, but a point with a curvature value within a predetermined range (eg, the range of the curvature value of the cusp region) is searched for and used as a reference point. This is because the accuracy of region selection increases when the tooth region is selected based on points.

Referring to the tooth image of FIG. 6A, points on the boundary area between the tooth and gingiva have relatively low values of k1 and are displayed in blue, and points in the tooth area have k1 values around the average value and are displayed in yellow. there is.

The 3D model processing apparatus 300 according to an embodiment may select an area having a curvature value within a threshold range based on the curvature value of the reference point as the tooth area while expanding the area around the reference point. Therefore, when the reference point is included in the blue region (ie, the region having a relatively low k1 value), when the 3D model processing apparatus 300 expands the selection region from the reference point, it is easy to expand out of the blue region. .

Hereinafter, with reference to FIG. 8 , a case in which the curvature value of the reference point is within a predetermined range and a case in which it is not are compared and described in detail.

8 is a diagram for explaining a reference point determined for selecting a tooth region according to an exemplary embodiment.

8 shows the k1 value range of the tooth boundary region and the k1 value range of the cusp region. The 3D model processing apparatus 300 according to an embodiment may use the k1 value range of the cusp region as a predetermined range for determining the reference point. However, the present disclosure is not limited to the example of "using the range of the k1 value of the cusp region as a predetermined range", and the predetermined range for determining the reference point may be determined in various ways.

As shown in FIG. 8 , when the curvature value of the first reference point cp1 is within a predetermined range, the 3D model processing apparatus 300 determines the curvature within a critical range based on the curvature value of the first reference point cp1. An area having a value may be selected as a tooth area. At this time, a region where the difference between the first reference point cp1 and the curvature value is within the critical range does not deviate from the tooth boundary.

On the other hand, the curvature value of the second reference point cp2 is outside the predetermined range, and the 3D model processing apparatus 300 determines a region having a curvature value within a critical range based on the curvature value of the second reference point cp2. area can be selected. At this time, since the region where the difference between the second reference point cp2 and the curvature value is within the critical range includes a part of the tooth boundary region, the region selected based on the second reference point cp2 may deviate from the tooth boundary. Therefore, the 3D model processing apparatus 300 according to an embodiment may determine a reference point having a k1 value within a predetermined range (eg, a k1 value range of the cusp region).

As described above with reference to FIGS. 7 and 8 , the groove area on the upper surface of the tooth and the boundary area between the teeth have a low curvature value. Accordingly, when selecting an area having a curvature value within a threshold range based on the curvature value of the reference point, the groove area of the upper surface of the tooth may not be selected. Accordingly, the data processing apparatus 300 according to an embodiment may select a final region corresponding to a tooth by repeating region expansion and contraction processing from the sporadically selected tooth region. Hereinafter, the region expansion and contraction process will be described in detail with reference to FIGS. 9A to 10D .

9A is a diagram illustrating a region having curvature values within a critical range on a 3D model of a plurality of teeth according to an embodiment.

9A shows a portion of an image rendered from a 3D model. The 3D model processing apparatus 300 may determine a region having a curvature value within a threshold range based on the curvature value of the reference point. The 3D model processing apparatus 300 may indicate curvature values within a threshold range based on the curvature value of the reference point in a predetermined color (eg, green) on the color bar 901 . Also, the 3D model processing apparatus 300 may display the region 913 having curvature values within a critical range with the same predetermined color.

9B is a diagram illustrating sporadically selected tooth regions according to an exemplary embodiment.

9B shows a 3D model represented by triangular meshes. The 3D model processing apparatus 300 according to an embodiment may start from a reference point and expand the selection area by selecting adjacent points having a difference between the reference point and a curvature value within a threshold range. When the 3D model processing device 300 reaches the tooth boundary area while expanding the selection area, the difference between the reference point and the curvature value becomes greater than or equal to the critical range, and thus may not expand the selection area any longer. Accordingly, as shown in FIG. 9B , the 3D model processing apparatus 300 may identify a boundary region between teeth and gingiva. However, the area primarily selected by the 3D model processing apparatus 300 may not include a recessed groove area on the upper surface of the tooth.

Therefore, the 3D model processing apparatus 300 according to an embodiment may expand the selected area to fill the empty space of the sporadically selected area.

10A is a diagram for explaining a method of enlarging a selection area according to an exemplary embodiment.

The 3D model processing apparatus 300 according to an embodiment may expand the selection area by selecting triangular meshes 1013 adjacent to the boundary of the first selection area 1011 .

10B is a diagram illustrating an extended tooth area according to an exemplary embodiment.

As shown in FIG. 10B, by extending the selection area, a previously unselected area may be selected. An empty space is not included in the extended tooth area 1022 of FIG. 10B.

10C is a diagram for explaining a method of shrinking an extended tooth area according to an exemplary embodiment.

The 3D model processing apparatus 300 according to an embodiment may contract the selected area by excluding the triangular meshes 1033 adjacent to the boundary of the expanded tooth area 1022 in an inward direction from the selected area.

10D is a diagram showing a tooth area finally determined through a process of area expansion and contraction according to an embodiment.

The 3D model processing apparatus 300 according to an embodiment may finally determine the region 1040 corresponding to the tooth by repeating region expansion and contraction processing from the selected tooth region a predetermined number of times.

Meanwhile, the 3D model processing apparatus 300 according to an embodiment may select a tooth region having a curvature value within a fixed threshold range based on the curvature value of the reference point. That is, the 3D model processing apparatus 300 may select a tooth region in which a difference in curvature value from the reference point is within a fixed critical range. For example, according to an embodiment, the 3D model processing apparatus 300 determines a reference point based on a location clicked by a user, and selects a tooth region in which a difference in curvature value from the reference point is within a fixed threshold range. You can choose.

However, the present disclosure is not limited to this embodiment, and the 3D model processing apparatus 300 according to an embodiment may select a tooth region having a curvature value within a predetermined threshold range regardless of the curvature value of the reference point. there is.

According to another embodiment, the 3D model processing apparatus 300 may select a tooth region by dynamically determining a threshold range based on a user's drag input. The 3D model processing apparatus 300 may change a threshold range of a curvature value for selecting a tooth region based on a dragging user input. The 3D model processing apparatus 300 may select a tooth region based on the changed threshold range.

11A, 11B, and 11C are views for explaining a method of expanding a tooth selection area based on a user's drag input according to an embodiment.

11a, 11b, and 11c show images rendered from a 3D model.

As shown in FIG. 11A , when a user clicks an arbitrary position on the 3D model, the 3D model processing apparatus 300 may determine a seed point 1103 corresponding to the position clicked by the user. The 3D model processing apparatus 300 may determine that the curvature value of the seed point 1103 is out of a predetermined range, and determine a reference point 1101 adjacent to the seed point 1103 . The 3D model processing apparatus 300 may select an area having a curvature value within a first range based on the curvature value of the reference point 1101 . The first range may be a preset threshold range.

When the user drags the pointer from the seed point 1103 to the first point 1105, the 3D model processing apparatus 300 may change the threshold range from the first range to the second range. The second range may be greater than the first range. The 3D model processing apparatus 300 may also increase the value of the threshold range as the drag distance increases. The 3D model processing apparatus 300 may select an area having a curvature value within a second range based on the curvature value of the reference point 1101 and display the selected area.

As shown in FIG. 11B , if the user drags the pointer to the second point 1107 longer, the 3D model processing apparatus 300 may change the threshold range from the second range to the third range. The third range may be a value greater than the second range. The 3D model processing apparatus 300 may also increase the threshold range as the drag distance increases. As the threshold range increases, the area selected by the 3D model processing device 300 also expands. The 3D model processing apparatus 300 may select an area having a curvature value within a third range based on the curvature value of the reference point 1101 and display the selected area. It can be seen that the area selected in FIG. 11B is larger than the area selected in FIG. 11A.

As shown in FIG. 11C , if the user drags the pointer from the seed point 1103 to the third point 1109 longer, the 3D model processing device 300 sets the threshold range from the third range to the fourth range. can be changed to The fourth range may be greater than the third range. The 3D model processing apparatus 300 may select an area having a curvature value within a fourth range based on the curvature value of the reference point 1101 and display the selected area. It can be seen that the area selected in FIG. 11c is larger than the area selected in FIG. 11b.

The 3D model processing apparatus 300 expands the selection area by increasing the threshold range as the distance of the user's drag input increases, but will no longer expand the selection area to an area having a curvature value below the threshold value. can The 3D model processing apparatus 300 may determine a threshold so that the selection area does not extend beyond the boundary between the teeth and the gingiva.

Hereinafter, referring to FIGS. 12 to 14 , interface screens provided to the user to implement the tooth region selection method described above will be described. However, the present disclosure is not limited to the examples shown in the drawings, and may be variously modified according to an implementation method.

12 to 14 illustrate examples of driving screens of programs to which a tooth region selection method according to an exemplary embodiment is applied.

As shown in FIG. 12 , the 3D model processing apparatus 300 may display a 3D model in which regions corresponding to a plurality of teeth are identified through segmentation of the 3D model. The 3D model processing apparatus 300 may assign a unique number to each tooth, automatically determine each tooth area, and display it on the screen. The 3D model processing apparatus 300 may display an image in which a plurality of teeth and a tooth number corresponding to each tooth are displayed on the 3D model.

The user can review whether individual tooth regions have been properly selected. The user may confirm that an empty space is included in the area corresponding to the tooth 1201 and determine that since the tooth area is incorrectly selected, it should be selected again. The user may select the tooth 1201 or click an icon displaying 27, which is a unique number of the tooth.

When the user receives an input for selecting a predetermined tooth, the 3D model processing apparatus 300 may display a pop-up window asking whether to reselect the predetermined tooth region, as shown in FIG. 13A. When the 3D model processing device 300 receives a user input requesting reselection of the tooth region using a smart selection function (eg, a user input of clicking the icon 1301), FIG. As shown in 13b, a screen in which a predetermined tooth portion is enlarged may be displayed.

As shown in FIG. 13B , since a partial area of the upper surface of the 27th tooth is not properly selected, the user can click the icon 1334 to deselect the entire previously selected area. The 3D model processing device 300 may display a pop-up window 1321 guiding a smart selection function when a user input of clicking the selection deselection icon 1334 is received.

The user may select a tooth region by clicking or clicking and dragging an arbitrary position of the 27th tooth according to information provided on the pop-up window 1321 . The description described above with reference to FIGS. 4 to 11 may be applied to a specific method for the 3D model processing apparatus 300 to select a tooth region based on a user's input. Redundant descriptions are omitted.

As shown in FIG. 13C , when it is determined that the tooth region is properly selected without any empty spaces, the user clicks an icon 1323 confirming that the selection has been completed.

When a user input of clicking the confirmation icon 1324 is received, the 3D model processing apparatus 300 may return to the initial screen displaying all of the plurality of teeth as shown in FIG. 14 . It can be seen that the 27th tooth area 1401 has been accurately reselected by the smart selection function according to an embodiment.

As described above, the 3D model processing apparatus 300 according to an embodiment of the present disclosure promotes user convenience and reduces work time by accurately and quickly selecting individual tooth areas with only a few clicks (or dragging) of the user. can be shortened

15 is a block diagram of a 3D model processing apparatus according to an embodiment.

The 3D model processing apparatus 300 illustrated in FIG. 15 may perform a 3D model processing method according to various embodiments of the present disclosure, and descriptions of FIGS. 1 to 14 may be applied. Therefore, overlapping content with the above description will be omitted.

The 3D model processing device 300 according to an embodiment is connected to an external device such as a 3D scanning device or an external server through a wired or wireless communication network, and obtains a 3D model of an object.

The 3D model processing device 300 may be any electronic device capable of generating, processing, displaying, and/or transmitting a 3D image of an object based on the obtained 3D model. The 3D model processing device 300 according to various embodiments of the present disclosure may be a fixed terminal or a mobile terminal. The 3D model processing device 300 may be, for example, a computing device such as a smart phone, a laptop computer, a desktop computer, a PDA, or a tablet PC, but is not limited thereto.

Referring to FIG. 15 , a 3D model processing apparatus 300 may include a processor 310, a display 320, a communication interface 330, a user input unit 340, and a memory 350.

The processor 310 according to an embodiment controls the 3D model processing device 300 to perform an intended operation by executing at least one instruction. At least one instruction may be stored in an internal memory (not shown) included in the processor 310 or a separate memory 350 .

The processor 310 according to an embodiment may control at least one component included in the 3D model processing apparatus 200 to perform an intended operation by executing at least one instruction. Therefore, even if the case where the processor 310 performs a predetermined operation is described as an example, the processor 310 configures at least one component included in the 3D model processing apparatus 200 to perform a predetermined operation. It can mean to control.

The processor 310 according to an embodiment stores signals or data input from the outside of the 3D model processing device 300, or is used as a storage area corresponding to various tasks performed by the 3D model processing device 300. RAM (not shown), a control program for controlling the 3D model processing device 300 and/or a ROM (not shown) storing a plurality of instructions, and at least one internal processor (not shown) that executes at least one instruction city) may be included.

In addition, the processor 310 may include a graphic processing unit (not shown) for graphic processing corresponding to video. In addition, the processor 310 may be implemented as a system on chip (SoC) in which a core (not shown) and a GPU (not shown) are integrated.

In the disclosed embodiment, the processor 310 may generate an image by rendering a 3D model of the oral cavity. For example, the 3D model may include surface shape information of an oral cavity including at least one of a plurality of teeth, gingiva, and an artificial structure.

The display 320 may display a predetermined screen according to the control of the processor 310 . Specifically, the display 320 may display a user interface screen including a 3D model. Alternatively, the display 320 may display a user interface screen including information related to diagnosis and treatment of an object.

The communication interface 330 may perform communication with at least one external electronic device (not shown) or server (not shown) through a wired or wireless communication network.

The user input unit 340 may receive a user input for controlling the 3D model processing device 300 . The user input unit 340 includes a touch panel that detects a user's touch, a button that receives a user's push manipulation, a mouse or a keyboard for indicating or selecting a point on a user interface screen, and the like. It may include a user input device, but is not limited thereto.

Also, the user input unit 340 may include a voice recognition device (not shown) for voice recognition. For example, a voice recognition device (not shown) may be a microphone, and the voice recognition device may receive a user's voice command or voice request. Accordingly, the processor 310 may control an operation corresponding to the voice command or voice request to be performed.

The memory 350 may store at least one instruction executed by the processor 310 . Also, the memory 350 may store at least one program executed by the processor 310 . The memory 350 may store data received from an external device or an external server (eg, raw data obtained by scanning an object, 2D image data, 3D model, etc.). The memory 350 may store an object image representing the object in 3D.

The processor 310 according to an embodiment of the present disclosure may control the overall operation of the 3D model processing device 200 by executing a program stored in the memory 350 .

The description of FIG. 4 may be applied to a specific method for the processor 310 to process the 3D model and select the object region, and redundant descriptions will be omitted.

First, the processor 310 according to an embodiment may obtain a 3D model of the oral cavity. The processor 310 may determine a region corresponding to the object by determining a reference point on the 3D model and gradually expanding a selection region based on the reference point. The processor 310 may display an area corresponding to the object on the 3D model through the display 320 .

The processor 310 according to an embodiment may automatically or manually determine a seed point on the 3D model and determine a reference point based on a curvature value of the seed point. The processor 310 may determine an area corresponding to the object by gradually expanding the selection area based on the curvature value of the reference point.

For example, the processor 310 may select a seed point on the first tooth from among a plurality of teeth represented by the 3D model. The processor 310 may control the display 320 to display the image rendered from the 3D model on the screen. The processor 310 may receive a user input for selecting a point on the rendered image, and determine a seed point on the 3D model based on the location of the selected point on the rendered image.

The processor 310 according to an embodiment may determine a reference point on the first tooth based on the curvature value of the seed point. The processor 310 may use at least one of the k1 value and the k2 value as the curvature value of the seed point. The processor 310 according to an embodiment may increase region selection accuracy by determining a reference point for tooth region selection based on the curvature value of the seed point.

The processor 310 may determine the seed point as a reference point when the curvature value of the seed point has a value within a predetermined range. On the other hand, if the curvature value of the seed point does not have a value within a predetermined range, the processor 310 may determine another point having a curvature value within a predetermined range as a reference point. The processor 310 may determine the nearest point having a curvature value within a predetermined range as a reference point.

When the curvature value of the selected seed point is not within the predetermined range, the processor 310 may search for a point closest to the seed point among points having a curvature value within the predetermined range. The processor 310 searches for points in an area within a certain distance (for example, 0.01 to 0.02 mm) from the seed point and gradually expands the search target area, and uses the searched point as having a curvature value within a certain range as a reference point. can be determined as

The processor 310 according to an embodiment may determine an area corresponding to the first tooth by gradually expanding the selection area based on the curvature value of the reference point.

The processor 310 may select a tooth region having a curvature value within a threshold range based on the curvature value of the reference point by gradually expanding the selection region from the reference point.

The processor 310 may use the k1 value of the reference point or both the k1 value and the k2 value as a reference value for selecting a tooth region. The processor 310 according to an embodiment may sporadically select a tooth region from By repeating the region expansion and contraction processing, a final region corresponding to the tooth can be selected.

Meanwhile, the processor 310 according to an embodiment may select a tooth region having a curvature value within a fixed threshold range based on the curvature value of the reference point. That is, the processor 310 may select a tooth region in which a difference in curvature value from the reference point is within a fixed threshold range.

However, the present disclosure is not limited to this embodiment, and the processor 310 according to an embodiment may select a tooth region having a curvature value within a predetermined threshold range regardless of the curvature value of the reference point.

According to another embodiment, the processor 310 may select a tooth area by dynamically determining a threshold range based on a user's drag input. The processor 310 may change a threshold range of a curvature value for selecting a tooth region based on a dragging user input based on the curvature value of the reference point. The processor 310 may select a tooth region based on the changed threshold range. For example, the processor 310 may increase the value of the threshold range as the drag distance increases. As the value of the threshold range increases, the processor 310 may expand the selection area. However, the processor 310 expands the selection area by increasing the value of the threshold range as the distance of the user's drag input increases. can The processor 310 may determine a predetermined value so that the selection area does not extend beyond the boundary between the tooth and the gingiva.

The above-described 3D model processing method according to various embodiments of the present disclosure may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer readable medium. Also, according to an embodiment of the present disclosure, a computer-readable storage medium having one or more programs including at least one instruction for executing a 3D model obtaining method may be provided.

The computer readable storage medium may include program instructions, data files, data structures, etc. alone or in combination. Here, examples of computer-readable storage media include magnetic media such as hard disks, floppy disks and magnetic tapes, optical media such as CD-ROMs and DVDs, floptical disks and Hardware devices configured to store and execute program instructions, such as magneto-optical media, and ROM, RAM, flash memory, and the like, may be included.

Here, the device-readable storage medium may be provided in the form of a non-transitory storage medium. Here, 'non-transitory storage medium' may mean that the storage medium is a tangible device. Also, the 'non-temporary storage medium' may include a buffer in which data is temporarily stored.

According to an embodiment, a method for displaying an oral cavity image according to various embodiments disclosed in this document may be included in a computer program product and provided. A computer program product may be distributed in the form of a machine-readable storage medium (eg compact disc read only memory (CD-ROM)). Alternatively, it may be distributed (eg, downloaded or uploaded) online through an application store (eg, play store, etc.) or directly between two user devices (eg, smartphones).

Although the embodiments have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also within the scope of the present invention. belong

300: 3D model processing device
310: processor
320: display
330: communication interface
340: user input unit
350: memory

Claims (19)

A method for determining a region corresponding to an object from a three-dimensional model of the oral cavity,
obtaining the 3D model;
determining a seed point on the 3D model;
determining a reference point on the 3D model based on the seed point;
determining an area corresponding to the object by gradually expanding a selection area based on the reference point; and
and displaying the determined area on the 3D model. According to claim 1,
The step of determining the reference point,
and determining the reference point based on the curvature value of the seed point. According to claim 1,
The three-dimensional model is acquired by a three-dimensional scanning device and includes shape information of a plurality of teeth in the oral cavity and a surface of the gingiva,
The method of determining a region, characterized in that the target object is a tooth or gingiva. According to claim 1,
Determining the seed point,
displaying the 3D model; and
Determining the seed point based on a user input for the displayed 3D model
Including, the area determination method. According to claim 1,
The step of determining the reference point,
determining the reference point based on the curvature value of the seed point determined on the 3D model;
The curvature value of the seed point is,
A curvature value (k1) having the largest absolute value among curvature values formed by a curve where normal planes including the normal of the seed point and the curved surface of the object intersect, and a curvature value (k1) orthogonal to the normal plane and including the normal of the seed point The method of determining a region including at least one of curvature values (k2) formed by a curve where an orthogonal normal plane intersects a curved surface of the object. According to claim 1,
The step of determining the reference point,
determining the seed point as a reference point when the curvature value of the seed point determined on the 3D model has a value within a predetermined range; and
and determining another point having a curvature value within the predetermined range as a reference point when the curvature value of the seed point does not have a value within the predetermined range. According to claim 1,
The step of determining a region corresponding to the object,
and determining a first region having a curvature value within a threshold range based on the curvature value of the reference point by gradually expanding a selection region from the reference point. According to claim 7,
The step of determining a region corresponding to the object,
and determining a second region corresponding to the object by repeating region expansion and contraction processing from the determined first region. According to claim 1,
The step of determining a region corresponding to the object,
determining a first region having a curvature value within a threshold range based on the curvature value of the reference point by gradually expanding a selection region from the reference point;
The area determination method,
changing the threshold range based on a user's drag input; and
The method of determining a second region based on the changed threshold range. According to claim 1,
Determining the seed point,
performing segmentation to divide the 3D model into regions corresponding to a plurality of objects; and
and determining the seed point on one of the plurality of regions. According to claim 1,
displaying an image displaying a plurality of teeth and a tooth number corresponding to each tooth on the 3D model; and
Receiving a user input for selecting a first tooth among the plurality of teeth as the object,
The step of determining the reference point,
determining the reference point on the first tooth. In the apparatus for processing a three-dimensional model of the oral cavity,
a display for displaying an image rendered from the 3D model; and
Determine a seed point on the 3D model,
Determine a reference point on the 3D model based on the seed point;
determining an area corresponding to the object by gradually expanding a selection area based on the reference point;
and at least one processor controlling the display to display the determined region on the 3D model. According to claim 12,
The display is
Display the 3D model,
The at least one processor,
Based on a user input for the displayed 3D model, the seed point is determined, the 3D model processing apparatus. According to claim 12,
The at least one processor,
determining a first region having a curvature value within a threshold range based on the curvature value of the reference point by gradually extending a selection region from the reference point;
and determining a second region corresponding to the object by repeating region expansion and contraction processing from the determined first region. According to claim 12,
The display is
Displaying an image displaying a plurality of teeth and a tooth number corresponding to each tooth on the 3D model;
The at least one processor,
Receiving a user input for selecting a first tooth among the plurality of teeth as the object;
Characterized in that for determining the reference point on the first tooth, a three-dimensional model processing device. A method for determining a region from a 3D model,
Obtaining a three-dimensional model of the oral cavity;
performing segmentation to divide the 3D model into a plurality of regions corresponding to each of a plurality of teeth;
selecting one of the plurality of teeth based on the segmented 3D model;
determining at least a partial region of a region to be selected in the oral cavity based on a seed point on the selected tooth;
determining a first region corresponding to the region to be selected from the 3D model based on the determined at least some region; and
and displaying the determined first area. According to claim 16,
Selecting one tooth among the plurality of teeth,
and selecting the one tooth based on a user input. According to claim 17,
The user input includes at least one gesture of click, hover, and drag.

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