KR102177886B1 - Method and apparatus for preprocessing computerized tomography image data - Google Patents

Abstract

The present invention relates to a method and apparatus for preprocessing computed tomography image data. The pre-processing method of computed tomography image data according to an embodiment of the present invention is a pre-processing method of CT image data performed before matching of a computed tomography (CT) image of the oral cavity and an image of a measurement method other than CT. An extraction step of extracting a reference surface; A setting step of setting an area spaced apart from the reference plane by a predetermined height as a root area; And a processing step of processing the CT image data so that the root region is removed from the CT image.

Description

Method and apparatus for preprocessing computerized tomography image data

The present invention relates to a method and apparatus for preprocessing image data of computerized tomography (hereinafter referred to as “CT”), and more particularly, image matching of disturbing factors when image matching between CT images and other images of the oral cavity. It relates to a method and apparatus for removing from CT image data before.

In the field of computer vision, when the same object is photographed at different times, measurement methods, or viewpoints, images having different coordinate systems are obtained, and image registration refers to processing for displaying these different images in one coordinate system.

In particular, in the dental field, image registration between a CT image and an oral scan image is performed before an implant or the like is performed. At this time, the matched image can be used as important data for determining the optimal implant location by allowing the location of bone tissue and neural tube to be identified.

However, the CT image contains information in more areas than the oral scan image. Accordingly, the CT image has no choice but to include an unnecessary area (hereinafter referred to as “unnecessary area”) during image registration. In particular, unnecessary regions such as the root region become a disturbing factor during image registration, and thus, there is a problem in that the time and efficiency of image registration may be reduced.

KR 10-1913586 B

In order to solve the problems of the prior art as described above, the present invention provides a method and apparatus for removing a root region, which is an obstructive factor when image matching between a CT image of the oral cavity and other images, from CT image data before image registration. There is a purpose.

However, the problem to be solved by the present invention is not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

The pre-processing method of CT image data according to an embodiment of the present invention for solving the above problems is a pre-processing of CT image data performed before matching of a computed tomography (CT) image of the oral cavity and a measurement method image other than CT. As a method, (1) an extraction step of extracting a reference plane from a CT image, (2) a setting step of setting an area separated by a predetermined height from the reference plane as a root area, and (3) CT image data so that the root area is removed from the CT image. And a processing step of processing.

In the extraction step, the height of the maxillary outermost tooth or a plane at a height spaced apart from it by a predetermined height as a reference plane for the maxilla, and a plane at the height of the mandibular outermost tooth or a height spaced apart from it by a predetermined height as a reference plane for the mandible It may include the step of setting.

The extraction step may include extracting, as a reference plane, a three-dimensional interface that is located in a space between the maxillary teeth and the mandibular teeth, and reflects the height of the maxillary teeth and the mandibular teeth.

The extracting step may include setting a 3D interface corresponding to the end shape of the maxillary teeth as a reference surface for the maxilla, and setting a 3D interface corresponding to the end shape of the mandibular teeth as a reference surface for the mandible.

The setting step may include setting a first distance spaced apart from the reference plane to set the root region for the maxilla and a second distance spaced apart from the reference plane to set the root region for the lower jaw.

An apparatus for pre-processing CT image data according to an embodiment of the present invention is an apparatus for pre-processing CT image data before matching a computed tomography (CT) image of the oral cavity and an image of a measurement method other than CT and CT. And a controller configured to process CT image data so that the root region is removed from the CT image after extracting a reference plane from the CT image received or previously stored in the storage unit, setting an area spaced apart from the reference plane by a predetermined height as a root region.

The control unit sets the height of the maxillary outermost tooth or a plane at a height spaced apart from it by a predetermined height as a reference plane for the maxilla, and a plane at the height of the mandibular outermost tooth or a height spaced apart from it by a predetermined height as a reference plane for the mandible. I can.

The control unit is located in the space between the maxillary teeth and the mandibular teeth, and may extract a 3D interface reflecting the height of the maxillary teeth and the mandibular teeth as a reference surface.

The control unit may set a 3D interface corresponding to the end shape of the maxillary teeth as a reference surface for the maxilla and a 3D interface corresponding to the end shape of the mandible teeth as a reference surface for the mandible.

The control unit may set a first distance spaced apart from the reference plane to set the root region for the maxilla and a second distance spaced apart from the reference plane to set the root region for the lower jaw.

The present invention configured as described above can easily remove the root region, which is an obstructive factor when image registration of CT images and other images of the oral cavity, before image registration, thereby improving the time and efficiency of image registration afterwards. There is this.

1 is a block diagram of a pre-processing apparatus 100 for CT image data according to an embodiment of the present invention.
2 is a flowchart illustrating a method of preprocessing CT image data according to an embodiment of the present invention.
3 and 4 are exemplary diagrams for explaining a pre-treatment method when a flat reference surface RP1 is applied.
5 and 6 are exemplary diagrams for explaining a preprocessing method when a reference plane RP2 having a three-dimensional interface is applied.

The above objects and means of the present invention, and effects thereof, will become more apparent through the following detailed description in connection with the accompanying drawings, and accordingly, a person having ordinary knowledge in the technical field to which the present invention belongs can facilitate the technical idea of the present invention. It will be possible to do it. In addition, in describing the present invention, when it is determined that a detailed description of known technologies related to the present invention may unnecessarily obscure the subject matter of the present invention, a detailed description thereof will be omitted.

The terms used in this specification are for describing exemplary embodiments, and are not intended to limit the present invention. In the present specification, the singular form also includes the plural form in some cases, unless specifically stated in the phrase. In the present specification, terms such as "include", "include", "provision" or "have" do not exclude the presence or addition of one or more other elements other than the mentioned elements.

In the present specification, terms such as “or” and “at least one” may represent one of words listed together, or a combination of two or more. For example, “or B” “at least one of “and B” may include only one of A or B, and may include both A and B.

In this specification, the description following “for example” may not exactly match the information presented, such as the recited characteristics, variables, or values, and tolerances, measurement errors, limitations of measurement accuracy, and other commonly known factors. It should not be limited to the embodiments of the invention according to the various embodiments of the present invention to effects such as modifications including.

In the present specification, when a component is described as being'connected' or'connected' to another component, it may be directly connected or connected to the other component, but other components exist in the middle. It should be understood that it may be possible. On the other hand, when a component is referred to as being'directly connected' or'directly connected' to another component, it should be understood that there is no other component in the middle.

In the present specification, when a component is described as being'on' or'adjacent' of another component, it may be directly in contact with or connected to another component, but another component exists in the middle. It should be understood that it is possible. On the other hand, when a component is described as being'directly above' or'directly' of another component, it may be understood that there is no other component in the middle. Other expressions describing the relationship between components, for example,'between' and'directly,' can be interpreted as well.

In this specification, terms such as'first' and'second' may be used to describe various elements, but the corresponding elements should not be limited by the above terms. In addition, the terms above should not be interpreted as limiting the order of each component, and may be used for the purpose of distinguishing one component from another component. For example, the'first element' may be named'second element', and similarly, the'second element' may also be named'first element'.

Unless otherwise defined, all terms used in the present specification may be used as meanings that can be commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, terms defined in a commonly used dictionary are not interpreted ideally or excessively unless explicitly defined specifically.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram of an apparatus 100 for preprocessing CT image data according to an embodiment of the present invention.

The preprocessing apparatus 100 for CT image data according to an embodiment of the present invention is an electronic device, and is a CT image before image registration between a CT image of the oral cavity and other images (i.e., an image photographed using a different measurement method than CT). It is a device that preprocesses data. In this case, the preprocessing apparatus 100 for CT image data according to an embodiment of the present invention may be a device that performs image matching between a CT image and other images.

Referring to FIG. 1, a preprocessing apparatus 100 for CT image data according to an embodiment of the present invention includes a communication unit 110, an input unit 120, a display unit 130, a storage unit 140, and a control unit 150. Can include.

The communication unit 110 is a component that communicates with an external device such as an image acquisition device (not shown) and a server (not shown), and may receive image data about the inside of the target's oral cavity. For example, the communication unit 110 5G (5 ^th generation communication), LTE-A (long term evolution-advanced), LTE (long term evolution), Bluetooth, BLE (bluetooth low energe), NFC (near field communication) Wireless communication such as, etc. may be performed, and wired communication such as cable communication may be performed.

In this case, the image data may include not only CT image data, but also other image data measured by a different measurement method for the oral cavity of the same object. For example, other image data may include oral scan image data, magnetic resonance image data, and the like. In this case, the CT image and the magnetic resonance image are 3D images that display the internal state of the tooth, while the oral scan image is a 3D image that displays the surface state of the tooth.

CT images are images taken through a computed tomography (CT) device using radiation. That is, the CT image may represent internal tissue distribution and bone density information such as a crown, a tooth root, and an alveolar bone in the oral cavity based on the transmittance of radiation.

The oral scan image is an image that provides information on the shape of the crown of the tooth exposed to the outside and the shape of the gum around the tooth. At this time, the oral scan image is obtained by directly scanning the inside of the patient's oral cavity through an oral scanner, etc., or by scanning an impression model that mimics the inside of the patient's oral cavity as an intaglio or a plaster model created through the relief of the impression model. It is also possible, and the scanned image of the impression model can be reversed and used as an oral scan image.

The input unit 120 generates input data in response to a user's input. The input unit 120 includes at least one input means. For example, the input unit 120 includes a keyboard, a key pad, a dome switch, a touch panel, a touch key, a mouse, a menu button ( menu button), etc.

The display unit 130 displays display data according to the operation of the preprocessor 100. For example, the display unit 130 includes a liquid crystal display (LCD), a light emitting diode (LED) display, an organic light emitting diode (OLED) display, and a micro electromechanical system (MEMS). mechanical systems) displays and electronic paper displays. In addition, the display unit 130 may be combined with the input unit 120 to be implemented as a touch screen or the like.

The storage unit 140 stores various types of information and programs necessary for the operation of the preprocessor 100. For example, the storage unit 140 may store image data received from an image acquisition device, etc., and an algorithm related to a preprocessing method of CT image data according to an embodiment of the present invention, which will be described later.

The control unit 150 performs a pre-processing operation on CT image data received from an image acquisition device or a server or previously stored in the storage unit 140. To this end, the control unit 150 may receive CT image data from an image acquisition device or a server and store it in the storage unit 140. In addition, the controller 150 may control operations of the communication unit 110, the input unit 120, the display unit 130, and the storage unit 140.

Hereinafter, a method of preprocessing CT image data according to an embodiment of the present invention controlled by the control unit 150 will be described.

2 is a flowchart illustrating a method of preprocessing CT image data according to an embodiment of the present invention.

Referring to FIG. 2, a method of preprocessing CT image data according to an embodiment of the present invention may include S201 to S203 for performing image processing on CT image data.

In S201, the controller 150 extracts the reference plane RP from the CT image.

The reference plane RP is a plane that serves as a reference for setting the root region RA, which is a root region of a tooth, and may be a plane RP1 or a three-dimensional interface RP2 having a curved shape. In addition, one reference plane RP may be extracted to be applied equally to the maxilla and mandible, or two or more may be extracted so as to be applied to each of the maxilla and mandible.

Thereafter, in S202, the control unit 150 sets an area spaced apart from the reference plane RP by a predetermined height as the root area RA of the CT image.

The root area (RA) is an unnecessary area of a CT image that is not included in other images such as an oral scan image, and acts as an obstruction factor in image registration between the CT image and the oral scan image, thereby reducing the time and efficiency of image registration. It is an area that can be Accordingly, it may be set in S202 what part of the CT image the root region RA is. However, when the root area RA is precisely set, the load for the setting operation may increase, so it may be desirable that the root area RA is approximately set according to the method described above or later. .

Thereafter, in S203, the controller 150 processes the CT image data so that the root area RA set in S202 is removed from the CT image. That is, data corresponding to the root area RA may be removed from the CT image data.

As a result of the preprocessing of S201 to S203, the CT image from which the root area RA has been removed may be used for image registration with other images according to various algorithms. In addition, after image registration according to these various algorithms is completed, a CT image and other images in which complete image registration is performed may be derived by adding the removed root area RA to the corresponding CT image.

Hereinafter, more detailed operations of S201 and S202 according to the type of the reference plane RP will be described. However, in FIGS. 3 to 5, the reference plane (RP) and pretreatment examples are shown only for the mandible, but the present invention is not limited thereto, and the same method as for the mandible may be applied to the maxilla.

3 and 4 are exemplary diagrams for explaining a pretreatment method when a flat reference surface RP1 is applied.

Meanwhile, referring to FIGS. 3 and 4, the reference plane RP may be a plane RP1. In this case, two different reference planes RP1 may be set for the maxilla and the mandible.

To this end, in S201, the control unit 150 is spaced apart by a predetermined height from the height (EH1, EH2) or the height (EH1, EH2) of the mandibular outermost teeth (ET1, ET2) (eg, molar or wisdom teeth, etc.) The plane at the height can be set as the reference plane (RP1) for the mandible. That is, the reference surface (RP1) for the mandible is a plane passing through the heights (EH1, EH2) of one ends of the two mandibular outermost teeth (ET1, ET2), or a height separated by a predetermined height from the heights (EH1, EH2). It may be a plane passing through.

Likewise, in S201, the control unit 150 may set the height of the outermost tooth of the maxilla or a plane at a height spaced apart from it by a predetermined height as the reference surface RP1 for the maxilla.

Thereafter, referring to FIG. 4, in S202, the control unit 150 refers to an area (checkered area) spaced downward by a predetermined height RH1 from the reference surface RP1 for the mandible to the root area for the mandible of the CT image. Set to (RA).

Similarly, in S202, the control unit 150 may set an area spaced upward by a predetermined height from the reference surface RP1 for the maxilla as the root area RA for the maxilla of the CT image.

However, in S202, the separation distance RH1 at the reference surface RP1 for the lower jaw and the separation distance RH1 at the reference surface RP1 for the maxilla may be different from each other. This is because the average height of the teeth of the maxilla and the teeth of the mandible may be different.

5 and 6 are exemplary diagrams for explaining a pre-processing method when a reference surface RP2 having a three-dimensional interface is applied.

5 and 6, the reference plane RP may be a three-dimensional interface RP2. At this time, the same one reference plane RP2 may be set for the maxilla and the mandible, or two different reference planes RP2 may be set.

First, a case of setting the reference plane RP2 of one 3D interface for the maxilla and mandible will be described.

That is, in 201, the controller 150 is located in the space between the maxillary teeth and the mandibular teeth (hereinafter referred to as “interval space”) in the CT image, but reflects the height of each of the maxillary teeth and the height of the mandible teeth. The dimensional boundary may be set as the reference plane RP2 of the CT image. At this time, the interspace is a three-dimensional interface having a shape corresponding to the ends of the maxillary teeth (hereinafter referred to as “upper three-dimensional interface”) and a three-dimensional interface having a shape corresponding to the ends of the mandibular teeth (hereinafter, “lower three-dimensional It is formed between the "interface").

Accordingly, in 201, the control unit 150 may set the upper 3D boundary surface, the lower 3D boundary surface, or a 3D boundary surface consisting of the average height values of the upper 3D boundary surface and the lower 3D boundary surface as the reference surface RP2.

Thereafter, referring to FIG. 6, in S202, the control unit 150 refers to a region (checkered region) spaced downward by a predetermined height RH2 from the reference plane RP2 as a root region RA for the mandible of the CT image. Set to Likewise, in S202, the control unit 150 may set an area spaced upward by a predetermined height from the reference plane RP2 as the root area RA for the maxilla of the CT image.

However, in S202, the separation distance RH2 at the reference plane RP2 for setting the root area RA for the mandible and the separation distance RH2 at the reference plane RP2 for setting the root area RA for the maxilla are different from each other. I can. This is because the average height of the teeth of the maxilla and the teeth of the mandible may be different.

Next, a case in which the reference plane RP2 of two different three-dimensional interface surfaces for the maxilla and mandible is set will be described.

That is, in 201, the control unit 150 may set the lower 3D interface as the reference surface RA2 for the mandible and the upper 3D interface as the reference surface for the maxilla, respectively.

Thereafter, referring to FIG. 6, in S202, the control unit 150 refers to a region (checkered region) spaced downward by a predetermined height RH2 from the reference surface RP2 for the mandible to the root region for the mandible of the CT image. Set to (RA). Likewise, in S202, the controller 150 may set an area spaced upward by a predetermined height from the reference plane RP2 for the maxilla as the root area RA for the maxilla of the CT image.

However, in S202, the separation distance RH2 at the reference plane RP2 for setting the root area RA for the mandible and the separation distance RH2 at the reference plane RP2 for setting the root area RA for the maxilla are different from each other. I can. This is because the average height of the teeth of the maxilla and the teeth of the mandible may be different.

Meanwhile, when the preprocessing apparatus 100 for CT image data according to an embodiment of the present invention is a device that performs image matching between a CT image and other images, after S203, the controller 150 removes the root area RA. It is possible to control performing an image matching operation between the CT image and other images.

In the detailed description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention is not limited to the described embodiments, and should be defined by the claims to be described later and equivalents to the claims.

100: preprocessor 110: communication unit
120: input unit 130: display unit
140: storage unit 150: control unit
RA: Root area RH: Reference plane separation distance
RP: reference plane EH: tooth height
ET: tooth

Claims (6)

As a pre-processing method of CT image data performed by an electronic device prior to matching a computed tomography (CT) image of the oral cavity and a non-CT measurement method image,
An extraction step of extracting a reference plane from a CT image;
A setting step of setting an area spaced apart from the reference plane by a predetermined height as a root area; And
A processing step of processing CT image data so that the root region is removed from the CT image;
Computed tomography image data preprocessing method comprising a. The method of claim 1,
In the extraction step, the height of the maxillary outermost tooth or a plane at a height spaced apart from it by a predetermined height as a reference plane for the maxilla, and a plane at the height of the mandibular outermost tooth or a height spaced apart from it by a predetermined height as a reference plane for the mandible. Computed tomography image data preprocessing method comprising the step of setting. The method of claim 1,
The extraction step includes extracting a 3D interface that is located in the space between the maxillary teeth and the mandibular teeth and reflects the heights of the maxillary teeth and the mandibular teeth as a reference plane. Way. The method of claim 1,
The extraction step comprises setting a three-dimensional interface corresponding to the end shape of the maxillary teeth as a reference plane for the maxilla and a three-dimensional interface corresponding to the end shape of the mandibular teeth as a reference plane for the mandible. Computed tomography image data preprocessing method. The method according to any one of claims 1 to 4,
The setting step comprises setting a first distance spaced apart from the reference plane to set the root region for the maxilla and a second distance spaced apart from the reference plane to set the root region for the lower jaw. Computed tomography image data preprocessing method. This is a device that pre-processes CT image data before matching computed tomography (CT) images of the oral cavity and CT and non-CT measurement methods,
A control unit that extracts a reference plane from a CT image received through the communication unit or previously stored in the storage unit, sets an area separated by a predetermined height from the reference plane as a root area, and processes CT image data so that the root area is removed from the CT image. Computed tomography image data preprocessing apparatus comprising:

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