Image processing device and image processing program

Abstract

To provide a stereoscopic image for display suitable for the observation in a wider range on the basis of image data on a maxillofacial region acquired by X-ray CT imaging.SOLUTION: An image processing device for performing processing of image data on a maxillofacial region obtained by X-ray CT imaging, includes: a storage unit for storing image data including an alveolus bone region; and an image processing unit for generating a stereoscopic image for display on the basis of the image data. The image processing unit executes processing for setting a continuous cross section curved along the alveolus bone region in the alveolus bone region (step S4), and processing for generating an image, as the stereoscopic image for display, displayed so that a transparency degree in a first region positioned in one side region with the continuous cross section as a boundary of the alveolus bone region is larger than a transparency degree in a second region positioned in the other side region with the continuous cross section as a boundary of the alveolus bone region (steps S5 and S6).SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a technique for processing image data of the maxillofacial region obtained by X-ray CT imaging. [Background technology]

[0002] Patent Document 1 discloses displaying a volume rendering image based on reconstruction data of a three-dimensional region obtained by X-ray CT imaging, and also discloses generating a volume rendering image including any one of tomographic images of an X-, Y-, or Z-plane of an XYZ coordinate system that passes through a point of interest in the three-dimensional region and is mutually orthogonal to each other, when generating the volume rendering image for display.

[0003] Techniques relating to displaying CT images are also disclosed in Patent Documents 2 and 3. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-305203 A [Patent Document 2] JP 2008-259822 A [Patent Document 3] Japanese Patent Application Publication No. 8-215192 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the volume rendering image of the maxillofacial region, it is difficult to grasp the internal structure of the volume rendering image, for example, the state of the alveolar bone and the state of the teeth, in a three-dimensional manner. In addition, the jawbone is curved, and multiple teeth are arranged in a curved arch shape. Therefore, even if the volume rendering image includes any of the cross-sectional images of the X-plane, the Y-plane, and the Z-plane, the region suitable for observation is limited.

[0006] Therefore, an object of the present disclosure is to provide a stereoscopic image for display suitable for observation over a wider range, based on image data of the maxillofacial region obtained by X-ray CT imaging. [Means for solving the problem]

[0007] The image processing device of the present disclosure is an image processing device that processes image data of the maxillofacial region obtained by X-ray CT imaging, and is equipped with a memory unit that stores the image data including the alveolar bone region, and an image processing unit that generates a three-dimensional image for display based on the image data, and the image processing unit executes a process of setting continuous cross-sections in the alveolar bone region that curve along the alveolar bone region, and a process of generating, as the three-dimensional image for display, an image in which the transparency of a first region located within one side of the alveolar bone region with the continuous cross-section as a boundary is displayed greater than the transparency of a second region located within the alveolar bone region with the continuous cross-section as a boundary.

[0008] In addition, the image processing program of the present disclosure is an image processing program for causing a computer that processes image data of the maxillofacial region obtained by X-ray CT imaging to execute the following processes: setting continuous cross sections that curve along the alveolar bone region in the alveolar bone region included in the image data; and generating a stereoscopic image for display in which the transparency of a first region located within one side of the alveolar bone region with the continuous cross sections as a boundary is displayed greater than the transparency of a second region located within the alveolar bone region with the continuous cross sections as a boundary. Effect of the Invention

[0009] According to the present disclosure, a stereoscopic image for display suitable for observation over a wider range can be provided based on image data of the maxillofacial region obtained by X-ray CT imaging. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic front view showing an X-ray imaging apparatus according to an embodiment. [Diagram 2]FIG. 2 is an explanatory diagram showing a state in which the subject support section supports the head. [Diagram 3] FIG. 3 is an explanatory diagram showing the positional relationship between the subject support part and the dental arch region. [Figure 4] FIG. 4 is a block diagram showing an example of the electrical configuration of the image processing device. [Diagram 5] FIG. 5 is an explanatory diagram for explaining characteristics when a stereoscopic image is viewed stereoscopically. [Figure 6] FIG. 6 is a flowchart showing an example of processing performed by the image processing device. [Figure 7] FIG. 7 is an explanatory diagram showing an example of setting continuous cross sections for the alveolar bone region. [Figure 8] FIG. 8 is a diagram showing an example of a continuous cross section. [Figure 9] FIG. 9 is an explanatory diagram showing an example of setting the transparency for the alveolar bone region. [Figure 10] FIG. 10 is a diagram showing a display example of a stereoscopic image for display. [Figure 11] FIG. 11 is an enlarged view of FIG. [Figure 12] FIG. 12 is a diagram showing a display example according to a comparative example. [Figure 13] FIG. 13 shows a state in which a tooth is embedded in the alveolar bone. [Figure 14] FIG. 14 shows a continuous cross section curved along the alveolar bone region of the maxilla. [Figure 15] FIG. 15 is an explanatory diagram showing an example of processing for identifying the surface of the alveolar bone region. [Figure 16] FIG. 16 is a diagram showing an example of setting continuous cross sections based on the surface of the alveolar bone region. [Figure 17] FIG. 17 is a diagram showing an example in which the continuous cross section is translated forward. [Figure 18] FIG. 18 is a diagram showing an example in which the continuous cross sections are moved in the buccolingual direction. [Figure 19] FIG. 19 is a diagram showing another example in which the continuous cross sections are moved in the buccolingual direction. [Figure 20] FIG. 20 shows an example in which the continuous cross sections are partially moved in the buccolingual direction. [Figure 21] FIG. 21 is an explanatory diagram showing an example of setting display colors. [Figure 22] FIG. 22 is a diagram showing a display example when the display colors in the second region are color-coded according to the positions in the buccolingual direction. [Figure 23] FIG. 23 is a diagram showing a volume rendering image in which the transparency of the first region is set to an intermediate value. [Figure 24] FIG. 24 is a diagram showing a display example of a stereoscopic image for display. [Diagram 25] FIG. 25 is an enlarged view of FIG. 24. [Figure 26] FIG. 26 is a diagram showing a display example according to a comparative example. [Figure 27] FIG. 27 is a diagram showing another display example of a stereoscopic image for display. [Figure 28] FIG. 28 is a diagram showing an example of a volume rendering image in which the transparency of the first region is set to an intermediate value. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Embodiment] Hereinafter, an image processing apparatus and an image processing program according to an embodiment will be described.

[0012] <Overall Configuration of X-ray Imaging Apparatus> The overall configuration of an X-ray imaging apparatus including an image processing apparatus will be described. FIG. 1 is a schematic front view showing the X-ray imaging apparatus 20.

[0013] For convenience of explanation, the directions are defined. The XYZ Cartesian coordinate system is an orthogonal coordinate system defined in a three-dimensional space in which the X-ray imaging device 20 is installed. The body axis direction of the imaging subject M when held by the X-ray imaging execution device 30 described later is the Z-axis direction, and when the X-ray imaging execution device 10 is a standing type as in this embodiment, the up-down direction along the direction of gravity is the Z-axis direction. The direction perpendicular to the Z-axis direction is the Y-axis direction, and the direction perpendicular to both the Z-axis direction and the Y-axis direction is the X-axis direction. In this embodiment, the front-back direction of the head P of the imaging subject M held by the subject support part 46 described later is the Y-axis direction, and the left-right direction of the head is the X-axis direction. A two-dimensional direction or plane consisting of multiple directions, for example, the X-axis direction, the Y-axis direction, and a composite direction thereof, may be expressed as "XY". For example, the "XY plane" is a plane perpendicular to the Z-axis direction.

[0014] The X-ray imaging apparatus 20 includes an X-ray imaging execution device 30 and an image processing device 50.

[0015] The X-ray imaging execution device 30 is configured to be capable of executing X-ray CT (Computed Tomography) imaging. The X-ray imaging execution device 30 executes X-ray CT imaging to collect X-ray imaging data (also called projection data). The collected X-ray imaging data is output to the image processing device 50. The image processing device 50 generates X-ray CT image data based on the X-ray imaging data. The X-ray CT image data is three-dimensional volume data. Furthermore, the image processing device 50 generates a stereoscopic image for display suitable for observation or diagnosis based on the X-ray CT image data.

[0016] The X-ray imaging execution device 30 may be configured to be capable of performing at least one of simple transmission X-ray imaging, panoramic X-ray, and cephalometric imaging in addition to X-ray CT imaging. In this case, the image processing device 50 may be configured to be capable of generating at least one of simple transmission image data, panoramic X-ray image data, and cephalometric imaging image data based on the X-ray imaging data.

[0017] In this application, when there is a statement that "at least one" is used in relation to multiple items connected by a conjunction such as "and," "at least one" does not refer to each individual item, but to all of the multiple items connected by "and." Therefore, for example, when there is an expression "at least one of A and B," it means "in the case of A," "in the case of B," or "in the case of both A and B."

[0018] More specifically, the X-ray imaging execution device 30 includes an X-ray generator 34, an X-ray detector 36, a swivel support unit 32, a drive mechanism 40, and a subject support unit 46. The X-ray generator 34 and the X-ray detector 36 are supported by the swivel support unit 32. The swivel support unit 32, the drive mechanism 40, and the subject support unit 46 are supported by a support frame 38 at a position above the floor.

[0019] More specifically, the support frame 38 includes a base 38a, a support column 38b, and an upper frame 38c. The base 38a extends horizontally on the floor. The support column 38b is supported by the base 38a in a vertical position extending upward from the floor. The base end of the upper frame 38c is supported in a cantilever state by the support column 38b. The upper frame 38c extends outward from the support column 38b in the horizontal direction. The upper frame 38c may be movable up and down relative to the support column 38b by an electric motor or the like, or manually.

[0020] The rotating support part 32 includes a body part 32a formed in an elongated shape, a generator support part 32b, and a detector support part 32c. A collimator 32s for collimating the generated X-rays is provided in front of the X-ray irradiation port of the X-ray generator 34 in the generator support part 32b, and for example, the collimated X-rays are used to form an X-ray cone beam for X-ray CT imaging or an X-ray slit beam for panoramic X-ray imaging.

[0021] A revolving support shaft 32aS protrudes upward from the longitudinal middle of the body 32a. An upper end of the revolving support shaft 32aS is rotatably supported by a bearing of a drive mechanism 40 provided in the upper frame 38c. The revolving support part 32 can revolve around the central axis X of the revolving support shaft 32aS while being suspended by the upper frame 38c via the drive mechanism 40.

[0022] The revolving support shaft 32aS may be moved along the XY plane, for example, may be rotated, in synchronization with the rotation of the revolving support unit 32. The movement of the revolving support shaft 32aS may be performed by an electric motor for applying an XY moving force separate from the electric motor for applying a rotation force to the revolving support unit 32. When the revolving support shaft 32aS is rotated in synchronization with the rotation of the revolving support unit 32 about the revolving support shaft 32aS, the rotation diameter of the generator support unit 32b or the detector support unit 32c can be made larger or smaller than the rotation diameter determined by the distance of the generator support unit 32b or the detector support unit 32c from the revolving support shaft 32aS.

[0023] In the following description, the center of curvature of the rotation path along which the generator support part 32b or the detector support part 32c actually moves is the rotation center X, regardless of whether the rotation support shaft 32aS rotates or not.

[0024] The generator support 32b is formed in a case shape capable of housing the X-ray generator 34. The detector support 32c is supported in a case shape capable of housing the X-ray detector 36. The generator support 32b and the detector support 32c are supported by the body 32a. The rotation center X is set to pass between the generator support 32b and the detector support 32c. In addition, a gap is set between the generator support 32b and the detector support 32c in which the head P can be arranged. For example, the generator support 32b is supported in a hanging manner at one end of the body 32a, and the detector support 32c is supported in a hanging manner at the other end of the body 32a. Then, with the head P arranged between the generator support 32b and the detector support 32c, the generator support 32b and the detector support 32c can rotate around the head P.

[0025] The X-ray generator 34 is an X-ray source that generates X-rays, and includes, for example, an X-ray tube. The X-ray generator 34 is housed in the generator support part 32b with the X-ray irradiation direction facing the detector support part 32c.

[0026] The X-ray detector 36 is a sensor that detects X-rays, and includes, for example, a flat panel detector (FPD) or an X-ray image intensifier (II). The X-ray detector 36 is housed in the detector support part 32c with the detection surface facing the detector support part 32c.

[0027] When the head P is positioned between the generator support part 32b and the detector support part 32c, the head P is positioned between the X-ray generator 34 and the X-ray detector 36. In this state, the X-ray generator 34 irradiates X-rays toward the head P. The X-ray detector 36 receives and detects the X-rays that have passed through the head P.

[0028] The drive mechanism 40 drives the revolving support part 32 to revolve. For example, the drive mechanism 40 includes an electric motor 41 incorporated in the upper frame 38c. The rotational drive force of the electric motor 41 is transmitted to the revolving support shaft 32aS of the revolving support part 32. The rotational drive force of the electric motor 41 may be transmitted directly to the revolving support shaft 32aS, or may be transmitted to the revolving support shaft 32aS via a transmission mechanism such as a motor or a pulley.

[0029] The driving mechanism 40 may be provided with an electric motor 41XY for driving and moving a bearing portion that receives the revolving support shaft 32aS. The bearing portion is guided in the XY directions by a bearing portion movement guide and moves along the XY plane by receiving the driving force of the electric motor 41XY. For example, the revolving support shaft 32aS can be revolved by revolving the bearing portion.

[0030] As described above, the swivel support part 32 can rotate with the head P disposed between the generator support part 32b and the detector support part 32c. During rotation, the X-ray generator 34 irradiates X-rays toward the head P, and the X-ray detector 36 receives and detects the X-rays that have passed through the head P. This allows the X-ray detector 36 to detect X-rays passing through the head P from multiple directions.

[0031] The subject support part 46 is a holder that holds the subject to be photographed, i.e., the head P of the person to be photographed M. Fig. 2 is an explanatory diagram showing a state in which the subject support part 46 supports the head P. Fig. 3 is an explanatory diagram showing the positional relationship between the subject support part 46 and the dental arch region Ar.

[0032] As shown in FIGS. 1 to 3, the subject support section 46 includes, for example, a chin rest 46a, a head holder 46b, and a subject support frame 46c.

[0033] The subject support frame 46c is formed in an elongated shape. The base end of the subject support frame 46c is supported in a cantilever manner by the support column 38b. The subject support frame 46c extends horizontally from the support column 38b. The subject support frame 46c extends from a position lower than the generator support part 32b and the detector support part 32c toward the inner periphery of the rotation path of the generator support part 32b and the detector support part 32c.

[0034] The chin rest 46a and head holder 46b are supported on the tip of the subject support frame 46c. The chin rest 46a and head holder 46b are supported so as to face between the X-ray generator 34 and the X-ray detector 36 supported by the swivel support part 32. The head P supported by the subject support part 46 is held at a fixed position between the X-ray generator 34 and the X-ray detector 36 while the X-ray generator 34 and the X-ray detector 36 are rotating.

[0035] The chin rest 46a supports the tip of the lower jaw of the head P, thereby fixing the maxillofacial region A at a fixed position. The maxillofacial surface refers to the jaw including the upper and lower teeth, and the maxillofacial region A refers to the region including the maxillofacial surface. The maxillofacial region A includes the dental arch region Ar and the alveolar bone region Alv (see FIG. 7). The dental arch refers to a curved line in which multiple teeth are arranged in an arch shape from the front teeth to the molars, and the dental arch region Ar refers to the region including multiple teeth arranged along such a dental arch. The dental alveolus refers to a depression into which the roots of the teeth fit, and the alveolar bone refers to a bone that forms multiple alveoli into which multiple teeth arranged along the dental arch fit, and the alveolar bone region Alv refers to the region including such alveolar bone. Only the region where the dental alveolus is located may be considered as the alveolar bone region Alv, or the region from the region where the dental alveolus is located to the temporomandibular joint region may be considered as the alveolar bone region Alv. The region where the dental alveolus is located and a part of the region connected to the temporomandibular joint region may be considered as the alveolar bone region Alv. A part of the region where the alveolus is located may be considered as the alveolar bone region Alv. The alveolar bone region in the tissue region to be displayed, which will be described later, may be considered as the alveolar bone region Alv.

[0036] In the present application, the maxillofacial region to be the subject of X-ray CT imaging and the maxillofacial region to be displayed do not necessarily have to be the entire region. For example, it is possible to image only one of the upper and lower jaws, only one of the left and right regions, only the right region of the upper or lower jaw, only the left region of the upper or lower jaw, only the region close to the front teeth, or only the upper or lower jaw part of the region close to the front teeth.

[0037] It is also possible to obtain image data from X-ray CT scans of a wide area, but only a portion of it can be processed. For example, it is possible to obtain image data from X-ray CT scans of the entire maxillofacial region, but extract only a local area of ​​interest for image processing.

[0038] The subject support portion 46 may be provided with a bite piece to be bitten by the upper and lower front teeth in addition to or instead of the chin rest 46a.

[0039] The head holder 46b holds the head P from both sides, thereby positioning the head P in the X-axis direction. In the subject support section 46, the chin rest 46a or the head holder 46b may be omitted.

[0040] The subject support section 46 may be movable up and down relative to the column 38b by an electric motor or the like, or manually.

[0041] The positions of the swivel support part 32 and the subject support part 46 are adjusted with reference to the support column 38b. Therefore, the positions and swivel trajectory of the X-ray generator 34 and the X-ray detector 36 with respect to the head P supported by the subject support part 46 can be treated as known information. Furthermore, in the volume data generated based on the X-ray imaging data, the positions of the dental arch region Ar and the alveolar bone region Alv can also be treated as known information.

[0042] With the head P supported by the subject support part 46, the swivel support part 32 can be rotated to rotate the X-ray generator 34 and the X-ray detector 36 around the head P. As a result, the X-ray imaging execution device 30 performs X-ray CT imaging of the head P.

[0043] The image processing device 50 is a computer that processes image data of the maxillofacial region obtained by X-ray CT imaging using the X-ray imaging execution device 30. The projection data obtained by X-ray CT imaging of the maxillofacial region is an example of image data of the maxillofacial region obtained by X-ray CT imaging. In this embodiment, the image processing device 50 is communicably connected to the X-ray imaging execution device 30 and controls the operation of the X-ray imaging execution device 30. In this embodiment, the image processing device 50 generates volume data as image data including the maxillofacial region based on detection data of the X-ray detector 36 obtained by X-ray CT imaging.

[0044] At least one of the process for controlling the operation of the X-ray imaging execution device 30 and the process for generating volume data may be executed by a computer other than the image processing device 50.

[0045] <Electrical configuration> FIG. 4 is a block diagram showing an example of the electrical configuration of the image processing device 50. As shown in FIG.

[0046] The image processing device 50 includes at least one processor 52 and a storage device 54 as a storage unit.

[0047] The storage device 54 is a non-transitory storage medium, such as a flash memory or a hard disk device. The storage device 54 stores volume data 54a of the maxillofacial region A as image data including the alveolar bone region Alv.

[0048] The storage device 54 stores a program 54b in which a processing procedure for generating a stereoscopic image for display based on the volume data 54a is described. The stereoscopic image for display is an image generated by performing a rendering process on the volume data 54a so as to be suitable for display on the display device 58. For example, the stereoscopic image for display may be an image that two-dimensionally expresses how the volume data 54a is viewed from an arbitrary viewpoint. In other words, the stereoscopic image for display may be a stereoscopic image displayed two-dimensionally. The viewpoint may be set in advance at a predetermined position in the coordinate system of the volume data, or may be set at an arbitrary position by the user.

[0049] The characteristics of a stereoscopic image are as follows: Consider the image of an object when viewed stereoscopically.

[0050] FIG. 5(a) illustrates a simple cube CB1. The cube CB1 has eight vertices Pa, Pb, Pc, Pd, Pe, Pf, Pg, and Ph. Now, the vertices closer to the observation viewpoint as viewed from the observation viewpoint are called near the line of sight, and the vertices farther from the observation viewpoint are called far from the line of sight. The relationship is that the face SF1 consisting of at least the vertices Pa, Pb, Pc, and Pd is located closer to the line of sight than the vertex Pg. In other words, the vertex Pg is located farther from the line of sight than the face SF1. If the transparency of the cube CB1 is 0 percent, the vertex Pg is not visible, as in the stereoscopic image IA of FIG. 5(b). If the transparency of the cube CB1 is greater than 0 percent, the vertex Pg is blocked by something closer to the line of sight, as in the stereoscopic image IB of FIG. 5(c), and thus lacks clarity in the observation. In this way, a stereoscopic image is a three-dimensional image, and it may be considered to be an image in which the things farther from the line of sight of the three-dimensional object on the line of sight path from the observation viewpoint have lower clarity in the observation than the things closer to the line of sight.

[0051] The stereoscopic image may be an image with a strong sense of depth that utilizes human left-right parallax so that it can be observed with a VR headset worn on the head.

[0052] The program 54b may include an imaging program that receives various instructions related to X-ray imaging and controls the drive mechanism 40, the X-ray generator 34, the X-ray detector 36, etc. in accordance with the various instructions to control the X-ray CT imaging operation.

[0053] The program 54b may include a program for generating the volume data 54a based on detection data from the X-ray detector 36 after X-ray CT imaging.

[0054] The processor 52 is an electric circuit and is configured by a CPU (Central Processing Unit), etc. The processor 52 executes the program 54b, thereby realizing various processing functions of the processor 52.

[0055] The processor 52 has an image processing function as, for example, a display stereoscopic image generating unit 52a as a functional block realized by executing the program 54b. That is, the processor 52 is an example of an image processing unit C52. In the case where there is a main circuit made up of a CPU and a sub-circuit subordinate to the main circuit, the main circuit and the sub-circuit may be considered as the processor 52. The display stereoscopic image generating unit 52a is a processing block that generates a display stereoscopic image based on the volume data 54a as image data. The image processing function will be described in more detail with reference to the flowchart of FIG. 6.

[0056] In this embodiment, the processor 52 may have processing functions as an operation control unit 52b and a volume data generating unit 52c. The operation control unit 52b is a processing block that controls the X-ray CT imaging operation of the X-ray imaging execution device 30, and the volume data generating unit 52c is a processing block that generates volume data 54a from the X-ray CT imaging data.

[0057] It should be noted that some or all of the functions realized in the processor 52 may be realized in hardware using a dedicated logic circuit, etc. Also, some or all of the functions realized in the processor 52 may be processed in an integrated manner by one processor, or may be processed in a distributed manner by a plurality of processors.

[0058] The image processing device 50 may be connected to the X-ray imaging execution device 30 , an operation reception unit 56 , and an external information source 57 via an interface circuit 55 .

[0059] The operation reception unit 56 is a man-machine interface that receives a support operation by a user, and may be configured with at least one of a switch, a keyboard, a touch panel, and a mouse. In FIG. 1, a mouse 56a and a keyboard 56b are illustrated as examples of the operation reception unit 56.

[0060] The external information source 57 is an information source that is provided outside the image processing device 50, not within the image processing device 50. The external information source 57 may be, for example, an external server that is provided outside the image processing device 50 and connected via a communication line. The volume data 54a may be stored in the external information source 57. Information on the subject M associated with the volume data 54a may be stored in the external information source 57. The information on the subject M is, for example, a name, a gender, or an identification code.

[0061] The image processing device 50 may be connected to a display device 58. The display device 58 is a display device that displays a stereoscopic image for display, and is, for example, a liquid crystal display device or an organic EL (Electroluminescent) display device. The image processing device 50 and the display device 58 may be integrated together.

[0062] <Examples of processing in image processing device> 6 is a flow chart showing an example of volume data generation processing and an example of a stereoscopic image for display generation processing performed by the image processing device 50. Specific processing is performed by the image processing unit C52.

[0063] That is, the X-ray imaging execution device 30 performs X-ray CT imaging by rotating the X-ray generator 34 around the head P. As a result, projection data corresponding to the distribution of the X-ray absorption coefficient of the head P is obtained for each of the X-rays projected from multiple directions onto the head P.

[0064] In step S1, the image processing device 50 calculates a three-dimensional distribution of X-ray absorbance of the head P based on projection data from multiple directions, and generates volume data 54a. The volume data 54a is data including, for example, multiple voxels arranged three-dimensionally according to the position of the head P, and each of the multiple voxels has a voxel value indicating the X-ray absorbance. The voxel value may be understood to be a CT value based on the X-ray absorption coefficient.

[0065] In this embodiment, the X-ray imaging execution device 30 performs X-ray CT imaging so as to include the maxillofacial region A of the head P. Therefore, the volume data 54a includes the dental arch region Ar and the alveolar bone region Alv.

[0066] The generated volume data 54 a is stored in the storage device 54 .

[0067] In the next step S2, it is determined whether or not a display instruction has been issued. For example, it is determined that a display instruction has been issued when a display instruction is input by the user via the operation receiving unit 56. The process of step S2 is repeated until it is determined that a display instruction has been issued, and when it is determined that a display instruction has been issued, the process proceeds to step S3.

[0068] In step S3, an initial continuous cross section is set. The initial continuous cross section is a cross section that is initially set as a continuous cross section that curves along the alveolar bone region Alv. An example of the continuous cross section that curves along the alveolar bone region Alv will be described later.

[0069] After the initial sequential cross sections are set in step S3, the process proceeds to step S4. In step S4, the initial sequential cross sections are set as sequential cross sections for display to be used for generating a stereoscopic image for display based on the volume data 54a. As a result, sequential cross sections for display that curve along the alveolar bone region Alv are set in the alveolar bone region Alv.

[0070] Steps S3 and S4 are carried out to set continuous cross sections that curve along the alveolar bone region Alv in the alveolar bone region Alv.

[0071] In the next step S5, a process of changing the transparency of the volume data 54a is executed based on the continuous cross sections for display. More specifically, the transparency of a first region located in one side of the boundary of the continuous cross sections for display, among the alveolar bone region Alv of the volume data 54a, is made larger than the transparency of a second region located in the other side of the boundary of the continuous cross sections for display. The process of making the transparency larger is called a transparency promotion process, and the process of making the transparency of the first region larger than that of the second region is called a first region transparency promotion process.

[0072] The transparency is a scale that indicates transparency. The higher the transparency, the closer it is to transparency, and the lower the transparency, the closer it is to opaque. The transparency may be, for example, a value expressed as a percentage between transparent and opaque. In this case, 100 percent transparency is transparent, and 0 percent transparency is opaque. If the transparency is between 100 percent and 0 percent, it is semi-transparent, and the higher the value, the closer it is to transparency.

[0073] 100 percent transparency may be referred to as completely transparent, and a completely transparent image may be referred to as a completely transparent image. 0 percent transparency may be referred to as completely opaque, and a completely opaque image may be referred to as a completely opaque image. Transparency between 100 percent and 0 percent may be referred to as partially transparent, and an partially transparent image may be referred to as an partially transparent image.

[0074] In the next step S6, a stereoscopic image for display is generated by volume rendering based on the volume data 54a with the transparency set, and the stereoscopic image for display is displayed on the display device 58. The image for display may be an image that is surface rendered based on the volume data 54a.

[0075] Steps S5 and S6 are used to generate a stereoscopic image for display in which the transparency of the first region bounded by the continuous cross sections for display is greater than the transparency of the second region. Steps S5 and S6 are used to generate a stereoscopic image for display in which the transparency of the first region is greater than the transparency of the second region as a display result. For this reason, it is not essential to generate intermediate data in which transparency is set in association with each voxel of the volume data 54a.

[0076] For example, in step S5, transparency may be set for at least one of the voxels in the first region and the second region of the volume data 54a. In this case, in step S6, a rendering process may be performed based on the volume data 54a in which the transparency is set, to generate a stereoscopic image for display. For example, in step S5, the transparency of the first region is set to 100 percent, and the transparency of the second region is set to 0 percent. In this case, when a stereoscopic image for display seen from the first region is generated in step S6, a stereoscopic image for display in which the first region is made invisible and the second region is made visible is generated. Also, for example, in step S5, the transparency of the first region is set to 50 percent, and the transparency of the second region is set to 0 percent. In this case, when a stereoscopic image for display seen from the first region is generated in step S6, a stereoscopic image for display in which the second region can be observed through the semi-transparent first region is generated.

[0077] Also, for example, if each voxel value of the volume data 54a indicates a display density, making the transparency 100% may be considered to be making the voxel value 0. Thus, for example, in step S5, the voxel value of the first region may be made 0. In this case, when a stereoscopic image for display seen from the first region is generated in step S6, a stereoscopic image for display in which the first region is made invisible and the second region is made visible is generated. Making the voxel value of the first region 0 may be considered to be deleting the image of the first region and generating and displaying the stereoscopic image for display.

[0078] In the next step S7, it is determined whether or not a change operation for the display continuous cross section position has been received. The change operation for the display continuous cross section position is performed by the user operating the operation receiving unit 56. For example, an operation for enlarging / reducing the display continuous cross section and changing the position forward / backward or left / right may be received by operating the mouse 56a. More specifically, an operation for enlarging / reducing the display continuous cross section may be received by operating the wheel of the mouse 56a, and an operation for changing the position forward / backward or left / right of the display continuous cross section may be received by a combination of operating any key on the keyboard and operating the wheel of the mouse 56a. Alternatively, an operation for changing the display continuous cross section position may be received by operating the keyboard or a touch operation using a touch screen. If it is determined in step S7 that a change operation has been received, the process proceeds to step S10.

[0079] In step S10, the changed consecutive cross sections are set as consecutive cross sections for display. After that, the process proceeds to step S5, and the above-mentioned processing is repeated.

[0080] If it is determined in step S7 that no operation for changing the position of the continuous cross sections for display has been performed, the process proceeds to step S8.

[0081] In step S8, the display of the stereoscopic image for display in step S6 is continued.

[0082] In the next step S9, it is determined whether or not an instruction to end the display has been given. The instruction to end the display is given by the user operating the operation reception unit 56. For example, the instruction to end the display is input by operating the pointer of the mouse 56a, operating the keyboard, etc. If it is determined that an instruction to end the display has not been given, the process returns to step S7 and the subsequent processes are repeated. If it is determined that an instruction to end the display has been given, the process for display is terminated.

[0083] <Continuous cross-sections curved along the alveolar bone region> Fig. 7 is an explanatory diagram showing an example of setting continuous cross sections for the alveolar bone region. Fig. 7 is a cross-sectional view along the XY plane, and shows the alveolar bone region Alv and dental arch region Ar of the lower jaw.

[0084] The continuous cross sections Q1 and Q2 curved along the alveolar bone region Alv are continuous cross sections curved in a U-shape along the direction in which the multiple alveoli 102 are arranged in the alveolar bone 100. Since the roots of the teeth (tooth region) 110 are embedded in each of the multiple alveoli 102, the continuous cross section Q1 curved along the alveolar bone region Alv may be understood to have the same shape as the continuous cross section curved in a U-shape along the direction in which the teeth 110 are arranged in the dentition supported by the alveolar bone 100.

[0085] For example, a continuous cross section Q1 curved along the alveolar bone region Alv may be set based on the tooth root 112. In this case, the continuous cross section Q1 may be set as a cross section having the same width in the height direction but continuing. The tooth root 112 of the tooth 110 may be considered to coincide with the deepest part of the tooth alveolus 102. Therefore, the continuous cross section Q1 curved along the multiple tooth roots 112 may be considered to be a continuous cross section Q1 curved along the deepest part of the multiple tooth alveolus 102.

[0086] A single tooth may have multiple roots. In this case, the position of the center of the apex of each root may be regarded as the position of the tooth root 112. The center may be the center of gravity of the figure formed by the multiple root apices as viewed from the Z direction.

[0087] In this case, the continuous cross section curved along the alveolar bone region Alv may be a cross section having a continuous same shape in the height direction.

[0088] Also, for example, a continuous cross section Q2 curved along the alveolar bone region Alv may be set based on the outer surface 100a or the inner surface 100b of the alveolar bone 100. In FIG. 7, the continuous cross section Q2 is set along the outer surface 100a. The continuous cross section may be set inside the outer surface 100a, or between the outer surface 100a and the inner surface 100b. In this case, in the height range in which the alveolar bone 100 exists, the continuous cross section Q2 may be determined for each coordinate in the height direction (Z-axis direction). Therefore, in this case, the continuous cross section Q2 may be set as a cross section whose shape changes continuously in the height direction.

[0089] The continuous cross sections Q1 and Q2 are along the alveolar bone region Alv. Therefore, the continuous cross sections Q1 and Q2 are likely to be set so as to continuously cross the multiple teeth 110. Preferably, in particular, the continuous cross section Q1 is likely to be set so as to continuously cross near the roots of the multiple teeth 110. By observing the alveolar bone 100 and the teeth 110 appearing in the continuous cross sections Q1 and Q2, it is easy to observe the multiple teeth 110 simultaneously and overall.

[0090] 7, if the cross section Qp is a plane, the number of teeth 110 that the cross section Qp can cross is smaller than the number of teeth 110 that the successive cross sections Q1 and Q2 can cross. In addition, the positions at which the cross section Qp can cross each tooth 110 differ greatly in the buccolingual direction. For this reason, even if the alveolar bone 100 and teeth 110 that appear on the cross section Qp are observed, it is difficult to observe the multiple teeth 110 simultaneously and overall.

[0091] As shown in FIG. 8, the continuous cross-sections may be set to be composed of a surface extending in the up-down direction of the subject's head and in a direction curving along the horseshoe shape of the dental arch. FIG. 8 shows a perspective view of the continuous cross-section Q1. The continuous cross-section Q1 is composed of a surface extending in the up-down direction UD of the head and in a direction HS that intersects with the direction UD and curving along the horseshoe shape of the dental arch. In this way, the continuous cross-sections are set to divide the alveolar bone region into a buccal region BA and a lingual region TA. One of the buccal region BA and the lingual region TA may be designated as a first region R1, and the other may be designated as a second region R2.

[0092] In this way, the continuous cross-section Q1 may be set to divide the alveolar bone region Alv into a buccal region BA and a lingual region TA, one of the buccal region BA and the lingual region TA being the first region R1 and the other being the second region R2.

[0093] The initial successive sections may be sections initially set regardless of the distribution of voxel values ​​in the coordinate system of the volume data 54a. That is, X-ray CT imaging is performed with the head P supported by the subject support part 46. Therefore, the support position of the head P in the volume data 54a has known coordinates. In the coordinate system of the volume data 54a, successive sections set assuming the dental arch region Ar or the alveolar bone region Alv included in the head P of a standard skeleton may be set as the initial successive sections.

[0094] The initial continuous cross sections may be continuous cross sections obtained based on image data of the maxillofacial region obtained by X-ray CT. For example, they may be continuous cross sections obtained based on the volume data 54a. An example of a process for obtaining continuous cross sections curved along the alveolar bone region Alv based on the volume data 54a will be described later.

[0095] <Example of transparency settings> 9 is an explanatory diagram showing an example of setting the transparency for the alveolar bone region, and is a cross-sectional view in which a part of FIG.

[0096] 9, the continuous cross sections for display are set in the alveolar bone region Alv. The continuous cross sections for display are the continuous cross sections Q1 that curve along the tooth root 112 described above.

[0097] A first region R1 exists within one side of the alveolar bone region Alv with the display continuous cross section Q1 as a boundary, and a second region R2 exists within the other side of the boundary. The first region R1 is, for example, the buccal side of the display continuous cross section Q1. The buccal side of the display continuous cross section Q1 is the outer circumferential side of the display continuous cross section Q1. The second region R2 is the lingual side of the display continuous cross section Q1. The lingual side of the display continuous cross section Q1 is the inner circumferential side of the display continuous cross section Q1.

[0098] Conversely, the first region R1 may be the lingual side of the display continuous cross section Q1, and the second region R2 may be the buccal side of the display continuous cross section Q1. When rendering the volume data 54a, it is preferable that the transparency of the side where the viewpoint is located is high. This is because if the transparency of the viewpoint side is high, it is easy to observe the area with low transparency through the area with high transparency.

[0099] For example, if it is desired to observe the alveolar bone region Alv and the dental arch region Ar from the buccal side, the first region R1 can be set on the buccal side of the display continuous cross section Q1, and the second region R2 can be set on the lingual side of the display continuous cross section Q1.

[0100] Steps S5 and S6 may include a process of identifying regions of a plurality of teeth 110 and generating a stereoscopic image for display in which the transparency of the regions of teeth 110 is displayed less than the transparency of the first region R1.

[0101] For example, in step S5 above, a plurality of teeth 110 may be identified, and the transparency of the regions of the teeth 110 may be set to be lower than the transparency of the first region R1.

[0102] The region of the teeth 110 may be specified by, for example, performing edge extraction processing and pattern matching processing based on voxel values ​​in the volume data 54a. Image processing may be performed by machine learning, or may be performed by a general segmentation process such as a watershed algorithm, a region growing method, a graph-cut method, a level-set method, or a snake method. The region of the teeth 110 may be a region in which multiple teeth are collectively specified as one region, or a region in which multiple teeth that are individually recognized are collectively treated as one region.

[0103] The region of the teeth 110 may be determined by, for example, a machine-learned trained model. The trained model is, for example, configured by a multi-layer neural network and stored in the storage device 54. The processor 52 reads out the program and parameters described in the trained model and executes the identification process, thereby identifying the region of the teeth 110 in the volume data 54a. The trained model is generated by, for example, a machine learning device configured by a computer. The machine learning device generates a trained model that identifies the region of the teeth 110 in the volume data using multiple volume data in which the regions of the teeth 110 are distinguished as training data. It is preferable that the tooth region and the alveolar bone region are processed to become three-dimensional data independent of each other in image processing. Therefore, for example, the region of the teeth 110 may be segmented as described above, and the alveolar bone region Alv may also be segmented. By performing such processing, for example, processing in which only one of the tooth region and the alveolar bone region is displayed in cross section is possible.

[0104] Then, in step S6, a three-dimensional image for display is generated and displayed by rendering the volume data 54a based on the transparency set for the region of the tooth 110, in which the transparency for the region of the tooth 110 is set lower than the transparency for the first region R1. Since the transparency for the region of the tooth 110 is lower, the tooth 110 is displayed more clearly than the first region R1 of the alveolar bone region Alv.

[0105] When the transparency of the tooth 110 is 0 percent and the transparency of the first region R1 is set to 100 percent, the voxel values ​​in the region of the tooth 110 are kept at their initial values, and the voxel values ​​of the first region R1 are set to 0. By performing rendering processing on the volume data 54a after this setting, a stereoscopic image for display is generated and displayed in which the transparency of the region of the tooth 110 appears smaller than the transparency of the first region R1.

[0106] As an example of setting the transparency, for example, the transparency of the first region R1 may be 100 percent, and the transparency of the region of the second region R2 and the teeth 110 may be 0 percent. In this case, the first region R1 is made invisible, and the second region R2 and the teeth 110 can be easily observed.

[0107] Examples of display stereoscopic images Im for display in this case are shown in Figs. 10 and 11. Fig. 11 is an enlarged view of Fig. 10. As shown in these figures, a cross section of the alveolar bone region Alv cut along the continuous cross sections Q1 is displayed. In the cross section, a plurality of teeth 110 are arranged along the continuous cross sections Q1. For simplicity, the illustration shows only the left side of the mandible. However, such processing may be performed when a local image is captured at the stage of X-ray CT imaging, as described above, or such processing may be performed as a result of image processing being performed only on a portion of image data obtained from X-ray CT imaging of a wide area. By cutting and displaying the cross section of the alveolar bone region Alv along the continuous cross sections Q1, the state in which the plurality of teeth 110 are embedded in the alveolar bone 100 can be easily grasped as a whole and at a time. As shown in the figure, the teeth 110 may not be displayed as cross sections, so that the observer can concentrate on observing the state of the alveolar bone 100. In addition, the shape of the mandibular canal and cyst along the alveolar bone region Alv (see the circled portion) can be easily grasped. In Fig. 11, the cyst is enlarged and displayed. In this manner, an image enlarged with the region of interest at the center may be generated.

[0108] An image of a cross-section may be called a cross-section display image. A target area of ​​a cross-section display may be called a cross-section display area. An image of a tooth 110 not shown in cross section may be called a non-cross-section display, and an image of a non-cross-section display may be called a non-cross-section display image. A target area of ​​a non-cross-section display may be called a non-cross-section display area.

[0109] In Fig. 10 and Fig. 11, the region of the teeth 110 (dental arch region Ar) is displayed in a non-sectional view, but it may also be possible to display it in a sectional view, as shown in square brackets in Fig. 10. In this case, the section may be cut along the continuous section Q1. In this case, similar to the alveolar bone region, it may be considered that one side is the first region TR1 of the tooth region and the other side is the second region TR2 of the tooth region, with the continuous section Q1 as the boundary. The tooth region may be switched between sectional and non-sectional display, for example, in Fig. 10 and Fig. 11, the tooth region may be switched between sectional and non-sectional display. The switching display may be performed by accepting an operation, or may be automatically switched by displaying for a predetermined period of time.

[0110] The continuous cross section Q1 may be set so as to divide the region (dental arch region Ar) of the tooth 110 into a buccal region TBA of the tooth region and a lingual region TTA of the tooth region. The transparency of the first region TR1 of the tooth region and the transparency of the second region TR2 of the tooth region are set in the same manner as the first region R1 and the second region R2.

[0111] Regarding one of the buccal region and the lingual region being the first region and the other being the second region, the alveolar bone region Alv and the region of the tooth 110 may be unified. That is, when the buccal region BA of the alveolar bone region Alv is the first region R1 and the lingual region TA is the second region R2, the region of the tooth 110 is also defined as the buccal region TBA as the first region TR1 of the tooth region and the lingual region TTA as the second region TR2 of the tooth region. When the buccal region BA of the alveolar bone region Alv is the second region R2 and the lingual region TA is the first region R1, the region of the tooth 110 is also defined as the buccal region TBA as the second region TR2 of the tooth region and the lingual region TTA as the first region TR1 of the tooth region.

[0112] A common continuous cross section Q1 may be set for the region of the tooth 110 and the alveolar bone region Alv, or the continuous cross sections may be set individually as described below. The image processor C52 may set a dental arch continuous cross section TQ1 that curves along the region of the tooth 110 (dental arch region Ar) in the region of the tooth 110 as well. The dental arch continuous cross section TQ1 may be set so as to divide the dental arch buccal region TBA and the dental arch lingual region TTA in the region of the tooth 110. The dental arch continuous cross section TQ1 may be continuous with the continuous cross section Q1, or may be discontinuous. The dental arch continuous cross section TQ1 may overlap the continuous cross section Q1 at the same position in the buccolingual direction, or may be set at a different position in the buccolingual direction.

[0113] The transparency of the first tooth region TR1 and the second tooth region TR2 are set in the same manner as the first region R1 and the second region R2. One of the buccal region and the lingual region is the first region and the other is the second region, and the same may be applied to the alveolar bone region Alv and the tooth 110 region, as in the case of dividing the tooth 110 region by the continuous cross section Q1.

[0114] The movements of the continuous section Q1 and the continuous dental arch section TQ1 may be independent of each other or may not be independent. Therefore, the following operations are possible. For example, one of the continuous section Q1 and the continuous dental arch section TQ1 may remain motionless and only the other may be moved, or the continuous section Q1 and the continuous dental arch section TQ1 may be moved in opposite directions. Both may move synchronously in the same direction. When both move in the same direction, they may move while overlapping at the same position in the buccolingual direction.

[0115] The region of the tooth 110 may be switchable between a cross-sectional view and a non-cross-sectional view.

[0116] Providing a completely opaque cross-sectional display may be called a completely opaque cross-sectional display, and an image of a completely opaque cross-sectional display may be called a completely opaque cross-sectional display image. Providing an incompletely transparent cross-sectional display may be called an incompletely transparent cross-sectional display, and an image of an incompletely transparent cross-sectional display may be called an incompletely transparent cross-sectional display image.

[0117] The cross-sectional display of the second region may be performed completely opaquely or incompletely transparently. The cross-sectional display of the second region can be realized, for example, by making the entire second region completely opaque or incompletely transparent. The target tissue region of image processing displayed on the display device to show the cross-sectional display region may be called the display target tissue region. For example, the region shown in the display stereoscopic image Im consisting of both the tooth region consisting of the teeth 110 and the alveolar bone region Alv consisting of the alveolar bone 100 in FIG. 10 is an example of the display target tissue region. Since the second region is a region cut along the continuous cross sections Q1 and has a lower transparency than the first region, by making the second region completely opaque or incompletely transparent, the second region is displayed as a cross-sectional display as long as the surface of the continuous cross sections Q1 is visible.

[0118] The first region may be displayed completely transparent or partially transparent. For example, the cross-section of the second region can be displayed by making the entire first region completely transparent or partially transparent and making it more transparent than the second region.

[0119] Providing a completely opaque non-cross-sectional display may be called a completely opaque non-cross-sectional display, and an image of a completely opaque non-cross-sectional display may be called a completely opaque non-cross-sectional display image. Providing an incompletely transparent non-cross-sectional display may be called an incompletely transparent non-cross-sectional display, and an image of an incompletely transparent non-cross-sectional display may be called an incompletely transparent non-cross-sectional display image.

[0120] The non-sectional display of the tooth region may be performed completely opaquely or partially transparently. For example, the non-sectional display of the tooth region can be realized by making the entire tooth region completely opaque or partially transparent.

[0121] However, the cross-section of the tooth region may be displayed completely opaquely or partially transparently. In this case, the cross-section of the tooth region can be displayed by making the entire second region of the tooth region completely opaque or partially transparent.

[0122] In particular, when rendering the volume data 54a, by performing global illumination processing that calculates and renders not only direct light from the light source but also indirect light due to reflection, etc., the unevenness and front-to-back feel of the second region R2 and teeth 110 that appear in the continuous cross section Q1 can be easily grasped.

[0123] FIG. 12 is a diagram showing a display example according to a comparative example. FIG. 12 shows a display example in the case where the alveolar bone region Alv is cut by a plane cross section Qp. In this case, the number of teeth 110 appearing on the cross section Qp is less than the number of teeth 110 appearing when cut by a continuous cross section along the dental arch region Ar. In addition, the positions of the multiple teeth 110 are different in the buccolingual direction, and when the cross section Qp is aligned with the position of the root 112 of one tooth 110, it is shifted from the root 112 of the other teeth 110. For this reason, it is difficult to collectively observe how the multiple teeth 110 are embedded in the alveolar bone 100.

[0124] In contrast, when cutting along the continuous cross sections Q1 along the dental arch region Ar as in this embodiment, many teeth 110 appear on the continuous cross sections Q1, making it easy to observe the many teeth 110 as a whole and all at once. Also, since similar positions of the multiple teeth 110 appear on the continuous cross sections Q1, it is easy to observe, for example, how the multiple teeth 110 are embedded in the alveolar bone 100 all at once.

[0125] In addition, since the transparency of the tooth 110 region is less than the transparency of the first region R1, the shape of the portion of the tooth 110 that was embedded in the first region R1 can be easily observed. This makes it easy to observe how the tooth 110 is embedded in the second region R2 of the alveolar bone 100. In the continuous cross section Q1 along the dental arch region Ar, the multiple teeth 110 are displayed in a convex state, so that the embedding of the multiple teeth 110 can be easily observed.

[0126] <Example 1 of continuous section setting processing> In step S3, continuous cross sections curved along the alveolar bone region Alv may be obtained based on the volume data 54a. An example of a process for obtaining the continuous cross sections will be described.

[0127] As a first setting process example, the positions of a plurality of tooth roots 112 in the dental arch may be identified, and the continuous cross sections Q1 may be set based on the positions of the plurality of tooth roots.

[0128] 13 is a longitudinal cross-sectional view showing a state in which some of the teeth 110 in the volume data 54a are embedded in the alveolar bone 100. As shown in the figure, in the volume data 54a, the voxel values ​​of the outer surfaces of the teeth 110 are higher than those of the surrounding areas. For this reason, for example, in the mandibular dental arch region Ar, it is possible to determine whether or not each voxel value has a voxel value equivalent to the outer surface of the teeth 110 from bottom to top, and when a voxel having a voxel value equivalent to the outer surface of the teeth 110 is detected, it is possible to determine that the position of the voxel is position P1 of the tooth root 112.

[0129] Also, for example, tooth roots may be identified by three-dimensional pattern recognition or by application of a trained model that has been machine-learned using volume data in which the tooth root positions are distinguished as training data.

[0130] The continuous cross section Q1 based on the positions of the tooth roots 112 may be, for example, a cross section in which a reference line determined based on the positions of the tooth roots 112 continues uniformly above and below. Such a reference line may be a curve determined so as to minimize the sum of the squares of the distances to the tooth roots 112 on the XY plane onto which the positions of the tooth roots 112 are projected, or may be a Bezier curve or a broken line set to pass through the tooth roots 112.

[0131] The number of tooth roots 112 may be more than two, for example, three or four. In this case, the position of the center of gravity of a figure formed by connecting the positions of the root tips with a straight line may be set as the position of the tooth root (total tooth root position). Even when the number of tooth roots 112 is two, the position of the center of gravity may be set as the position of the tooth root.

[0132] There may be a case where the alveolar bone region Alv includes the alveolar bone regions Alv of the upper and lower jaws. In this case, the continuous cross sections Q1 may be set separately for the upper and lower jaws. In Fig. 7, the lower continuous cross section Q1 is illustrated as a cross section that curves along the alveolar bone region Alv of the lower jaw in the alveolar bone region Alv of the lower jaw.

[0133] 14, in the maxillary alveolar bone region Alv, an upper continuous cross section Q1, which is a cross section curved along the maxillary alveolar bone region Alv, is illustrated. In the following description, to distinguish from the mandible, the upper jaw alveolar bone region Alv(U) and the upper continuous cross section Q1(U) may be used. Similarly, the mandibular alveolar bone region and the lower continuous cross section may be used as the mandibular alveolar bone region Alv(D) and the lower continuous cross section Q1(D).

[0134] As with the alveolar bone region Alv of the mandible, by identifying the position of the tooth root 112, an upper continuous cross section Q1(U) that curves along the alveolar bone region Alv(U) of the maxilla can be set.

[0135] If continuous cross sections Q1, S1(U) are set separately along the alveolar bone regions Alv, Alv(U) of the upper and lower jaws, appropriate continuous cross sections Q1, S1(U) can be set according to the shapes of the upper and lower alveolar bone regions Alv, Alv(U).

[0136] The upper and lower boundaries in the volume data 54a may be preset as known positions in the volume data 54a, or may be set at a height position a preset distance away from the bottom of the jawbone recognized by pattern recognition or the like, or may be set at a position between the upper and lower dental arches after processing to recognize the upper and lower dental arches as described above.

[0137] <Example 2 of continuous section setting processing> When determining continuous cross sections curved along the alveolar bone region Alv based on the volume data 54a, as a second setting processing example, the surface position of the alveolar bone region Alv may be identified, and the continuous cross sections Q2 may be set according to the distance from the surface position.

[0138] Fig. 15 is an explanatory diagram showing an example of processing for identifying the surface position of the alveolar bone region Alv. Fig. 15 is a cross-sectional view of the alveolar bone region Alv and the dental arch region Ar along the XY plane. XY axes are shown in Fig. 15.

[0139] A horizontal cross section of the alveolar bone region Alv appears in an XY plane according to a predetermined height position. In the XY plane, the front end of the alveolar bone region Alv is set to face downward. In the XY plane, a plurality of discretized x coordinates x(0), x(1), x(n), x(n+1), x(n+2), are set in the X-axis direction. At any x coordinate, it is determined whether the voxel values ​​of the voxels aligned in the Y-axis direction exceed the value corresponding to the cortical bone (or are equal to or greater than the value corresponding to the cortical bone). The determination may be performed sequentially in the +Y direction. The x, y coordinates of the voxel having a voxel value exceeding the value corresponding to the cortical bone (or are equal to or greater than the value corresponding to the cortical bone) are identified as the position of the cortical bone, that is, the surface of the alveolar bone region Alv. By performing the above process for each of the plurality of x coordinates, the position of the surface of the alveolar bone region Alv, here the outer surface line La, is set. The outer surface line La may be obtained by performing an edge extraction process on the voxel values.

[0140] The continuous line L is set based on the outer surface line La. The continuous line L is a line that is set so as to pass through the alveolar bone region Alv based on the outer surface line La. For example, as shown in Fig. 16, a line that extends a certain distance from the continuous line L into the alveolar bone region Alv may be set as the continuous line L. The continuous line L may be set as a line that passes as close to the tooth root 112 as possible.

[0141] By repeating the above process while changing the height in the Z-axis direction, the continuous line L is obtained for each height. The set of continuous lines L in the Z-axis direction is obtained as a continuous cross section Q2 that changes in the Z-axis direction.

[0142] Similarly, for the maxilla, continuous cross sections are obtained according to the surface of the alveolar bone region of the maxilla.

[0143] In the above example, the continuous cross section is obtained based on the buccal surface of the alveolar bone region Alv. The continuous cross section may be obtained based on the lingual surface of the alveolar bone region Alv, or may be obtained based on both the buccal surface and the lingual surface. For example, the intermediate position between the buccal surface and the lingual surface may be set as the continuous cross section.

[0144] <Example of changing continuous sections> A processing example of step S7 will be described in more detail. The change of the cross-sectional position may be performed, for example, by horizontal movement (movement in the horizontal direction) or buccolingual movement of the continuous cross sections Q1. The change of the cross-sectional position may be performed based on an operation received by the operation receiving unit 56. The operation on the operation receiving unit 56 may be, for example, a wheel operation of the mouse 56a, a combination of a key operation on the keyboard and a wheel operation of the mouse 56a, or a drag operation by the mouse 56a.

[0145] The image processor C52 changes the transparency based on the moved continuous cross sections Q1 as a reference and generates a stereoscopic image for display. The display device 58 displays the stereoscopic image for display.

[0146] FIG. 17 shows an example in which the continuous section Q1 is translated forward. The continuous section Q1 is translated forward with its shape unchanged. The transparency is changed based on the continuous section Q1 after the translation, and a stereoscopic image for display is generated and displayed. The continuous section Q1 may be translated forward and backward, or may be translated left and right. The translation may be considered as an example of horizontal movement. Since the dental arch has a shape that spreads from the anterior tooth region to the left and right molar regions, the translation may generally be considered to include an element of movement of the continuous section in the buccolingual direction. In addition, the translation may generally be considered to be a movement that includes an element of movement from the lingual side to the buccal side in almost the entire dental arch, or a movement that includes an element of movement from the buccal side to the lingual side in almost the entire dental arch. Even if a component of movement in a diagonal direction is added to the translation, as long as it has a component of movement in a parallel direction, the movement generally includes an element of movement of the continuous section in the buccolingual direction. Such movements that include an element of movement in the buccolingual direction may also be considered as movement in the buccolingual direction.

[0147] Also, the image processor C52 may automatically process the consecutive slices Q1 to change the transparency based on the consecutive slices Q1, generate and display a three-dimensional image for display, and allow the surgeon to stop the change at a desired position. Also, the image processor C52 may automatically process a lesion candidate to automatically determine the consecutive slices Q1 at the position of the lesion candidate.

[0148] 18 and 19 show an example in which the continuous cross sections Q1 are moved in the buccal-lingual direction. The movement of the continuous cross sections Q1 in the buccal-lingual direction may be understood as the expansion and contraction of the continuous cross sections Q1. The movement of the continuous cross sections Q1 in the buccal direction is the expansion of the continuous cross sections Q1, and the movement of the continuous cross sections Q1 in the lingual direction is the contraction of the continuous cross sections Q1.

[0149] The movement of the continuous cross sections Q1 may be partial. For example, the continuous cross sections Q1pt may be moved in the buccal-lingual direction only for the partial area PT1, as shown in Fig. 20. In the illustrated example, the continuous cross sections Q1pt are moved in the buccal-lingual direction.

[0150] 18 shows the continuous cross section Q1 moved toward the cheek, i.e., the enlarged continuous cross section Q1e1 is shown. The enlarged continuous cross section Q1e1 is obtained by similarly enlarging the continuous cross section Q1 with respect to the point Pi on the tongue side. The continuous cross section Q1 may be similarly reduced to become a reduced continuous cross section.

[0151] 19 shows the enlarged continuous cross section Q1e2, which is the result of moving the continuous cross section Q1 toward the cheek by another process, that is, enlarged. The enlarged continuous cross section Q1e2 is a line that passes through a position that is a certain distance away from each point on the continuous cross section Q1 on the outer side in a direction perpendicular to the tangent direction. The reduced continuous cross section may be set so as to pass through a position that is a certain distance away from each point on the continuous cross section Q1 on the inner side in a direction perpendicular to the tangent direction.

[0152] The continuous cross sections may be set by combining the above-mentioned parallel movement and the movement in the buccolingual direction. The movement and scaling operations may be set so that the operation applied to a part of the continuous cross sections Q1 covers the entire continuous cross sections Q1 in the tissue region to be displayed.

[0153] In any case, the translated continuous cross section Q1 or the enlarged continuous cross sections Q1e1, Q1e2 are set as the continuous cross sections for display (see step S10), the transparency is changed based on the changed continuous cross sections for display, and a stereoscopic image for display is generated and displayed on the display device 58 (see steps S5 and S6).

[0154] The parallel movement of the continuous cross sections Q1 while maintaining the shape as shown in Fig. 17 and the similarity enlargement / reduction of the continuous cross sections Q1 based on the lingual point Pi as shown in Fig. 18 are examples of the movement of the continuous cross sections Q1 in the buccolingual direction according to the geometric rules. When the image processing unit C52 receives the change operation in step 7, it moves the continuous cross sections Q1 in the buccolingual direction according to the geometric rules.

[0155] <Effects, etc.> According to the image processing device 50 configured as above, in the alveolar bone region Alv, the continuous cross sections Q1 and Q2 curved along the alveolar bone 100 are set, and a display stereoscopic image Im is generated in which the transparency of the first region R1 located on one side of the continuous cross sections Q1 and Q2 in the alveolar bone region Alv is greater than the transparency of the second region R2 located on the other side of the continuous cross sections Q1 and Q2 in the alveolar bone region Alv. Therefore, the second region R2 appearing in the continuous cross sections Q1 and Q2 curved along the alveolar bone 100 can be easily observed by the display stereoscopic image Im. In the continuous cross sections Q1 and Q2, a large number of teeth 110 are displayed side by side, compared to when the cross sections are flat. As a result, a display stereoscopic image Im suitable for observing a wider range along the alveolar bone region Alv is provided based on the volume data 54a of the maxillofacial region obtained by X-ray CT imaging.

[0156] Furthermore, if the successive cross sections Q1, Q2 are obtained based on the volume data 54a obtained by X-ray CT imaging, the successive cross sections Q1, Q2 suitable for observing the alveolar bone 100 corresponding to the skeleton of the head P that was the subject of the X-ray CT imaging can be obtained.

[0157] In addition, by setting a lower continuous cross section Q1 that curves along the alveolar bone region Alv of the mandible and an upper continuous cross section Q1(U) that curves along the alveolar bone region Alv(U) of the maxilla as the continuous cross sections Q1, S1(U), a stereoscopic image for display suitable for observing a wider range along the separate upper and lower alveolar bone regions Alv, Alv(U) can be provided.

[0158] In the display stereoscopic image Im, when the first region R1 is made invisible, that is, when the first region R1 is transparent, the second region R2 is easily observed clearly in the continuous cross sections Q1.

[0159] Furthermore, if the transparency of the region of the teeth 110 is displayed less than the transparency of the first region R1 in the stereoscopic image for display Im, the teeth 110 can be easily observed.

[0160] Furthermore, if the continuous cross sections Q1 are set based on the position of the tooth root 112, it is possible to easily observe how the teeth 110 aligned along the dental arch are embedded in the alveolar bone region Alv.

[0161] Furthermore, if the continuous cross section Q2 is set according to the distance from the surface position of the alveolar bone region Alv, it is easy to observe a cross section of a uniform internal depth based on the surface of the alveolar bone region Alv.

[0162] In addition, since the continuous cross section Q2 is along the surface of the alveolar bone region Alv, the continuous cross section Q2 is a cross section that changes in the height direction. Therefore, in the continuous cross section Q2, a cross section in which the alveolar bone 100 is cut obliquely with respect to the X-axis direction and the Y-axis direction appears. Therefore, the internal structure of the alveolar bone 100 can be easily observed from various directions. In addition, the teeth 110 can be easily exposed in various directions, and the teeth 110 can be easily observed.

[0163] Furthermore, by changing the continuous cross sections Q1 and Q2 based on an operation received by the operation receiving unit 56, the alveolar bone 100 can be observed in various cross sections.

[0164] Furthermore, by moving the continuous cross section Q1 in the buccolingual direction, the entire dental arch can be easily observed at various depths from the surface of the alveolar bone 100.

[0165] <Modifications of display color> As a first modification, an example in which the display color of a stereoscopic image for display is modified will be described.

[0166] That is, the display color of the second region R2 displayed on the continuous cross sections Q1 may differ depending on the position in the buccal-lingual direction.

[0167] As shown in FIG. 21, a continuous cross section Q1 is set for the alveolar bone 100, and the set continuous cross section Q1 is set as a continuous cross section at a reference position. Boundary surfaces T1, T2, and T3 are set toward the buccal side with respect to the continuous cross section Q1. The boundary surfaces T1, T2, and T3 may be surfaces obtained by reducing the continuous cross section Q1 toward the buccal side. A different display color is set for each region of the second region R2 of the alveolar bone 100 that is divided by the continuous cross section Q1 and the boundary surfaces T1, T2, and T3. For example, the display color may be set so that it changes from cool to warm colors as it moves away from the continuous cross section Q1 (e.g., toward the buccal side), or the display color may be set so that it gradually changes from light to dark colors as it moves away from the continuous cross section Q1 (e.g., toward the buccal side).

[0168] The changed display color may be allocated according to the distance from the continuous cross-section of the reference position in this way, but may also be allocated according to the distance from the buccal surface BSF of the alveolar bone or the distance from the lingual surface TSF of the alveolar bone. In this way, the changed display color may be allocated according to the buccal-lingual distance from a reference position surface such as the continuous cross-section Q1 of the reference position, the buccal surface BSF of the alveolar bone, or the lingual surface TSF of the alveolar bone.

[0169] A rendering process is performed on the volume data 54a so as to present the set display color, and a stereoscopic image Imv for display is generated and displayed on the image processing device 50.

[0170] Fig. 22 is a diagram showing a display example in which the display color of the second region R2 is color-coded according to the position in the buccolingual direction. The buccolingual position of the continuous cross section Q1 is different between Fig. 22(a) and Fig. 22(b). In Fig. 22(a), it is closer to the buccolingual side in the buccolingual direction, and in Fig. 22(b), it is closer to the lingual side in the buccolingual direction. In Fig. 22(a), the display color of the alveolar bone is color CL1, and in Fig. 22(b), the display color of the alveolar bone is color CL2. In the example shown in Fig. 22, a cavity CV due to bone resorption is observed in the alveolar bone, and in Fig. 22(a), the cavity CV appears small because its extent is narrow at this depth, but in Fig. 22(b), it appears large because its extent is large at this depth.

[0171] Since the alveolar bone is actually composed of a mesh-like tissue inside, if the display color of the second region R2 displayed in the continuous cross sections Q1 varies depending on the position in the buccolingual direction, the depth of the unevenness and depressions of each part of the second region R2 displayed in the continuous cross sections Q1 can be easily grasped. Also, the position of each part of the second region R2 in the buccolingual direction can be easily grasped (see FIG. 27 described later).

[0172] The display color may be displayed only at the continuous cross section Q1, but the tissues that have a visible depth may be displayed in different colors according to the depth. For example, as shown in square brackets in Fig. 22(b), the colors CL2, CL3, and CL4 may be displayed differently according to the depth of the cavity.

[0173] <Transparency variation> Examples of setting the transparency are not limited to the above examples. In order to be able to observe the teeth 110 through the first region R1, it is preferable that the transparency of the region of the teeth 110 is smaller than the transparency of the first region R1.

[0174] For example, the transparency of the first region R1 may be an intermediate value greater than 0 percent and less than 100 percent (e.g., 80 percent; hereinafter, transparency greater than 0 percent and less than 100 percent will simply be referred to as the intermediate value), the transparency of the second region R2 may be an intermediate value less than the transparency of the first region R1 (e.g., 50 percent), and the transparency of the region of the teeth 110 may be an intermediate value less than the transparency of the second region R2 (e.g., 20 percent).

[0175] Alternatively, the transparency of the first region R1 may be an intermediate value (e.g., 80 percent), the transparency of the second region R2 may be an intermediate value (e.g., 20 percent) lower than the transparency of the first region R1, and the transparency of the region of the tooth 110 may be a value between the transparency of the first region R1 and the transparency of the second region R2 (e.g., 50 percent). If the transparency of the region of the tooth 110 is higher than the transparency of the second region R2, the tooth 110 is displayed more transparent than the second region R2, which is suitable for observing the second region R2 while grasping the general shape of the tooth 110.

[0176] When it is desired to closely observe the teeth 110, the transparency of the region of the teeth 110 may be less than the transparency of the second region R2.

[0177] For example, the transparency of the first region R1 may be an intermediate value (e.g., 80 percent), the transparency of the second region R2 may be an intermediate value (e.g., 50 percent) lower than the transparency of the first region R1, and the transparency of the region of the teeth 110 may be a value lower than that of the second region R2 (e.g., 20 percent). Since the second region R2 is displayed more transparent than the teeth 110, it is easy to observe the teeth 110 while grasping the general shape of the second region R2.

[0178] When the transparency of the first region R1 or the second region R2 is set to an intermediate value, a volume-rendered stereoscopic image for display may be generated based on the volume data 54a. Fig. 23 shows a volume-rendered image in which the transparency of the first region R1 is set to an intermediate value. In this case, the internal structure of the alveolar bone region Alv is easily grasped. Furthermore, if the difference in transparency between the first region R1 and the second region R2 is appropriately set, the second region R2 appearing in the continuous cross sections can be easily observed.

[0179] <Other Modifications> In the above embodiment, an example is shown in which a stereoscopic image for display is generated with the buccal side as the viewpoint. The viewpoint direction of the stereoscopic image for display may be variably adjusted by, for example, dragging a mouse or operating a cursor. When a stereoscopic image for display is generated and displayed with the viewpoint located on the buccal side as a reference, the second region may be located on the buccal side and the first region may be located on the lingual side with the continuous cross sections Q1 and Q2 as the boundary.

[0180] In this embodiment, an X-ray imaging device including an image processing device has been described. The image processing device that performs the processing for display may be a device separate from the device that performs X-ray CT imaging and the device that executes the processing for reconstructing three-dimensional data from the captured data. For example, the image processing device may perform the image processing on image data provided from the outside via communication or a storage medium to generate a stereoscopic image for display.

[0181] In addition, in the stereoscopic image for display, the color of the tooth 110 and the color of the second region R2 may be different. For example, the tooth 110 may be displayed in an achromatic color, such as white, and the second region R2 may be displayed in a chromatic color. Also, the surface of the tooth 110 may be displayed in an achromatic color, such as white, and the second region R2 may be displayed in a chromatic color.

[0182] Figures 10, 11, 12, 22, and 23 are figures generated by CT scanning of the actual maxillofacial region and processing the images, as shown in Figures 24 to 28. Figure 24 corresponds to Figure 10, Figure 25 corresponds to Figure 11, Figure 26 corresponds to Figure 12, Figure 27 corresponds to Figure 22, and Figure 28 corresponds to Figure 23. However, Figures 24, 26, 27, and 28 differ from Figures 10, 12, 22, and 23 in that the processing target is the entire upper and lower jaws.

[0183] The configurations described in the above embodiment and modifications can be combined as appropriate as long as they are not mutually inconsistent.

[0184] The present disclosure discloses the following aspects.

[0185] The first aspect is an image processing device that processes image data of the maxillofacial region obtained by X-ray CT imaging, and includes a memory unit that stores the image data including the alveolar bone region, and an image processing unit that generates a three-dimensional image for display based on the image data, wherein the image processing unit executes a process of setting continuous cross-sections in the alveolar bone region that curve along the alveolar bone region, and a process of generating, as the three-dimensional image for display, an image in which the transparency of a first region located within one side of the alveolar bone region with the continuous cross-sections as a boundary is displayed greater than the transparency of a second region located within the alveolar bone region with the continuous cross-sections as a boundary.

[0186] According to this image processing device, continuous cross sections that curve along the alveolar bone region are set in the alveolar bone region, and a stereoscopic image for display is generated in which the transparency of a first region located in one side of the alveolar bone region with the continuous cross sections as a boundary is greater than the transparency of a second region located in the other side of the alveolar bone region with the continuous cross sections as a boundary. Therefore, the continuous cross sections that curve along the alveolar bone can be easily observed by the stereoscopic image for display. This provides a stereoscopic image for display that is suitable for observing a wider range along the alveolar bone region based on image data of the maxillofacial region obtained by X-ray CT imaging.

[0187] A second aspect is the image processing device according to the first aspect, wherein the image processing unit determines the continuous cross sections curved along the alveolar bone region based on the image data.

[0188] This allows for the determination of continuous cross sections suitable for image data obtained by X-ray CT imaging.

[0189] A third aspect is an image processing device according to the first or second aspect, wherein the alveolar bone region includes an alveolar bone region of the upper jaw and an alveolar bone region of the lower jaw, and the image processing unit may set, as the continuous cross sections, an upper continuous cross section which is a cross section that curves along the alveolar bone region of the upper jaw in the alveolar bone region of the upper jaw, and a lower continuous cross section which is a cross section that curves along the alveolar bone region of the lower jaw in the alveolar bone region of the lower jaw.

[0190] In this case, a stereoscopic image for display suitable for observing a wider range along the upper and lower alveolar bone regions is provided based on image data of the maxillofacial region obtained by X-ray CT imaging.

[0191] A fourth aspect is an image processing device relating to any one of the first to third aspects, wherein the image processing unit may generate a volume-rendered image based on the image data as the stereoscopic image for display.

[0192] This makes it easy to grasp the internal structure if the transparency is set appropriately.

[0193] A fifth aspect is the image processing device according to any one of the first to fourth aspects, wherein the stereoscopic image for display may be an image in which the first region is made invisible.

[0194] In this way, when the first region is made invisible in the stereoscopic image for display, the second region is easily and clearly observed in the successive cross sections.

[0195] A sixth aspect is an image processing device relating to any one of the first to fifth aspects, wherein the image data includes a dental arch region in which a plurality of teeth are arranged in an arch shape, and the image processing unit identifies the region of the plurality of teeth, and generates, as the stereoscopic image for display, an image in which the transparency of the tooth region is displayed less than the transparency of the first region.

[0196] In this case, the teeth are easily observed since their transparency is small.

[0197] A seventh aspect is an image processing device relating to any one of the first to sixth aspects, wherein the image data includes a dental arch region in which a plurality of teeth are arranged in an arch shape, and the image processing unit may identify a root position in the dental arch region and set the continuous cross-section based on the root position.

[0198] This makes it easy to observe how the teeth along the dental arch are embedded in the alveolar bone region.

[0199] An eighth aspect is an image processing device relating to any one of the first to seventh aspects, wherein the image processing unit may identify a surface position of the alveolar bone region and set the continuous cross-sections according to a distance from the surface position of the alveolar bone region.

[0200] This allows continuous cross sections corresponding to the distance from the surface of the alveolar bone region to be easily observed.

[0201] A ninth aspect is an image processing device relating to any one of the first to eighth aspects, further comprising an operation receiving unit that receives operations from an operator, and the image processing unit may change the continuous cross-sections based on the operation received by the operation receiving unit.

[0202] Thereby, the continuous cross section is changed by operating the operation receiving unit.

[0203] A tenth aspect is the image processing device according to the ninth aspect, wherein the image processing unit may move the continuous cross sections in a buccal-lingual direction based on an operation received by the operation receiving unit.

[0204] The successive sections moving in the buccolingual direction facilitate the observation of the entire dental arch at various depths relative to the surface of the alveolar bone region Alv.

[0205] An eleventh aspect is an image processing device relating to any one of the first to tenth aspects, wherein the image processing unit may generate, as the stereoscopic image for display, an image in which the display color of the second region displayed in the successive cross sections varies depending on the position in the buccolingual direction.

[0206] This makes it easy to grasp the position in the buccal-lingual direction of each part of the second display region displayed in the continuous cross sections.

[0207] A twelfth aspect is any one of the image processing devices from the first to the eleventh aspects, in which the continuous cross-sections are configured as a surface extending in the up and down directions of the subject's head and in a direction curving along the horseshoe shape of the dental arch, and may be configured to divide the alveolar bone region into a buccal region and a lingual region.

[0208] This makes it easier to view the upper and lower teeth along the dental arch.

[0209] The image processing program of the 13th aspect is an image processing program for causing a computer that processes image data of the maxillofacial region obtained by X-ray CT imaging to execute the following processes: setting continuous cross sections that curve along the alveolar bone region in the alveolar bone region included in the image data; and generating a three-dimensional image for display in which the transparency of a first region located within one side of the alveolar bone region with the continuous cross sections as a boundary is displayed greater than the transparency of a second region located within the alveolar bone region with the continuous cross sections as a boundary.

[0210] According to this image processing program, continuous cross sections curved along the alveolar bone are set in the alveolar bone region, and a stereoscopic image for display is generated in which the transparency of a first region located in one side of the alveolar bone region with the continuous cross sections as a boundary is greater than the transparency of a second region located in the other side of the alveolar bone region with the continuous cross sections as a boundary. Therefore, the continuous cross sections curved along the alveolar bone can be easily observed by the stereoscopic image for display. This provides a stereoscopic image for display suitable for observing a wider range along the alveolar bone region based on image data of the maxillofacial region obtained by X-ray CT.

[0211] A fourteenth aspect is an image processing device according to the sixth aspect, which enables the successive cross sections to be moved horizontally or buccolingually, and the image processing unit executes a process of changing the transparency based on the successive cross sections after the movement as the stereoscopic image for display, and generating a stereoscopic image for display.

[0212] A fifteenth aspect is an image processing device according to the fourteenth aspect, which generates the stereoscopic image for display in which the tooth region is a non-sectional display image.

[0213] A sixteenth aspect is an image processing device according to the fifteenth aspect, which generates the stereoscopic image for display with the transparency of the tooth area set to 0 percent.

[0214] A seventeenth aspect is an image processing device according to the sixteenth aspect, which generates the stereoscopic image for display with the transparency of the first region set to 100 percent.

[0215] An 18th aspect is an image processing device according to the 17th aspect, which generates the stereoscopic image for display with the transparency of the second region set to 0 percent. [Explanation of symbols]

[0216] 11 Root 20 X-ray equipment 30 X-ray imaging device 50 Image processing device 52 processors 52a Display 3D image generation unit 52b Motion control section 52c Volume data generation unit 54 Storage device 54a Volume Data 54b Program 56 Operation reception section 56a Mouse 56b Keyboard 58 Display device 100 Alveolar bone 100a outer surface 100b inner surface 102 Tooth Alveolar 110 teeth 112 Tooth root A. Maxillofacial region Alv Alveolar bone region Ar Arch Region Im Display Stereo Image M. Subject of the photo P head Q1, Q2 continuous section R1 1st area R2 2nd area

Claims

1. An image processing device that processes image data of a maxillofacial region obtained by X-ray CT, A storage unit that stores the image data including an alveolar bone region; an image processing unit that generates a stereoscopic image for display based on the image data; Equipped with The image processing unit includes: A process of setting continuous cross sections in the alveolar bone region, the cross sections being curved along the alveolar bone region; a process for generating, as the stereoscopic image for display, an image in which a transparency of a first region located within one side of the alveolar bone region with the continuous cross-section as a boundary is displayed greater than a transparency of a second region located within the alveolar bone region with the continuous cross-section as a boundary on the other side; An image processing device that performs the above.

2. 2. The image processing device according to claim 1, The image processing unit includes: An image processing device that determines the continuous cross sections curved along the alveolar bone region based on the image data.

3. 3. The image processing device according to claim 1, The alveolar bone region includes an upper jaw alveolar bone region and a lower jaw alveolar bone region, The image processing device sets, as the continuous sections, an upper continuous section, which is a section that curves along the alveolar bone region of the upper jaw in the alveolar bone region of the upper jaw, and a lower continuous section, which is a section that curves along the alveolar bone region of the lower jaw in the alveolar bone region of the lower jaw.

4. 3. The image processing device according to claim 1, The image processing device is configured to generate, as the display stereoscopic image, a volume-rendered image based on the image data.

5. 3. The image processing device according to claim 1, The image processing device, wherein the stereoscopic image for display is an image in which the first region is made invisible.

6. 3. The image processing device according to claim 1, The image data includes a dental arch region in which a plurality of teeth are arranged in an arch shape, The image processing unit includes: Identifying regions of the plurality of teeth; an image processing device that generates, as the stereoscopic image for display, an image in which the transparency of the tooth region is displayed less than the transparency of the first region;

7. 3. The image processing device according to claim 1, The image data includes a dental arch region in which a plurality of teeth are arranged in an arch shape, The image processing unit includes: Identifying a tooth root location in the dental arch region; An image processing device that sets the continuous cross sections based on the tooth root position.

8. 3. The image processing device according to claim 1, The image processing unit includes: Identifying a surface location of the alveolar bone region; An image processing device that sets the continuous cross sections in accordance with a distance from a surface position of the alveolar bone region.

9. 3. The image processing device according to claim 1, Further comprising an operation receiving unit for receiving an operation by an operator, The image processing unit changes the continuous cross sections based on an operation received by the operation receiving unit.

10. 10. The image processing device according to claim 9, The image processing unit moves the continuous cross sections in a buccal-lingual direction based on an operation received by the operation receiving unit.

11. 3. The image processing device according to claim 1, The image processing unit includes: an image processing device that generates, as the stereoscopic image for display, an image in which a display color of the second region displayed in the successive cross sections varies depending on a position in a buccolingual direction.

12. 3. The image processing device according to claim 1, An image processing device that configures the continuous cross-sections as surfaces that extend in the up and down directions of the subject's head and in a direction that curves along the horseshoe shape of the dental arch, and sets the alveolar bone region to be divided into a buccal region and a lingual region.

13. A computer that processes image data of the maxillofacial region obtained by X-ray CT scans. A process of setting continuous cross sections curved along an alveolar bone region in an alveolar bone region included in the image data; a process for generating a stereoscopic image for display in which a transparency of a first region located within one side of the boundary of the continuous cross-section in the alveolar bone region is displayed greater than a transparency of a second region located within the other side of the boundary of the continuous cross-section in the alveolar bone region; An image processing program for executing the above.

Images