Image processing device, image processing method and program

Abstract

The purpose is to make it easier to recognize biometric feature areas. [Solution] An image processing device includes a processing device and a display device that displays an image for observation. The processing device generates three-dimensional image data of the tissues that make up the dentition, detects biological feature regions in the tissues that make up the dentition, identifies three-dimensional positions where the biological feature regions L exist in the coordinate system of the three-dimensional image data, generates a dentition expansion image Ep in which the tissues that make up the dentition are expanded, identifies positions in the dentition expansion image that correspond to the three-dimensional positions of the biological feature regions, displays on the display device a biological feature region arrangement expansion image Eq in which an annotation image Q indicating the biological feature region is superimposed on the dentition expansion image so that the annotation image Q indicating the biological feature region is located at the corresponding position of the biological feature region, generates a detailed observation image D at the three-dimensional position based on the three-dimensional image data, and displays the detailed observation image D together with the biological feature region arrangement expansion image Eq on the display device.

Description

[Technical Field]

[0001] This disclosure relates to techniques for facilitating recognition of biometric feature regions. [Background technology]

[0002] Patent Document 1 discloses a technique for displaying a detected region of interest on a CT scan image.

[0003] Patent Document 2 discloses a technique for obtaining a panoramic tomographic image of the dentition using X-ray projection data of the dental and maxillofacial region obtained by X-ray CT imaging.

[0004] Patent Document 3 discloses a technology for detecting lesions by inputting CT images into a trained model. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2021-528751 [Patent Document 2] Japanese Patent Application Laid-Open No. 2008-229322 [Patent Document 3] Special Publication No. 2021-528751 Summary of the Invention [Problem to be solved by the invention]

[0006] According to the technique of displaying a detected region of interest on a CT scan image, as in Patent Document 1, it may be time-consuming to search for a CT scan image that displays the region of interest.

[0007] Therefore, an object of the present disclosure is to make it easier to recognize biometric feature regions. [Means for solving the problem]

[0008] The image processing device processes image data obtained by CT scanning of the tissues forming the dental arch to generate images for diagnosis, and is equipped with a storage device that stores the image data, a processing device, and a display device that displays an image for observation based on the output of the processing device, wherein the processing device generates three-dimensional image data of the tissues forming the dental arch based on the image data, detects biological feature areas in the tissues forming the dental arch based on the image data, identifies the three-dimensional position at which the biological feature area is located in the coordinate system of the three-dimensional image data, generates a dental arch expanded image in which the tissues forming the dental arch are expanded based on the three-dimensional image data, identifies a biological feature area corresponding position in the dental arch expanded image that corresponds to the three-dimensional position, displays on the display device a biological feature area arrangement expanded image in which the annotation image showing the biological feature area is superimposed on the dental arch expanded image so that the annotation image showing the biological feature area is located at the biological feature area corresponding position, generates an image for detailed observation at the three-dimensional position based on the three-dimensional image data, and displays the detailed observation image on the display device simultaneously with the biological feature area arrangement expanded image.

[0009] The image processing method processes image data obtained by CT scanning of the tissues forming the dental arch to generate an image for diagnosis, and includes generating three-dimensional image data of the tissues forming the dental arch based on the image data, detecting biological feature areas in the tissues forming the dental arch based on the image data, identifying the three-dimensional positions at which the biological feature areas are located in the coordinate system of the three-dimensional image data, generating a dental arch expanded image in which the tissues forming the dental arch are expanded based on the three-dimensional image data, identifying biological feature area corresponding positions in the dental arch expanded image that correspond to the three-dimensional positions, generating a biological feature area arrangement expanded image in which an annotation image showing the biological feature area is superimposed on the dental arch expanded image so that the annotation image showing the biological feature area is located at the biological feature area corresponding position, generating an image for detailed observation at the three-dimensional position based on the three-dimensional image data, and simultaneously displaying the biological feature area arrangement expanded image and the image for detailed observation on a display device.

[0010] The program processes image data obtained by CT scanning of the tissues forming the dental arch to generate an image for diagnosis, and causes a computer to execute the following processes: generate three-dimensional image data of the tissues forming the dental arch based on the image data; detect biological feature areas in the tissues forming the dental arch based on the image data; identify the three-dimensional positions at which the biological feature areas exist in the coordinate system of the three-dimensional image data; generate a dental arch expanded image in which the tissues forming the dental arch are expanded based on the three-dimensional image data; identify the biological feature area corresponding positions in the dental arch expanded image that correspond to the three-dimensional positions; display on a display device a biological feature area arrangement expanded image in which an annotation image showing the biological feature area is superimposed on the dental arch expanded image so that the annotation image showing the biological feature area is located at the biological feature area corresponding position; generate an image for detailed observation at the three-dimensional position based on the three-dimensional image data; and display the detailed observation image on the display device simultaneously with the biological feature area arrangement expanded image. [Effects of the Invention]

[0011] According to the present disclosure, biometric feature areas are easily recognized. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a schematic diagram showing an image processing device and a CT imaging device according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing the electrical configuration of the image processing device and the CT imaging device. [Figure 3] FIG. 3 is a functional block diagram of the arithmetic circuit. [Figure 4] FIG. 4 is a flowchart showing an example of processing by the image processing device. [Figure 5] FIG. 5 is an explanatory diagram showing the FOV region. [Figure 6] FIG. 6 is an explanatory diagram showing an example of a region where the tissues constituting the dentition spread. [Figure 7] FIG. 7 is an explanatory diagram showing the positional relationship between the tissues constituting the dentition and the lesion area within the FOV region. [Figure 8]FIG. 8 is an explanatory diagram showing an example of coordinates of a lesion area in a tissue constituting the dentition. [Figure 9] FIG. 9 is an explanatory diagram showing an example of processing for developing tissues constituting the dentition into an expanded image of the dentition. [Figure 10] FIG. 10 is a diagram showing a developed image of the layout of biometric feature regions. [Figure 11] FIG. 11 is a diagram showing a display example of a detailed observation image and a biological feature region layout expanded image. [Figure 12] FIG. 12 is a flowchart showing a specific example of the process of step S10 in FIG. [Figure 13] FIG. 13 is an explanatory diagram showing an example of a moving operation process for a detailed observation image. [Figure 14] FIG. 14 is a diagram showing a developed image of a biometric feature area layout according to the first modified example. [Figure 15] FIG. 15 is a diagram showing an expanded image of a row of teeth according to the second modified example. [Figure 16] FIG. 16 is an explanatory view showing a state in which the head is positioned by the head holder in the third modified example. [Figure 17] FIG. 17 is an explanatory diagram showing the positional relationship between the head holding part and the tissues E that constitute the dentition. [Figure 18] FIG. 18 is a schematic diagram showing an image processing device according to a fourth modified example. [Figure 19] FIG. 19 is a block diagram showing the electrical configuration of the image processing device. DETAILED DESCRIPTION OF THE INVENTION

[0013] {Embodiment} An image processing apparatus, an image processing method, and a program according to an embodiment will be described below.

[0014] <Configuration including image processing device and CT imaging device> FIG. 1 is a schematic diagram showing an image processing device 20 connected to a CT imaging device 10. As shown in FIG.

[0015] The CT imaging device 10 is a device that performs CT (Computed Tomography) imaging of the tissues that make up the dentition to obtain image data. The obtained image data includes data related to the tissues that make up the dentition. The image processing device 20 processes the image data to generate an image for diagnosis.

[0016] For example, the CT imaging device 10 includes an X-ray generator 11, an X-ray detector 12, a rotating arm 13, a support 14, and an imaging processing unit 15.

[0017] Three-dimensional coordinates are set for calculation purposes in the space in which the CT imaging device 10 exists. For example, the three-dimensional coordinates are set based on the orientation of the subject positioned for imaging, with the Z direction along the body axis, the X direction perpendicular to the Z direction and extending along the left-right direction of the subject, and the Y direction perpendicular to the Z direction and extending along the front-to-back direction of the subject. In this embodiment, the subject is positioned at the examination position in an upright position, so the Z direction is perpendicular to the floor surface, along which the support 14 extends.

[0018] The X-ray generator 11 includes an X-ray tube and is configured to emit an X-ray beam toward the subject. The X-ray detector 12 includes an X-ray detection sensor. The X-rays emitted from the X-ray generator 11 pass through the subject and are detected by the X-ray detector 12.

[0019] The rotating arm 13 is, for example, a member formed in a U-shape that opens downward. An X-ray generator 11 and an X-ray detector 12 are supported at both ends of the rotating arm 13 in an opposing state. A subject can be placed between the X-ray generator 11 and the X-ray detector 12. The subject is a part of the human body that includes tissues that form the dentition, i.e., the head including the jaw.

[0020] The support pillar 14 is erected so as to extend in the direction of gravity (vertical direction). A cantilever arm 14a is supported on the support pillar 14 so as to be movable up and down. A swivel arm 13 is rotatably supported on the cantilever arm 14a. The height position of the swivel arm 13 is adjusted along the support pillar 14 to match the height position of the head.

[0021] With the subject's head positioned between both ends of the rotary arm 13, the rotary arm 13 is rotated, causing the X-ray generator 11 and the X-ray detector 12 to rotate around the head, thereby performing X-ray CT imaging of the head and obtaining image data.

[0022] For example, when the rotating arm 13 rotates, X-ray imaging is performed at each small rotation angle. This allows X-ray projection image data (frame data) to be obtained for each small rotation angle. Three-dimensional volume data of the subject is generated based on a group of X-ray projection image data (frame data group) captured at different rotation angles. This three-dimensional volume data is three-dimensional image data that indicates the distribution of X-ray absorption rate of the subject in a three-dimensional coordinate system.

[0023] The CT imaging device 10 may include a head holder 9. The head holder 9 is a part that holds the head, which is the subject of imaging. The head holder 9 may include a chin rest 9a that supports the chin. The chin rest 9a can support the front and bottom of the chin of the head. This positions the head in a fixed position in the front-to-back and up-to-down directions. The head holder 9 may also include two side holders 9b that position the head from both sides. The two side holders 9b may be, for example, ear rods that contact both ears of the head. The two side holders 9b position the head in a fixed position in the left-to-right direction.

[0024] The image processing device 20 processes image data obtained by CT imaging to generate an image for diagnosis. The image data obtained by CT imaging may be a group of X-ray projection image data for each small rotation angle, or may be three-dimensional volume data. In this embodiment, an example will be described in which the image data obtained by CT imaging is a group of X-ray projection data for each small rotation angle.

[0025] The image processing device 20 comprises a processing unit 30, a display device 22, and user interfaces 24, 26.

[0026] The processing unit 30 is configured with a computer, a workstation, or the like. The processing unit 30 is connected to the imaging processing unit 15 of the CT imaging device 10 via a wired or wireless connection, and can transmit and receive various data to and from the imaging processing unit 15. In this embodiment, the processing unit 30 can receive image data obtained by CT imaging from the imaging processing unit 15. Some or all of the functions of the processing unit 30 may be realized by a cloud server.

[0027] The display device 22 is, for example, a liquid crystal display or an organic EL (electro-luminescence) display, and is connected by wire or wirelessly to the processing unit 30. The display device 22 can display an image for diagnosis based on the output for display of the processing unit 30.

[0028] The user interfaces 24, 26 are devices that accept instructions from a user of the image processing device 20. The user interface 24 may be, for example, a switch device such as a keyboard. The user interface 26 may be, for example, a pointer device such as a mouse. If the user interface is a switch device, the user's instructions can be input using the switch device alone. If the user interface is a pointer device, the user's instructions can be input by operating characters or images displayed on the display device 22. The user interface may be a touch panel.

[0029] <Electrical configuration of the image processing device and CT imaging device> FIG. 2 is a block diagram showing the electrical configuration of the image processing device 20 and the CT imaging device 10.

[0030] The CT imaging device 10 includes an imaging processing unit 15, an imaging unit driving mechanism 18, and a user interface 19.

[0031] The photographing processing unit 15 is composed of a computer including an arithmetic circuit 16 and a storage device 17 .

[0032] The arithmetic circuit 16 includes a processor 16a. The processor 16a may be a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit).

[0033] The storage device 17 is configured by a non-volatile storage device such as a flash memory or a hard disk drive. The storage device 17 may also be a memory circuit. The storage device 17 stores a program. The program describes the procedure for the CT imaging device 10 to perform CT imaging.

[0034] The imaging unit drive mechanism 18 is connected to the photographing processing unit 15. The imaging unit drive mechanism 18 includes a rotation drive mechanism for rotating the rotating arm 13. The rotation drive mechanism includes an actuator and a transmission mechanism. The actuator is an electric motor or the like that generates a rotation drive force. The transmission mechanism is gears, pulleys, or the like that transmit the rotation drive force of the actuator. The rotation drive force of the actuator is transmitted to the rotating arm 13 via the transmission mechanism, and the rotating arm 13 rotates at a timing and rotation speed according to a command from the photographing processing unit 15.

[0035] The user interface 19 is an interface for giving instructions to the CT imaging apparatus 10, and is a switch device, a pointer device, or the like. The user interface 19 is connected to the imaging processing unit 15. A user can give various instructions to the CT imaging apparatus 10 through the user interface 19.

[0036] The X-ray generator 11 and the X-ray detector 12 are also connected to the imaging processing unit 15. The X-ray generator 11 irradiates X-rays at the timing and output according to instructions from the imaging processing unit 15, and the X-ray detector 12 outputs the detection result to the imaging processing unit 15.

[0037] The processor 16a executes processing according to the program in the storage device 17, whereby the imaging unit drive mechanism 18 controls the rotation of the rotation arm 13 and also controls the X-ray irradiation operation of the X-ray generator 11. For each minute rotation angle of the rotation arm 13, the detection results of the X-ray detector 12 are input to the imaging processing unit 15, and the processor 16a generates X-ray projection image data for each minute rotation angle based on the detection results. The data 17a is stored in the storage device 17.

[0038] The image processing device 20 comprises a processing unit 30, a display device 22, and user interfaces 24, 26.

[0039] The processing unit 30 is connected to the display device 22 and the user interfaces 24, 26. The processing unit 30 can receive instructions from a user via the user interfaces 24, 26. The processing unit 30 can control the display of the display device 22.

[0040] The processing unit 30 is configured by a computer having an arithmetic circuit 32 as a processing device and a storage device 34 .

[0041] The arithmetic circuit 32 includes a processor 32a. The processor 32a may be a central processing unit (CPU). The processor 32a may include a graphics processing unit (GPU) or a processor for artificial intelligence (AI).

[0042] The storage device 34 is configured by a nonvolatile storage device such as a flash memory or a hard disk drive, or may be a memory circuit. The storage device 34 stores a program 34a and data 34b.

[0043] The program 34a describes a procedure for the image processing device 20 to process image data obtained by CT imaging and generate an image for diagnosis.

[0044] The data 34b includes image data transmitted from the CT imaging device 10 and data generated by the processing for generating the diagnostic image. After processing, the data 34b may be left as history data or may be deleted.

[0045] The processing unit 30 includes a connection port 36. The processing unit 30 is connected to the CT imaging device 10 through the connection port 36. The connection port 36 may include a terminal connected to a signal line of a wired cable extending from the CT imaging device 10 and a circuit for communication processing. The processing unit 30 and the CT imaging device 10 may be connected wirelessly, in which case the connection port 36 may include a circuit for wireless processing. The data 17a of the X-ray projection image data group from the CT imaging device 10 is transmitted to the processing unit 30 via the connection port 36 and stored in the storage device 34.

[0046] The arithmetic circuitry 32 reads the program 34a stored in the storage device 34 and executes the processes described in the program 34a, thereby enabling the arithmetic circuitry 32 to execute various processes for generating images for diagnosis, as will be described later. The processing unit 30 may also control CT imaging by the CT imaging device 10.

[0047] 3, the processing function unit realized by the arithmetic circuit 32 reading the program 34a may include a biological data processing unit 33. The biological data processing unit 33 may include a biological tissue data processing unit 33a and a biological feature region data processing unit 33b.

[0048] The biological tissue data processing unit 33a performs processing to generate three-dimensional data of the tissues constituting the dentition based on image data. The tissues constituting the dentition are, for example, tissues including the dentition and alveolar bone. The tissues constituting the dentition may be tissues including the dentition and jawbone. The jawbone in the tissues constituting the dentition may be the region of the jawbone that supports the teeth, and may include not only the alveolar bone but also its surrounding region. In this application, the alveolar bone is understood to be a partial region of the jawbone, that is, the part of the jawbone that forms the alveolus and supports the teeth. This understanding is in accordance with the explanation in the Encyclopedia of Dentistry. The tissues constituting the dentition may be horseshoe-shaped in a planar view. Note that the planar view may be considered as a planar view with the line of sight extending from the head to the feet in the axial direction of the body axis. The tissues constituting the dentition may extend to have a thickness in the buccolingual direction. The tissues constituting the dentition may be tissues that have at least the thickness of the dentition in the buccolingual direction. The tissues constituting the dentition may be tissues that have a thickness in the region of the jawbone that supports the dentition. The tissues constituting the dentition may include upper and lower dental arches and upper and lower jawbones supporting the upper and lower dental arches. Each of the upper and lower dental arches includes a plurality of teeth arranged in an arch shape. The upper jawbone has an alveolar bone supporting the teeth of the upper dental arch. The lower jawbone has an alveolar bone supporting the teeth of the lower dental arch. The biological tissue data processing unit 33a, for example, identifies the regions of each of the plurality of teeth and the regions of the upper and lower jawbones in the 3D volume data. The identification of the regions of the teeth and the upper and lower jawbones may be performed by applying a trained machine learning model. For example, a large amount of data in which the regions of the teeth and the regions of the upper and lower jawbones are mapped onto the 3D volume data is prepared as training data. Using the training data, a machine learning model trained to segment the regions of the teeth and the regions of the upper and lower jawbones in the 3D volume data is prepared. The machine learning model may be, for example, a model trained based on a semantic segmentation algorithm. The trained machine learning model is applied to the 3D volume data to identify the regions of each tooth and the upper and lower jaw bones in the 3D coordinate system, thereby distinguishing the tooth row region from the alveolar bone region based on the 3D volume data.

[0049] The regions of the plurality of teeth and the regions of the upper and lower jaw bones in the three-dimensional volume data may be identified by a region extraction process according to a predetermined rule, such as a pattern matching process.

[0050] The processing performed by the biological feature region data processor 33b is processing for detecting characteristic regions in the tissues constituting the dentition based on image data. Characteristic regions in the tissues constituting the dentition are, for example, regions in the tissues constituting the dentition where lesions have occurred. Lesions are changes caused by disease. Regions in which lesions have occurred exhibit a distribution of X-ray attenuation that differs from the distribution of X-ray attenuation exhibited by normal tissues constituting the dentition. Examples of diseases include chronic suppurative apical periodontitis and root granuloma. In the case of apical periodontitis, regions in the periphery of the tip of the tooth root exhibit lower X-ray attenuation than the normal state and its surroundings. Therefore, apical periodontitis can be detected when a low X-ray attenuation region is widespread around the periphery of the tooth root. For other lesions, regions in which lesions have occurred can be detected based on three-dimensional volume data obtained by CT imaging, based on the position of the tooth or jawbone in the tissues constituting the dentition, the spread pattern or distribution pattern of the X-ray attenuation region, and the like.

[0051] The detection by the biological feature area data processing unit 33b may be performed by applying a trained machine learning model similar to that used to identify the tissues constituting the dentition. For example, a large amount of data in which lesion areas are mapped onto 3D volume data is prepared as training data. Using the training data, a machine learning model trained to segment the lesion areas in the 3D volume data is prepared. The trained machine learning model is applied to the 3D volume data to detect the lesion area in a 3D coordinate system.

[0052] The detection of the lesion area in the three-dimensional volume data may be performed by image extraction processing, for example, pattern matching processing.

[0053] The detection of the lesion area does not have to be performed based on the three-dimensional volume data. For example, the lesion area may be detected by applying a machine learning model or pattern matching based on slice data obtained by slicing the three-dimensional volume data in any direction.

[0054] <Processing unit processing example> An example of processing by the processing unit 30 will be described with reference to the flowchart of FIG.

[0055] After starting the process, in step S1, the processing unit 30 acquires captured image data from the CT imaging device 10. The captured image data is, for example, data of a field of view (FOV) region including the dental arch Ht and jawbone Hj of the head H (see FIG. 5). The FOV may be set to, for example, a cylindrical region, an elliptical cylindrical region, or a triangular prism region.

[0056] In the next step S2, the processing unit 30 generates three-dimensional volume data based on the captured image data.

[0057] In this embodiment, in step S1, the captured image data acquired from the CT imaging device 10 is a group of X-ray projection image data. In step S2, three-dimensional volume data is generated based on the group of X-ray projection image data. The three-dimensional volume data may be generated based on the group of X-ray projection image data in the CT imaging device 10. In this case, the processing unit 30 may acquire the three-dimensional volume data as image data.

[0058] It is also possible that the CT imaging device 10 generates multiple tomographic images based on a group of X-ray projection image data. In this case, the processing unit 30 may acquire multiple tomographic images as image data from the CT imaging device 10 and generate three-dimensional volume data by superimposing the multiple tomographic images.

[0059] In the next step S3, the processing unit 30 executes a process of generating three-dimensional image data of the tissues that constitute the dentition based on the image data, and a process of detecting a biological characteristic region L in the tissues that constitute the dentition based on the image data.

[0060] As shown in FIG. 6, the area Ee in which the tissues constituting the dentition E extend includes the dental arch Ht in which multiple teeth T are arranged, and the upper and lower jawbones Hj, as described above. The tissues constituting the dentition may also include the temporomandibular joint Hjo. In the three-dimensional volume data, the area Ee in which the tissues constituting the dentition E extend may be called the tissues constituting the dentition area Ee. The tissues constituting the dentition area Ee is a horseshoe-shaped area that is set by calculation, and it need only be an area that matches the shape and position of the tissues constituting the dentition. The shape of the tissues constituting the dentition area Ee may match the shape of the tissues constituting the dentition E of a standard skeleton, and when the shape of the tissues constituting the dentition E of an individual is known, it may be set to a shape that matches that individual.

[0061] As described above, the process of generating three-dimensional image data of the tissues that make up the dentition based on image data may also be a process of identifying each region of a plurality of teeth and each region of the upper and lower jaw bones based on three-dimensional volume data, and combining these regions to generate three-dimensional data of the tissues that make up the dentition.

[0062] Each region of the multiple teeth and each region of the upper and lower jawbones may be identified by the surface of the teeth and jawbones, i.e., the boundaries between the interior and exterior of the teeth and jawbones. The planes formed by the boundaries may be considered surfaces. In other words, each region of the multiple teeth and each region of the upper and lower jawbones may be identified as the surface shapes of each tooth and jawbone in the three-dimensional coordinate system of the three-dimensional volume data. Functional tissues that constitute a living body, such as teeth and jawbones, may be referred to as functional tissues that constitute the dentition of a living body. For example, teeth are functional tissues that constitute the dentition, with the function of chewing food, and jawbones are functional tissues that support the teeth. The tissues that constitute the dentition may be considered to include multiple functional tissues that constitute the dentition. Because the region of the jawbone boundary facing the teeth is important, a learning model including segmentation of the alveolar inner wall may be prepared to enable highly accurate detection of the alveolar inner wall.

[0063] Furthermore, the process of detecting a biometric feature region in the tissues that form the dentition based on image data may be a process of detecting a characteristic region in the tissues that form the dentition based on three-dimensional volume data, as described above. In this embodiment, an example is described in which the biometric feature region is a region where a lesion has occurred. Here, if the biometric feature region is, for example, a plurality of lesion regions, the collection of biometric feature regions is naturally composed of a collection of individual lesion regions. An individual biometric feature region that constitutes a collection of biometric feature regions, such as this individual lesion region, may be called a unitary biometric feature region. A region where a plurality of unitary biometric feature regions are collected may be called a collective biometric feature region. An image of a biometric feature region may be called a biometric feature region image.

[0064] Step S3 generates three-dimensional image data of the dental arch-forming tissues E, including the dental arch and jawbone, within the FOV, and detects the presence of a lesion area L (biological characteristic area L) in the dental arch-forming tissues E (see Figure 7).

[0065] The processing unit 30 may detect multiple biometric feature regions. In other words, when one biometric feature region (unitary biometric feature region) is detected, the processing unit 30 does not end the detection of the biometric feature region, but continues to detect other biometric feature regions. In this way, if multiple biometric feature regions exist in the dentition-forming structures E, the multiple biometric feature regions (collective biometric feature region) are detected.

[0066] In this embodiment, the explanation is given on the assumption that some kind of biometric feature region is present. If no biometric feature region is detected, the processing may end.

[0067] In step S4, the processing unit 30 calculates the three-dimensional position of the detected biometric feature area, i.e., the three-dimensional coordinates, in the coordinate system of the three-dimensional image data of the dentition-forming tissues E. The coordinates of the biometric feature area are the positions to be displayed as the positions of the biometric feature area in the developed image described below. The coordinates of the biometric feature area may be point coordinates located within the boundary of the lesion area detected in step S4. The coordinates of the biometric feature area may be, for example, the geometric center of the surface of the lesion area detected in step S3 (see FIG. 8). They may also be any position on the surface of the lesion area (e.g., the lower or upper end). For the three-dimensional coordinates of the three-dimensional image data, the X1 direction, which is the same as the X direction, the Y1 direction, which is the same as the Y direction, and the Z1 direction, which is the same as the Z direction, are set based on the spatial coordinates of the CT imaging device, for example, based on the orientation of the subject during imaging. The three-dimensional position where the biometric feature area exists may be referred to as the three-dimensional position of the biometric feature area.

[0068] In the next step S5, the processing unit 30 determines whether or not there is a command to display an unfolded image. The command to display an unfolded image is accepted using the user interfaces 24, 26. When the user inputs a command to display an unfolded image using the user interfaces 24, 26, the processing unit 30 determines that there is a command to display an unfolded image, and proceeds to step S6. When the user does not input a command to display an unfolded image, the processing unit 30 determines that there is no command to display an unfolded image, and proceeds to step S13.

[0069] In step S13, the processing unit 30 determines whether or not there is another command via the user interface 24, 26, etc. If it is determined that there is another command, the processing unit 30 executes the other process. If it is determined that there is no other command, the process returns to step S5, and the processing unit 30 repeats the process of determining whether or not there is a command to display the unfolded image.

[0070] When the process proceeds to step S6, the processing unit 30 generates a dentition expanded image Ep by expanding the dentition-forming tissues E based on the three-dimensional image data of the dentition-forming tissues E. The dentition expanded image Ep is an image in which the dentition-forming tissues E, which are arch-shaped or horseshoe-shaped in a planar view, are expanded to form a straight line in a planar view (see FIG. 9). For example, the dentition expanded image Ep is generated as follows: At each coordinate position in the vertical direction, a curve forming an arch or horseshoe shape that passes through the center of the dentition-forming tissues E in the buccolingual direction is calculated. At each position along the curve, the presence or absence of an image or the transparency in a direction perpendicular to the tangent to the curve is calculated. The presence or absence of an image or the transparency at each coordinate on the curve is expressed as the presence or absence of an image or the transparency at each coordinate on the straight line. The dentition expanded image Ep is generated by performing the above process at each coordinate position in the vertical direction and overlapping them in the vertical direction.

[0071] In addition, when the three-dimensional image data of the dental arch-forming tissues E is represented by semi-transparent data of the surface of the dental arch-forming tissues E, the areas that are the boundaries of the dental arch-forming tissues in the dental arch expanded image Ep are represented with low transparency and in dark colors.

[0072] The dentition expansion image Ep is a type of panoramic image in which the dental arch is expanded in a plane. The dentition expansion image Ep may also include the alveolar bone. The dentition expansion image Ep may also include the jawbone. The dentition expansion image Ep may be an image of the dentition-constituting tissues E transmitted through the thickness direction, or may be a tomographic image of an arbitrary position in the thickness direction.

[0073] The dentition expanded image Ep may be an image obtained by viewing the entire area of ​​the tissues constituting the dentition E in a normal view. An image obtained by viewing the entire area of ​​the tissues constituting the dentition E in a normal view is an image obtained by viewing the entire tissues constituting the dentition E from in front of the midline of the head H (from a normal viewing direction Dv that views the anterior tooth region normal) when the dentition expanded image Ep is expanded in a direction perpendicular to the midline Md of the head H, as shown in Fig. 9.

[0074] The dentition expanded image Ep may be superimposed not only with 3D image data of the dentition-forming structures E but also with data obtained by converting 3D volume data into a panoramic image. The dentition expanded image Ep does not necessarily have to be expanded to form a straight line in a planar view, and may include curvature or refraction. In other words, the dentition expanded image Ep may be an image that allows the entire dentition-forming structures E to be observed at a glance. For example, the expansion may be processed so that the left and right end regions of the dentition-forming structures region Ee are displaced more anteriorly than the central region. A linear or nearly linear expansion in a planar view is referred to as "flat expansion," and the dentition expanded image Ep may be an image that is flatly expanded. The image process for generating the dentition expanded image Ep so that the entire dentition-forming structures E can be observed at a glance may be called an expansion process. In particular, a flat expansion process may be called a flat expansion process. A flat expansion may also be called a flat expansion.

[0075] By applying the above process to the biometric feature region in a similar manner, a biometric feature region corresponding position P2 in the dentition expansion image Ep is calculated. The biometric feature region corresponding position P2 may be considered to be a position obtained by converting the three-dimensional position P1 of the biometric feature region calculated in step S4 using the same geometric conversion process as that used to expand the dentition-constituting structures E into the dentition expansion image Ep. The three-dimensional position P1 can be determined, for example, at the center of the biometric feature region. The center of the biometric feature region may be the geometric center or the center of gravity.

[0076] The three-dimensional position P1 may be the position of a point (i.e., a position indicating a specific point) as the object of calculation, but if the biometric feature area has a certain extent, it may also be the position of at least a part of that area. For example, the three-dimensional position P1 may be a certain area around the center including the center. The three-dimensional position P1 may also be the position of the entire biometric feature area. Therefore, the corresponding position P2 may also be the position of a point or an area as the object of calculation.

[0077] The area set by calculation when the dentition tissue area Ee is expanded may be considered to be the dentition expanded area Ex. A flat expansion of the dentition tissue area Ee may also be called a flat expansion, and in particular, the flatly expanded dentition expanded area Ex may be considered to be the dentition flat expanded area Exp.

[0078] The expansion of the tissues forming the dentition E may be performed by an expansion process that expands image data of the tissues forming the dentition area Ee so that it fits the shape of the dentition expanded area Ex. In the following discussion, it is assumed that the area occupied by the tissues forming the dentition E and the tissues forming the dentition area Ee match, and that the area occupied by the expanded image of the dentition Ep matches the dentition expanded area Ex.

[0079] The state of the dentition-constituting tissue region Ee before expansion may be called the pre-expansion curved state, and the state of the dentition expansion region Ex after expansion may be called the post-expansion view state. The expansion process is preferably performed so that the buccolingual direction BLD in the pre-expansion curved state corresponds to the normal view direction NVD in the post-expansion view state.

[0080] The normal viewing direction may be a direction perpendicular to or normal to the normal plane of the dentition spread area Ex, but a viewing direction based on another concept may also be set. For example, a virtual viewpoint Ey1 may be set in the normal viewing direction at the center of the dentition spread area Ex, and image processing may be performed along the viewing direction EVD from this viewpoint.

[0081] In the dentition spread area Ex and / or dentition spread image Ep, the area that exists at the biometric feature area corresponding position P2 and corresponds to the biometric feature area L may be called a biometric feature area corresponding area Lc.

[0082] Since the dentition tissue region Ee has a thickness in the buccolingual direction, the dentition expanded region Ex also has a thickness in the normal viewing direction corresponding to the thickness in the buccolingual direction. Furthermore, since the dentition tissue E has a thickness in the buccolingual direction as described above, the dentition expanded image Ep also has a thickness in the normal viewing direction corresponding to the buccolingual direction.

[0083] The dentition expansion area Ex has a thickness corresponding to the dentition tissue area Ee, and therefore, unlike a thin panoramic slice, it can be contained within the area even if the location of the biological feature area is biased in the buccolingual direction (in image processing, the biological feature area image is contained within the area without blurring). The coordinates of the three-dimensional position P1 may be calculated as coordinates within the FOV area, or as coordinates within the dentition tissue area Ee.

[0084] In the expansion, a calculation may be performed to associate the three-dimensional position P1 of the biometric feature region with the biometric feature region corresponding position P2. The calculation to perform this correspondence may be called an original coordinate calculation. The original coordinate calculation may include a calculation to identify the position of the three-dimensional position P1 of the biometric feature region in the buccolingual direction. Also, a calculation may be performed to identify the position of the biometric feature region corresponding position P2 in the normal viewing direction corresponding to the buccolingual direction.

[0085] Then, as shown in FIG. 10, the processing unit 30 displays on the display device 22 a biometric feature region arrangement expanded image Eq in which the annotation image Q is superimposed on the row of teeth expanded image Ep.

[0086] For calculation purposes, three-dimensional coordinates may be set for the dentition spread area Ex. For example, the left-right extension direction of the dentition spread area Ex when unfolded is defined as the R direction. The direction parallel to the body axis is defined as the T direction. In this embodiment, the T direction, Z direction, and Z1 direction are the same direction. The direction parallel to the normal viewing direction is defined as the S direction. In the dentition spread image Ep, the left-right direction is defined as the R direction, and the up-down direction is defined as the T direction. Once the conditions for specifying the RT coordinate on the dentition spread image Ep and the S direction are determined, it becomes possible to mutually identify the X1Y1Z1 coordinate. Therefore, in areas where both the RT coordinate and the S coordinate are determined, such as the biometric feature area corresponding area Lc in the dentition spread area Ex, it is possible to mutually identify the X1Y1Z1 coordinate of the biometric feature area L. Coordinates on the three-dimensional image data, such as the X1Y1Z1 coordinates, may be referred to as three-dimensional image data coordinates, and three-dimensional coordinates may be referred to as three-dimensional image data three-dimensional coordinates. Coordinates on the dentition spread area Ex, like the RST coordinates, may be called dentition spread area coordinates, and the three-dimensional coordinates may be called dentition spread area three-dimensional coordinates.

[0087] The annotation image Q is an image showing a biometric feature area. The annotation image Q may be an image that exhibits a color, shape, or change that is distinguishable from the background expanded image of the arch of teeth Ep. For example, the annotation image Q may be an image that exhibits a color different from that of the expanded image of the arch of teeth Ep. More specifically, the annotation image Q may be an image that exhibits a conspicuous warm color, such as red, orange, or yellow. The annotation image Q may be an image that exhibits a change in display, such as blinking, a change in color, or a change in shape, that makes it distinguishable from the expanded image of the arch of teeth Ep. The annotation image Q may be an image that exhibits a shape that is distinguishable from the expanded image of the arch of teeth Ep, such as a circle, a regular polygon, a radial shape, a cross shape, or an exclamation mark shape.

[0088] The annotation image Q may have a shape that shows the outline of the lesion area L. In this case, the approximate shape and size of the lesion area L can be known by looking at the biological feature area layout expanded image Eq.

[0089] The annotation image Q is superimposed on the row of teeth extruded image Ep so as to be positioned at the biological feature region corresponding position P2 in the row of teeth extruded image Ep.

[0090] In the example shown in FIG. 10, the boundaries between the teeth and jawbone are indicated by lines in the dentition expansion image Ep. The annotation image Q is indicated by a double circle with a dashed line. In the example shown in FIG. 10, two annotation images Q are shown. In other words, if multiple biometric feature regions are detected, multiple annotation images Q corresponding to each of the multiple biometric feature regions are recognizably displayed in the biometric feature region arrangement expansion image Eq. The number of annotation images Q may be one or more. The functional dentition-constituting tissues may be made semi-transparent by forming the boundaries (which may be considered as the boundaries between presence and absence) of the functional dentition-constituting tissues with uniform, sparsely-spaced dots, as in the tooth image THd. This results in high transparency in the area Or perpendicular to the line of sight, and low transparency in the area Bd aligned with the line of sight, making the boundaries easily visible despite the semi-transparency. The dots may be non-uniform to the extent that they do not cause visual difficulties. As long as the boundary surface has transparency, the image processing is not limited to dots, and can also be of a see-through surface such as a mesh. Whether it is dots or a mesh, the transparency changes depending on the line of sight as the density differs. Image processing in which the transparency changes depending on the line of sight may be called line of sight compatible transparency image processing.

[0091] An element whose transparency is increased, such as a dot that has become sparse compared to a dense state or a dot that has disappeared, is called a parent transparent element. In addition, increasing transparency is called parent transparency.

[0092] An element that reduces transparency, such as a dense dot compared to a sparse or non-existent state, is called an anti-transparency element. Also, reducing transparency is called anti-transparency.

[0093] The gaze direction compatible image processing for making transparent may be a combination of at least one of the following group A and at least one of the following group B. Group A: · Processing to enlarge or increase the parent transparency element of the normal boundary surface -Processing to promote parent transparency at the boundary of normal vision Treatment to reduce, diminish or eliminate the anti-transparency elements of the normal vision interface Treatment to suppress anti-transparency of the normal vision interface Group B: - Processing to reduce, decrease or eliminate parent transparency elements on the boundary surface of oblique or side views - Processing to suppress parent transparency at the boundary surface of oblique or side views Treatment to enlarge or increase the anti-transparency factor at the oblique or lateral viewing interface Treatment to promote anti-transparency at the interface of oblique or lateral vision The alveolar bone and jawbone portions may also be subjected to gaze direction-compatible transparent image processing.

[0094] Note that the case where multiple annotation images Q are displayed in a recognizable manner includes not only the case where multiple annotation images Q are displayed simultaneously, but also the case where multiple annotation images Q are displayed sequentially so that the presence of multiple annotation images Q can be recognized. For example, multiple annotation images Q may be displayed sequentially within 5 seconds, 3 seconds, or 1 second.

[0095] If no biometric feature region is detected in step S3, the process may not end and a row of teeth expanded image Ep without the annotation image Q may be displayed.

[0096] Step S5 may be omitted, and after the processing of step S4 is completed, the processing of step S6 may be performed regardless of whether or not a command is issued.

[0097] In the next step S7, the processing unit 30 determines whether or not a characteristic region has been designated. The characteristic region may be designated, for example, by selecting one of a plurality of annotation images Q with a pointer device such as a mouse. The characteristic region may also be designated by designating an annotation image Q with a switch device such as a keyboard. The processing of step S7 is repeated until a characteristic region is designated, and once a characteristic region is designated, the processing proceeds to the next step S8.

[0098] In step S8, the three-dimensional coordinates of the characteristic region designated in step S7 are calculated. For example, in step S6, when a dentition-exposed image Ep is generated by developing the dentition-exposed structures E based on the three-dimensional image data of the dentition-exposed structures E, the three-dimensional position P1 of the biological characteristic region is converted into a biological characteristic region corresponding position P2. This correspondence is stored in the storage device 34 as a table. The three-dimensional coordinates of the characteristic region designated in step S7 are calculated by referring to the table. Alternatively, the three-dimensional coordinates of the characteristic region designated in step S7 may be calculated by an inverse transformation process of the geometric transformation process that develops the dentition-exposed structures E into the dentition-exposed image Ep. This identifies the position of the designated characteristic region in the three-dimensional image data of the dentition-exposed structures E.

[0099] In the next step S9, a detailed observation image D is generated at the three-dimensional position of the three-dimensional image data based on the three-dimensional image data of the dentition-forming tissues E. Then, the detailed observation image D is displayed on the display device 22 simultaneously with the biological feature region arrangement expanded image Eq (see FIG. 11).

[0100] The detailed observation image D is an image that allows for more detailed observation than the dentition expansion image Ep and is suitable for more detailed diagnosis. In this embodiment, an example will be described in which the detailed observation image D includes multiple cross-sectional images Da, Db, and Dc, more specifically, three cross-sectional images Da, Db, and Dc that are orthogonal to each other (see FIG. 11).

[0101] The three cross-sectional images Da, Db, and Dc are cross sections taken along mutually orthogonal planes that pass through the three-dimensional position P1 of the biological feature region. The three cross-sectional images Da, Db, and Dc are generated by identifying a plane that passes through the three-dimensional position P1 in the three-dimensional image data of the dentition-forming tissues E and determining the distribution of X-ray transmittance along that plane. The three cross-sectional images Da, Db, and Dc may represent the distribution of X-ray transmittance in a thick slice layer. The correspondence between the three-dimensional position P1 of the biological feature region and the biological feature region-corresponding position P2 is determined in the unfolding process, so it is also determined which coordinates of the three-dimensional position P1 correspond to in the FOV region and / or which coordinates of the dentition-forming tissue region Ee. The same applies to the coordinates of each point in the region shown in the dentition unfolded image Ep. Of course, the original coordinate calculation described above may be performed.

[0102] The three cross-sectional images Da, Db, and Dc may include a cross-sectional image Dc orthogonal to the buccal-lingual direction, a cross-sectional image Db orthogonal to the body axis direction, and a cross-sectional image Da orthogonal to both cross-sectional images Dc and Db. The cross-sectional image Dc orthogonal to the buccal-lingual direction may be a cross-section along the tangent direction of a curve along the extension direction of the tissues E constituting the dentition. The cross-sectional image Dc orthogonal to the buccal-lingual direction is an example of a cross-sectional image that views the biological characteristic area squarely. As the default cross-sections can be arbitrarily determined, the assignment of each cross-sectional image to each of the cross-sectional images Da, Db, and Dc can be changed as appropriate.

[0103] The detailed observation image D may be, for example, a cross-sectional image with a higher resolution than the dentition expansion image Ep, or a transmission image. The detailed observation image D may be a three-dimensional image whose line of sight is changeable.

[0104] As a result, a detailed observation image D is generated at the three-dimensional position P1 of the biometric feature area corresponding to the annotation image Q selected through the user interfaces 24 and 26.

[0105] The display device 22 displays the image for detailed observation D simultaneously with the developed image for biological feature area arrangement Eq. At this time, the position of the image for detailed observation D relative to the developed image for biological feature area arrangement Eq is arbitrary. In Fig. 11, the developed image for biological feature area arrangement Eq and the image for detailed observation D are arranged side by side. The developed image for biological feature area arrangement Eq and the image for detailed observation D may also be arranged side by side vertically. The image for detailed observation D may also be displayed superimposed so as to partially enter the developed image for biological feature area arrangement Eq.

[0106] Furthermore, the layout of the cross-sectional images Da, Db, and Dc in the detailed observation image D is arbitrary. In Fig. 11, the rectangular display area of ​​the detailed observation image D is divided into two parts, vertically and horizontally. The cross-sectional image Dc orthogonal to the buccal-lingual direction is displayed in the lower right area, the cross-sectional image Db orthogonal to the body axis direction is displayed in the upper left area, and the cross-sectional image Da orthogonal to those is displayed in the lower left area.

[0107] Each of the three cross-sectional images Da, Db, and Dc may include an index Li indicating the position of the other cross-section. The index Li may be a straight line, a dashed line, a short line located in the central region of the cross-sectional images Da, Db, and Dc, or two marks located on the periphery of the cross-sectional images Da, Db, and Dc. In other words, the index Li may be any indication that can indicate the linear position of the other cross-section. In FIG. 11, each of the cross-sectional images Da, Db, and Dc includes a vertical line and a horizontal line as the index Li, which indicate the position of the other cross-section.

[0108] It is preferable that the selected annotation image Q in the biometric feature area arrangement expanded image Eq is displayed so as to be distinguishable from the other annotation images Q. For example, the selected annotation image Q may be displayed in a different color or a different size from the other annotation images Q. For example, the selected annotation image Q may be displayed in red and the other annotation images Q in orange. Furthermore, the selected annotation image Q may be displayed in a different display mode from the other annotation images Q. The difference in display mode may be achieved by, for example, displaying the selected annotation image Q in a blinking manner and the other annotation images Q in a non-blinking manner, or by making the blinking interval of the selected annotation image Q faster than the blinking interval of the other annotation images Q.

[0109] If the selected annotation image Q is displayed distinctly from the others, it is easy to understand the target image of the detailed observation image D. Furthermore, when multiple annotation images Q partially overlap each other, it is easy to understand the selected image.

[0110] When a characteristic region is designated by processing steps S7 to S9, a process for automatically displaying an image D for detailed observation corresponding to the characteristic region is automatically executed.

[0111] Note that even if no characteristic region is specified, a detailed observation image D corresponding to any one of the characteristic regions may be automatically displayed. The one of the characteristic regions for which the detailed observation image D is initially displayed may be a randomly selected characteristic region, or may be the characteristic region closest to a reference position such as the upper left.

[0112] In the next step S10, the processing unit 30 performs processing for display related to an adjustment operation, which will be described later, on the detailed observation image D. Specifically, step S10 is processing whose main contents range from step S20, which is the start step of processing related to an adjustment operation for an image for detailed observation, which will be described later, to step S23, which is the step of generating and displaying an image for detailed observation after adjustment.

[0113] In the next step S11, the processing unit 30 determines whether or not another feature region has been designated through the user interface 24, 26. The designation of another feature region may be performed in the same manner as described in step S7. If it is determined that another feature region has been designated, the process returns to step S8, and the subsequent processes are repeated. If it is determined that another feature region has not been designated, the process proceeds to step S12, where it is determined whether or not the process for diagnosis has ended. If an input indicating that the process is to end is made through the user interface 24, 26, etc., the process ends. If the process has not ended, the process returns to step S11, and the process of step S12 is repeated.

[0114] <Example of display processing for detailed observation images> An example of display processing for the detailed observation image D will be described below. Fig. 12 is a flowchart showing a specific example of processing in step S10 in Fig. 4.

[0115] When the detailed observation image D is displayed on the display device 22, the cross-sectional positions of the cross-sectional images Da, Db, and Dc of the detailed observation image D are changed in accordance with movement operations received through the user interfaces 24 and 26.

[0116] That is, after the display of the image D for detailed observation, the process proceeds to step S20, the process related to the image adjustment operation for detailed observation is started, and step S21 is processed. In step S21, the processing unit 30 determines whether or not a movement operation has been performed. The movement operation is accepted by, for example, an operation on an index Li through the user interfaces 24, 26. For example, as shown in FIG. 13, by moving any of the indexes Li (denoted as index Lia in FIG. 13) with a pointer device such as a mouse, the cross-sectional position indicated by the index Lia is moved. In this way, the movement operation is accepted. The movement operation may be performed by a switch device such as a keyboard.

[0117] The movement operation in step S21 may be an operation to change the tilt of the index Li. For example, when a central region of the index Li is dragged with a pointer device such as a mouse, the position of the index Li may be changed, and when an end region of the index Li is dragged with a pointer device such as a mouse, the tilt of the index Li may be changed. A rotation operation of the three-dimensional image may be performed by adding a pointing operation to a location outside the index Li of the cross-sectional image Da, the cross-sectional image Db, or the cross-sectional image Dc. Depending on the direction and amount of the dragging operation, the tilt of the index Li is changed, and a movement operation to tilt the cross-sectional position is accepted.

[0118] If it is determined in step S21 that no movement operation has been performed, the process proceeds to step S24, and if it is determined that a movement operation has been performed, the process proceeds to step S22.

[0119] In step S22, coordinates and orientation corresponding to the movement operation are calculated. The coordinates corresponding to the movement operation are coordinates obtained by shifting the coordinates of the three-dimensional position P1 before the movement by the amount of movement corresponding to the movement operation. The coordinates after the movement operation are converted using the same process as the conversion from the three-dimensional position P1 to the biological feature area corresponding position P2, thereby calculating the coordinates of the biological feature area after the movement operation in the biological feature area-arranged expanded image Eq. Furthermore, the orientation corresponding to the movement operation is an orientation obtained by tilting the direction perpendicular to any of the cross-sectional images Da, Db, Dc at the three-dimensional position P1 before the movement by the amount of tilt corresponding to the movement operation.

[0120] Step S23 may be inserted after step S22. In step S23, the processing unit 30 changes the position of the annotation image Q in the dentition development image Ep to the position after the movement operation. Furthermore, cross-sectional images Da, Db, and Dc are generated and displayed based on the coordinates and orientation after the movement operation. After the movement operation, the cross-sectional images Da, Db, and Dc are generated so that they are centered on the coordinates after the movement operation. Therefore, in the cross-sectional images Da, Db, and Dc, the image before the operation may be shifted to the opposite side of the movement operation direction, or an image toward the depth or front of the image before the operation may be displayed (see the outline indicated by the two-dot chain line in FIG. 13). The processing of step S23 may be configured to be optionally executable, allowing the user to select whether to proceed to step S23 through the user interfaces 24 and 26. In this case, step S23 may be skipped. Alternatively, step S23 itself may be omitted.

[0121] When step S23 is completed, the process proceeds to step S24 (when the process of step S23 is omitted, the process proceeds to step S24 when step S22 is completed).

[0122] In step S24, it is determined whether or not there is a signal to end the display of the image for detailed observation D. The signal to end the display is transmitted, for example, when the user issues an instruction to end the display via the user interfaces 24, 26. If there is a signal to end the display, the display of the image for detailed observation D ends. If there is no signal to end the display, the process returns to step S21.

[0123] <Effects, etc.> According to the image processing device 20, image processing method, and program 34a configured as described above, a biometric feature area arrangement expanded image Eq is displayed on the display device 22. In the biometric feature area arrangement expanded image Eq, an annotation image Q is superimposed on the dentition expanded image Ep. This annotation image Q is an image showing a biometric feature area, and is located at a biometric feature area corresponding position P2. Therefore, by looking at the biometric feature area arrangement expanded image Eq, the user can easily recognize the existence and position of a lesion area L, which is an example of a biometric feature area in the dentition-forming tissues E. Moreover, by looking at the detailed observation image D, the lesion area L can be observed in detail. This makes it easy to recognize the lesion area L.

[0124] If a position is simply specified on a panoramic image, a position in the buccal-lingual direction cannot be specified. Therefore, it is difficult to provide an image for detailed observation at a position suitable for observation in a direction perpendicular to the buccal-lingual direction. In this embodiment, the annotation image Q is located at a biological feature area corresponding position P2 that corresponds to the three-dimensional position P1 of the biological feature area in the three-dimensional volume data. Therefore, it is easy to provide an image for detailed observation at a position suitable for observation in a direction perpendicular to the buccal-lingual direction, using the three-dimensional position P1 of the biological feature area in the three-dimensional volume data as a clue.

[0125] Furthermore, the dentition expansion image Ep is an image of the entire area of ​​the tissues E that constitute the dentition, viewed from the front, and the annotation image Q is displayed on this image. In this case, it is easy to recognize the position of the biological characteristic area within the entire area of ​​the tissues E that constitute the dentition.

[0126] Furthermore, in the biological feature region arrangement expanded image Eq, multiple annotation images Q are displayed so that they can be recognized. Then, an image D for detailed observation corresponding to the selected annotation image Q is displayed. Therefore, when multiple biological feature regions are detected, the image D for detailed observation of the selected biological feature region is displayed on the display device 22. Therefore, the biological feature region corresponding to the annotation image Q selected for detailed observation can be displayed in as large an area as possible, making detailed observation easy. Furthermore, the biological feature region being subjected to detailed observation can be observed in detail while being able to grasp the position of the biological feature region in the dentition-forming tissues E.

[0127] Furthermore, if the detailed observation image D includes three cross-sectional images Da, Db, and Dc that are orthogonal to one another, it is easy to observe the biological characteristic region in detail.

[0128] Furthermore, the cross-sectional position of at least one of the three cross-sectional images Da, Db, and Dc can be changed in response to a movement operation of the index Li via the user interfaces 24 and 26. Therefore, by changing the cross-sectional positions of the cross-sectional images Da, Db, and Dc, it is easy to observe the biological characteristic region.

[0129] Furthermore, the position of the annotation image Q in the dentition development image Ep is changed in response to a movement operation on the index Li via the user interfaces 24, 26. This makes it easy to grasp the position of the detailed observation image in the dentition development image Ep after the movement operation.

[0130] Simply performing a movement operation on the index Li will not change the position of the annotation image Q in the dentition unfolded image Ep, but after the movement operation, an operation to change the position of the annotation image Q can be performed to accept the change and change the position of the annotation image Q in the dentition unfolded image Ep.

[0131] The operation of changing the position of the annotation image Q may be performed, for example, by an operation on the detailed observation image D, or by an operation using the index Li. The change of the position of the annotation image Q may be called an annotation position change. The operation of changing the annotation position may be called an annotation position change operation. The annotation position change operation is an operation that converts an operation on the X1Y1Z1 coordinates into a change of the annotation position on the RT coordinates or a change of the annotation position on the RST coordinates. In addition, the annotation position change operation is an operation that converts an operation on the captured image data 3D image into a change of the annotation position on the tooth arch expansion area coordinates.

[0132] Furthermore, because the detailed observation image D includes a cross-sectional image Da that views the biometric characteristic area from the front and two cross-sectional images that are perpendicular to the first image, the biometric characteristic area is easy to observe. In particular, by using the cross-sectional image Da that views the biometric characteristic area from the front, it is easy to grasp the position and orientation of the biometric characteristic area relative to the teeth.

[0133] {Variation} Various modifications will be described based on the above embodiment.

[0134] In the above embodiment, an example has been described in which the biological characteristic region is the lesion region L. As in the biological characteristic region-arranged expanded image Eqa of the first modified example shown in FIG. 14 , the biological characteristic region need only be an image-characteristic region in the dentition-forming tissue E, and does not have to be the lesion region L. For example, the biological characteristic region may be the root apex Lb of a tooth. In this case, an annotation image Q is displayed at each root apex Lb of multiple teeth T in the dentition-forming tissue E. The user can sequentially select multiple annotation images Q. A detailed observation image D of the root apex Lb corresponding to the selected annotation image Q is displayed. This allows the user to sequentially observe the multiple root apexes Lb in detail while grasping the position of each.

[0135] Multiple types of biological characteristic regions may be simultaneously displayed in the dentition-forming tissues E. In this case, different annotation images Q may be used for each type. For example, the lesion region L and the root apex Lb may be displayed using annotation images Q of different colors, shapes, or sizes.

[0136] The biometric feature area may be the mandibular canal.

[0137] Furthermore, as described in the above embodiment, the tooth row region and the alveolar bone region are distinguished based on the three-dimensional volume data by a segmentation algorithm or the like.

[0138] As in a second modified example shown in Fig. 15, in step S6, the processing unit 30 may perform image processing to display the dentition region Et and the alveolar bone region Eb in different modes in the dentition expanded image Epm. To display the dentition region Et and the alveolar bone region Eb in different modes, the dentition region Et and the alveolar bone region Eb may be displayed in different colors. For example, the dentition region Et may be displayed in green, and the alveolar bone region Eb in blue. It is preferable that the dentition region Et and the alveolar bone region Eb have different hues.

[0139] For example, if the surfaces of the teeth in the dental region Et and the surfaces of the jawbone in the alveolar bone region Eb are colored in different colors and a transparent image of the surfaces of the teeth in the dental region Et and the surfaces of the alveolar bone region Eb is generated, an image of the dental region Et and the alveolar bone region Eb can be generated in which the boundaries between the teeth and the jawbone are colored dark and the inside is colored light.

[0140] In order to enable observation of the tooth region Et in the region where the tooth region Et and the alveolar bone region Eb overlap, it is preferable that the transparency of the alveolar bone region Eb be set to an extent that the tooth region Et can be seen through. In this case, the region where the tooth region Et and the alveolar bone region Eb overlap may be colored a mixture of both colors.

[0141] 15, the difference in color is expressed by the difference in pattern. That is, the tooth region Et is given a downward-to-right striped pattern, the alveolar bone region Eb is given an upward-to-right striped pattern, and the area where the tooth region Et and the alveolar bone region Eb overlap is given a mesh-like pattern in which the downward-to-right striped pattern and the upward-to-right striped pattern overlap.

[0142] According to this modification, the dentition expansion image Epm displays the dentition region Et and the alveolar bone region Eb in different display modes. Therefore, the dentition region Et and the alveolar bone region Eb are displayed separately in the dentition expansion image Epm, making it easy to grasp the positions of the biological characteristic regions.

[0143] Furthermore, by using different colors for the tooth region Et and the alveolar bone region Eb, the tooth region Et and the alveolar bone region Eb can be easily distinguished from each other.

[0144] Furthermore, by setting the transparency of the alveolar bone region Eb to a level that allows the tooth row region Et to be seen through, it is possible to observe the biological characteristic region, even for the part of the tooth row that is inside the alveolar bone, while understanding the positional relationship between the alveolar bone and the tooth row.

[0145] In the above embodiment, an example has been described in which each position of the structures E constituting the dentition is identified based on three-dimensional volume data, and the identified structures E constituting the dentition are developed into an expanded image Ep of the dentition.

[0146] However, as a third modified example, instead of individually identifying the positions of the structures E that constitute the dentition based on the three-dimensional volume data, the dentition may be developed into an expanded image Ep of the dentition based on a standard region of the structures E that constitute the dentition.

[0147] For example, as shown in Fig. 16, when performing CT imaging with the CT imaging device 10, the head H is positioned at a fixed position by the head holder 9. As a result, the dentition-forming tissues E are also positioned at a fixed position relative to the head holder 9, as shown in Fig. 17.

[0148] The positional relationship between the head holder 9 and the X-ray generator 11 and X-ray detector 12 can be a known positional relationship. Furthermore, the area in the head H where the tissues constituting the dentition E extend can be considered to be more or less constant. For this reason, in the three-dimensional volume data based on CT imaging data, the area of ​​the standard tissues constituting the dentition E can be treated as the area of ​​the actual tissues constituting the dentition E.

[0149] Furthermore, assuming a standard tissue forming the dentition E, it is possible to determine in advance a general-purpose conversion process for converting the standard tissue forming the dentition E into a dentition expansion image Ep. The region of the three-dimensional volume data where the tissue forming the dentition E is expected to exist can be converted into a dentition expansion image Ep by the general-purpose conversion process. Furthermore, by performing the general-purpose conversion process on the biometric feature region detected in the three-dimensional volume data, it is possible to calculate the corresponding position of the biometric feature region in the dentition expansion image Ep.

[0150] In the above embodiment, the case where the image processing device 20 is used in combination with the CT imaging device 10 has been described.

[0151] The image processing device 20 can also be configured as a device separate from the CT imaging device 10.

[0152] In this case, like the image processing device 120 according to the fourth modification shown in FIGS. 18 and 19, the image processing device 120 may include a data access device 130 that is connected by turning the connection port 36. The data access device 130 is, for example, a device that can read data recorded on a recording medium 128. The recording medium 128 may be an optical recording medium such as an optical disc, or may be a flash memory such as a USB memory or an SD card. The data access device 130 may be an optical disc reader or a card reader.

[0153] Image data obtained by CT imaging is recorded on the recording medium 128. The image data may be a group of X-ray projection image data, three-dimensional volume data, or a data group of multiple tomographic images.

[0154] The image processing device 120 can execute the same processing as in the above embodiment by reading image data obtained by CT imaging via the data access device 130.

[0155] Image data obtained by CT scanning may be stored in a server device, and the image processing device 120 may access the server device via a communication network to obtain the image data obtained by CT scanning. In this case, the server device may be located within the facility where the image processing device 120 is located, or may be located outside the facility. The server device may also be a cloud server. The image processing device 120 can access the server device via a dedicated line or a public line network to obtain the image data obtained by CT scanning.

[0156] {Other variations} In the above embodiment and various modified examples, other information may be displayed around the biological feature area arrangement expanded image Eq or the detailed observation image D. For example, the name of a disease may be written. For example, when multiple lesion areas L are detected, the disease name of each of the multiple lesion areas may be displayed. The disease name may be displayed together with the cross-sectional image.

[0157] The configurations described in the above embodiment and modifications can be combined as appropriate as long as they are not mutually contradictory.

[0158] The present disclosure discloses the following aspects.

[0159] The first aspect is an image processing device that processes image data obtained by CT scanning of tissues forming the dentition to generate images for diagnosis, and is equipped with a storage device that stores the image data, a processing device, and a display device that displays an image for observation based on the output of the processing device, wherein the processing device generates three-dimensional image data of the tissues forming the dentition based on the image data, detects biological feature areas in the tissues forming the dentition based on the image data, identifies the three-dimensional position where the biological feature area is located in the coordinate system of the three-dimensional image data, generates a dentition expansion image in which the tissues forming the dentition are expanded based on the three-dimensional image data, identifies a biological feature area corresponding position in the dentition expansion image that corresponds to the three-dimensional position, displays on the display device a biological feature area arrangement expansion image in which the annotation image showing the biological feature area is superimposed on the dentition expansion image so that the annotation image showing the biological feature area is located at the biological feature area corresponding position, generates an image for detailed observation at the three-dimensional position based on the three-dimensional image data, and displays the detailed observation image on the display device simultaneously with the biological feature area arrangement expansion image.

[0160] With this image processing device, the presence and location of a biometric feature region can be recognized by viewing the expanded biometric feature region layout image. The biometric feature region can be observed in detail by viewing the detailed observation image. This makes it easy to recognize the biometric feature region.

[0161] A second aspect is the image processing device according to the first aspect, wherein the processing device generates, as the dentition development image, an image of the entire area of ​​the tissues that constitute the dentition viewed from the front.

[0162] In this case, an annotation image showing the biological characteristic area is displayed on an image of the entire area of ​​the tissues that make up the dentition, making it easy to recognize the position of the biological characteristic area within the entire area of ​​the tissues that make up the dentition.

[0163] The processing device may set a dentition-forming tissue region, which is the region in which the dentition-forming tissues extend, and a dentition-formed region in which the dentition-forming tissue region is expanded, and the expansion of the dentition-forming tissues may be performed by an expansion process in which image data of the dentition-forming tissues in the dentition-forming tissue region is expanded to fit the shape of the dentition-formed region, thereby enabling appropriate image data processing for visual recognition of biological feature regions.

[0164] The unfolding process may be performed so that the buccal-lingual direction in the curved state before unfolding, which is the state of the tissue region constituting the dentition before unfolding, corresponds to the normal viewing direction in the view state after unfolding, which is the state of the unfolded dentition region after unfolding. This makes it easy to understand the position of the biological feature region.

[0165] The dentition-forming tissue region may be set to have a thickness in the buccolingual direction, and the dentition-unfolded region may be set to have a thickness in the normal viewing direction corresponding to the buccolingual direction, thereby enabling recognition of a biometric feature region within an appropriate range.

[0166] The unfolding process may include performing an original coordinate calculation to associate the biometric feature region with the three-dimensional position of the biometric feature region corresponding position. The original coordinate calculation may include specifying the position of the three-dimensional position of the biometric feature region in the buccolingual direction, and performing a calculation to specify the position of the biometric feature region corresponding position in the normal viewing direction corresponding to the buccolingual direction. This makes it possible to accurately calculate the three-dimensional position of the biometric feature region and the biometric feature region corresponding position.

[0167] A third aspect is an image processing device according to the first or second aspect, further comprising a user interface, wherein the processing device detects a plurality of the biometric feature areas, generates an image as the biometric feature area arrangement expansion image in which a plurality of the annotation images corresponding to each of the biometric feature areas are recognizably displayed, and generates the detailed observation image at the three-dimensional position of the biometric feature area corresponding to the annotation image selected through the user interface.

[0168] In this case, when a plurality of biometric feature regions are detected, the detailed observation image of the selected biometric feature region can be displayed on the display device.

[0169] A fourth aspect is the image processing device according to any one of the first to third aspects, wherein the detailed observation image includes three cross-sectional images that are orthogonal to each other.

[0170] In this case, since the detailed observation image includes three cross-sectional images that are orthogonal to each other, it is easy to observe the biological characteristic area in detail.

[0171] A fifth aspect is an image processing device according to the fourth aspect, further comprising a user interface, wherein each of the three cross-sectional images includes an indicator indicating the position of the other cross-section, and the processing device changes the cross-sectional position of at least one of the three cross-sectional images in response to a movement operation on the indicator via the user interface.

[0172] In this way, if the cross-sectional position of the detailed observation image can be changed, it becomes easier to observe the biological characteristic area.

[0173] A sixth aspect is an image processing device according to the fifth aspect, wherein the processing device changes the position of the annotation image in the dentition expansion image in response to a movement operation on the indicator via the user interface.

[0174] This makes it easy to grasp the position of the detailed observation image after the moving operation in the developed image of the row of teeth.

[0175] A seventh aspect is the image processing device according to any one of the fourth to sixth aspects, wherein the detailed observation image includes a cross-sectional image of the biological characteristic area viewed from the front.

[0176] In this way, the biological characteristic region can be easily observed based on an image in which the biological characteristic region is viewed from the front and two cross-sectional images perpendicular to the image.

[0177] The eighth aspect is an image processing device according to any one of the first to seventh aspects, wherein the processing device performs processing to distinguish between the dentition region and the alveolar bone region based on the three-dimensional image data, and performs image processing to display the dentition region and the alveolar bone region in different ways in the dentition expanded image.

[0178] This allows the tooth row region and the alveolar bone region to be displayed separately in the tooth row expansion image, making it easier to grasp the position of the biometric feature region.

[0179] A ninth aspect is the image processing device according to the eighth aspect, wherein the processing device uses different colors for the dentition region and the alveolar bone region in the dentition expansion image.

[0180] This makes it easy to distinguish and recognize the tooth arch region and the alveolar bone region.

[0181] A tenth aspect is the image processing device according to the eighth or ninth aspect, wherein the processing device sets a transparency for the alveolar bone region that allows the dentition region to be seen through.

[0182] This makes it possible to observe the biological characteristic area even for the part of the dentition that is located inside the alveolar bone, while grasping the positional relationship between the alveolar bone and the dentition.

[0183] The processing device may display the functional tissues constituting the dentition, which are tissues classified by function that make up the tissues constituting the dentition of a living body, using a boundary surface between presence and absence. In this case, the processing device may perform gaze direction-responsive transparency image processing, which is image processing in which the transparency of the boundary surface changes depending on the gaze direction. This makes it easier to visually recognize the shapes of the functional tissues constituting the dentition.

[0184] When the element that increases transparency is a parent transparency element, and increasing transparency is parent transparency, and the element that decreases transparency is an anti-transparency element, and decreasing transparency is anti-transparency, the gaze direction-compatible transparency image processing may be a combination of at least one of the following group A and at least one of the following group B. Group A: Processing to enlarge or increase the parent transparency element of the boundary surface of normal vision Processing to promote parent transparency of the boundary surface of normal vision Treatment to reduce, diminish or eliminate the anti-transparency elements of the interface of normal vision Treatment to suppress the anti-transparency of the boundary surface of normal vision Group B: Processing to reduce, decrease or eliminate the parent transparency elements of the boundary surface in oblique or side views - Processing to suppress parent transparency of the boundary surface in oblique or side view Treatment to enlarge or increase the anti-transparency factor of the said boundary surface in oblique or lateral view Treatment to promote anti-transparency of the boundary surface in oblique or lateral views This makes it easier to visually recognize the three-dimensional shapes of the functional tissues that constitute the dentition.

[0185] The eleventh aspect is an image processing method for generating an image for diagnosis by processing image data obtained by CT scanning of the tissues forming the dental arch, which generates three-dimensional image data of the tissues forming the dental arch based on the image data, detects biological feature areas in the tissues forming the dental arch based on the image data, identifies the three-dimensional position where the biological feature area is located in the coordinate system of the three-dimensional image data, generates a dental arch expanded image in which the tissues forming the dental arch are expanded based on the three-dimensional image data, identifies a biological feature area corresponding position in the dental arch expanded image that corresponds to the three-dimensional position, generates a biological feature area arrangement expanded image in which an annotation image showing the biological feature area is superimposed on the dental arch expanded image so that the annotation image showing the biological feature area is located at the biological feature area corresponding position, generates an image for detailed observation at the three-dimensional position based on the three-dimensional image data, and simultaneously displays the biological feature area arrangement expanded image and the image for detailed observation on a display device.

[0186] According to the eleventh aspect, the presence and position of a biometric feature region can be recognized by viewing the biometric feature region layout expanded image. The biometric feature region can be observed in detail by viewing the detailed observation image. Therefore, the biometric feature region can be easily recognized.

[0187] A twelfth aspect is a program for generating an image for diagnosis by processing image data obtained by CT scanning of tissues forming the dental arch, which program causes a computer to execute the following processes: generate three-dimensional image data of the tissues forming the dental arch based on the image data; detect biological feature areas in the tissues forming the dental arch based on the image data; identify the three-dimensional positions at which the biological feature areas exist in the coordinate system of the three-dimensional image data; generate a dental arch expanded image in which the tissues forming the dental arch are expanded based on the three-dimensional image data; identify biological feature area corresponding positions in the dental arch expanded image that correspond to the three-dimensional positions; display on a display device a biological feature area arrangement expanded image in which an annotation image showing the biological feature area is superimposed on the dental arch expanded image so that the annotation image showing the biological feature area is located at the biological feature area corresponding position; generate an image for detailed observation at the three-dimensional position based on the three-dimensional image data; and display the detailed observation image on the display device simultaneously with the biological feature area arrangement expanded image.

[0188] According to the twelfth aspect, the presence and position of a biometric feature region can be recognized by viewing the biometric feature region layout expanded image. The biometric feature region can be observed in detail by viewing the detailed observation image. Therefore, the biometric feature region can be easily recognized.

[0189] The above description is illustrative in all respects and is not intended to limit the scope of the present invention. It is understood that numerous variations not illustrated can be envisaged without departing from the scope of the present invention. [Explanation of symbols]

[0190] 10 CT imaging device 20, 120 Image processing device 22 Display device 24, 26 User Interface 30 processing units 32 Arithmetic circuit 32a processor 34 Storage device 34a Program 34b Data D. Detailed observation image Da, Db, Dc cross-sectional images E. Tissues that make up the dentition Eb Alveolar bone area Ep, Epm dental arch expansion image Eq, Eqa Biometric feature area layout expansion image Et dental region H head L Lesion area Lb root apex Li, Lia indicators P1 3D position P2 Biometric feature area corresponding position Q Annotation image

Claims

1. An image processing device that processes image data obtained by CT imaging of tissues constituting the dentition to generate an image for diagnosis, a storage device that stores the image data; a processing device; a display device that displays an image for observation based on the output of the processing device; Equipped with The processing device includes: generating three-dimensional image data of the tissues constituting the dentition based on the image data; detecting a biological characteristic area in the tissues constituting the dentition based on the image data; Identifying a three-dimensional position where the biometric feature area exists in a coordinate system of the three-dimensional image data; generating a dental arch expanded image in which the dental arch constituent tissues are expanded based on the three-dimensional image data; identifying a biometric feature region corresponding position in the dental arch expansion image that corresponds to the three-dimensional position; displaying, on the display device, a biometric feature area arrangement expanded image in which the annotation image indicating the biometric feature area is superimposed on the dentition expanded image so that the annotation image indicating the biometric feature area is located at a position corresponding to the biometric feature area; generating a detailed observation image at the three-dimensional position based on the three-dimensional image data; an image processing device that displays the detailed observation image and the biological feature area layout expanded image on the display device simultaneously;

2. 2. The image processing device according to claim 1, The processing device includes: an image processing device that generates, as the dentition expansion image, an image of the entire area of ​​the tissues that constitute the dentition viewed from the front;

3. 3. The image processing device according to claim 1, further comprising a user interface; The processing device includes: Detecting a plurality of the biometric feature regions; generating, as the biometric feature area layout expanded image, an image in which the plurality of annotation images corresponding to the plurality of biometric feature areas are recognizably displayed; an image processing device that generates the detailed observation image at the three-dimensional position of the biometric feature area corresponding to the annotation image selected through the user interface;

4. 3. The image processing device according to claim 1, An image processing device, wherein the detailed observation image includes three cross-sectional images that are orthogonal to each other.

5. 5. The image processing device according to claim 4, further comprising a user interface; each of the three cross-sectional images includes an index indicating the position of each of the other cross-sectional images; The processing device includes: an image processing device that changes a cross-sectional position of at least one of the three cross-sectional images in response to a movement operation on the index through the user interface;

6. 6. The image processing device according to claim 5, The processing device includes: An image processing device that changes a position of the annotation image in the dental arch expansion image in response to a movement operation on the index through the user interface.

7. 5. The image processing device according to claim 4, An image processing device in which the detailed observation image includes a cross-sectional image of the biological characteristic area viewed from the front.

8. 3. The image processing device according to claim 1, The processing device includes: performing a process for distinguishing between a tooth row region and an alveolar bone region based on the three-dimensional image data; An image processing device that performs image processing to display the dentition region and the alveolar bone region in different display modes in the dentition expanded image.

9. 9. The image processing device according to claim 8, The processing device includes: An image processing device that uses different colors for the tooth row region and the alveolar bone region in the tooth row expansion image.

10. 9. The image processing device according to claim 8, The processing device includes: An image processing device that sets a transparency for the alveolar bone region to such an extent that the dentition region can be seen through.

11. An image processing method for generating a diagnostic image by processing image data obtained by CT imaging of tissues constituting a dental arch, comprising: generating three-dimensional image data of the tissues constituting the dentition based on the image data; detecting a biological characteristic area in the tissues constituting the dentition based on the image data; Identifying a three-dimensional position where the biometric feature area exists in a coordinate system of the three-dimensional image data; generating a dental arch expanded image in which the dental arch constituent tissues are expanded based on the three-dimensional image data; identifying a biometric feature region corresponding position in the dental arch expansion image that corresponds to the three-dimensional position; generating a biometric feature area arrangement expanded image in which the annotation image indicating the biometric feature area is superimposed on the dentition expanded image so that the annotation image indicating the biometric feature area is positioned at a position corresponding to the biometric feature area; generating a detailed observation image at the three-dimensional position based on the three-dimensional image data; an image processing method in which the biological feature area layout expanded image and the image for detailed observation are simultaneously displayed on a display device;

12. A program for generating diagnostic images by processing image data obtained by CT imaging of tissues constituting the dental arch, On the computer, generating three-dimensional image data of the tissues constituting the dentition based on the image data; detecting a biological characteristic area in the tissues constituting the dentition based on the image data; Identifying a three-dimensional position where the biometric feature area exists in a coordinate system of the three-dimensional image data; generating a dental arch expanded image in which the dental arch constituent tissues are expanded based on the three-dimensional image data; identifying a biometric feature region corresponding position in the dental arch expansion image that corresponds to the three-dimensional position; displaying, on a display device, a biometric feature area arrangement expanded image in which the annotation image indicating the biometric feature area is superimposed on the dentition expanded image so that the annotation image indicating the biometric feature area is located at a position corresponding to the biometric feature area; generating a detailed observation image at the three-dimensional position based on the three-dimensional image data; a program for executing a process of displaying the detailed observation image and the biological feature area layout expanded image on the display device at the same time;

Images