WO2025115505A1 - Tooth row image generation device, tooth row image generation method, and program - Google Patents

Abstract

A tooth row image generation device comprises: an acquisition unit (51) that acquires a captured image obtained by imaging the surface of a tooth row and dental plaque within an oral cavity being irradiated with light including a wavelength region of blue light; a combination unit (53) that generates a tooth row image obtained by combining a plurality of tooth row block images, which are partial tooth row images based on the captured image; and a processing unit (52) that performs a white balancing process on the combined tooth row image.

Description

DENTAL ROW IMAGE GENERATION DEVICE, DENTAL ROW IMAGE GENERATION METHOD, AND PROGRAM

The present disclosure relates to a dentition image generating device, a dentition image generating method, and a program.

Patent Document 1 discloses a device that has an excitation light emitting unit that emits excitation light to cause plaque, lesions, etc. to emit fluorescence, and an illumination light emitting unit that emits illumination light to illuminate the periphery of plaque, lesions, etc., and that the irradiation means is capable of irradiating the illumination light and excitation light simultaneously. Patent Document 1 also discloses that in order to improve the visibility of plaque, lesions, etc., the amount of light emitted from the excitation light emitting unit is greater than the amount of light emitted from the illumination light emitting unit.

International Publication No. WO 2005/104926

Incidentally, it is desirable for a dentition image generating device that generates a dentition image that creates a less unnatural feeling.

The present disclosure provides a dentition image generating device, a dentition image generating method, and a program that are capable of generating a dentition image with reduced discomfort.

A dentition image generating device according to one aspect of the present disclosure includes an acquisition unit that acquires a captured image obtained by photographing the surface of the dentition and dental plaque in an oral cavity irradiated with light including a wavelength range of blue light, a synthesis unit that generates a dentition image by synthesizing a plurality of dentition block images, which are partial dentition images based on the captured images, and a processing unit that performs white balance processing on the synthesized dentition image.

A dentition image generating method according to one aspect of the present disclosure obtains an image obtained by photographing the surface of the dentition and dental plaque in an oral cavity irradiated with light including a wavelength range of blue light, generates a dentition image by synthesizing a plurality of dentition block images, which are partial dentition images based on the photographed image, and performs white balance processing on the synthesized dentition image.

A program according to one aspect of the present disclosure is a program for causing a computer to execute the above-mentioned tooth row image generating method.

According to one aspect of the present disclosure, it is possible to realize a dentition image generating device or the like that is capable of generating a dentition image with reduced discomfort.

FIG. 1 is a perspective view of an intraoral camera in a dentition image generating system according to an embodiment. FIG. 2 is a schematic diagram of a dentition image generating system according to an embodiment. FIG. 3 is a block diagram illustrating a functional configuration of the mobile terminal according to the embodiment. FIG. 4 is a sequence diagram showing the operation of the dentition image generating system according to the embodiment. FIG. 5 is a diagram for explaining the processing of the dentition image generating system according to the embodiment.

(Background to this disclosure)
Before describing the present disclosure, the background to the development of the present disclosure will be described.

Patent Document 1 discloses that an LED (Light Emitting Diode) with a central wavelength of 365 nm, 405 nm, or 470 nm is used as the light source of the excitation light. When the affected area and the surrounding area are photographed using such excitation light, the color tone of the plaque-free tooth area and the surrounding area in the obtained image is close to the color of the excitation light. As a result, the color tone of the plaque-free tooth area and the surrounding area of the affected area is far from the actual color tone, and the user may feel uncomfortable with the obtained image. For example, when the obtained image is used to observe the condition of normal tissue around the affected area or to explain it to the user, the user may feel uncomfortable because the color tone is far from the actual color tone.

In addition, when adjusting the excitation light emitting unit and the illumination light emitting unit to improve the visibility of plaque, lesions, etc., the reproducibility of the color tone of each image obtained is low, and the user may feel uncomfortable with the obtained image.

As such, the device of Patent Document 1 has room for improvement in terms of generating a dentition image with reduced discomfort. The inventors of the present application therefore conducted extensive research into dentition image generating devices etc. capable of generating dentition images with reduced discomfort, and have devised the dentition image generating device etc. shown below.

The dentition image generating device according to the first aspect of the present disclosure includes an acquisition unit that acquires a captured image obtained by photographing the surface of the dentition and dental plaque in an oral cavity irradiated with light including a wavelength range of blue light, a synthesis unit that generates a dentition image by synthesizing a plurality of dentition block images, which are partial dentition images based on the captured images, and a processing unit that performs white balance processing on the synthesized dentition image.

This allows the white balance of a row of teeth image, which is a composite of multiple row of teeth block images, to be adjusted with an appropriate gain. In other words, the color tones in the composite row of teeth image can be made closer to the actual color tones. This makes it possible to generate a composite row of teeth image with reduced discomfort in the color tones.

Also, for example, the dentition image generating device according to the second aspect may be the dentition image generating device according to the first aspect, and the processing unit may perform the white balance processing based on color information of the central tooth of the dentition image after synthesis.

This allows the white balance of the central tooth to be adjusted with an appropriate gain. In other words, the color tone of the central tooth in the synthesized dentition image can be made closer to the actual color tone. Therefore, for example, if the area that the user focuses on is an area that includes the central tooth, the plaque area in that area can be effectively emphasized.

Also, for example, the dentition image generating device according to the third aspect may be the dentition image generating device according to the first aspect, and the processing unit may perform the white balance processing based on color information of the entire dental region of the dentition image after synthesis.

This allows the white balance of all the teeth in the combined dentition image to be adjusted with an appropriate gain (average gain). In other words, the overall color tone of the teeth in the combined dentition image can be made closer to the actual color tone.

Also, for example, a dentition image generating device according to a fourth aspect may be a dentition image generating device according to any one of the first to third aspects, in which the processing unit adjusts the blue color level of the dental region of each of the plurality of dentition block images, and the synthesis unit synthesizes the plurality of dentition block images with the blue color level adjusted.

This allows the blue color level of each of the multiple dentition block images to be uniform, and therefore the color (color information) of the tooth area in the dentition image after WB processing can be uniform. For example, it is possible to prevent the user from feeling discomfort (discomfort due to the white color not being uniform) caused by slight differences in the color of the tooth area in each of the multiple dentition block images.

Also, for example, the dentition image generating device according to the fifth aspect may be a dentition image generating device according to any one of the first to fourth aspects, and may include a detection unit that detects plaque in an image based on the captured image, and a generation unit that generates a composite dentition image in which the plaque area detected by the detection unit is highlighted.

This allows plaque areas to be highlighted in the composite dentition image. For example, when such a composite dentition image is presented to a user, the user can easily identify the plaque areas.

Furthermore, for example, the dentition image generating device according to the sixth aspect may be the dentition image generating device according to the fifth aspect, and may include a display unit that displays the synthesized dentition image in which the plaque area is highlighted.

This allows the user to be presented with a synthesized image of the dentition in which the areas of plaque are highlighted. For example, by taking an image of the dentition after brushing and identifying the areas of plaque, it is possible to present the user with areas that have not been brushed.

Also, for example, the dentition image generating device according to the seventh aspect may be a dentition image generating device according to any one of the first to sixth aspects, and the plurality of dentition block images may include images of anterior teeth.

This allows an image taken from the right side teeth (e.g., the back teeth on the right side) to the front teeth and an image taken from the left side teeth (e.g., the back teeth on the left side) to the front teeth to be synthesized based on the front teeth. Therefore, a synthesized tooth row image from the right side teeth to the left side teeth can be generated.

Furthermore, for example, the dentition image generating device according to the eighth aspect may be a dentition image generating device according to any one of the first to seventh aspects, and the surface of the dentition may include a side surface of the dentition.

This makes it possible to generate a composite image of the side of the dentition, which reduces the discomfort caused by color tones.

Furthermore, for example, the dentition image generating device according to the ninth aspect may be a dentition image generating device according to any one of the first to eighth aspects, and the surface of the dentition may include an occlusal surface of the dentition.

This makes it possible to generate a composite image of the occlusal surfaces of the dentition, resulting in a dentition image with reduced discomfort in terms of color tones.

Also, for example, the teeth image generating device according to the tenth aspect may be a teeth image generating device according to any one of the first to ninth aspects, and may include a saturation enhancement processing unit that generates a converted image by converting the combined teeth image into an HSV image, identifies a specific pixel area in which one or more pixels of the converted image that satisfy at least one of a first predetermined range for saturation, a second predetermined range for hue, and a third predetermined range for brightness are located, and performs saturation enhancement processing on the specific pixel area in the combined teeth image to generate the combined teeth image with enhanced saturation.

As a result, specific pixel regions in the synthesized dentition image that are plaque regions are identified, and saturation enhancement processing is performed on the specific pixel regions, making it possible to generate a synthesized dentition image (dentition image with enhanced saturation S) in which plaque regions are easier to distinguish.

Also, for example, the dentition image generating device according to the eleventh aspect may be a dentition image generating device according to any one of the first to tenth aspects, and may include a shading display processing unit that generates a converted image by converting the combined dentition image into an HSV image, identifies a specific pixel area in which one or more pixels of the converted image that satisfy at least one of a first predetermined range for saturation, a second predetermined range for hue, and a third predetermined range for brightness are located, detects an accumulation level distribution of fluorescent substances accumulated in the plaque from the brightness value in the specific pixel area of the converted image, and performs shading image processing according to the accumulation level distribution of the fluorescent substances detected for the specific pixel area in the combined dentition image to generate the combined dentition image including a shading display.

This makes it possible to generate a composite dentition image that can inform the user of the concentration distribution of the fluorescent material, for example.

A dentition image generating method according to one aspect of the present disclosure obtains a photographed image obtained by photographing the surface of the dentition and dental plaque in an oral cavity irradiated with light including a wavelength range of blue light, generates a dentition image by synthesizing a plurality of dentition block images, which are partial dentition images based on the photographed image, and performs white balance processing on the synthesized dentition image. A program according to one aspect of the present disclosure is a program for causing a computer to execute the above-mentioned dentition image generating method.

This achieves the same effect as the above-mentioned dentition image generation system.

These general or specific aspects may be realized by a system, a method, an integrated circuit, a computer program, or a non-transitory recording medium such as a computer-readable CD-ROM, or by any combination of a system, a method, an integrated circuit, a computer program, or a recording medium. The program may be pre-stored in the recording medium, or may be supplied to the recording medium via a wide area communication network including the Internet.

In addition, each figure is a schematic diagram and is not necessarily an exact illustration. Therefore, for example, the scales of the figures do not necessarily match. In addition, in each figure, the same reference numerals are used for substantially the same configurations, and duplicate explanations are omitted or simplified.

In addition, in this specification, terms that indicate relationships between elements, such as "identical," as well as numerical values and numerical ranges, are not expressions that express only the strict meaning, but are expressions that include a substantially equivalent range, for example, a difference of about a few percent (or about 10%).

In addition, in this specification, ordinal numbers such as "first" and "second" do not refer to the number or order of components, unless otherwise specified, but are used for the purpose of avoiding confusion between and distinguishing between components of the same type.

(Embodiment)
Hereinafter, a dentition image generating system and a dentition image generating method according to the present embodiment will be described with reference to FIGS. 1 to 5. FIG.

[1. Configuration of the dentition image generating system]
First, the configuration of a dentition image generating system including an intraoral camera according to the present embodiment will be described with reference to Figures 1 to 3. Figure 1 is a perspective view of an intraoral camera 10 in the dentition image generating system according to the present embodiment.

As shown in FIG. 1, the intraoral camera 10 has a toothbrush-like housing that can be handled with one hand, and the housing has a head portion 10a that is placed in the user's oral cavity when photographing the dentition, a handle portion 10b that is held by the user, and a neck portion 10c that connects the head portion 10a and the handle portion 10b.

The photographing unit 21 photographs the surfaces of the dentition and dental plaque in the oral cavity irradiated with light including the wavelength range of blue light. The surfaces of the dentition include at least one of the buccal (outer) side surface of the dentition, the lingual (inner) side surface of the dentition, and the occlusal surface of the dentition.

The imaging unit 21 is incorporated into the head portion 10a and the neck portion 10c. The imaging unit 21 has an image sensor (not shown) and a lens (not shown) arranged on its optical axis LA.

The imaging element is a photographing device such as a CMOS (Complementary Metal Oxide Semiconductor) sensor or a CCD (Charge Coupled Device) element, and an image of the teeth is formed by a lens. The imaging element outputs a signal (image data) corresponding to the formed image to the outside. The image photographed by the imaging element is also referred to as an RGB image. The RGB image is an image sequence obtained by irradiating the dentition with blue light, and may be, for example, an image sequence of the side of the dentition, or an image sequence of the occlusal surface of the dentition. The image sequence includes, for example, one or more images (e.g., time-series images) photographed along the direction of the dentition. The side of the dentition may be the tongue side or the cheek side.

The photographing unit 21 may further have an optical filter that blocks light of a color irradiated from the illumination unit (illumination device) and transmits fluorescence emitted by plaque in response to the light. In this embodiment, the photographing unit 21 may have an optical filter that is a blue light cut filter that cuts blue wavelength light components contained in the light incident on the image sensor. When light including the blue wavelength range is irradiated onto teeth to detect plaque, if the light including the blue wavelength range is strengthened to strengthen the excitation fluorescence of plaque, the blue pixel values become dominant compared to the red pixel values and green pixel values, and the entire RGB image becomes blue. To address this, the blue light cut filter cuts out a portion of the light including the blue wavelength range from the light before it enters the image sensor. Note that the photographing unit 21 does not need to have a blue light cut filter.

The intraoral camera 10 is also equipped with multiple first to fourth LEDs 23A to 23D as an illumination unit that irradiates light onto the teeth to be photographed during photography. The first to fourth LEDs 23A to 23D irradiate plaque with light of a color that causes the plaque to fluoresce when irradiated thereon (e.g., light of a single color). The first to fourth LEDs 23A to 23D are, for example, blue LEDs that irradiate blue light that includes a wavelength (an example of a predetermined wavelength) with a peak at 405 nm. Note that the first to fourth LEDs 23A to 23D are not limited to blue LEDs, and may be any light source that irradiates light that includes the wavelength range of blue light.

FIG. 2 is a schematic diagram of a dentition image generating system according to this embodiment. The dentition image generating system according to this embodiment is generally configured such that the imaging unit 21 captures fluorescence emitted by plaque in response to light from the illumination unit 23, and then synthesizes (links and combines) multiple images based on the captured RGB images (e.g., a first dentition block image, described below) to generate a panoramic image in which the teeth are aligned horizontally. The panoramic image is an image that represents the condition of at least a portion (e.g., the entirety) of the user's mouth.

As shown in FIG. 2, the dentition image generation system includes an intraoral camera 10 and a mobile terminal 50.

The intraoral camera 10 comprises a hardware unit 20, a signal processing unit 30, and a communication unit 40.

The hardware unit 20 is a physical element of the intraoral camera 10, and includes an imaging unit 21, a sensor unit 22, an illumination unit 23, and an operation unit 24.

The photographing unit 21 generates image data by photographing the teeth in the user's oral cavity. It can also be said that the photographing unit 21 generates image data by photographing the surface of the dentition in the oral cavity and the plaque irradiated with light of a specific wavelength that excites fluorescent substances contained in the plaque. The photographing unit 21 receives a control signal from the camera control unit 31, performs operations such as photographing in accordance with the received control signal, and outputs image data of a moving image or a still image obtained by photographing to the image processing unit 32. The photographing unit 21 has the above-mentioned image sensor, optical filter, and lens. The image data is generated, for example, based on light that has passed through the optical filter. Furthermore, the image data is an image showing multiple teeth, but it is sufficient that the image shows at least one tooth.

The sensor unit 22 detects external light entering the photographing area of the RGB image. For example, the sensor unit 22 detects whether external light is entering the oral cavity. The sensor unit 22 is arranged, for example, near the photographing unit 21. The sensor unit 22 may be arranged, for example, in the head unit 10a of the intraoral camera 10, similar to the photographing unit 21. In other words, the sensor unit 22 is located in the user's oral cavity when the photographing unit 21 captures images.

The lighting unit 23 irradiates light onto the area of the multiple areas in the oral cavity that is to be photographed by the imaging unit 21. As is also known from quantitative visible light induced fluorescence (QLF) method, it is known that when blue light is irradiated, a substance called porphyrin, which is excreted by bacteria in plaque, fluoresces a reddish pink color (excited fluorescence), and in this embodiment, the lighting unit 23 irradiates blue light onto the area that is to be photographed by the imaging unit 21.

The illumination unit 23 has the above-mentioned first to fourth LEDs 23A to 23D. The first to fourth LEDs 23A to 23D, for example, irradiate the shooting area with light from different directions. This makes it possible to prevent shadows from appearing in the shooting area.

Each of the first to fourth LEDs 23A to 23D is configured so that at least the dimming can be controlled. Each of the first to fourth LEDs 23A to 23D may be configured so that the dimming and color can be controlled. The first to fourth LEDs 23A to 23D are arranged to surround the image capture unit 21.

The illumination unit 23 has its illumination intensity (light emission intensity) controlled according to the shooting area. The illumination intensity of each of the first to fourth LEDs 23A to 23D may be controlled uniformly, or may be controlled to be different from one another. The number of LEDs in the illumination unit 23 is not particularly limited, and may be one, or may be five or more. Furthermore, the illumination unit 23 is not limited to having LEDs as a light source, and may have other light sources.

The operation unit 24 accepts operations from the user. The operation unit 24 is configured, for example, with push buttons, but may also be configured to accept operations by voice, etc.

The hardware unit 20 may further include a battery (e.g., a secondary battery) that supplies power to each component of the intraoral camera 10, a coil for wireless charging by an external charger connected to a commercial power source, and an actuator required for at least one of composition adjustment and focus adjustment.

The signal processing unit 30 has various functional components realized by a CPU (Central Processing Unit) or MPU (Micro Processor Unit) that execute various processes described below, and a memory unit 35 such as a ROM (Read Only Memory) or RAM (Random Access Memory) that stores programs for causing each functional component to execute various processes. Specifically, the signal processing unit 30 has a camera control unit 31, an image processing unit 32, a control unit 33, a lighting control unit 34, and a memory unit 35.

The camera control unit 31 is mounted, for example, on the handle unit 10b of the intraoral camera 10, and controls the image capture unit 21. The camera control unit 31 controls at least one of the aperture and the shutter speed of the image capture unit 21 in response to a control signal from the image processing unit 32, for example.

The image processing unit 32 is mounted, for example, on the handle unit 10b of the intraoral camera 10, acquires the RGB image (image data) captured by the imaging unit 21, performs image processing on the acquired RGB image, and outputs the RGB image after the image processing to the camera control unit 31 and the control unit 33. The image processing unit 32 may also output the RGB image after the image processing to the memory unit 35, and store the RGB image after the image processing in the memory unit 35.

The image processing unit 32 is, for example, composed of a circuit, and performs image processing such as noise removal and edge enhancement on an RGB image. Note that noise removal and edge enhancement may be performed by the mobile terminal 50.

The RGB image output from the image processing unit 32 (the RGB image after image processing) may be transmitted to the mobile terminal 50 via the communication unit 40, and an image based on the transmitted RGB image (for example, a third dentition image described below) may be displayed on the display unit 56 of the mobile terminal 50. This makes it possible to present an image based on the RGB image to the user.

The control unit 33 is a control device that controls the signal processing unit 30. The control unit 33 controls each component of the signal processing unit 30 based on, for example, the detection results of external light, etc. by the sensor unit 22.

The lighting control unit 34 is mounted, for example, on the handle portion 10b of the intraoral camera 10, and controls the turning on and off of the first to fourth LEDs 23A to 23D. The lighting control unit 34 is composed of, for example, a circuit. For example, when a user performs an operation on the display unit 56 of the mobile terminal 50 to start up the intraoral camera 10, a corresponding signal is sent from the mobile terminal 50 to the signal processing unit 30 via the communication unit 40. The lighting control unit 34 of the signal processing unit 30 turns on the first to fourth LEDs 23A to 23D based on the received signal.

In addition to the above programs, the memory unit 35 stores RGB images (image data) captured by the image capture unit 21. The memory unit 35 is realized by, for example, semiconductor memory such as ROM and RAM, but is not limited to this.

The communication unit 40 is a wireless communication module for wirelessly communicating with the mobile terminal 50. The communication unit 40 is mounted, for example, on the handle portion 10b of the intraoral camera 10, and performs wireless communication with the mobile terminal 50 based on a control signal from the signal processing unit 30. The communication unit 40 executes wireless communication with the mobile terminal 50 that complies with existing communication standards such as WiFi (registered trademark) and Bluetooth (registered trademark). Via the communication unit 40, an RGB image is transmitted from the intraoral camera 10 to the mobile terminal 50, and an operation signal is transmitted from the mobile terminal 50 to the intraoral camera 10.

The mobile terminal 50 displays the plaque area in the second dentition image including two or more teeth based on an RGB image of the dentition surface and plaque that are fluorescently reacting when light including a wavelength range of blue light is irradiated onto the teeth. The mobile terminal 50 also functions as a user interface for the dentition image generation system. The mobile terminal 50 is an example of a dentition image generation device.

FIG. 3 is a block diagram showing the functional configuration of the mobile terminal 50 according to this embodiment.

As shown in FIG. 3, the mobile terminal 50 includes an acquisition unit 51, a processing unit 52, a synthesis unit 53, a detection unit 54, a generation unit 55, and a display unit 56. The mobile terminal 50 includes a processor and a memory. The memory is a ROM, a RAM, or the like, and can store a program executed by the processor. The acquisition unit 51, the processing unit 52, the synthesis unit 53, the detection unit 54, and the generation unit 55 are realized by a processor that executes a program stored in the memory. The mobile terminal 50 may be realized, for example, by a smartphone or tablet terminal capable of wireless communication.

The acquisition unit 51 acquires RGB images from the intraoral camera 10. Specifically, the acquisition unit 51 acquires images (image sequence) of multiple teeth generated by the imaging unit 21. The RGB images are images obtained by the intraoral camera 10 photographing teeth that are undergoing a fluorescent reaction by irradiating the teeth with light that includes the wavelength range of blue light. The acquisition unit 51 is configured to include, for example, a wireless communication module that performs wireless communication.

Here, the RGB image acquired by the acquisition unit 51 has a bluish tint overall. This is because when light including a wavelength range of blue light is irradiated onto teeth to detect plaque, the illumination unit 23 strengthens the light including a wavelength range of blue light in order to strengthen the excited fluorescence of plaque. As a result, the blue pixel value (B) becomes dominant compared to the red pixel value (R) and the green pixel value (G). In other words, a color cast occurs in the RGB image acquired by the acquisition unit 51. In this state, it is difficult to present the plaque adhesion state to the user in an easy-to-understand manner. Therefore, the mobile terminal 50 performs a process to present the plaque adhesion state to the user in an easy-to-understand manner by performing a predetermined image processing on the RGB image acquired by the acquisition unit 51 as shown below.

The processing unit 52 generates a plurality of first dentition block images, which are partial dentition images, from the RGB image (image sequence) generated by the imaging unit 21, and performs image processing on an image based on the generated plurality of first dentition block images. In this embodiment, the processing unit 52 performs image processing on each of the plurality of first dentition block images and each of the first dentition image or second dentition image obtained by combining the plurality of first dentition block images.

The first dentition block image is an image obtained by cutting out a specified range including the center of the angle of view from an image captured at a certain shooting position. Each of the multiple first dentition block images is an image based on an image captured at a different shooting position (or shooting direction).

Furthermore, each of the multiple first dentition block images is an image including at least one tooth or space between teeth. The first dentition block image may be, for example, an image of at least one tooth or space taken from the front. The first dentition block images may be the same or different in size (image size). Furthermore, in each of the first dentition block images, at least a portion of the dental area shown in that first dentition block image overlaps with a portion of the dental area shown in at least one other first dentition block image.

The RGB image may be the first dentition block image itself, or the first dentition block image may be generated by dividing the RGB image so that some of the images overlap each other.

The processing unit 52 performs an exposure correction process on the multiple first dentition block images as image processing before composition by the composition unit 53. The exposure correction process adjusts the blue level of each tooth region by multiplying the R, G, and B components by equal gains. The processing unit 52 adjusts the blue level so that the blue levels of the tooth regions of each of the multiple first dentition block images approach (for example, match). For example, the processing unit 52 adjusts the color of each tooth of one or more other first dentition block images so that the color of the tooth (reference tooth) of the first dentition block image located in the center when the multiple first dentition block images are arranged in the order of the dentition is unified. The reference tooth may be, for example, a tooth located in the center of the angle of view in the RGB image captured by the imaging unit 21. For example, since both ends of the angle of view may be unevenly irradiated with light from the illumination unit 23, it is possible to reproduce the color of the tooth illuminated in the same way as the central tooth by adjusting the blue level. The blue level adjustment may be performed only on the tooth region, or on the entire first dentition block image (e.g., the region including the teeth and gums).

The processing unit 52 also performs WB (White Balance) processing on the dentition image (first dentition image or second dentition image) as image processing after synthesis by the synthesis unit 53. WB processing is processing to adjust the color balance in the image by multiplying each of the R, G, and B components by a different gain (white balance gain). WB processing is processing to adjust the gain of at least two color components of the red, green, and blue components of the image to be processed so that, for example, the red pixel average value of multiple red pixel values of multiple pixels constituting the tooth region of the first dentition block image to be processed, the green pixel average value of multiple green pixel values of the multiple pixels, and the blue pixel average value of multiple blue pixel values of the multiple pixels become closer (for example, equal).

The processing unit 52 performs WB processing on the dentition image, assuming that the tooth region shown in the dentition image is a white region. The processing unit 52 performs WB processing on the dentition image based on the color (color information) of the tooth region shown in the dentition image. The processing unit 52 may perform WB processing based on the color (color information) of an arbitrary tooth (e.g., a tooth shown in the center of the dentition image) or on a statistical value (e.g., average value, median, etc.) of the color (color information) of the tooth region. The processing unit 52 may perform WB processing by multiplying the entire tooth region by a gain calculated based on the arbitrary tooth or the statistical value. Also, for example, if the blue level is adjusted before composition by the composition unit 53, the blue level of the composite dentition image can be made uniform, so that the tooth region of the dentition image can be white-balanced collectively. "Bulk" means that the gain used for white-balance processing is common.

This allows the tooth area to be displayed in white (achromatic color). In other words, it is easier to reproduce the user's actual tooth color. This not only reduces the sense of incongruity in the image, but also makes it easier to highlight plaque areas. Also, when white balance processing is performed collectively, it is possible to unify the color of the tooth area to the same color (white). For example, it is possible to prevent the user from feeling uncomfortable about the color of the tooth area.

The processing unit 52 only needs to adjust the blue level and perform at least WB processing.

The tooth area shown in the dentition image may be the area of the natural tooth in the teeth shown in the dentition image. In other words, the processing unit 52 may perform WB processing assuming that the natural tooth area is a white area (for example, based on the color (color information) of the natural tooth area shown in the dentition image). The natural tooth area may be the area of the natural tooth in one tooth shown in the dentition image, the area of the natural tooth in a specific tooth, or the area of the natural tooth in multiple teeth. When the area of the natural tooth in multiple teeth is used as the reference, a statistical value of the color (e.g., chromaticity) of the natural tooth area of each of the multiple teeth may be used in the WB processing. The statistical value is, for example, the average value, but may also be a maximum value, minimum value, mode, median, etc.

It is known that when excitation light is applied to natural teeth, excitation fluorescence is emitted from the dentin, which penetrates the enamel and fluoresces green. It is also known that fillings in caries treatment scars (e.g., metal inlays) do not emit excitation fluorescence under blue LED light, and are captured darkly (at low brightness) by the camera. As described above, it is also known that plaque (plaque areas) fluoresces reddish pink (excitation fluorescence) when irradiated with blue light. For these reasons, the processing unit 52 can detect natural teeth, excluding caries treatment scars and plaque, from the dentition image.

The processing unit 52 may further identify the type of tooth (e.g., a specific tooth) included in the image from the first dentition block image, the first dentition image, or the dentition image (the second dentition image or the third dentition image). Identifying the type of tooth may mean identifying whether the tooth is an incisor, a canine, or a molar, or whether the tooth is a central incisor, a lateral incisor, a canine, a first premolar, a second premolar, a first molar, a second molar, or a third molar (wisdom tooth). The processing unit 52 may also identify in which region of the oral cavity (upper jaw, lower jaw, left or right) the tooth is located. The method by which the processing unit 52 identifies the type of tooth is not particularly limited, and may be, for example, a method using a machine learning model, a method using pattern matching, or any other known method. The machine learning model is a learning model that is trained to output the type of tooth shown in an image containing teeth when the image is input. In the method using pattern matching, an image showing each tooth of a standard shape may be used as a reference, or an image of the teeth in the user's mouth captured in advance may be used as a reference. The processing unit 52 may also present the user with information identifying the teeth to be photographed before photographing, and determine that the teeth appearing in the image acquired after the information is presented are the teeth to be photographed, or have the user input which teeth are included in the acquired image, and determine that the input type of tooth is shown in the image.

The synthesis unit 53 synthesizes a plurality of first tooth row block images whose blue color levels have been adjusted by the processing unit 52 to generate a single tooth row image (panoramic image) in which a plurality of teeth are lined up. In this embodiment, the synthesis unit 53 uses a stitching process to synthesize a plurality of tooth row block images whose blue color levels have been adjusted, but the synthesis method is not limited to this. The stitching process may be performed, for example, using the contours of the teeth.

Note that the stitching process here is a process of combining multiple images (here, multiple first dentition block images) having overlapping areas to generate one or more dentition images. In the stitching process, the multiple first dentition block images are first arranged on a two-dimensional plane so that their overlapping portions line up. Then, the multiple first dentition block images are scaled (magnified), positioned, and oriented so that at least some of the feature points and surface points appear in the same location on the two-dimensional grid. In this manner, the multiple first dentition block images are registered where they are aligned. That is, the multiple first dentition block images are aligned to represent a series of adjacent teeth and are aligned to match the positions of the teeth.

Note that any type of feature detection algorithm may be used to detect the feature points, including scale invariant feature transform (SIFT) or speed up robust feature transformation (SURF). In this embodiment, feature points may be provided on the contour of the tooth region. The location of the surface point can be calculated by measuring the distance between the focal points of the viewpoints at which the two first dentition block images, including the overlapping portion, were captured, extracting the angle of the optical axis at each viewpoint, and measuring the triangle at a common position in the image.

Note that hereinafter, an example will be described in which the synthesis unit 53 generates a second teeth row image P20 (see FIG. 5 described later) showing the left molar to the right molar by synthesis, but this is not limited to this, and it is sufficient to generate a second teeth row image P20 that includes some teeth, such as two or more teeth. In this case, the synthesis unit 53 may include information regarding the type or position within the oral cavity of those some teeth in the second teeth row image P20. This makes it possible to notify the user which area within the oral cavity the second teeth row image P20 corresponds to. Note that the type of tooth or its position within the oral cavity (e.g., upper jaw, lower jaw, left or right area, etc.) is identified by the processing unit 52.

The detection unit 54 detects plaque (plaque regions) on the image on which WB processing has been performed (an example of an image based on a captured image). In this embodiment, the detection unit 54 detects plaque based on color information of the tooth region in the dentition image generated by the synthesis unit 53. The color information includes brightness V, hue H, and saturation S. The detection unit 54 detects plaque, for example, based on brightness V. The detection unit 54 detects, for example, a region where brightness V is equal to or greater than a threshold value as a plaque region.

The detection unit 54 may input the dentition image on which WB processing has been performed, and detect plaque (plaque area) that appears in the dentition image using a machine learning model that has been trained to output plaque (plaque area) that appears in the dentition image.

The detection unit 54 may detect plaque before the compositing unit 53 performs the compositing, or after the compositing unit 53 performs the compositing and before the processing unit 52 performs the WB processing. In other words, the detection unit 54 may detect plaque using a color-cast image (an example of an image based on a captured image).

The generating unit 55 is a processing unit for generating a dentition image (for example, a third dentition image described below) in which the plaque region detected by the detecting unit 54 is highlighted. The generating unit 55 highlights the detected plaque region on the dentition image generated by the synthesizing unit 53. The generating unit 55, for example, superimposes a highlight on the plaque region of the dentition image.

If the detection unit 54 detects plaque before the WB processing, the generation unit 55 may superimpose a highlight on the plaque area of the third dentition image after the WB processing.

The display unit 56 is a display device included in the mobile terminal 50, and displays the image generated by the generation unit 55. The display unit 56 may be realized, for example, by a liquid crystal display panel.

The detection unit 54 and the generation unit 55 may function as a saturation emphasis processing unit that performs saturation emphasis processing. For example, the detection unit 54 may generate a converted image by converting the dentition image (e.g., the third dentition image) that has been synthesized by the synthesis unit 53 and has been subjected to WB processing into an HSV image, and may identify a specific pixel area in which one or more pixels that satisfy at least one of the following conditions are located: saturation S is within a first predetermined range (e.g., 30 to 80 in 8-bit representation), hue H is within a second predetermined range (e.g., 140 to 170 in 8-bit representation), and brightness V is within a third predetermined range (e.g., 100 to 180 in 8-bit representation). The generation unit 55 may also generate a dentition image in which saturation S is emphasized by performing saturation emphasis processing on a specific pixel area in the dentition image (e.g., the third dentition image). The HSV image is generated, for example, by converting the color space of the dentition image into an HSV space. The display unit 56 may also display a row of teeth image that has been subjected to saturation enhancement processing.

The first, second and third specified ranges can be determined by comparing the actual plaque and tooth areas with the HSV image, and are not limited to the above numerical ranges. For example, the ranges of values for lightness V, hue H and saturation S can be determined by administering a plaque stain and comparing the degree of staining by the plaque stain.

The detection unit 54 and the generation unit 55 may function as a shade display processing unit that performs shade image processing according to the concentration distribution (accumulation level distribution) of the fluorescent substance. For example, the detection unit 54 may detect the concentration distribution of the fluorescent substance accumulated in the plaque from the value of the brightness V in a specific pixel region of the converted image. Furthermore, the generation unit 55 may generate a dentition image (e.g., a third dentition image) including a shade display by performing shade image processing according to the concentration distribution of the fluorescent substance detected for a specific pixel region in the dentition image.

As blue light passes through each layer, porphyrins in the plaque are excited, generating red fluorescence. Furthermore, the intensity of the fluorescence does not reflect the current bacterial flora, but is thought to indicate the accumulation of fluorescent substances (porphyrins). In other words, the more fluorescent substances accumulate, the stronger the red fluorescence becomes. In other words, the level of porphyrin accumulation increases as plaque matures. Therefore, the fluorescence intensity of mature plaque is stronger than that of young plaque.

The detection unit 54 detects the accumulation level (concentration or density) of fluorescent substances by comparing the intensity of red fluorescence per unit area of the plaque region.

As described above, a plaque region may be extracted from one or more pixels in the HSV image that satisfy at least one of the following: saturation S within a first predetermined range, hue H within a second predetermined range, and brightness V within a third predetermined range.

In addition, in an image that has undergone WB processing, in plaque regions, the brightness V is determined by the value of R, regardless of the hue H and saturation S.

It is also known that the fluorescent wavelength of porphyrin, a fluorescent substance in dental plaque, is 600 nm to 740 nm, with a peak fluorescent wavelength of 630 nm. In other words, the concentration of porphyrin accumulated in the plaque area can be evaluated by detecting the brightness V value of the HSV image of the plaque area.

2. Operation of the Tooth Row Image Generating System
Next, the operation of the dentition image generating system configured as above will be described with reference to Figs. 4 and 5. Fig. 4 is a sequence diagram showing the operation (dentition image generating method) of the dentition image generating system according to this embodiment. The process shown in Fig. 4 is executed by a mobile terminal 50. Note that the process shown in Fig. 4 is, for example, a process performed in real time, and is performed every time one frame or multiple frames of image data are obtained. Fig. 5 is a diagram for explaining the process of the dentition image generating system according to this embodiment. Note that in Fig. 5, color-cast images are shown with diagonal hatching.

As shown in FIG. 4, image data is generated when a user uses the intraoral camera 10 to capture an image of the teeth and gums in his or her oral cavity (S101). This image data is obtained, for example, by irradiating the teeth with light that includes the wavelength range of blue light and capturing an image of the teeth that are reacting fluorescently.

Next, the communication unit 40 of the intraoral camera 10 transmits the captured image data to the mobile terminal 50, and the acquisition unit 51 of the mobile terminal 50 acquires the image data (S102). The image data may be a video or one or more still images. Furthermore, when the image data is a video or multiple still images, the image data may be transmitted for each frame of the video or for each still image. Furthermore, when the image data is a video, the image data may be transmitted for each multiple frames.

In addition, image data may be transmitted in real time, or may be transmitted all at once after a series of photographs (e.g., photographs of all teeth in the oral cavity) have been taken.

The processing unit 52 of the mobile terminal 50 adjusts the blue level of the received image data (S103). The processing unit 52 may multiply each of the R, G, and B components by different gains so that the blue levels of the tooth regions of each of the multiple first dentition block images, which are partial dentition images based on the image data, become closer to each other.

Each of the multiple first dentition block images P1 to P5 shown in FIG. 5(a) is an image on which no WB processing has been performed. Also, each of the multiple first dentition block images P1 to P5 is an image on which the blue color level has been adjusted.

Referring again to FIG. 4, next, the synthesis unit 53 of the mobile terminal 50 synthesizes the multiple first dentition block images P1 to P5 for which no WB processing has been performed and for which the blue color level has been adjusted (S104).

As shown in (a) and (b) of FIG. 5, the synthesis unit 53 performs a stitching process on the first dentition block images P1, P2, and P3 to generate a first dentition image P11 including the first dentition block images P1 and P2 and at least a portion of the first dentition block image P3. The synthesis unit 53 also performs a stitching process on the first dentition block images P3, P4, and P5 to generate a first dentition image P12 including at least a portion of the first dentition block image P3 and the first dentition block images P4 and P5. The first dentition images P11 and P12 are images in which at least a portion of the dental region overlaps. In the example of FIG. 5, at least a portion of the dental region of the first dentition block image P3 overlaps in the first dentition images P11 and P12.

The processing unit 52 also performs stitching processing so that the first teeth row image includes the central part of the angle of view of each of the first teeth row block images to be synthesized. Using the first teeth row image P11 as an example, the processing unit 52 performs stitching processing so that the first teeth row image P11 includes the central part of the angle of view of each of the first teeth row block images P1 to P3. The first teeth row image P11 thus generated is an image in which light hits each tooth from the front, making it less likely to create shadows and making it easier to see the spaces between the teeth.

Here, the first teeth row block image P3 may be an image including the two lower front teeth, for example, an image including the space between the two front teeth. In this case, the first teeth row image P11 may be, for example, a panoramic image showing the area from the left back tooth to the front teeth, and the first teeth row image P12 may be, for example, a panoramic image showing the area from the right back tooth to the front teeth.

In addition, the image including the space between the front teeth may be, for example, an image taken after an announcement such as "Please take a picture of your front teeth" is made when taking a picture with the imaging unit 21, or it may be an image in which the user has input that it is an image of the front teeth.

The number of first dentition images generated by the synthesis unit 53 is not particularly limited, and may be three or more.

Then, the synthesis unit 53 generates a second teeth row image P20 by performing a stitching process on the two first teeth row images P11 and P12. The second teeth row image P20 is a panoramic image in which multiple first teeth row block images P1 to P5 are synthesized. The second teeth row image P20 is a panoramic image that shows at least a portion of the teeth row in the user's oral cavity, and may be, for example, a panoramic image that shows the user's left molar to right molar. The second teeth row image P20 is an example of a teeth row image after synthesis.

The synthesis unit 53 may generate the second dentition image P20 directly based on the multiple first dentition block images P1 to P5. In other words, the first dentition images P11 and P12 do not need to be generated.

Referring again to FIG. 4, next, the processing unit 52 of the mobile terminal 50 performs image processing on the second dentition image P20 synthesized by the synthesis unit 53 (S105). In step S105, the processing unit 52 performs at least WB processing on the second dentition image P20.

5(c) and (d), the processing unit 52 performs WB processing on the second dentition image P20 based on the color information of the tooth region of the second dentition image P20 to generate a third dentition image P30. The processing unit 52 may perform WB processing based on the color information of the central tooth in the second dentition image P20 (e.g., the tooth shown in the first dentition block image P3) as a reference. The processing unit 52 may perform WB processing based on, for example, the color information of only the central tooth in the second dentition image P20 (e.g., the tooth shown in the first dentition block image P3).

The third teeth row image P30 is composed of a plurality of second teeth row block images P31 to P35. The second teeth row block image P31 corresponds to an image obtained by performing white balance processing on the first teeth row block image P1, the second teeth row block image P32 corresponds to an image obtained by performing white balance processing on the first teeth row block image P2, the second teeth row block image P33 corresponds to an image obtained by performing white balance processing on the first teeth row block image P3, the second teeth row block image P34 corresponds to an image obtained by performing white balance processing on the first teeth row block image P4, and the second teeth row block image P35 corresponds to an image obtained by performing white balance processing on the first teeth row block image P5.

Referring again to FIG. 4, next, the detection unit 54 of the mobile device 50 detects plaque in the third dentition image P30 (S106). The detection unit 54 detects the presence or absence of plaque, but may also detect, for example, the concentration distribution of fluorescent substances, i.e., the accumulation level of plaque.

Then, the generating unit 55 of the mobile device 50 generates an image in which the plaque region detected by the detecting unit 54 is highlighted (S107). In this embodiment, the generating unit 55 generates an image in which a highlight display indicating the plaque region is superimposed on the third dentition image P30, but it may also generate an image in which a shading display according to the concentration distribution of the fluorescent substance is superimposed on the third dentition image P30.

Next, the display unit 56 of the mobile device 50 displays the image generated by the generation unit 55 (S108).

By using such a dentition image generation system, a user can take an image of the user's own oral cavity with the intraoral camera 10 and check the condition of the oral cavity in a panoramic image displayed on the mobile terminal 50. Furthermore, the concentration distribution of the fluorescent material is shown in the displayed panoramic image, allowing the user to easily check the health condition of their own teeth.

The mobile device 50 also performs white balance processing, so that it can generate a third dentition image P30 in which the plaque area is superimposed (e.g., highlighted) regardless of the color of light emitted by the illumination unit 23 of the intraoral camera 10.

The mobile terminal 50 may also generate a three-dimensional model of multiple teeth in the oral cavity from multiple captured image data. The mobile terminal 50 may also display an image based on the generated three-dimensional model.

In addition, instead of detecting plaque on the second dentition image P20, the detection unit 54 may detect plaque on the first dentition images P11 and P12.

Although an example has been described in which the mobile terminal 50 processes images of teeth, some or all of this processing may be performed by the intraoral camera 10.

Other Embodiments
Although the dentition image generating system according to the embodiment of the present disclosure has been described above, the present disclosure is not limited to this embodiment.

For example, in the above embodiment, an example was described in which an intraoral camera 10 is used whose main purpose is to photograph teeth, but the intraoral camera 10 may also be an oral care device equipped with a camera. For example, the intraoral camera 10 may also be an oral irrigator equipped with a camera.

In addition, in the above embodiment, a mobile terminal 50 is given as an example of a user's information terminal, but the information terminal may be a stationary information terminal.

In addition, in the above embodiment, the multiple first dentition block images may be images captured after an announcement of the tooth position or tooth type, etc., is made when capturing images with the imaging unit 21, or may be images in which the position of the tooth is input by a user, etc.

Furthermore, each processing unit included in the dentition image generating system according to the above embodiment is typically realized as an LSI, which is an integrated circuit. These may be individually implemented as single chips, or may be integrated into a single chip that includes some or all of them.

In addition, the integrated circuit is not limited to LSI, but may be realized by a dedicated circuit or a general-purpose processor. It is also possible to use an FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connections and settings of the circuit cells inside the LSI.

In addition, in each of the above embodiments, each component may be configured with dedicated hardware, or may be realized by executing a software program suitable for each component. Each component may be realized by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

Furthermore, the division of functional blocks in the block diagram is one example, and multiple functional blocks may be realized as one functional block, one functional block may be divided into multiple blocks, or some functions may be transferred to other functional blocks. Furthermore, the functions of multiple functional blocks having similar functions may be processed in parallel or in a time-shared manner by a single piece of hardware or software.

Furthermore, the mobile terminal 50 according to the above embodiment may be realized as a single device, or may be realized by multiple devices. When the mobile terminal 50 is realized by multiple devices, the components of the mobile terminal 50 may be distributed in any manner among the multiple devices. For example, at least some of the functions of the mobile terminal 50 may be realized by the intraoral camera 10 (e.g., the signal processing unit 30). When the mobile terminal 50 is realized by multiple devices, the communication method between the multiple devices is not particularly limited, and may be wireless communication or wired communication. Furthermore, wireless communication and wired communication may be combined between the devices.

The present disclosure may also be realized as a dentition image generation method executed by a dentition image generation system. The present disclosure may also be realized as an intraoral camera, a mobile terminal, or a cloud server included in the dentition image generation system.

In addition, the order in which each step is executed in the sequence diagram is merely an example to specifically explain the present disclosure, and an order other than the above may also be used. In addition, some of the steps may be executed simultaneously (in parallel) with other steps.

Another aspect of the present disclosure may be a computer program that causes a computer to execute each of the characteristic steps included in the dentition image generation method shown in FIG. 4.

Furthermore, for example, the program may be a program to be executed by a computer. Furthermore, one aspect of the present disclosure may be a non-transitory computer-readable recording medium on which such a program is recorded. For example, such a program may be recorded on a recording medium and distributed or circulated. For example, the distributed program may be installed in a device having another processor, and the program may be executed by that processor, thereby making it possible to cause that device to perform each of the above processes.

The above describes the dentition image generating system and the like relating to one or more aspects based on the embodiment, but the present disclosure is not limited to this embodiment. As long as it does not deviate from the spirit of the present disclosure, various modifications conceivable by a person skilled in the art to this embodiment and forms constructed by combining components in different embodiments may also be included within the scope of one or more aspects.

This disclosure can be applied to a dentition image generation system.

REFERENCE SIGNS LIST 10 Intraoral camera 10a Head section 10b Handle section 10c Neck section 20 Hard section 21 Photography section 22 Sensor section 23 Illumination section 23A First LED
23B Second LED
23C Third LED
23D 4th LED
24 Operation unit 30 Signal processing unit 31 Camera control unit 32 Image processing unit 33 Control unit 34 Illumination control unit 35 Memory unit 40 Communication unit 50 Portable terminal (dentition image generating device)
51 Acquisition unit 52 Processing unit 53 Synthesis unit 54 Detection unit (saturation emphasis processing unit, grayscale display processing unit)
55 Generation unit (saturation emphasis processing unit, gray scale display processing unit)
56 Display unit P1, P2, P3, P4, P5 First dentition block image P11, P12 First dentition image P20 Second dentition image (dentition image)
P30 Third dentition image P31, P32, P33, P34, P35 Second dentition block images

Claims (13)

an acquisition unit that acquires an image obtained by photographing a surface of a dentition and dental plaque in an oral cavity irradiated with light having a wavelength range including blue light;
a synthesis unit for generating a row of teeth image by synthesizing a plurality of row of teeth block images, which are partial row of teeth images based on the photographed images;
a processing unit that performs white balance processing on the combined row-of-teeth image. The device for generating a row-of-teeth image according to claim 1 , wherein the processing unit performs the white balance processing based on color information of a central tooth in the row-of-teeth image after synthesis. The device for generating a row-of-teeth image according to claim 1 , wherein the processing unit performs the white balance processing based on color information of an entire tooth region of the row-of-teeth image after synthesis. The processing unit adjusts a blue level of a tooth region of each of the plurality of dentition block images,
4. The device for generating an image of a row of teeth according to claim 1, wherein the synthesis unit synthesizes the plurality of row of teeth block images in which the blue color level has been adjusted. A detection unit that detects plaque from an image based on the captured image;
The dentition image generating device according to any one of claims 1 to 3, further comprising: a generating unit for generating a synthesized dentition image in which the plaque area detected by the detecting unit is highlighted. The dentition image generating device according to claim 5 , further comprising a display unit that displays the dentition image after synthesis in which the plaque region is highlighted. The dentition image generating device according to claim 1 , wherein the plurality of dentition block images include an image of anterior teeth. The dentition image generating device according to claim 1 , wherein the surface of the dentition includes a side surface of the dentition. The dentition image generating device according to claim 1 , wherein the surfaces of the dentition include an occlusal surface of the dentition. The device for generating an image of a row of teeth according to any one of claims 1 to 3, further comprising a saturation emphasis processing unit that generates a converted image by converting the synthesized image of the row of teeth into an HSV image, identifies a specific pixel area in which one or more pixels among a plurality of pixels in the converted image that satisfy at least one of a first predetermined range for saturation, a second predetermined range for hue, and a third predetermined range for brightness are located, and performs saturation emphasis processing on the specific pixel area in the synthesized image of the row of teeth to generate the synthesized image of the row of teeth with emphasized saturation. The device for generating an image of a row of teeth according to any one of claims 1 to 3, further comprising a shading display processing unit that generates a converted image by converting the synthesized row of teeth image into an HSV image, identifies a specific pixel area in which one or more pixels among a plurality of pixels in the converted image are located, the saturation of which falls within at least one of a first predetermined range, a hue of which falls within a second predetermined range, and a brightness of which falls within a third predetermined range, detects an accumulation level distribution of fluorescent substances accumulated in the plaque from the brightness value in the specific pixel area of the converted image, and performs shading image processing according to the accumulation level distribution of the fluorescent substances detected for the specific pixel area in the synthesized row of teeth image, thereby generating the synthesized row of teeth image including a shading display. Obtaining a photographed image obtained by photographing the surface of the dentition and dental plaque in the oral cavity irradiated with light having a wavelength range of blue light;
generating a row of teeth image by synthesizing a plurality of row of teeth block images, which are partial row of teeth images based on the photographed images;
The method for generating a row-of-teeth image further comprises performing white balance processing on the combined row-of-teeth image. A program for causing a computer to execute the dentition image generation method described in claim 12.

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