JP3989522B2 - Dental colorimetry apparatus, system, method, and program - Google Patents

Description

  The present invention relates to a dental colorimetry apparatus, system, method, and program for performing processing for color reproduction of a subject with high accuracy.

In recent years, interest in beauty and health has increased. For example, in beauty, whitening that suppresses melanin pigments in the skin is showing a trend as a field of aesthetic pursuit.
Conventional skin diagnosis uses a camera system for skin diagnosis that is configured so that the surface of the skin can be enlarged and observed on a monitor, for example, dermatology, esthetic salon, beauty counseling, etc. Used in. Of these, for example, in the case of dermatology, by observing images of skin grooves and dermis, the characteristics of the skin surface are captured and diagnosed, and counseling is performed.

  In the field of dentistry, treatment by the ceramic crown method or the like is performed as one means in consideration of aesthetics in dental treatment. This ceramic crown method is performed by producing a crown (ceramic crown prosthesis) having a color close to the color of the original tooth of the patient and covering the crown of the patient with the crown. In the treatment by the ceramic crown method, it is essential to produce a crown which is a prosthesis.

Conventionally, a crown is manufactured as follows.
First, in a dental clinic, imaging of the patient's oral cavity is performed by a dentist or the like. For example, photographing of the entire oral cavity including a plurality of teeth or a tooth surface of a living tooth to be crowned is performed. Photographing is performed using a digital camera or the like developed for dentistry.
Further, the dentist selects a shade guide having a color closest to the patient's vital tooth from a plurality of tooth samples (hereinafter referred to as “shade guides”) having different colors (hereinafter referred to as “shade”). "Take"). The shade guide is obtained by processing different colored ceramics into a tooth shape, for example. When the above operation is completed, the dentist sends the above-mentioned photographed photograph and the unique identification number assigned to the selected shade guide to the laboratory that produces the crown. Thereby, in the technical laboratory, the crown is manufactured based on these pieces of information.

  However, since the above-mentioned shade take is performed by the dentist's subjectivity, it lacks quantitativeness. Furthermore, the appearance of the shade guide and the color of the patient's teeth changes depending on various factors such as the color of the gums, the surrounding environment, lighting conditions (for example, lighting conditions, lighting colors, etc.), and the fatigue level of the doctor. For this reason, it is very difficult to select an optimum shade guide, and there is a drawback that a burden on a doctor is great.

  Therefore, in order to reduce the burden on the doctors mentioned above, an apparatus that supports a work such as a shade take is proposed by providing a function such as automatically selecting a shade guide that most closely matches the color of the living tooth. ing.

For example, in Patent Document 1, a computer stores in advance a data table in which identification information data of a plurality of tooth reference colors and L ^* a ^* b ^* color system color information data of the tooth reference colors correspond to each other, L ^* a of the tooth reference color L ^* a of the reference tool analyzed in the image data by inputting image data obtained by simultaneously photographing a vital tooth and a reference tool having a color tone of the tooth reference color (corresponding to the “shade guide” described above) ^* B ^{* The} color tone correction value that substantially matches the color tone information data of the color system and the color information data of the tooth reference color in the data table that matches the identification information data of the tooth reference color is calculated to calculate the color tone of the living tooth A technique is disclosed that corrects, extracts and outputs identification information data of a tooth reference color of tone information data that matches or approximates the tone information data of the color tone of the corrected vital tooth.
Japanese Patent No. 3710802 (FIGS. 5 and 6)

However, in the invention disclosed in Patent Document 1 described above, the color information data of the L ^* a ^* b ^* color system in the predetermined area set for the vital tooth and the L in the predetermined area set for the reference tool. ^{* A *} b ^{* Since} the color information of the color system is comprehensively compared, only a rough comparison result can be obtained, and a more detailed comparison result within the predetermined area cannot be known. There was a problem.
Furthermore, in the above-mentioned Patent Document 1, since the comparison result is expressed by a numerical value, there is a drawback that it is difficult for a user such as a dentist or a technician to compare the features of both.

  The present invention has been made in view of such circumstances, and is capable of expressing differences in color and the like between living teeth and tooth samples with high accuracy and in an easily comparable manner. It is an object to provide a color measuring apparatus, system, method, and program for use.

In order to solve the above problems, the present invention employs the following means.
The present invention provides a first storage unit that stores, for each pixel , photographed image data of vital teeth and colorimetric information obtained based on the photographed image data, and photographed image data of the tooth sample and the photographed image data. A second storage unit that stores colorimetric information obtained on the basis of each pixel; a reference acquisition unit that acquires reference colorimetric information used as a reference when comparing the colorimetric information; and the reference colorimetry A first extraction unit that compares information and the colorimetric information of the vital tooth on a pixel basis, and extracts a pixel whose difference between the colorimetric information of the vital tooth and the reference colorimetric information is a predetermined threshold value or less ; The reference colorimetric information is compared with the colorimetric information of the tooth sample in units of pixels, and the difference between the colorimetric information of the tooth sample and the reference colorimetric information is equal to or less than the predetermined threshold value. a second extraction unit for extracting, composed of pixels extracted by the first extraction unit And one pixel group, a first image creating section that creates a vital tooth comparison image representing a second pixel group including pixels that are not extracted in different shades, which is extracted by the second extraction unit A second image creation unit for creating a sample comparison image in which a third pixel group including pixels and a fourth pixel group including non-extracted pixels are expressed in different tones; and the first image generation unit A dental colorimetric device comprising: a display control unit configured to display the vital tooth comparison image created by the above and the sample comparison image created by the second image creation unit .

According to such a configuration, the reference colorimetric information acquired by the reference acquisition unit is transferred to the first extraction unit, and the first extraction unit generates the reference colorimetric information and the vital tooth colorimetry information. Comparison is made in pixel units. Further, the first extraction unit determines whether or not the comparison result obtained for each pixel satisfies a predetermined condition, a pixel that satisfies the predetermined condition is extracted, and this pixel information is extracted from the first image. Transferred to the creation section. In the first image creation unit, the first pixel group composed of pixels extracted by the first extraction unit is different from the second pixel group composed of pixels not extracted by the first extraction unit. A vital tooth comparison image expressed in color tone is created, and the vital tooth comparison image is displayed on a screen such as a monitor by the display control unit.
The reference colorimetric information acquired by the reference acquisition unit is also transferred to the second extraction unit, and the second extraction unit compares the reference colorimetry information and the color measurement information of the tooth sample in pixel units. Is done. Further, the second extraction unit determines whether or not the comparison result obtained for each pixel satisfies a predetermined condition, a pixel that satisfies the predetermined condition is extracted, and this pixel information is extracted from the second image. Transferred to the creation section. In the second image creation unit, the third pixel group composed of pixels extracted by the second extraction unit is different from the fourth pixel group composed of pixels not extracted by the second extraction unit. A sample comparison image expressed in color tone is created. Then, the sample control image is displayed on a screen such as a monitor together with the above-mentioned vital tooth comparison image by the display control unit.

As described above, according to the above configuration, the colorimetric information is classified into pixels that satisfy the predetermined condition and pixels that do not satisfy the predetermined colorimetric relationship with the reference colorimetric information, and the classified pixels are expressed in different color tones. Since the vital tooth comparison image is displayed, the user who sees this screen can easily recognize which part of the vital tooth satisfies the condition.
Also, in the sample, the sample comparison image in which the colorimetric information is classified into pixels that do not satisfy the predetermined condition and pixels that do not satisfy the predetermined colorimetric relationship with the reference colorimetric information, and the classified pixels are expressed in different tones. Since it is displayed, the user who sees this screen can easily recognize which part of the tooth sample satisfies the condition.
Furthermore, since the vital tooth comparison image and the sample comparison image are displayed on the same screen, it is possible to easily compare the characteristics of the vital tooth and the characteristics of the tooth sample based on these images.
“Colorimetric information” includes, for example, chromaticity values, spectral characteristics, color temperatures, and the like. Specifically, RGB values, L ^* a ^* b ^* values, CMYK values, XYZ values, LCH values, spectral compositions, Spectral reflectance, color temperature value, etc. It is sufficient if at least one of these RGB values is stored in the first storage unit.
“To make the color tone different” means, for example, that the distinction between the first pixel group and the second pixel group is visibly expressed in the vital tooth comparison image, for example, other than making the color different It is possible to adopt an expression mode such as different shades and brightness in the same color. Further, “to make the tone different” includes the concept of making the shade display different in halftone dots or meshes.

  In the dental colorimetric device, in the sample comparison image and the vital tooth comparison image, the first pixel group and the third pixel group are expressed in the same color tone, and the second pixel group and the The fourth pixel group may be expressed in the same color tone.

  According to such a configuration, in the sample comparison image and the vital tooth comparison image, it is possible to unify the color tone of the pixels that satisfy the predetermined condition and the pixels that do not satisfy the predetermined condition. Can be compared.

In the dental colorimetric device, the first image creating unit changes at least one of brightness, saturation, and hue of each pixel in the vital tooth comparison image according to colorimetric information of the pixel,
The second image creation unit may change at least one of brightness, saturation, and hue of each pixel in the sample comparison image according to colorimetric information of the pixel.

  According to such a configuration, in the sample comparison image and the vital tooth comparison image, at least one of brightness, saturation, and hue changes according to the colorimetric information of each pixel. It is possible to visually recognize how the colorimetric information of each pixel is changing. Thereby, the characteristics of the tooth sample and the characteristics of the vital tooth can be recognized in more detail.

  In the dental colorimetric device, the first image creating unit creates the vital tooth comparison image in which pixels belonging to the first pixel group are represented by captured image data of the vital tooth, and the second The image creation unit may create the sample comparison image in which pixels belonging to the third pixel group are expressed by captured image data of the tooth sample.

  According to such a configuration, in the sample comparison image and the vital tooth comparison image, captured image data is adopted for pixels that satisfy a predetermined condition. As a result, for the portion that satisfies the predetermined condition, the photographed tooth sample and the color of the vital tooth are substantially reproduced as it is, so that the user can recognize even a slight color difference. Become. In this case, the pixels determined not to satisfy the predetermined condition, that is, the pixels belonging to the second pixel group and the fourth pixel group can be expressed in a manner in which brightness, saturation, and luminance are reduced. preferable. By doing in this way, since the part which employ | adopted picked-up image data is emphasized compared with another part, comparison of both colors etc. can be made easier.

In the dental colorimetric device, the first image creation unit may set the brightness, saturation, or luminance of each pixel belonging to the second pixel group in the vital tooth comparison image to the first pixel group. Expressed in a manner that is lower than the brightness, saturation, or luminance of each pixel to which the pixel belongs, the second image creation unit, the brightness, saturation, or each pixel belonging to the fourth pixel group in the sample comparison image The luminance may be expressed in a manner that is lower than the brightness, saturation, or luminance of each pixel belonging to the third pixel group.
In the dental colorimetric device, the first image creating unit measures at least one of the brightness, saturation, and hue of each pixel belonging to the second pixel group in the vital tooth comparison image. According to color information, the second image creating unit is configured to measure at least one of brightness, saturation, and hue of each pixel belonging to the fourth pixel group in the sample comparison image. It is good also as changing according to information.

  According to such a configuration, in the sample comparison image and the vital tooth comparison image, even in a pixel group that does not satisfy the predetermined condition, at least one of brightness, saturation, and hue changes according to the colorimetric information of each pixel. Thus, the user who sees this screen can recognize the colorimetric information in detail even for pixels that do not satisfy the predetermined condition.

  In the dental colorimetric apparatus, the display control unit may display a reference input unit for inputting the reference colorimetric information on a screen on which the vital tooth comparison image is displayed.

  According to such a configuration, since the reference input unit for inputting the reference colorimetric information is displayed on the screen on which the vital tooth comparison image is displayed, the user can select a desired reference colorimetry from the reference input unit. It becomes possible to input information.

In the dental colorimetry apparatus, the display control unit may display a condition input unit for inputting the predetermined threshold on a screen on which the vital tooth comparison image is displayed.

  According to such a configuration, since the condition input unit for inputting a predetermined condition is displayed on the screen on which the vital tooth comparison image is displayed, the user inputs a desired condition from the condition input unit. It becomes possible.

  The dental colorimetric device includes a region specifying unit for specifying a region of a vital tooth to be measured from an intraoral image captured by an imaging device, and at least one measurement for the specified vital tooth region. A measurement region setting unit for setting a region; and a sample selection unit for selecting at least one tooth sample that approximates the spectrum of each measurement region from a plurality of pre-registered tooth samples, The second extraction unit may compare the reference colorimetric information with the colorimetric information of the tooth sample selected by the sample selection unit on a pixel basis.

  According to such a configuration, the region of the vital tooth to be measured is identified by the region identification unit from the intraoral photographed image photographed by the photographing device, and at least one measurement is performed in the identified vital tooth region. The region is set by the measurement region setting unit, and at least one tooth sample that approximates the spectrum of the set measurement region is selected by the sample selection unit, and the color measurement information about the selected at least one tooth sample is second. From the storage unit and transferred to the second extraction unit. As a result, the color measurement information of the tooth sample selected by the sample selection unit and the reference color measurement information are compared in pixel units. Thereby, it becomes possible to compare with the sample of the tooth having the feature closest to the feature of the vital tooth.

The present invention includes an imaging device that images an intraoral area, a dental colorimetric device that processes an image acquired by the imaging device, and a display device that displays an image processed by the dental colorimetric device. The dental colorimetric device includes a first storage unit that stores, for each pixel, photographed image data of living teeth and colorimetric information obtained based on the photographed image data, photographed image data of a tooth sample, and A second storage unit that stores, for each pixel, colorimetric information obtained based on the captured image data; a reference acquisition unit that acquires reference colorimetric information that is used as a reference when comparing the colorimetric information; The reference colorimetric information and the vital tooth colorimetric information are compared on a pixel basis, and a pixel whose difference between the vital tooth colorimetric information and the reference colorimetric information is equal to or less than a predetermined threshold is extracted. and 1 extractor, measuring lust swatch of the reference calorimetric information and the teeth Comparing the door in the pixel unit, and a second extraction unit for extracting a pixel difference is less than the predetermined threshold value between the colorimetric information and the reference calorimetric information of sample of the tooth, extracting the first a first image creating section that creates a first pixel group including pixels that are extracted, the vital tooth comparison image representing a second pixel group including pixels that are not extracted in different color tones by parts, the A second image creation unit that creates a sample comparison image in which a third pixel group composed of pixels extracted by the second extraction unit and a fourth pixel group composed of pixels not extracted are expressed in different tones. When, a dental colorimetry comprising said first of said vital tooth comparison image created by the image creating unit, and a display control unit for displaying said sample comparison image created by the second image generating unit Provide a system.

In the dental colorimetry system, the first image creation unit creates the vital tooth comparison image in which pixels belonging to the first pixel group are represented by captured image data of the vital tooth, and the second The image creation unit may create the sample comparison image in which pixels belonging to the third pixel group are expressed by captured image data of the tooth sample .

The present invention provides a reference acquisition process for acquiring reference colorimetric information that is used as a reference when comparing colorimetric information obtained based on captured image data of vital teeth, the reference colorimetric information, and the vital tooth A first extraction process of comparing colorimetric information with a unit of pixel, and extracting a pixel whose difference between the colorimetric information of the vital tooth and the reference colorimetric information is a predetermined threshold value or less, and photographing of a tooth sample The colorimetric information obtained based on the image data is compared with the reference colorimetric information in units of pixels, and the difference between the colorimetric information of the tooth sample and the reference colorimetric information is less than or equal to the predetermined threshold value. A second extraction process for extracting a certain pixel, a first pixel group composed of pixels extracted by the first extraction unit, and a second pixel group composed of pixels not extracted are expressed in different tones. a first image creating process for creating a vital tooth comparison image, extracted the second A third pixel group consisting of extracted pixels by degree, and the second image creation process of creating a fourth sample comparison image representing a pixel group in different shades of pixels not extracted, the life Provided is a dental colorimetric method comprising a display control process for displaying a tooth comparison image and the sample comparison image .

In the first color creation process, the dental colorimetric method creates the vital tooth comparison image in which pixels belonging to the first pixel group are expressed by captured image data of the vital tooth, and In the image creation process, the sample comparison image in which pixels belonging to the third pixel group are represented by captured image data of the tooth sample may be created .

The present invention provides a reference acquisition process for acquiring reference colorimetric information used as a reference when comparing colorimetric information obtained on the basis of photographed image data of vital teeth, the colorimetric information of vital teeth, and the reference A first extraction process that compares colorimetric information with a pixel unit and extracts a pixel whose difference between the colorimetric information of the vital tooth and the reference colorimetric information is a predetermined threshold value or less, and imaging of a tooth sample The colorimetric information obtained based on the image data is compared with the reference colorimetric information in units of pixels, and the difference between the colorimetric information of the tooth sample and the reference colorimetric information is less than or equal to the predetermined threshold value. The second extraction process for extracting a certain pixel, the first pixel group composed of pixels extracted by the first extraction process, and the second pixel group composed of pixels not extracted are expressed in different colors. a first image creating process for creating a vital tooth comparison image, the second extraction A third pixel group including pixels extracted by the processing, and the second image creation processing for creating a sample comparison image representing a different color and the fourth pixel group consisting of not extracted pixels, the life A dental colorimetry program for causing a computer to execute a display control process for displaying a tooth comparison image and the sample comparison image is provided.

In the first image creation process, the dental colorimetry program creates the vital tooth comparison image in which pixels belonging to the first pixel group are represented by captured image data of the vital tooth, and In the image creation process, the sample comparison image in which pixels belonging to the third pixel group are represented by captured image data of the tooth sample may be created .

  According to the present invention, it is possible to express the difference in color and the like between the vital tooth and the tooth sample with high accuracy and to express in an easily comparable manner.

DESCRIPTION OF EMBODIMENTS Embodiments of a dental colorimetry apparatus, a dental colorimetry system, a dental colorimetry method, and a dental colorimetry program according to the present invention will be described below with reference to the drawings.
[First Embodiment]
As shown in FIGS. 1 and 4, the dental color measurement system according to the first embodiment of the present invention includes an imaging device 1, a cradle 2, a dental color measurement device 3, and a display device 4. ing.

The imaging device 1 includes a light source 10, an imaging unit 20, an imaging control unit 30, a display unit 40, and an operation unit 50 as main components as shown in FIG.
The light source 10 is disposed in the vicinity of the tip of the photographing apparatus 1 and emits illumination light having four or more different wavelength bands for illuminating the subject. Specifically, the light source 10 includes seven light sources 10a to 10g that emit light in different wavelength bands. Each of the light sources 10a to 10g includes four LEDs. As shown in FIG. 2, the central wavelengths of the light sources 10a are about 450 nm, the light source 10b is about 465 nm, the light source 10c is about 505 nm, and the light source 10d is about 525 nm. The light source 10e is about 575 nm, the light source 10f is about 605 nm, and the light source 10g is about 630 nm. The emission spectrum information of the LED is stored in the LED memory 11 and used in the dental color measuring device 3 described later.

  These light sources 10a to 10g are arranged in a ring shape, for example. The arrangement is not particularly limited, and for example, four LEDs may be arranged in the order of shorter wavelengths, or may be arranged in reverse order or at random. Further, in addition to the arrangement in which all the LEDs form one ring, the LEDs may be divided into a plurality of groups, and these one group may be arranged to form one ring. Note that the LED arrangement is not limited to the ring shape, and a cross-shaped arrangement, a rectangular arrangement, a left / right one-line arrangement, an upper / lower one-line arrangement, a random arrangement, etc., as long as there is no hindrance to imaging by the imaging unit 20 described later. It is possible to adopt an appropriate arrangement. The light emitting element of the light source 10 is not limited to an LED, and for example, a semiconductor laser such as an LD (laser diode) or other light emitting elements can be used.

  In the imaging apparatus 1, an illumination optical system (not shown) for irradiating illumination light from the light source 10 onto the subject surface substantially uniformly is provided on the subject side of the light source 10. A temperature sensor 13 for detecting the temperature of the LED is provided in the vicinity of the light source 10.

  The imaging unit 20 includes an imaging lens 21, an RGB color imaging device 22, a signal processing unit 23, and an AD converter 24. The imaging lens 21 forms a subject image irradiated with the light source 10. The RGB color image sensor 22 captures a subject image formed by the imaging lens 21 and outputs an image signal. The RGB color image pickup element 22 is constituted by, for example, a CCD, and the sensor sensitivity is such that it substantially covers the visible wide area. This CCD may be a monochrome type or a color type. The RGB color image sensor 22 is not limited to a CCD, and a CMOS type or other various image sensors can be widely used.

  The signal processing unit 23 performs gain correction, offset correction, and the like on the analog signal output from the RGB color image sensor 22. The A / D converter 24 converts the analog signal output from the signal processing unit 23 into a digital signal. A focus lever 25 for adjusting the focus is connected to the imaging lens 21. The focus lever 25 is for manually adjusting the focus, and a position detection unit 26 for detecting the position of the focus lever 25 is provided.

  The imaging control unit 30 includes a CPU 31, an LED driver 32, a data I / F 33, a communication I / F controller 34, an image memory 35, and an operation unit I / F 36. Each of these units is connected to the local bus 37 and is configured to be able to exchange data via the local bus 37.

  The CPU 31 controls the imaging unit 20, records the subject spectral image acquired and processed by the imaging unit 20 in the image memory 35 via the local bus 37, and outputs it to the LCD controller 41 described later. The LED driver 32 controls light emission of various LEDs included in the light source 10. The data I / F 33 is an interface for receiving the contents of the LED memory 11 provided in the light source 10 and the information of the temperature sensor 13. The communication I / F controller 34 is connected to a communication I / F contact 61 serving as a connection point with the outside, and has a function for realizing communication compliant with USB 2.0, for example. The operation unit I / F 36 is connected to various operation buttons provided in the operation unit 60 described later, and functions as an interface for transferring an input instruction input via the operation unit 50 to the CPU 31 via the local bus 37. The image memory 35 temporarily records image data captured by the imaging unit 20. In the present embodiment, the image memory 35 has a memory capacity capable of recording at least seven spectral images and one RGB color image.

  The display unit 40 includes an LCD controller 41 and an LCD 42. The LCD controller 41 causes an LCD (liquid crystal display) 42 to display an image based on the image signal transferred from the CPU 31, for example, an image currently captured by the imaging unit 20 or an already captured image. At this time, if necessary, the image pattern stored in the overlay memory 43 may be superimposed on the image acquired from the CPU 31 and displayed on the LCD 42. Here, the image pattern recorded in the overlay memory 43 is, for example, a horizontal line that captures the entire tooth horizontally, a cross line that intersects this, an imaging mode, an identification number of the tooth to be imaged, or the like. .

  The operation unit 50 includes various operation switches and operation buttons for a user to input an instruction to start a spectral image shooting operation or to input an instruction to start or end a moving image shooting operation. Specifically, a shooting mode changeover switch 51, a shutter button 52, a viewer control button 53, and the like are provided. The shooting mode switch 51 is a switch for switching between normal RGB shooting and multiband shooting. The viewer control button 53 is a switch for performing operations such as changing the image displayed on the LCD 42.

  Moreover, the imaging device 1 is equipped with a lithium battery 60 as a storage battery. The lithium battery 60 is used to supply power to each unit included in the imaging apparatus 1 and is connected to a connection contact 62 that is a contact for charging. Further, a battery LED 63 for notifying the charging state of the lithium battery is provided. In addition, the imaging apparatus 1 is provided with a power LED 64 for notifying the camera state and an alarm buzzer 65 for notifying danger during photographing.

The battery LED 63 includes, for example, three LEDs of red, yellow, and green, notifies that the charging capacity of the lithium battery 60 is sufficient by lighting in green, and in other words, indicates that the battery capacity is low by lighting in yellow. The fact that charging is necessary is notified, and the fact that the battery capacity is extremely low by lighting in red, in other words, the fact that urgent charging is required is notified.
The power LED 64 includes, for example, two LEDs of red and green, and notifies that the preparation for shooting is completed by lighting in green, and that the preparation for shooting (initial warming, etc.) is in progress by blinking green. Then, it is notified that the battery is being charged by lighting in red.
The alarm buzzer 65 notifies that the captured image data is invalid by warning.

  The cradle 2 that supports the imaging device 1 described above includes a color chart 100 for calibrating the imaging unit 20, a micro switch 101 for confirming whether the imaging device 1 is mounted at a normal position, The power supply 102 for turning on / off the power, the power lamp 103 which is turned on / off in conjunction with the on / off of the power switch 102, and the light on / off in conjunction with the microswitch 101, the imaging apparatus 1 A mounting lamp 104 for notifying whether or not the camera is mounted at the normal position is provided.

  For example, when the imaging apparatus 1 is mounted at a normal position, the mounting lamp 104 is lit green, and when it is not mounted, the mounting lamp 104 is lit red. In addition, the cradle 2 is provided with a power connection connector 105 to which an AC adapter 106 is connected. Then, when the charging capacity of the lithium battery 60 included in the imaging device 1 is reduced and the yellow or red of the battery LED 63 is lit, charging of the lithium battery is started when the imaging device 1 is mounted on the cradle. It is configured as follows.

  In the imaging device 1 of the dental colorimetry system configured as described above, illumination light in seven types of wavelength bands (seven primary color illumination lights) is sequentially irradiated onto the subject, and the seven subject spectral images are used as still images. In addition to multiband imaging, it is also possible to capture RGB images. One method of capturing RGB images is to use an RGB color CCD, which has a subject illuminated by natural light or room light, without illumination light of the seven primary colors, as in a normal digital camera. Imaging is performed. Also, each of one or more illumination lights from the seven primary colors can be selected as RGB three-color illumination lights, and these can be sequentially irradiated to capture a frame sequential still image. ing.

Among these imaging modes, RGB imaging is used when imaging a wide area, such as when imaging the entire patient's face or when imaging the entire jaw. On the other hand, multiband imaging is used when measuring the color of one or two teeth of a patient accurately, that is, when measuring the color of teeth.
Hereinafter, the color measurement processing of teeth by multiband imaging, which is a characteristic part of the present invention, will be described.

[Multiband shooting]
First, the imaging device is lifted from the cradle 2 by a doctor, and a contact cap is attached to an attachment port (not shown) provided on the projection port side of the housing of the imaging device. The contact cap is formed in a substantially cylindrical shape from a flexible material.

  Subsequently, when the photographing mode is set to the “colorimetry mode” by the doctor, the subject image is displayed on the LCD 42 as a moving image. While checking the image displayed on the LCD 42, the doctor positions the patient's vital teeth to be measured at an appropriate position in the imaging range, and performs focus adjustment using the focus lever 25. . At this time, since the contact cap is formed in a shape that guides the vital tooth to be measured to an appropriate photographing position, positioning can be easily performed.

  When the doctor presses the shutter button 52 in a state where the positioning and focus adjustment have been performed, a signal to that effect is transferred to the CPU 31 via the operation unit I / F 36, and multiband imaging is executed under the control of the CPU 31. Is done.

  In multi-band imaging, the LED driver 32 sequentially drives the light sources 10a to 10g, so that LED irradiation light having different wavelength bands is sequentially irradiated onto the subject. The reflected light of the subject is imaged on the surface of the RGB imaging element 22 of the imaging unit 20 and is captured as an RGB image. The captured RGB image is transferred to the signal processing unit 23. The signal processing unit 23 performs predetermined image processing on the input RGB image signal and selects predetermined one-color image data corresponding to the wavelength bands of the light sources 10a to 10g from the RGB image signal. Specifically, the signal processing unit 23 selects B image data from the image signals corresponding to the light sources 10a and 10b, selects G image data from the image signals corresponding to the light sources 10c to 10e, and selects the light sources 10f and 10f. R image data is selected from the image signal corresponding to 10g. In this manner, the image processing unit 23 selects image data having a wavelength that substantially matches the center wavelength of the irradiation light.

The image data selected by the signal processing unit 23 is transferred to the A / D converter 24 and recorded in the image memory 35 via the CPU 31. As a result, an image of a color selected from the RGB image corresponding to the center wavelength of the LED is recorded in the image memory 35 as a multiband image. When photographing, the CPU 31 controls the irradiation time of the LED, the irradiation intensity, the electronic shutter speed of the image sensor, etc. so that the photographing of each wavelength is properly exposed, and the temperature change during the photographing is severe. In this case, the alarm buzzer 65 sounds and issues a warning.
Note that an image of the vital tooth is further taken without irradiating the LED, and is recorded in the image memory 35 as an external light image.

Subsequently, when the imaging is finished and the imaging device 1 is placed on the cradle 2 by the doctor, the calibration image is measured.
The calibration image is measured by photographing the color chart 100 according to the same procedure as the multiband photographing described above. As a result, the multiband image of the color chart 100 is recorded in the image memory 35 as a color chart image.
Subsequently, the color chart 100 is shot in a state where the LEDs are not lit at all (under dark), and this image is recorded in the image memory 35 as a dark current image. Note that this dark current image may be captured a plurality of times and an image obtained by averaging these images may be used.

Subsequently, signal correction using the external light image and dark current image recorded in the image memory 35 is performed on each of the multiband image and the color chart image. The signal correction for the multiband image is performed, for example, by subtracting the signal value of the external light image data for each pixel from the image data of the multiband image to remove the influence of the external light at the time of shooting. it can.
Similarly, the signal correction for the color chart image is performed, for example, by subtracting the signal value of the dark current image data for each pixel from the image data of the color chart image. (Dark Noise) can be removed.

FIG. 3 shows an example of the signal correction result for the color chart image. In FIG. 3, the vertical axis indicates the sensor signal value, the horizontal axis indicates the input light intensity, the solid line indicates the original signal before correction, and the broken line indicates the signal after signal correction.
The multiband image and color chart image after the signal correction is performed in this manner are used for the dental colorimetry shown in FIG. 4 via the local bus 37, the communication I / F controller 34, and the communication / I / F contact 61. It is transmitted to the apparatus 3 and recorded in the multiband image memory 110 in the dental colorimetric apparatus 3.

  In this case, the multiband image and the dark current image of the color chart 100 are not recorded in the image memory 35 in the imaging apparatus 1, but are stored in the local bus 37, the communication I / F controller 34, and the communication / I / F contact. The image data may be directly transmitted to the dental colorimetric device 3 via 61 and recorded in the multiband image memory 110 in the dental colorimetric device 3. In this case, the signal correction described above is performed in the dental color measuring device 3.

  The dental colorimetric device 3 receives a multiband image and a color chart image output via the communication I / F contact 61 of the imaging device 1, and performs various processes on the multiband image, thereby providing a subject. In addition to creating an image in which advanced color reproduction of the tooth is made, a shade guide number suitable for the tooth is selected, and this information is displayed on the display device 4.

  For example, as shown in FIG. 4, the dental colorimetric device 3 includes a chromaticity calculation unit 70, a shade guide calculation processing unit 80, a multiband image memory 110, an RGB image memory 111, a color image creation processing unit 112, and an image filing. Unit (first storage unit) 113, shade guide information storage unit (second storage unit) 114, and image display GUI unit (display control unit) 115.

  The chromaticity calculation unit 70 includes a spectrum estimation calculation unit 71, an observation spectrum calculation unit 72, and a chromaticity value calculation unit 73. The shade guide calculation processing unit 80 includes a shade guide selection unit (area specifying unit, measurement area setting unit, sample selection unit) 81 and a comparison calculation processing unit 82. The comparison calculation processing unit 82 includes a pixel extraction unit (first extraction unit, second extraction unit) 821 and an image creation unit (first image creation unit, second image creation unit) 822. Yes.

In the shade guide information storage unit 114, for example, for each manufacturer that manufactures a shade guide in which color samples are arranged in a row, the captured image data of the shade guide manufactured by the manufacturer is associated with the shade guide number. In addition to being stored, a spectral spectrum (specifically, spectral reflectance spectrum) of a predetermined area of the shade guide and a shade guide image with gingiva are stored. Further, the color guide information (for example, RGB value, L ^* a ^* b ^* value, CMYK value, XYZ value, Yuv value, Lv) obtained based on the captured image data of the shade guide is stored in the shade guide information storage unit 114. ^* C ^* h value) is stored for each pixel of the captured image data.

  In the dental colorimetric device 3 having such a configuration, the multiband image and the color chart image transferred from the imaging device 1 are first recorded in the multiband image memory 110 and then transferred to the chromaticity calculation unit 70. Is done. In the chromaticity calculation unit 70, first, spectrum estimation calculation unit 71 performs spectrum (in this embodiment, spectrum of spectral reflectance) estimation processing and the like.

  As shown in FIG. 5, the spectrum estimation calculation unit 71 includes a conversion table creation unit 711, a conversion table 712, an input γ correction unit 713, a pixel interpolation calculation unit 714, an in-plane unevenness correction unit 715, a matrix calculation unit 716, and a spectrum. An estimation matrix creating unit 717 is provided. The input γ correction unit 713 and the pixel interpolation calculation unit 714 are individually provided for each of the multiband image and the color chart image. The input γ correction unit 713a and the pixel interpolation calculation unit 714a are provided for the multiband image. An input γ correction unit 713b and a pixel interpolation calculation unit 714b are provided for the color chart image.

  In the spectrum estimation calculation unit 71 having such a configuration, first, the multiband image and the color chart image are respectively transferred to the separately provided input γ correction units 713a and 713b, and input γ correction is performed. After that, image interpolation calculation processing is performed by the pixel interpolation calculation units 714a and 714b. The signals after these processes are transferred to the in-plane unevenness correction unit 715, where the in-plane unevenness correction processing of the multiband image using the color chart image is performed. Thereafter, the multiband image is transferred to the matrix calculation unit 716, and the spectral reflectance is calculated using the matrix created by the spectrum estimation matrix creation unit 717.

Hereinafter, each image processing performed in each unit will be specifically described.
First, a conversion table 712 is created by the conversion table creation unit 711 as a pre-stage of input γ correction. Specifically, the conversion table creation unit 711 has data in which the input light intensity is associated with the sensor signal value, and creates the conversion table 712 based on these data. The conversion table 712 is created from the relationship between the input light intensity and the output signal value. For example, as shown by the solid line in FIG. 6A, the input light intensity and the sensor signal value are approximately proportional to each other. Created to be

  Each input γ correction unit 713a and 713b performs input γ correction on the multiband image and the color chart image by referring to the conversion table 712. This conversion table is created so that an input light intensity D corresponding to the sensor value A at the present time is obtained, and an output sensor value B corresponding to the input light intensity D is output. As a result, the conversion table shown in FIG. It becomes like this. In this way, when the input γ correction is performed on the multiband image and the color chart image, the corrected image data is transferred to the pixel interpolation calculation units 714a and 714b, respectively.

  In the pixel interpolation calculation units 714a and 714b, a low-pass filter for pixel interpolation is applied to each of the multiband image data and color chart image data after the input γ correction. FIG. 7 shows an example of a low-pass filter applied to the R signal and the B signal. FIG. 8 shows a low-pass filter applied to the G signal. By multiplying each multiband image data by such a low-pass filter for pixel interpolation, for example, an image of 144 pixels × 144 pixels is changed to an image of 288 pixels × 288 pixels.

The image data g _k (x, y) on which the image interpolation calculation has been performed is transferred to the in-plane unevenness correction unit 715.
The in-plane unevenness correction unit 715 corrects the luminance at the center of the screen of the multiband image data using the following equation (1).

In the above equation (1), c _k (x, y) is color chart photographed image data, g _k (x, y) is multiband image data after input γ correction, and (x ₀ , y ₀ ) is the center pixel. The position, δ (= 5) is the area average size, and g ′ _k (x, y) is the image data after in-plane unevenness correction (where k = 1,..., N (number of bands)).
The in-plane unevenness correction is performed on each image data of the multiband image data.

The multiband image data g ′ _k (x, y) after the in-plane unevenness correction is transferred to the matrix calculation unit 716. The matrix calculation unit 716 performs spectrum (in the present embodiment, spectral reflectance) estimation processing using the multiband image data g ′ _k (x, y) from the in-plane unevenness correction unit 715. In this spectrum estimation process, spectral reflectance is estimated at 1 nm intervals in a wavelength band from 380 nm to 780 nm. That is, in this embodiment, a 401-dimensional spectral reflectance is estimated.

In general, a heavy and expensive spectroscopic measuring instrument is used to obtain the spectral reflectance for each wavelength. However, in this embodiment, since the subject is limited to teeth, the subject has a certain amount. By utilizing the feature, the 401-dimensional spectral reflectance is estimated with a small number of bands.
Specifically, a 401-dimensional spectrum signal is calculated by performing a matrix operation using the multiband image data g ′ _k (x, y) and the spectrum estimation matrix Mspe.
The spectrum estimation matrix Mspe is created by the spectrum estimation matrix creation unit 717 based on the spectral sensitivity data of the camera, the LED spectrum data, and the statistical data of the subject (tooth). The creation of the spectrum estimation matrix is not particularly limited, and a well-known method can be used. For example, SKPark and FOHuck “Estimation of spectral
reflectance curves from multispectrum image data ”, Applied Optics, 16, pp 3107-3114 (1977).

  Note that the spectral sensitivity data of the camera, the LED spectrum data, the subject (tooth) statistical data, and the like are stored in advance in the image filing unit 113 shown in FIG. Further, when the spectral sensitivity of the camera changes depending on the position of the sensor, spectral sensitivity data may be acquired according to the position, or the center position may be appropriately corrected and used. .

  When the spectral reflectance is calculated by the spectrum estimation calculation unit 71, the calculation result is stored in the shade guide selection unit 81 and the chromaticity calculation unit 70 in the shade guide calculation processing unit 80 shown in FIG. 4 together with the multiband image data. To the observed spectrum calculation unit 72.

In the shade guide selection unit 81 in the shade guide calculation processing unit 80, first, an area specifying process for specifying a tooth area to be measured is performed.
Here, the multiband image data picked up by the image pickup apparatus 1 includes not only the tooth to be measured but also information such as the tooth adjacent to the tooth and the gums. Therefore, in the area specifying process, a process for specifying the tooth area to be measured from the intraoral image data is performed.

  FIG. 9 shows an example of a tooth reflection spectrum (sample number n = 2), and FIG. 10 shows an example of a gum reflection spectrum (sample number n = 5). 9 and 10, the horizontal axis indicates the wavelength and the vertical axis indicates the reflectance. Since the teeth are generally white and the gums are red, the spectra of both are blue wavelength band (for example, 400 nm to 450 nm) and green wavelength band (for example, 530 nm), as can be seen from FIGS. To 580 nm). In this embodiment, paying attention to the fact that the tooth has a specific reflection spectrum in this way, the tooth region is specified by extracting pixels having the specific reflection spectrum of the tooth from the image data. .

[Tooth region identification method 1]
In this method, wavelength band characteristic values determined by signal values of n types of wavelength bands in a region (pixel or set of pixels) in an image indicated by captured multiband image data are represented in the n-order space. . Then, in the n-order space, a plane area representing the characteristics of the measurement target is defined, and when the wavelength band characteristic value represented in the n-order space is projected onto the plane area, the wavelength band characteristic value is By determining that the region in the image that is included in the tooth region to be measured is included, the region (contour) to be measured is specified.

  FIG. 11 illustrates a method for specifying a tooth region to be measured by this method. As shown in FIG. 11, a seven-dimensional space is formed by seven wavelengths λ1 to λ7. In the 7-dimensional space, a classification plane that best separates the teeth to be measured is set. Specifically, classification spectra d1 (λ) and d2 (λ) for plane projection are obtained. First, a predetermined region is cut out from the captured multiband image data, and a feature amount represented in the 7-dimensional space is calculated as a wavelength band characteristic value. The feature amount is a group of seven signal values when each band is averaged in this region and converted into seven signal values. The size of the region to be cut out is, for example, 2 pixels × 2 pixels, but is not limited thereto, and may be 1 pixel × 1 pixel or 3 pixels × 3 pixels or more.

  The feature amount is represented by one point in the 7-dimensional space of FIG. One point in the 7-dimensional space represented by this feature amount is projected onto the classification plane to obtain one point on the classification plane. The coordinates of one point on the classification plane can be obtained from the inner product calculation with the classification spectra d1 (λ) and d2 (λ). If one point on the classification plane is included in the area T on the classification plane defined by the characteristic spectrum of the tooth, that is, the plane area representing the feature to be measured, the extracted area is included in the tooth outline. Judged to be an area. On the other hand, if one point on the classification plane is included in the region G on the classification plane defined by the characteristic spectrum of the gums, it is determined that the extracted region is an area included in the outline of the gums.

  In this method, the tooth region is specified by sequentially performing such a determination while changing the region to be cut out. In particular, since the tooth region to be measured is usually located near the center of the image indicated by the captured multiband image data, the region to be cut out is changed from near the center of the image toward the periphery. However, by sequentially determining whether or not the region is included in the tooth region, the tooth region to be measured (that is, the tooth contour to be measured) is specified. In particular, in the present embodiment, since the feature amount is defined in a 7-dimensional space that is larger than the 3-dimensional space represented by normal RGB, it is preferable because the measurement target region (contour) can be specified more accurately. .

[Tooth region identification method 2]
In addition to the above method for identifying regions based on the classification spectrum, in this method, for example, only specific signal values (spectrums) corresponding to the blue wavelength band and the green wavelength band are extracted, and these signal values are compared. Thus, a region having a signal value (spectrum) peculiar to a tooth is specified as a tooth region. According to such a method, since the number of samples to be compared is reduced, it is possible to easily specify a region in a short time.

Specifically, as in the case of region specification based on the classification spectrum, the position is measured by detecting the position of the inflection point where the spectral feature value changes suddenly from the center of the image toward the periphery. Confirm as the contour of the target tooth. For example, compared with the subject (tooth) to be detected and the subject to be separated (for example, gums other than the tooth), characteristic bands λ1 and λ2 are selected, and the ratio is set as the spectral feature value. Assuming that the subject is a tooth to be detected, for example, the ratio of two points is calculated with λ1 = 450 nm and λ2 = 550 nm, and the inflection point of the ratio is obtained. Thereby, the outline with an adjacent tooth | gear is decided and the pixel of the tooth of a measuring object can be obtained. In addition to specifying for each pixel, an average of a pixel group composed of a plurality of pixels may be taken, and the specification may be made for each pixel group based on this average.
In addition, in this embodiment, although the tooth | gear area | region specification was performed even if it uses any of the identification methods 1 and 2 of the above-mentioned tooth | gear area | region, the area | region specification of a gum is also possible. In addition to the above-described region specifying method, for example, it is possible to display the tooth to be measured on the monitor 4 and allow the user to set the contour on the screen displayed on the monitor 4.

  Thus, when the pixel of the tooth to be measured is specified, a measurement area setting process for setting the measurement area in the tooth area of the measurement target is subsequently performed. As shown in FIG. 12, this measurement area is set as a rectangular area at the upper part (Cervical), the center (Body), and the lower part (Incisal) of the tooth surface. For example, an area having an area with a certain ratio with respect to the tooth height is set. That is, the setting region and its position are set at a constant ratio for both small and large teeth. Note that the shape of the measurement region is not limited to a rectangle as shown in FIG. 12, and may be, for example, a circle, an ellipse, or an asymmetric shape.

Subsequently, a shade guide selection process for selecting a shade guide that is closest to each measurement region set as described above is performed. In this shade guide selection process, a comparison determination is made between the color of the tooth to be measured and the color of the shade guide. This comparison is performed for each measurement region set in advance, and the spectrum of the target measurement region (in this embodiment, the spectral reflectance) and the spectrum of each shade guide registered in advance in the shade guide information storage unit 114. (In this embodiment, the spectral reflectance spectrum) is compared, and the difference between the two is determined to be the smallest.
Such shade guide selection processing is performed, for example, by obtaining a spectrum determination value Jvalue based on the following equation (2).

In the above equation (2), Jvalue is a spectrum judgment value, C is a normalization coefficient, n is a statistical number (the number of λ used in the calculation), λ is a wavelength, and f ₁ (λ) is a tooth to be judged. Spectral reflectance spectrum value, f ₂ (λ) is a shade guide spectral reflectance spectrum value, and E (λ) is a determination sensitivity correction value. In the present embodiment, weighting relating to spectral sensitivity according to λ is performed by E (λ).

In this way, the spectrum value of the shade guide of each company is substituted into f ₂ (λ) in the above equation (2), and each spectrum judgment value Jvalue is calculated. Then, it is determined that the shade guide having the smallest spectrum determination value Jvalue is the shade guide number that most closely approximates the tooth. In the present embodiment, a plurality of (for example, three) candidates are extracted in ascending order of the spectrum determination value Jvalue. Of course, one candidate can be extracted. In the above equation (2), the determination sensitivity correction value E (λ) may be variously weighted.

When the shade guide number is selected in this way, the shade guide selection unit 81 converts the chromaticity value (colorimetric information) L2 ^* a2 ^* b2 ^* and the captured image data in each pixel of the selected shade guide into shade guide information. Acquired from the storage unit 114 and outputs the acquired chromaticity value L2 ^* a2 ^* b2 ^*, captured image data, and shade guide number to the image display GUI unit 115 and the comparison calculation unit 82.

  On the other hand, the observation spectrum calculation unit 72 of the chromaticity calculation unit 70 multiplies the tooth spectrum obtained by the spectrum estimation calculation unit 71 by the illumination light S (λ) to be observed, so that it is under the illumination light to be observed. The subject's spectrum is required. This S (λ) is a light source for observing the color of teeth, such as D65, D55 light source, fluorescent light source, etc., and this data is stored in the image filing function unit 112 in advance. The spectrum of the subject under the illumination light to be observed, obtained by the observation spectrum calculator 72, is transferred to the chromaticity value calculator 73.

In the chromaticity value calculating portion 73, a chromaticity value from the spectrum of the object under the illumination light used for observation ^L1 * ^a1 * b1 ^* is calculated for each pixel, ^* chromaticity values ^L1 * ^a1 * b1 of each pixel A value obtained by averaging the chromaticity values related to the predetermined area is transferred to the image display GUI unit 115 while being output to the comparison calculation processing unit 82 in the shade guide calculation processing unit 80. This predetermined area is set at, for example, three positions of the upper, middle and lower portions of the tooth.

  Further, the spectrum G (x, y, λ) of the subject under the illumination light desired to be observed is sent to the color image creation processing unit 112, and is displayed as RGB image data (photographed image data of vital teeth) for display on the monitor. ) RGB2 (x, y) is created. The RGB image data of vital teeth created by the color image creation processing unit 112 is output to the image display GUI unit 115 and transferred to the comparison calculation processing unit 82 in the shade guide calculation processing unit 80. Furthermore, the RGB image data of this vital tooth is stored by being output to the image filing unit 113. Note that the color image creation processing unit 112 may create RGB image data of a desired color tone by further performing correction such as edge enhancement on the RGB image data.

The chromaticity value L1 ^* a1 ^* b1 ^{* for} each vital tooth pixel output from the chromaticity value calculation unit 73 described above, the shade guide number selected by the shade guide selection unit 81, and the chromaticity value L2 ^{* of} each pixel ^. The a2 ^* b2 ^* and the captured image data (shade guide RGB image data) are transferred to the pixel extraction unit 821 in the comparison calculation processing unit 82.

In the chromaticity value L1 ^* a1 ^* b1 ^{* for} each vital tooth pixel received from the chromaticity value calculation unit 73, the pixel extraction unit 821 uses the chromaticity value of a pixel registered in advance as a reference pixel as a default reference color. It is acquired as a degree value L3 ^* a3 ^* b3 ^* (corresponding to “reference colorimetric information” of the present invention) (reference acquisition unit). In the present embodiment, the reference pixel is set to the center pixel of the vital tooth image. Specifically, when the image of the vital tooth is represented by 288 pixels × 288 pixels, the center pixel, that is, the pixel at the coordinates of (x, y) = (144, 144) is adopted as the reference pixel. The reference pixel may be an arbitrary coordinate and can be registered in advance by the user. For example, the registration by the user can be performed by inputting a specific coordinate value on the setting screen or by designating a desired pixel with a mouse or the like on a tooth image displayed on the setting screen. Is possible.
The reference pixel, in other words, the reference chromaticity value can be changed by a reference input unit (reference input unit) 200 displayed in FIGS. 13 and 14 described later. Note that the reference chromaticity value may be registered in advance as an absolute value instead of being acquired from the vital tooth image as described above.

In this way, when the pixel extraction unit 821 acquires the reference chromaticity value L3 ^* a3 ^* b3 ^* , subsequently, the chromaticity value L2 ^* a2 ^* b2 ^* and the reference chromaticity value L3 ^* a3 of each pixel of the shade guide. ^* B3 ^* is compared with each other. Specifically, the pixel extraction unit 821 calculates a difference ΔE ^* between the chromaticity value L2 ^* a2 ^* b2 ^* and the reference chromaticity value L3 ^* a3 ^* b3 ^* of each pixel of the shade guide. Then, a pixel whose difference ΔE ^* is a predetermined threshold value registered as a default, for example, “3” or less is extracted (hereinafter, a pixel group composed of the extracted pixels is referred to as a “third pixel group”. That said.)
ΔE ^* can be obtained by the following equation (3).

^{ΔE * = √ {(L3 *} -L2 *) 2 + (a3 * -a2 *) 2 + (b3 * -b2 *) 2} (3)

Similarly, the pixel extraction unit 821 calculates a difference ΔE ^* between the chromaticity value L1 ^* a1 ^* b1 ^* of the vital tooth and the reference chromaticity value L3 ^* a3 ^* b3 ^*, and this difference ΔE ^* is set as a default. Pixels having a registered threshold value, for example, “3” or less are extracted (hereinafter, a pixel group composed of the extracted pixels is referred to as a “first pixel group”). In this way, when the pixel extracting unit 821 extracts a pixel that satisfies a predetermined condition, the pixel extracting unit 821 outputs coordinate information of each pixel belonging to the third pixel group and the first pixel group to the image creating unit 822. The “predetermined condition” according to the present embodiment is “the difference from the reference chromaticity value is equal to or less than the threshold“ 3 ””. Here, the difference ΔE ^* = “3”, which is a threshold value, can be determined that, for example, a dentist or a technician objectively sees that the color of the living teeth and the color of the shade guide substantially match. Corresponds to the boundary value. Note that this threshold value, in other words, “predetermined conditions” can also be changed by a condition input unit (condition input unit) 202 displayed in FIGS. 13 and 14 described later.

  When the image creation unit 822 receives the coordinate information of the pixels related to the first pixel group and the coordinate information of the pixels related to the third pixel group from the pixel extraction unit 821, the image creation unit 822 relates to the pixels belonging to the third pixel group. Adopts the shooting data of the shade guide and does not belong to the third pixel group, that is, a pixel whose difference from the reference chromaticity value described above is larger than the threshold value “3” (hereinafter, composed of this pixel). For the pixel group to be processed is referred to as a “fourth pixel group”), a sample comparison image expressed in a color tone corresponding to the chromaticity value in the pixel is created.

  Similarly, for the pixels belonging to the first pixel group, the image creating unit 822 employs vital tooth imaging data, and does not belong to the first pixel group, that is, the reference chromaticity value described above. For pixels in which the difference is larger than the threshold “3” (hereinafter, a pixel group composed of these pixels is referred to as a “second pixel group”), a life in which a color tone corresponding to the chromaticity value in the pixel is adopted Create a tooth comparison image.

For example, pixels of 0 ≦ ΔE ^* ≦ 3 are the first and third pixel groups, pixels of 3 <ΔE ^* are the second and fourth pixel groups, and the second and fourth pixel groups. When the target range is 3 <ΔE ^* <10 and the target range is 10 ≦ ΔE ^* , the image creation unit 822 represents each pixel belonging to the second and fourth pixel groups as follows: To do.
For example, the image creation unit 822 defines a pixel of ΔE ^* = 0 as black and a pixel of ΔE ^* = 10 as white, and the pixel of 3 <ΔE ^* <10 becomes whiter as the value of ΔE ^* increases. It is expressed in gray, and all pixels in 10 ≦ ΔE ^* are expressed in white.
Specifically, in the case of a pixel satisfying 3 <ΔE ^* <10, the image creating unit 822 represents the pixel with an RGB value of the following equation (4).
R = ΔE ^** 25.5
G = ΔE ^** 25.5 (4)
B = ΔE ^** 25.5

Thus, since the pixels of 0 ≦ ΔE ^* ≦ 3 are the first and third pixel groups, they are expressed by various shooting data, for example, real images, and the pixels of 3 <ΔE ^* <10 are gray. The state of change is expressed in a scale so that it is easy to understand visually, and pixels of 10 ≦ ΔE ^* are all expressed in white.

As another expression, for example, pixels of 0 ≦ ΔE ^* <10 are the first and third pixel groups, pixels of 10 ≦ ΔE ^* are the second and fourth pixel groups, and For the second and fourth pixel groups, when the target range is 10 ≦ ΔE ^* <24 and the target range is 24 ≦ ΔE ^* , the image creating unit 822 includes each pixel belonging to the second and fourth pixel groups. Is expressed as follows.
For example, the image creation unit 822 defines a pixel of ΔE ^* = 0 as black and a pixel of ΔE ^* = 24 as white, and a pixel of 10 <ΔE ^* <24 becomes whiter as the value of ΔE ^* increases. Gray representation is used, and all pixels of 24 ≦ ΔE ^* are expressed in white.

Specifically, for a pixel of 10 <ΔE ^* <24, the image creation unit 822 represents the pixel with an RGB value of the following equation (5).
R = ΔE ^** 10.625
G = ΔE ^** 10.625 (5)
B = ΔE ^** 10.625

Thus, as in the previous example, the pixels of 0 ≦ ΔE ^* ≦ 10 are the first and third pixel groups, and therefore are represented by various shooting data, for example, real images, and 10 <ΔE ^* <24. The pixels are expressed in grayscale, and the state of change is expressed in an easy-to-understand manner visually, and the pixels of 24 ≦ ΔE ^* are all expressed in white.
It should be noted that the gray scale expression described above may be changed to a shading expression with halftone dots or meshes.
In the above equations (4) and (5), each coefficient multiplied by the color difference ΔE ^* is for expressing the maximum value of ΔE ^* to be 255. The maximum value of ΔE ^* is not limited to 255, and the setting can be changed according to the OS.

After creating the above-described sample comparison image and vital tooth comparison image, the image creation unit 822 outputs these images to the image display GUI unit 115.
The image display GUI unit 115 creates screen image data based on the sample comparison image, the vital tooth comparison image obtained as described above, the RGB image of the vital tooth, the RGB image of the shade guide, the shade guide number, and the like. A screen as shown in FIG. 13 is displayed on the display screen of the display device 4.

  As shown in FIG. 13, the image display GUI unit 115 displays the color image A of the vital tooth that is the measurement target at the upper center of the display screen, and displays the color image B of the shade guide on the right side thereof. Under the color image of the vital tooth, the vital tooth comparison image C created by the image creation unit 822 is displayed, and a sample comparison image D is displayed on the right side of the vital tooth comparison image C.

  In this screen, a reference input unit 200 for inputting a reference chromaticity value used in the pixel extraction unit 821 described above is provided on the vital tooth comparison image C. In the present embodiment, the reference input unit 200 includes a vertical scanning line Y that can move left and right and a horizontal scanning line X that can move left and right. Then, the intersection of the vertical scanning line Y and the horizontal scanning line X is handled as a reference pixel used in the pixel extraction unit 821 described above. Therefore, in this screen, the vertical scanning line Y and the horizontal scanning line X are displayed so that the intersection point thereof coincides with the center pixel (x, y) = (144, 144) of the vital tooth comparison image C as a default. ing.

  Since the vertical scanning line Y and the horizontal scanning line X are configured to be arbitrarily movable by the user, when the user scans the vertical scanning line Y and the horizontal scanning line X, the pixel extraction unit 821 is scanned. Thus, the reference pixel used can be changed, and as a result, the reference chromaticity value can be changed.

  Further, the display screen of the image display GUI unit 115 is provided with an image selection unit 201 for selecting which comparison image the reference input unit 200 is displayed on. In the image selection unit 201, when the user selects one of them, the reference input unit 200 described above is displayed when both a desired comparison image (hereinafter, “life tooth comparison image” and “sample comparison image” are displayed). Is referred to as a “comparison image”). As a result, the reference chromaticity value can be selected in both the vital tooth comparison image and the sample comparison image. FIG. 14 shows a screen example in which the sample comparison image D is selected in the image selection unit 201. As shown in this figure, the reference input unit 200 is displayed on the sample comparison image D.

Further, as shown in FIGS. 13 and 14, the image display GUI unit 115 displays the reference line Q on the comparison screen on which the reference input unit 200 is not displayed. That is, the image display GUI unit 115 displays the reference line Q on the sample comparison image D in FIG. This reference line Q is represented as a vertical line (Y-axis) that can move left and right. Then, the difference ΔE ^* between the chromaticity value of each pixel existing on the reference line Q and the above-described reference chromaticity value is displayed as a line graph F on the right side of the sample comparison image D. At this time, by displaying the Y-axis memory of the line graph F and the Y-axis (horizontal scanning line X) memory in the sample comparison image D in a matching manner, the user can determine which part (pixel) has such a color difference. It becomes possible to grasp very easily whether it has ΔE ^* .
In FIG. 13, on the vital tooth comparison image C on which the reference input unit 200 is displayed, the horizontal scanning line X of the reference input unit 200 plays the role of the reference line Q. The difference ΔE ^* between the chromaticity value of a certain pixel and the reference chromaticity value is displayed as a line graph E on the left side of the vital tooth comparison image C. Also in this case, the Y-axis memory of the line graph E and the Y-axis (horizontal scanning line X) memory in the vital tooth comparison image C are displayed in alignment.

  In FIG. 14, since the reference input unit 200 is displayed on the sample comparison image D, the line graph F along the horizontal scanning line X of the reference input unit 200 is on the right side of the sample comparison image D. The line graph E along the reference line Q displayed and displayed on the vital tooth comparison image C is displayed on the left side of the vital tooth comparison image C.

Further, the image display GUI unit 115 displays colorimetric information in each region of vital teeth as a list G at the lower left portion of the screen. Specifically, the average of lightness L ^* , saturation C ^* , and hue h as colorimetric information in each region of vital teeth, in this embodiment, upper “Cervical”, center “Body”, and lower “Incisal” Each value is displayed as a list. Similarly, the image display GUI unit 115 displays the color measurement information in the above-mentioned area of the shade guide as a list H at the lower right portion of the screen. Specifically, in each region “Cervical”, “Body”, and “Incisal” of the shade guide (in this embodiment, the shade guide with the identification number “A2”) selected as the closest to the color of the vital tooth Average values of the colorimetric information L ^* , C ^* , and h are displayed as a list H, respectively.

Further, the image display GUI unit 115 sets the shade guide number selected by the shade guide selection unit 81 shown in FIG. Furthermore, the average value M of the difference between each colorimetric information of the vital tooth and each colorimetric information of the shade guide is displayed for each shade guide. Here, as the shade guide candidate J, the first candidate “A2”, the second candidate “B2”, and the third candidate “B1” are displayed. Further, in FIG. 13 and FIG. 14, as the average value M of the difference between the color measurement information of the shade guide of the first candidate “A2” and the color measurement information of the vital tooth, the spectrum difference average value “spect”, A chromaticity difference average value “ΔE ^* ”, a lightness difference average value “ΔL ^* ”, a saturation difference average value “ΔC ^* ”, and a hue difference average value “Δh ^* ” are displayed.

  Here, the shade guide candidate J for which the difference average of the colorimetric information is displayed is configured to be arbitrarily selectable, and the user can switch the shade guide candidate J to change the colorimetric information in each shade guide. The difference information M can be switched and displayed.

The display screen by the image display GUI unit 115 is provided with a condition input unit 202 for inputting the “predetermined condition” described above. In this embodiment, the condition input unit 202 has a configuration in which the color difference ΔE ^* is taken on the horizontal axis, and the bar P is movably provided on the horizontal axis. The user can change the predetermined threshold used in the pixel extraction unit 821 shown in FIG. 4 by moving the bar P to a desired value. 13 and 14, the bar P is set to the threshold value “3” registered as the default.
Furthermore, the image display GUI unit 115 displays the first candidate for the shade guide in each region of the vital tooth as a list R on the right side of the color image of the vital tooth.

  In such a screen, when the reference input unit 200 is operated by the user, the reference pixel employed in the pixel extraction unit 821 illustrated in FIG. 4, that is, the reference chromaticity value is updated, and newly The calculation process based on the set reference chromaticity value is performed again. Then, a vital tooth comparison image and a sample comparison image based on the reference chromaticity value updated by the user are created by the image creation unit 822, and the vital tooth comparison image C and the sample comparison image D shown in FIGS. The image will be updated. Similarly, when the condition input unit 202 is operated by the user, the pixel extraction unit 821 and the image creation unit 822 perform similar processing based on the newly input condition, so that FIG. 13 and FIG. The vital tooth comparison image C and the sample comparison image D shown in FIG. 14 are updated to new images.

As described above, according to the dental colorimetry system according to the present embodiment, it is obtained based on the chromaticity value of each pixel obtained based on the photographed image of the vital tooth and the photographed image of the tooth sample. The chromaticity value of each pixel is compared with the reference chromaticity value in units of pixels, and a difference ΔE ^* is calculated. In this case, a pixel having a difference ΔE ^* of “3” or less, which is a predetermined threshold value, is represented by photographing data, that is, an actual tooth color or a tooth sample color, while the difference ΔE ^*. Pixels with a value exceeding the predetermined threshold “3” are expressed in gray with a density corresponding to the color difference ΔE ^* . The vital tooth comparison image C and the sample comparison image D expressed in this way are displayed on the same screen.

Thereby, the user can easily determine which part satisfies the condition and which part does not satisfy the condition by checking the vital tooth comparison image C and the sample comparison image D displayed on the same screen. It becomes possible. In particular, in the present embodiment, the threshold value is set to “3”, which is a boundary value that can be determined that the color of the vital tooth substantially matches the color of the shade guide. It is possible to easily grasp how the distribution is made.
For example, in the screen example shown in FIG. 13, the user widely distributes pixels whose difference ΔE ^* from the reference chromaticity value (center pixel of vital teeth) is “3” or less in the central portion of vital teeth. In the shade guide, it can be easily confirmed that the shade guide is sparsely distributed throughout the center.

Furthermore, for the pixels where the difference ΔE ^* is “3” or less, the photographed image data is adopted, so it is possible to judge a more subtle color difference, etc., by comparing the colors of this part. It becomes. In addition to this, for other parts where the photographed image data is not adopted, that is, for pixels where the difference ΔE ^* exceeds “3”, a gray scale from black to white corresponding to the value of ΔE ^* which is a colorimetric value is used. Therefore, the user who sees this screen can more easily compare the color of the living tooth with the color of the shade guide. As a result, the user can easily determine what color to add to the color tone of the living teeth compared to the conventional method in which the shade guide image that is the reference image must be subjectively evaluated. Therefore, a crown or the like closer to the color tone of the vital tooth can be produced.

Furthermore, according to the dental colorimetry system according to the above-described embodiment, even in a pixel having a chromaticity value difference ΔE ^* exceeding “3”, the gray density is changed according to the color difference ΔE ^{* of the} pixel. Therefore, the user can grasp how the color difference ΔE ^* is changing from the gradation.

13 and 14 show examples of screens on which only one sample comparison image D is displayed. However, the present invention is not limited to this example, and chromaticity values in a plurality of shade guides are used as reference chromaticity values. It is also possible to create a sample comparison image corresponding to the chromaticity values of a plurality of shade guides by comparing with the value, and to display the plurality of created sample comparison images on the same screen.
By displaying a plurality of sample comparison images, it becomes possible to compare more shade guides with vital teeth, so it is possible to efficiently select shard guides having characteristics that approximate the characteristics of vital teeth It becomes possible.

In the above-described first embodiment, the reference pixel is handled as one pixel. However, the present invention is not limited to this mode, and the reference pixel is an area composed of a plurality of pixels such as 2 × 2 pixels and 3 × 3 pixels. It may be handled. As described above, when the reference pixel is handled as an area including a plurality of pixels, an average value of chromaticity values of the pixels in the area may be used as the reference chromaticity value.
Further, in the shade guide, the chromaticity value in each pixel is not compared with the reference chromaticity value, but the average value of the chromaticity values in an area composed of a plurality of pixels is compared with the reference chromaticity value. It is good as well. In the above-described embodiment, the chromaticity value is used as the colorimetric information. However, the present invention can be similarly applied when other colorimetric information is adopted.

In the first embodiment described above, in the pixel where the chromaticity value difference ΔE ^* exceeds “3”, the gray density is changed according to the color difference ΔE ^{* of the} pixel. Instead of this ΔE ^* , the lightness L ^* value (for example, a range of 0 ≦ L ^* ≦ 100) of the pixel may be used to express the light and shade. Specifically, the pixels belonging to the second and fourth are expressed by RGB values of the following expression (6).
R = L ^** 2.55
G = L ^** 2.55 (6)
B = L ^** 2.55
By expressing in this way, L ^* can be expressed in gray having gradations from 0 to 255. Further, the range of the lightness L ^* may be set to 40 ≦ L ^* ≦ 90 according to the characteristics of vital teeth. In this case, when L ^* <40, the RGB values are all 0, and when L ^* > 90, the RGB values are both 255, and when 40 ≦ L ^* ≦ 90, The RGB value may be expressed by the following equation (7).
R = L ^** 2.833
G = L ^** 2.833 (7)
B = L ^** 2.833

In the first embodiment described above, the shade guide whose spectral reflectance spectrum approximates to the vital tooth is selected as a candidate, and the sample comparison image is created only for the selected shade guide. The sample comparison image may be created for all shade guides stored in the shade guide information storage unit 114. According to this aspect, since it is not necessary to select a shade guide having a spectral reflectance spectrum that is most approximate to the spectral reflectance spectrum of the vital tooth, the shade guide selection unit 81 can be dispensed with.
Further, in addition to the above aspect, a shade guide specifying unit for inputting a shade guide number that the user desires to compare is provided on the screen, and the shade guide identified by the shade guide number input by the shade guide specifying unit is provided. The sample comparison image may be created as a comparison target.

In the first embodiment described above, the dental colorimetric device 3 is premised on processing by hardware, but is not limited to such a configuration. For example, a configuration in which processing is performed separately by software is also possible. In this case, the dental color measuring device 3 includes a main storage device such as a CPU and a RAM, and a computer-readable recording medium on which a program for realizing all or part of the above processing is recorded. Then, the CPU reads out the program recorded in the storage medium and executes information processing / calculation processing, thereby realizing processing similar to that of the above-described failure diagnosis apparatus.
Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

Hereinafter, the processing procedure of the dental colorimetry method realized by the CPU executing the dental colorimetry program will be described with reference to FIG.
First, in step SA1 in FIG. 15, RGB color image data is created from the captured images of 7 bands of vital teeth. Subsequently, in step SA2, the spectral spectrum (specifically, spectral reflectance spectrum) of each pixel is calculated based on the image of the vital tooth. In step SA3, a chromaticity value is calculated based on a photographed image of vital teeth. In step SA4, the spectral guide calculated in step SA2 is compared with the spectral spectra of the shade guides stored in the shade guide information storage unit 114, thereby selecting the shade guide with the closest spectrum.

In the subsequent step SA5, the chromaticity value registered for each pixel is obtained from the shade guide information storage unit 114 as the colorimetric information corresponding to the selected shade guide, and the chromaticity value and the reference chromaticity value are obtained. The difference ΔE ^* is calculated for each pixel. At step SA6, the difference Delta] E ^* is determined whether the threshold value "3" or less in pixel units, when the difference Delta] E ^* is less than "3", the flow proceeds to step SA7, imaging of the shade guide on the pixel On the other hand, when the image data is adopted and the difference ΔE ^* is larger than “3”, the process proceeds to step SA8, and gray of a density corresponding to the chromaticity value is adopted. Specifically, a value obtained by multiplying the RGB value by (difference ΔE * 25.5) is employed. Then, by performing the above determination on all the pixels and creating a sample comparison image in step SA9, subsequently, in step SA10, the chromaticity value is compared with the reference chromaticity value for each pixel for vital teeth. Then, a vital tooth comparison image is created by the same method. In step SA11, the created sample comparison image and vital tooth comparison image are displayed on the monitor (display device) 4.

[Second Embodiment]
Next, a dental colorimetric system according to the second embodiment of the present invention will be described.
In the first embodiment described above, the chromaticity value is used as the colorimetric information, and the sample comparison image and the vital tooth comparison image are created based on the difference ΔE between the chromaticity value and the reference chromaticity value. In this embodiment, a spectral spectrum (specifically, a spectral reflectance spectrum) is used as colorimetric information, and a sample comparison image and a vital tooth comparison image are created based on the difference Δspect between the spectral spectrum and the reference spectral spectrum. To do.
Hereinafter, regarding the dental color measurement system according to the present embodiment, description of points that are the same as those in the first embodiment described above will be omitted, and only differences will be described.

FIG. 16 is a diagram illustrating a schematic configuration of a dental colorimetric apparatus according to the present embodiment. In the dental colorimetric apparatus according to the present embodiment, a sample comparison image or the like is created based on the spectral spectrum, so that the chromaticity value calculation unit 73 (see FIG. 4) for calculating chromaticity values is not necessary. In FIG. 16, the spectral spectrum f ₁ (λ) calculated by the spectrum estimation calculation unit 71 is transferred to the shade guide selection unit 81 and the comparison calculation unit 82 in the shade guide calculation processing unit 80. The shade guide selection unit 81 selects a shade guide having a feature that most closely resembles the vital tooth feature based on the spectral spectrum f ₁ (λ) acquired from the spectrum estimation calculation unit 71, and the shade guide number is an image display GUI. Is output to the pixel extraction unit 823 in the unit 115 and the comparison calculation unit 82 ′.

The pixel extraction unit 823 includes the spectral spectrum f ₃ (λ) of the reference pixel (hereinafter referred to as “reference spectral spectrum”) among the spectral spectra f ₁ (λ) of the vital tooth pixels acquired from the spectrum estimation calculation unit 71. ) And the spectral spectrum f ₂ (λ) for each pixel of the shade guide specified by the shade guide number acquired from the shade guide selection unit 81 is acquired from the shade guide information storage unit 114. Then, the pixel extraction unit 823 compares the shade guide spectral spectrum f ₂ (λ) and the reference spectral reflectance f ₃ (λ) in units of pixels to obtain a difference Δspect. Subsequently, the pixel extraction unit 823 extracts pixels whose difference Δspect is registered as a default threshold value, for example, “4000” or less (hereinafter, a pixel group including the extracted pixels is referred to as “ A third pixel group).

Similarly, the pixel extraction unit 823 compares the vital tooth spectral spectrum f ₁ (λ) with the reference spectral spectrum f ₃ (λ) for each pixel, and calculates a difference Δspect. Subsequently, the pixel extraction unit 823 extracts pixels having a difference Δspect that is registered as a default, for example, a pixel that is equal to or less than “4000” (hereinafter, a pixel group including the extracted pixels is referred to as a “first pixel”). 1 pixel group). In this manner, when the pixel extracting unit 823 extracts a pixel that satisfies a predetermined condition, the pixel extracting unit 823 outputs coordinate information of each pixel belonging to the first pixel group and the third pixel group to the image creating unit 824. The “predetermined condition” according to the present embodiment is “the difference from the reference spectral spectrum is equal to or less than the threshold“ 4000 ””.

  When the image creation unit 824 receives the coordinate information of the pixels related to the first pixel group and the coordinate information of the pixels related to the third pixel group from the pixel extraction unit 823, the image creation unit 824 relates to the pixels belonging to the first pixel group. Adopts imaging data of vital teeth and does not belong to the first pixel group, that is, a pixel whose difference from the above-described reference spectral spectrum is larger than the threshold “4000” (hereinafter, composed of this pixel). For the pixel group is referred to as “second pixel group”), a vital tooth comparison image expressed in a color tone according to the spectral spectrum of the pixel is created.

Similarly, for the pixels belonging to the third pixel group, the image creating unit 824 adopts the shooting data of the shade guide, and the difference from the pixels that do not belong to the third pixel group, that is, the above-described reference spectral spectrum. For a pixel having a value greater than the threshold value “4000” (hereinafter, a pixel group including these pixels is referred to as a “fourth pixel group”), a sample comparison image expressed in a color tone corresponding to the spectral spectrum of the pixel Create
Note that the method of expressing the second and fourth pixel groups is the same as in the first embodiment described above.

Then, when the image comparison unit 822 generates the above-described sample comparison image and vital tooth comparison image, these images are output to the image display GUI unit 115.
The image display GUI unit 115 displays a sample comparison image, a vital tooth comparison image, and the like on the monitor 4. Thereby, on the screen as shown in FIG. 13 or 14, the vital tooth comparison image created by the image creation unit 824 is displayed as the image C on the monitor 4 and the image creation unit 824 displays the image D as the image D. The created sample comparison image is displayed.

  As described above, according to the dental colorimetry system according to the present embodiment, the shade guide and the vital tooth are compared based on the spectrum, so that the dental according to the first embodiment shown in FIG. Therefore, the chromaticity value calculation unit 73 included in the color measuring apparatus can be eliminated, and the apparatus can be downsized and the processing load can be reduced.

Note that the dental colorimetric device 3 ′ according to the second embodiment of the present invention may be configured to be processed by software separately, similar to the dental colorimetric device 3 according to the first embodiment described above. .
Hereinafter, the processing procedure of the dental color measurement method realized by the CPU executing the dental color measurement program according to the present embodiment will be described with reference to FIG.

First, in step SB1 in FIG. 17, RGB color image data is created from the captured images of 7 bands of vital teeth. Subsequently, in step SB2, the spectral spectrum (specifically, spectral reflectance spectrum) of each pixel is calculated based on the captured image of the vital tooth. In step SB3, the spectral guide calculated in step SB2 is compared with the spectral spectrum of each shade guide stored in the shade guide information storage unit 114, thereby selecting the shade guide with the closest spectrum. In step SB4, as the color measurement information of the shade guide specified by the selected shade guide number, a spectral spectrum registered for each pixel is acquired from the shade guide information storage unit 114, and the spectral spectrum and the reference spectral spectrum are obtained. The difference Δspect is calculated.
Here, any of the following (8) to (11) can be used as a method for calculating the difference Δspect.

  In step SB5, it is determined whether or not the difference Δspect is equal to or smaller than the threshold “4000”. If the difference Δspect is equal to or smaller than “4000”, the process proceeds to step SB6, and the captured image data of the shade guide is included in the pixel. On the other hand, if the difference Δspect is larger than “4000”, the process proceeds to step SB7 and is expressed in gray having a density corresponding to the difference Δspect. Then, by making the above-mentioned determination for all the pixels and creating a sample comparison image in step SB8, subsequently, in step SB9, for each vital tooth, the spectral spectrum and the reference spectral spectrum are compared for each pixel, A vital tooth comparison image is created by the same method. In step SB10, the created sample comparison image and vital tooth comparison image are displayed on the monitor 4.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. The dental colorimetric system according to the present embodiment is characterized by having the functions of the dental colorimetric apparatus in the first and second embodiments described above. Therefore, according to the dental colorimetric device according to the present embodiment, a comparison image can be created based on the chromaticity value, and a comparison image can also be created based on the spectral spectrum.

According to the first to third embodiments described above, the chromaticity value or the spectral spectrum in one pixel of the vital tooth or shade guide is adopted as the reference chromaticity value or the reference spectral spectrum. For example, the screen shown in FIG. 13 or 14 may be configured such that the user can manually input the reference chromaticity value or the reference spectral spectrum.
Further, in the above-described embodiment, the chromaticity value or the spectral spectrum is used as the reference colorimetric information. However, the present invention is not limited to this information, and for example, a color temperature may be adopted.

  In the above-described embodiment, the pixels belonging to the first and third pixel groups are represented by captured image data, and the pixels belonging to the second and fourth pixel groups are referred to as reference colorimetric information. Although expressed in gray of a density corresponding to the comparison result, the method of expressing these pixels by the image creating units 822 and 824 is not limited to the above example. That is, it is sufficient that the first tooth group and the second pixel group are expressed by visual recognition in the vital tooth comparison image, and the third pixel group and the fourth pixel group in the sample comparison image. It only needs to be expressed so that it can be distinguished from the pixel group by visual recognition.

  For example, the first and third pixel groups may be expressed in a color tone different from the second and fourth color tones, in addition to adopting captured image data. In this case, in the first and third pixel groups as well, as in the second and fourth pixel groups described above, a predetermined color having a density corresponding to the comparison result between the colorimetric information and the reference colorimetric information ( For example, it may be expressed in red or orange. Moreover, it is not restricted to the aspect which changes the color shading, For example, it is good also as using other aspects, such as changing a brightness | luminance. That is, an expression mode in which a difference from the reference colorimetric information is reflected, and preferably, the change is expressed in gradation. In the first to third embodiments described above, the captured image data is employed for the pixels belonging to the first and third pixel groups. Conversely, the pixels belonging to the second and fourth pixel groups. The captured image data may be employed for the pixels belonging to the first and third pixel groups, and may be represented by gray shades according to the difference.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like without departing from the gist of the present invention.

FIG. 1 is a block diagram illustrating a schematic configuration of an imaging apparatus and a cradle according to the first embodiment of the present invention. It is a figure which shows the spectrum of the light source shown in FIG. It is a figure explaining signal correction. 1 is a block diagram illustrating a schematic configuration of a dental colorimetric device according to a first embodiment of the present invention. It is a figure which shows the schematic internal structure of the spectrum estimation calculating part shown in FIG. It is a figure explaining input gamma correction. It is a figure which shows an example of the low-pass filter applied to R signal and B signal in pixel interpolation calculation. It is a figure which shows an example of the low pass filter applied to G signal in pixel interpolation calculation. It is a figure which shows an example of the reflection spectrum (sample number n = 2) of a tooth | gear. It is a figure which shows an example of the reflectance spectrum (sample number n = 5) of a gum. It is explanatory drawing explaining the method of specifying the tooth | gear area | region which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the measurement area | region set by a measurement area | region setting process. It is a figure which shows an example of a display screen. It is a figure which shows an example of a display screen. It is the flowchart which showed the procedure of the process implement | achieved by the dental colorimetric apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows schematic structure of the dental colorimetric apparatus which concerns on the 2nd Embodiment of this invention. It is the flowchart which showed the procedure of the process implement | achieved by the dental colorimetric apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Imaging apparatus 2 Cradle 3 Dental colorimetric apparatus 4 Display apparatus 10 Light source 70 Chromaticity calculation part 71 Spectrum estimation calculation part 72 Observation spectrum calculation part 73 Chromaticity value calculation part 80 Shade guide calculation processing part 81 Shade guide selection part 82 Comparison Arithmetic processing unit 114 Shade guide information storage unit 115 Image display GUI unit 200 Reference input unit 201 Image selection unit 202 Condition input units 821 and 823 Pixel extraction units 822 and 824 Image creation unit

Claims (15)

A first storage unit that stores captured image data of vital teeth and colorimetric information obtained based on the captured image data for each pixel;
A second storage unit that stores, for each pixel, photographed image data of a tooth sample and colorimetric information obtained based on the photographed image data;
A reference acquisition unit that acquires reference colorimetric information that is used as a reference when comparing the colorimetric information;
The reference colorimetric information and the vital tooth colorimetric information are compared on a pixel basis, and a pixel having a difference between the vital tooth colorimetric information and the reference colorimetric information equal to or less than a predetermined threshold is extracted. An extractor of
The reference colorimetric information and the colorimetric information of the tooth sample are compared in units of pixels, and a pixel in which a difference between the colorimetric information of the tooth sample and the reference colorimetric information is equal to or less than the predetermined threshold value. A second extraction unit for extracting;
A first image that creates a vital tooth comparison image in which a first pixel group composed of pixels extracted by the first extraction unit and a second pixel group composed of pixels that have not been extracted are expressed in different tones. The creation department;
Second image creation for creating a sample comparison image in which a third pixel group consisting of pixels extracted by the second extraction unit and a fourth pixel group consisting of pixels not extracted are expressed in different tones And
A dental colorimetric device comprising: a display control unit that displays the vital tooth comparison image created by the first image creation unit and the sample comparison image created by the second image creation unit . In the sample comparison image and the vital tooth comparison image, the first pixel group and the third pixel group are expressed in the same color tone, and the second pixel group and the fourth pixel group are the same. The dental colorimetric device according to claim 1 , which is expressed by a color tone of The first image creation unit changes at least one of brightness, saturation, and hue of each pixel in the vital tooth comparison image according to colorimetric information of the pixel,
The dental colorimetry according to claim 1 , wherein the second image creation unit changes at least one of brightness, saturation, and hue of each pixel in the sample comparison image according to colorimetric information of the pixel. apparatus. The first image creation unit creates the vital tooth comparison image in which pixels belonging to the first pixel group are expressed by captured image data of the vital tooth,
2. The dental colorimetric device according to claim 1 , wherein the second image creation unit creates the sample comparison image in which pixels belonging to the third pixel group are represented by captured image data of the tooth sample. The first image creation unit determines the brightness, saturation, or luminance of each pixel belonging to the second pixel group in the vital tooth comparison image, and the brightness, saturation, or luminance of each pixel belonging to the first pixel group. Or expressed in a manner that is lower than the brightness,
  The second image creating unit determines the brightness, saturation, or luminance of each pixel belonging to the fourth pixel group in the sample comparison image, and the brightness, saturation, or luminance of each pixel belonging to the third pixel group. The dental colorimetric device according to claim 4, wherein the dental colorimetric device is expressed in a more dropped form. The first image creating unit changes at least one of brightness, saturation, and hue of each pixel belonging to the second pixel group in the vital tooth comparison image according to colorimetric information of the pixel,
The second image creation unit changes at least one of brightness, saturation, and hue of each pixel belonging to the fourth pixel group in the sample comparison image according to colorimetric information of the pixel. 4. A dental colorimetric device according to 4.   The dental measurement according to claim 1, wherein the display control unit displays a reference input unit for inputting the reference colorimetric information on a screen on which the vital tooth comparison image is displayed. Color device. The dental colorimetry according to any one of claims 1 to 7, wherein the display control unit displays a condition input unit for inputting the predetermined threshold on a screen on which the vital tooth comparison image is displayed. apparatus. An area specifying unit for specifying an area of a vital tooth to be measured from a taken image in the oral cavity taken by an imaging device;
A measurement region setting unit that sets at least one measurement region in the identified vital tooth region;
A sample selection unit that selects at least one tooth sample that approximates the spectrum of each measurement region from among a plurality of tooth samples registered in advance;
The second extraction unit, according to any one of claims 8 and calorimetric information of sample of said reference colorimetric data and said sample the teeth which is selected by the selection unit from claim 1 to be compared in pixel units Dental colorimetric device. An imaging device for imaging the oral cavity;
A dental colorimetric device for processing an image acquired by the imaging device;
A display device for displaying an image processed by the dental colorimetry device,
The dental colorimetric device is:
A first storage unit that stores captured image data of vital teeth and colorimetric information obtained based on the captured image data for each pixel;
A second storage unit that stores, for each pixel, photographed image data of a tooth sample and colorimetric information obtained based on the photographed image data;
A reference acquisition unit that acquires reference colorimetric information that is used as a reference when comparing the colorimetric information;
The reference colorimetric information and the vital tooth colorimetric information are compared on a pixel basis, and a pixel having a difference between the vital tooth colorimetric information and the reference colorimetric information equal to or less than a predetermined threshold is extracted. An extractor of
The reference colorimetric information and the colorimetric information of the tooth sample are compared in units of pixels, and a pixel in which a difference between the colorimetric information of the tooth sample and the reference colorimetric information is equal to or less than the predetermined threshold value. A second extraction unit for extracting;
A first image that creates a vital tooth comparison image in which a first pixel group composed of pixels extracted by the first extraction unit and a second pixel group composed of pixels that have not been extracted are expressed in different tones. The creation department;
Second image creation for creating a sample comparison image in which a third pixel group consisting of pixels extracted by the second extraction unit and a fourth pixel group consisting of pixels not extracted are expressed in different tones And
A dental colorimetry system comprising: a display control unit that displays the vital tooth comparison image created by the first image creation unit and the sample comparison image created by the second image creation unit .   The first image creation unit creates the vital tooth comparison image in which pixels belonging to the first pixel group are expressed by captured image data of the vital tooth,
  The dental colorimetric system according to claim 10, wherein the second image creation unit creates the sample comparison image in which pixels belonging to the third pixel group are represented by captured image data of the tooth sample. A reference acquisition process for acquiring reference colorimetric information that is used as a reference when comparing colorimetric information obtained based on image data of vital teeth,
The reference colorimetric information and the vital tooth colorimetric information are compared on a pixel basis, and a pixel having a difference between the vital tooth colorimetric information and the reference colorimetric information equal to or less than a predetermined threshold is extracted. The extraction process of
The colorimetric information obtained based on the photographed image data of the tooth sample and the reference colorimetric information are compared in units of pixels, and the difference between the colorimetric information of the tooth sample and the reference colorimetric information is A second extraction process for extracting pixels that are below a predetermined threshold;
A first image that creates a vital tooth comparison image in which a first pixel group composed of pixels extracted by the first extraction unit and a second pixel group composed of pixels that have not been extracted are expressed in different tones. Creation process,
Second image creation for creating a sample comparison image in which a third pixel group composed of pixels extracted by the second extraction process and a fourth pixel group composed of pixels that have not been extracted are expressed in different tones Process,
A dental colorimetric method comprising: a display control process for displaying the vital tooth comparison image and the sample comparison image .   In the first image creation process, the vital tooth comparison image in which pixels belonging to the first pixel group are represented by captured image data of the vital tooth is created,
  13. The dental colorimetric method according to claim 12, wherein in the second image creation process, the sample comparison image is created in which pixels belonging to the third pixel group are represented by captured image data of the tooth sample. Reference acquisition processing for acquiring reference colorimetric information that is used as a reference when comparing calorimetric information obtained on the basis of photographed image data of vital teeth;
The reference colorimetric information and the vital tooth colorimetric information are compared on a pixel basis, and a pixel having a difference between the vital tooth colorimetric information and the reference colorimetric information equal to or less than a predetermined threshold is extracted. Extraction process,
The colorimetric information obtained based on the photographed image data of the tooth sample and the reference colorimetric information are compared in units of pixels, and the difference between the colorimetric information of the tooth sample and the reference colorimetric information is A second extraction process for extracting pixels that are less than or equal to a predetermined threshold;
A first image that creates a vital tooth comparison image in which a first pixel group composed of pixels extracted by the first extraction process and a second pixel group composed of pixels that have not been extracted are expressed in different tones. Creation process,
Second image creation for creating a sample comparison image in which a third pixel group composed of pixels extracted by the second extraction process and a fourth pixel group composed of pixels not extracted are expressed in different colors Processing,
A dental colorimetry program for causing a computer to execute display control processing for displaying the vital tooth comparison image and the sample comparison image .   In the first image creation processing, the vital tooth comparison image in which pixels belonging to the first pixel group are expressed by captured image data of the vital tooth is created,
  15. The dental colorimetric program according to claim 14, wherein in the second image creation process, the sample comparison image is created in which pixels belonging to the third pixel group are represented by captured image data of the tooth sample.

Images