KR102462061B1 - Calibration Method of Image Deviation between Devices Using Gray Reference Panel and Facial Skin Diagnosis Device with this Function - Google Patents

Abstract

The present invention is a technology for simultaneously correcting the corresponding image with color and brightness under the same shooting conditions by using the color and brightness information of the gray reference panel and the color and brightness information of the gray reference panel image of the image in which the gray reference panel is photographed is about
The method for correcting image deviation using a gray reference panel according to the present invention includes a first step of registering the brightness value of the gray reference panel and the panel color value for each R, G, and B in an image processing apparatus, and the image processing apparatus includes the gray reference panel The second step of collecting the captured images, the third step of the image processing device extracting the gray reference panel image from the collected image, and obtaining the panel image color values for each R, G, and B of the gray reference panel image; A fourth step in which the image processing apparatus converts the panel color values for each R, G, and B of the gray reference panel registered in the first step into converted color values for each R, G, and B that are color values in the brightness environment of the collected image , a fifth step of calculating, by the image processing apparatus, a color correction value for each R, G, and B through a difference (subtraction) operation between the panel image color value obtained in the third step and the converted color value obtained in the fourth step; and , the image processing apparatus corrects the color of the collected image using the color correction values for each R, G, and B, and corrects the brightness of the collected image based on the brightness value of the gray reference panel registered in the first step. and a sixth step of generating a corrected image, wherein the fourth step is to calculate the respective brightness ratios for each R, G, and B of the gray reference panel, and the brightness ratio of the panel image to the R, G, and B brightness ratios of the gray reference panel It is characterized by generating a converted color value for R, G, B, and stars by multiplying the values.

Description

Calibration Method of Image Deviation between Devices Using Gray Reference Panel and Facial Skin Diagnosis Device with this Function

The present invention is a technology for simultaneously correcting the corresponding image with color and brightness under the same shooting conditions by using the color and brightness information of the gray reference panel and the color and brightness information of the gray reference panel image of the image in which the gray reference panel is photographed is about

In recent years, various types of skin diagnosis devices have been developed that measure and diagnose skin conditions at dermatologists or skin care centers to discover characteristics or problems of skin conditions and take appropriate measures accordingly.

As an example, an image is obtained by polarizing light of a specific wavelength band to pigmented lesions of the epidermis and dermal papilla of the facial skin, which are difficult to observe with the naked eye, and the current skin condition can be measured and diagnosed by analyzing the image. A facial skin diagnosis apparatus has been disclosed.

1 illustrates a conventional facial skin diagnosis apparatus 1 for diagnosing a facial skin condition by photographing a user's face. Referring to FIG. 1A , the facial skin diagnosis apparatus 1 includes a camera 3 capable of capturing an image of a user's face inside a photographing space 2 where the user's face is disposed, and a camera 3 around the camera 3 . The light source unit 4 made of a plurality of light sources arranged, the chin rest 5 arranged below the photographing space 2 , the forehead rest 6 and the forehead rest 6 arranged above the photographing space 2 . ) and a brightness reference panel 7 disposed on the left and right sides.

The brightness reference panel 7 is made in the form of a flat plate of ivory color as shown in FIG. Left and right are photographed together.

That is, the conventional facial skin diagnosis apparatus 1 extracts the left and right brightness reference panels from the photographed image to obtain the brightness of the portion, obtains the difference from the brightness set for each light source, and corrects the brightness by software to always By generating a facial image in which a brightness reference is expressed with the same brightness, the user's facial skin condition is diagnosed using the facial correction image under the same brightness condition.

However, depending on the shooting location, changes in external conditions such as excessive sunlight or severe external light or brightness changes such as light source failure or light loss due to lifespan may occur. There are limits to

Accordingly, there may be supplementary measures such as timely replacement of the light source according to the failure or lifespan of the light source, or blocking external light by changing the installation location, but no matter how stable the light source (flash, lamp or LED) is illuminating the circuit There may be a change in brightness whenever the light source is turned on due to electrical changes, lifetime, and structural causes of the light source.

Also, in general, the conventional method of correcting the brightness of an image uses a method of always photographing an image brighter than a certain brightness, and darkening the brightness of the image measured brightly to a set brightness and correcting the image. This is because the correction of darkening the captured image improves the gradation without affecting the contrast.

However, in the conventional facial skin diagnosis apparatus 1 as shown in FIG. 1 , the user's chin is entangled in the chin rest 5 at a certain position, and the height of the forehead rest 6 is adjusted according to the size of the face, and then the picture is taken. , a person with a large head or standing hair may have hair covering the brightness reference panel 7 placed around the forehead rest 6 Incorrect calibration may occur.

In addition, in the conventional facial skin diagnosis apparatus 1, since the brightness reference panel 7 is disposed at the top of the imaging space 2, external light is introduced to the top left after the user's head is positioned, so that the effect of external light is more severe than actual. It can be photographed in a state of receiving a lot.

In other words, for facial skin analysis, it is always basic to secure facial images taken in the same shooting environment. There is a problem that different facial skin analysis results are derived every time or every time the imaging equipment is changed.

1. Korea Patent Registration No. 10-0698828 (Title of the invention: Image distortion correction system and method based on illumination-reflectance model) 2. Korean Patent Laid-Open Patent No. 10-2021-0017448 (Title of Invention: Facial Skin Diagnosis Machine)

Accordingly, the present invention was created in consideration of the above circumstances, and when shooting an image, a gray reference panel is photographed together, and a photographed image using the unique registration value of the gray reference panel and the brightness and color values of the gray reference panel image of the image Its technical purpose is to provide a method for correcting the image deviation between devices using a gray reference panel that can correct the color and brightness of the image at the same time.

In addition, the present invention minimizes the effect of external light flowing into the gray reference panel during facial imaging by disposing a gray reference panel on the lower side of the facial skin diagnosis device, thereby stably correcting the color and brightness of the facial image using the gray reference panel image. It is a technical object to provide a facial skin diagnosis apparatus having an image deviation correction function using a gray reference panel that enables the diagnosis of facial skin conditions by performing

여기서, R_C,G_C,B_C 는 제1 단계에서 등록된 회색 레퍼런스 패널의 R,G,B별 패널 색상값이며. 상기 패널 이미지의 밝기값(I_I)은 하기 수학식에 의해 산출되는 것을 특징으로 하는 회색 레퍼런스 패널을 이용한 장치간 영상 편차 보정방법이 제공된다.

여기서, R_IC,G_IC,B_IC 는 제3 단계에서 획득한 회색 레퍼런스 패널 이미지의 R,G,B별 이미지 패널 색상값이다.According to one aspect of the present invention for achieving the above object, in a method for correcting image deviation between devices using a gray reference panel in a plurality of image processing devices that compare and process photographed images, the image processing device includes a gray reference panel. In the first step of registering the brightness value and the panel color value for each R, G, and B, the image processing device collects the image photographed with the gray reference panel in the second step, and the image processing device collects the image in the second step The third step of extracting the gray reference panel image and obtaining the panel image color values for each R, G, and B for the gray reference panel image, the image processing device R, G, B of the gray reference panel registered in the first step A fourth step of converting each panel color value into a converted color value for each R, G, and B that is a color value in the brightness environment of the collected image, the image processing apparatus compares the panel image color value obtained in the third step A fifth step of calculating a color correction value for each R, G, and B through a difference (subtraction) operation between the converted color values obtained in the step, and the image processing apparatus collects the color correction values for each R, G, and B a sixth step of correcting the color of the image and correcting the brightness of the collected image based on the brightness value of the gray reference panel registered in the first step to generate a corrected image, wherein the fourth step comprises: Calculate the brightness ratio for each R, G, and B of the gray reference panel, multiply the brightness ratio for each R, G, and B by the brightness value of the panel image to generate R, G, B, and star conversion color values, Each brightness ratio (R _R , G _R , B _R ) of each R, G, and B of the gray reference panel is calculated by the following equation,

Here, R _C ,G _C ,B _C are the panel color values for each R, G, and B of the gray reference panel registered in the first step. The brightness value I _I of the panel image is provided with a method for correcting image deviation between devices using a gray reference panel, characterized in that calculated by the following equation.

Here, R _IC , G _IC , B _IC are the image panel color values for each R, G, and B of the gray reference panel image obtained in the third step.

In addition, the image collected in the second step includes two or more gray reference panels having the same brightness disposed at different positions, and in the third step, the image processing apparatus performs R, G, Provided is a method for correcting image deviation between devices using a gray reference panel, characterized in that the average of the panel image color values for each B is determined as the panel image color value.

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여기서, R_C,G_C,B_C 는 기 등록된 회색 레퍼런스 패널의 R,G,B별 패널 색상값이며, 이 R,G,B별 밝기 비율에 하기 수학식을 통해 산출된 패널 이미지의 밝기값(I_I)을 곱 연산하여 산출되는 것을 특징으로 하는 회색 레퍼런스 패널을 이용한 장치간 영상 편차 보정방법이 제공된다.

여기서, R_IC,G_IC,B_IC 는 회색 레퍼런스 패널 이미지의 R,G,B별 이미지 패널 색상값이다.In addition, according to another aspect of the present invention for achieving the above object, an opening in which the user's face is disposed is formed on one side of the front side, a body having a photographing space formed therein, and a user installed on the lower side of the body A chin rest supporting the chin of The user's face is photographed, but a camera installed on one side of the inside of the body so that the gray reference panel is photographed together with the face, a light source unit installed on one side of the body for irradiating light, and collecting facial images taken through the camera to generate a corrected image of the same shooting condition based on the gray reference panel information, and an image processing apparatus for diagnosing a user's facial skin condition using the corrected image, wherein the image processing apparatus is a gray reference of the facial image Calculates the panel image color value for each R, G, and B of the panel image, and converts the previously registered color value of the gray reference panel into the converted color value for each R, G, and B of the gray reference panel in the corresponding facial image brightness environment. , R, G, and B color correction values are calculated based on the difference between the panel image color value for each R, G, and B color value and the converted color value for each R, G, B color correction value is calculated to correct the color of the facial image, and a preset gray reference panel is configured to generate a corrected image by correcting the brightness of this facial image using the panel brightness value of R _R ,G _R ,B _R ) is calculated through the following formula,

Here, R _C , G _C , B _C are the panel color values for each R, G, and B of the previously registered gray reference panel, and the brightness ratio of each R, G, and B of the panel image calculated through the following equation There is provided a method for correcting image deviation between devices using a gray reference panel, which is calculated by multiplying a value (I _I ).

Here, R _IC , G _IC , and B _IC are the image panel color values for each R, G, and B of the gray reference panel image.

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In addition, the gray reference panel is provided with a facial skin diagnosis device having an image deviation correction function using a gray reference panel, characterized in that the surface has a matte characteristic, and is made of a material that is resistant to moisture and has little discoloration including plastic or ceramic. do.

According to the present invention, it is possible to easily correct the color and brightness of a photographed image by shooting a gray reference panel when taking an image and using the unique registration value of the gray reference panel and the brightness and color values of the gray reference panel image of the image. have.

In addition, the present invention removes the color and brightness deviation of the photographed image for each time of photographing a user's face and a facial image photographed together with a gray reference panel disposed on the lower side of the facial skin diagnosis apparatus or by photographing equipment, so that it is always in the same photographing environment. By correcting the image, it is possible to reliably diagnose the user's facial skin condition anytime, anywhere.

1 is a diagram schematically showing the configuration of a conventional facial skin diagnosis apparatus.
2 is a diagram schematically showing the configuration of a facial skin diagnosis apparatus having an image deviation correction function using a gray reference panel according to a first embodiment of the present invention;
FIG. 3 is a diagram illustrating an arrangement form of the gray reference panel 140 shown in FIG. 2 .
FIG. 4 is a functionally separated view showing the internal configuration of the image processing apparatus 200 shown in FIG. 2 .
FIG. 5 is a view for explaining the operation of the facial skin diagnosis apparatus having an image deviation correction function using the gray reference panel shown in FIG. 2 .

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. It should be noted that the same components in the drawings are denoted by the same reference numerals wherever possible. On the other hand, prior to this, the terms or words used in the present specification and claims should not be construed as being limited to conventional or dictionary meanings, and the inventors have to understand the concept of terms in order to explain their invention in the best way. Based on the principle that it can be appropriately defined, it should be interpreted as meaning and concept consistent with the technical idea of the present invention. Therefore, the configuration shown in the embodiments and drawings described in this specification is only the most preferred embodiment of the present invention, and does not represent all of the technical idea of the present invention, so at the time of the present application, various It should be understood that there may be equivalents and variations.

2 is a diagram schematically illustrating the configuration of a facial skin diagnosis apparatus having an image deviation correction function using a gray reference panel according to a first embodiment of the present invention.

Referring to FIG. 2 , a facial skin diagnosis apparatus having an image deviation correction function using a gray reference panel according to the present invention includes a face photographing apparatus 100 for photographing a user's face, and and an image processing apparatus 200 for diagnosing a facial skin condition by correcting a facial image with an image of the same photographing condition. In this case, the image processing apparatus 200 may be disposed in the face photographing apparatus 100 to implement the facial skin diagnosis apparatus in the form of a single terminal.

The face photographing apparatus 100 includes a camera 110 capable of photographing an image of the user's face on the inside of the main body in which an opening in which the user's face is disposed is formed on one side of the front side, and a photographing space S is formed therein, and a camera; A light source unit 120 made of a plurality of light sources disposed around 110 , a chin rest 130 disposed below the imaging space S, and a gray reference panel disposed on one side of the chin rest 130 ( 140), and may further include a forehead supporter 150 on the upper side of the photographing space (S).

Here, at least one gray reference panel 140 is on the same focus plane as the user's face supported on the chin rest 130 on the side facing the camera 110 of the chin rest 130 as shown in FIG. 3 . this is placed 3 exemplifies a shape in which two gray reference panels 140 are arranged in the shape of “11” on one side of the chin rest 130 . Placing the gray reference panel 140 on the chin rest 130 in this way minimizes the influence from the face size or hair while the user's face is positioned in the photographing space S, and the user's face and This is to minimize the occurrence of a change in brightness due to the body naturally covering the lower side of the face photographing apparatus 100 and introducing external light to the gray reference panel 140 side. Accordingly, in the present invention, a portion of the gray reference panel 140 in the face image captured by the face photographing apparatus 100 always has the same brightness environment.

The gray reference panel 140 is a rectangular panel having a certain width and length having a gray color, and the gray-based colors have the same color values as R (Red), G (Green), and B (Blue). It has a characteristic that varies according to the brightness value. In the present invention, image correction processing is performed using the color characteristics of the gray color.

In addition, the gray reference panel 140 is configured so that the surface of the panel has a matte characteristic so that there is little change in color or brightness due to light reflection, and the material has little discoloration even after long exposure to light and is resistant to moisture, so it changes with time is small, and may be made of, for example, a plastic or ceramic material. And, it is preferable that the gray color has a medium brightness that is not too dark or too bright.

On the other hand, in FIG. 2 , the image processing apparatus 200 controls the face photographing apparatus 100 to photograph a user's face image, collects the facial image, and always takes a constant photograph using a gray reference panel image of the collected facial image. The color and brightness of the corresponding facial image are corrected so that it becomes a facial image captured in the environment. Then, the image processing apparatus 200 analyzes the facial skin condition using the corrected facial image.

As shown in FIG. 4 , the image processing apparatus 200 includes a camera setting unit 210 , an information registration unit 220 , an image collection unit 230 , an image correction unit 240 , and an image analysis unit 250 . do.

The camera setting unit 210 sets various camera parameters including the distance between the camera 110 and the subject's face and the lens magnification so that the gray reference panel 140 is photographed together with the user's face in the face photographing apparatus 100 . In this case, the camera parameters include aperture and shutter speed, sensitivity of a sensor responding to light (ISO), and white balance. That is, the facial image is always taken under the same camera conditions. At this time, when there are a plurality of face photographing apparatuses 100, by setting the camera parameters of each facial photographing apparatus 100, the brightness value of the gray reference panel, and the panel color values for each R, G, and B to be the same, measurement of facial skin When providing the service, it is possible to always obtain a facial image of the same brightness and color without any deviation for each shooting device.

The information registration unit 220 registers reference information of the gray reference panel 140 for image deviation correction. The reference information includes R, G, and B color values and panel brightness values measured using a colorimeter or a colorimeter of the gray reference panel 140 .

The R, G, and B color values of the gray reference panel 140 may be Lab color coordinates defined by CIE, an international lighting committee, or RGB color coordinates. At this time, in the case of Lab color coordinates, it can be converted into RGB color coordinate conversion formula and registered, and when converting from Lab to RGB, it can be converted to RGB after intermediate change to the XYZ color space stipulated by the International Lighting Commission (CIE).

In addition, the panel brightness value of the gray reference panel 140 is arbitrarily set to a value between 0 and 255.

The image collection unit 230 operates the face photographing apparatus 100 to collect a facial image in which the user's face and the gray reference panel 140 are photographed together.

The image correction unit 240 extracts the gray reference panel image as an image of interest from the facial image collected through the image collection unit 230 to calculate panel image color information for each R, G, and B panel image, and R R, G, B color correction values are calculated based on the difference between the panel image color values for each , G and B and the converted color values for each R, G, and B of the gray reference panel in the corresponding facial image brightness environment.

In addition, the image correction unit 240 corrects the color of the facial image collected through the image collection unit 230 using the R, G, and B color correction values, and uses the preset panel brightness value of the gray reference panel. A corrected image is generated by correcting the brightness of the facial image.

The image analyzer 250 analyzes the corrected image generated by the image corrector 240 to diagnose the user's facial skin condition.

Next, an operation of the facial skin diagnosis apparatus having an image deviation correction function using the gray reference panel having the above configuration will be described with reference to the flowchart shown in FIG. 5 .

Referring to FIG. 5 , the manager registers panel color information and panel brightness information of the gray reference panel 140 in the image processing apparatus 200 (ST100). In this case, the panel color information of the gray reference panel is a color value obtained using a colorimeter or a colorimeter, and the panel brightness can be set arbitrarily to a value between 0 and 255 by the administrator.

Then, the manager arranges the gray reference panel 140 on the upper end of the chin rest 130 of the face photographing apparatus 100 . At this time, one or more gray reference panels 140 may be disposed on the chin rest 130 , and preferably, two gray reference panels 140 having the same brightness are provided at both ends of the chin rest 130 as shown in FIG. 3 . can be placed in each.

In addition, the image processing apparatus 200 uses the face photographing apparatus 100 to capture the user's face when photographing the user's face with the subject (user's face) so that the user's face positioned on the face photographing apparatus 100 and the gray reference panel 140 are photographed together. In addition to setting the distance and the lens magnification, camera parameters of the face photographing apparatus 100 including aperture, shutter speed, sensor sensitivity (ISO), and white balance are set (ST200).

In the above state, the user places the face in the photographing space (S) of the face photographing apparatus 100 and in a state in which external light is blocked, the image processing apparatus 200 operates the camera 120 to photograph the face, , the image processing apparatus 200 collects a facial image including the gray reference panel image photographed by the face photographing apparatus 100 (ST300).

The image processing apparatus 200 extracts a gray reference panel image from the facial image, and acquires R, G, and B panel image color values corresponding to the extracted gray reference panel image (ST400). At this time, as shown in FIG. 3 , when a plurality of gray reference panels 140 are disposed in the face photographing apparatus 100 and a plurality of gray reference panel images are extracted from the facial image, each R, G, and B panel in each gray reference panel image Each image color value is acquired, the average value is calculated, and it is determined as the panel image color value for each R, G, and B of the gray reference panel image.

Next, the image processing apparatus 200 sets the R, G, and B panel color values of the gray reference panel 140 registered in step ST100 to R, G, and B panel color values in the face image brightness environment obtained in ST400. , that is, converted into a converted color value (ST500). In this case, the image processing apparatus 200 uses the characteristic that the brightness value of the object color may vary depending on the intensity of illumination, but the color ratio is maintained the same, so that the panel colors for each R, G, and B of the gray reference panel 140 are used. The value is converted into a color value in the face image brightness environment obtained in ST400.

That is, in step ST500, the image processing apparatus 200 uses the R, G, and B reference color values (R _C , G _C , B _C ) of the gray reference panel 140 to determine the R, G, and B brightness ratio ( R _R ,G _R , _BR ) are calculated respectively. At this time, the ratio of R,G,B brightness (R _R ,G _R ,B _R ) is calculated through Equation 1 below.

Here, R _C , G _C , B _C are panel color values for each R, G, and B of the gray reference panel 140 .

Then, the image processing apparatus 200 multiplies the brightness ratio of each R, G, and B of the gray reference panel 140 by the brightness value of the gray reference panel image, and the gray reference panel 140 in the gray reference panel image brightness environment. Calculate the converted color values for each R, G, and B of . In this case, the converted color values (R _RC , G _RC , B _RC ) for each R, G, and B of the gray reference panel 140 in the gray reference panel image brightness environment are calculated through Equation 2 below.

Here, I _I is a gray reference panel image brightness value calculated by the panel image color values for each R, B, and G of the gray reference panel image, and is calculated through Equation 3 below.

Here, R _IC , G _IC , and B _IC are the panel image color values for each R, B, and G of the gray reference panel image.

Then, the image processing apparatus 200 compares the panel image color values (R _IC , G _IC , B _IC ) for each R, G, and B of the gray reference panel image obtained in the ST400 step and the gray reference panel converted in the ST500 step. Calculate the color correction values (R', G', B') for each R, G, and B by calculating the difference between the converted color values (R _RC , G _RC , B _RC ) for each R, G, and B (ST600) . The R, G, and B color correction values (R', G', B') are calculated through Equation (4).

Next, the image processing apparatus 200 corrects the color of the facial image collected in step ST200 using the color correction values for each R, G, and B, and uses the brightness value registered in step ST100 to adjust the color of the facial image. A corrected image is generated by correcting the brightness (ST700). That is, the image processing apparatus 200 always obtains a corrected image under the same shooting conditions by using the previously registered color and brightness values of the gray reference panel 140 and the gray reference panel image included in the face image.

Thereafter, the image processing apparatus 200 analyzes the corrected image to diagnose the facial skin condition of the user (ST800).

On the other hand, in the present embodiment, the gray reference panel was applied to the facial skin diagnosis apparatus for correcting the facial image, but it can be applied to various fields that compare and process images under the same imaging conditions.

100: face photographing device, 110: camera,
120: light source unit, 130: chin rest,
140: gray reference panel, 150: forehead support,
200: image processing device, 210: camera setting unit,
220: information register, 230: image collection unit,
240: an image correction unit, 250: an image analysis unit.

Claims (7)

In a method for correcting image deviation between devices using a gray reference panel in a plurality of image processing devices that compare and process captured images,
A first step of registering the brightness value of the gray reference panel and the panel color value for each R, G, and B in the image processing device;
A second step in which the image processing device collects the image captured with the gray reference panel,
A third step in which the image processing device extracts a gray reference panel image from the collected images in the second step, and obtains panel image color values for each R, G, and B for the gray reference panel image;
A fourth step in which the image processing apparatus converts the panel color values for each R, G, and B of the gray reference panel registered in the first step into converted color values for each R, G, and B that are color values in the brightness environment of the collected image ,
a fifth step of calculating, by the image processing apparatus, a color correction value for each R, G, and B through a difference (subtraction) operation between the panel image color value obtained in the third step and the converted color value obtained in the fourth step;
The image processing apparatus corrects the color of the collected image using the color correction values for each R, G, and B, and corrects the brightness of the collected image based on the brightness value of the gray reference panel registered in the first step and a sixth step of generating an image,
The fourth step is to calculate each brightness ratio for each R, G, and B of the gray reference panel, multiply the brightness ratio for each R, G, and B by the brightness value of the panel image, and convert colors for R, G, B, and stars create a value,
Each brightness ratio (R _R , G _R , B _R ) of each R, G, and B of the gray reference panel is calculated by the following equation,

Here, R _C , G _C , B _C are the panel color values for each R, G, and B of the gray reference panel registered in the first step.
The brightness value (I _I ) of the panel image is an image deviation correction method between devices using a gray reference panel, characterized in that calculated by the following equation.

Here, R _IC ,G _IC ,B _IC are the image panel color values for each R, G, and B of the gray reference panel image obtained in the third step.
delete delete The method of claim 1,
The images collected in the second step include two or more gray reference panels having the same brightness disposed at different positions,
In the third step, the image processing apparatus determines the average of the panel image color values for each R, G, and B for each gray reference panel image as the panel image color value. Way.
A main body having an opening in which the user's face is disposed on one side of the front side, and a photographing space is formed therein;
A chin rest installed on the lower side of the main body to support the user's chin,
A gray color panel having a certain width and length, a gray reference panel disposed on one side of the chin rest and disposed on the same focus plane as the user's face;
A camera installed on one side of the inside of the body to photograph the user's face located in the opening of the body, and to photograph the gray reference panel together with the face;
A light source unit installed on one side of the inside of the body to irradiate light,
and an image processing device that collects facial images taken through the camera, generates a corrected image of the same shooting condition based on gray reference panel information, and diagnoses a user's facial skin condition using the corrected image,
The image processing device calculates the panel image color values for each R, G, and B for the gray reference panel image of the facial image, and sets the previously registered color value of the gray reference panel to the R of the gray reference panel in the corresponding facial image brightness environment. Converts to converted color values by ,G,B, and calculates R,G,B color correction values based on the difference between the panel image color value by R,G,B and the converted color value by R,G,B to calculate facial image is configured to correct the color of , and correct the brightness of this facial image using the panel brightness value of the preset gray reference panel to generate a corrected image,
The R, G, B, and star conversion color values are calculated by calculating the respective brightness ratios (R _R , G _R , B _R ) of each R, G, and B of the gray reference panel through the following equation,

Here, R _C , G _C , B _C are the panel color values for each R, G, and B of the previously registered gray reference panel.
An image deviation correction method between devices using a gray reference panel, which is calculated by multiplying the brightness ratio for each R, G, and B by the brightness value (I _I ) of the panel image calculated through the following equation.

Here, R _IC ,G _IC ,B _IC are the image panel color values for each R, G, and B of the gray reference panel image.
delete 6. The method of claim 5,
The gray reference panel has a matte surface, and is made of a material that is resistant to moisture and has little discoloration including plastic or ceramic.

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