JP6200767B2 - Skin internal structure estimation method and skin color unevenness evaluation method - Google Patents

Description

  The present invention relates to a method for estimating a nipple structure existing in the dermis inside the skin. The present invention also relates to a method for evaluating skin color unevenness.

  At the part where the epidermis and the dermis constituting the skin are in contact with each other, there is a basal layer on the epidermis side and a papillary layer on the dermis side, and a papillary structure is formed as an interface between them. The papillary structure is a structure in which the epidermal process (papillary body) protrudes from the basal layer side to the dermis, and the papillary process (dermal process) is arranged so as to bite between the epidermal processes from the nipple layer side. The papillary process has fine connective fibers, capillaries, and sensory nerve endings, which are responsible for supplying oxygen and nutrients to the dermis and epidermis, collecting carbon dioxide from the dermis and epidermis, and receiving information. ing.

  It is known that the structure of the nipple is flattened and disappears due to age and exposure to ultraviolet rays, and it is easy to cause skin talmi. In addition, the dermis can freely expand and contract, but the epidermis in contact with the dermis is a sheet-like structure in which cells are in close contact with each other, so the elasticity is poor, and the difference in elasticity between the dermis and the epidermis is buffered. It is said that there is a nipple structure. In addition, the capillaries in the nipple structure are arranged along the irregularities, but it is also known that the capillaries directly under the epidermis affect the color of the skin. For this reason, attention has been paid to the relationship between the nipple structure and the skin condition.

  For example, it is known that the thickness of the nipple dermis and the arrangement of the nipple structure affect the skin color (Patent Documents 1 and 2), and that the nipple structure and the degree of aging correlate in the lips (Patent Document 3). Further, based on the fact that the elasticity of the skin caused by the nipple structure is correlated with the texture, a method for estimating the skin internal structure using skin surface information such as texture and skin color as an index (Patent Document 4), A method for evaluating the conspicuousness of pores based on the shape (Patent Document 5) and a method for classifying sensitive skin using the dermal papilla layer density as an index have been proposed (Patent Document 6).

Special table 2001-504020 gazette Special table 2003-501651 gazette JP 2002-291722 A JP 2011-101738 A JP 2004-337317 A JP 2004-97436 A

  It is an object of the present invention to provide a new method for estimating the internal structure of the skin and a method for evaluating skin color unevenness based on the characteristics of the nipple structure.

The present inventors have advanced research on the nipple structure existing in the dermis of the skin, and have already applied for a patent with some knowledge (for example, PCT / JP2013 / 059271).
In the present invention, knowledge about the relationship between light diffusion by the skin and the nipple structure was newly obtained, and the invention was completed based on these findings.

The first embodiment of the present invention is a method for estimating a skin internal structure. In particular,
A measurement step of irradiating the skin surface with light and measuring the light diffusion; and if the light diffusion measured in the measurement step is greater than or equal to a threshold prepared in advance for the irradiation spot, the number of nipples inside the skin is large And when the light diffusion is smaller than a threshold value prepared in advance for the irradiation spot, an estimation step of estimating that the number of nipples in the skin is small is included.

In addition, the second embodiment of the present invention is a method for evaluating skin color unevenness, specifically,
A measurement step of irradiating the skin surface with light and measuring the light diffusion; and if the light diffusion measured in the above step is equal to or greater than a threshold prepared in advance for the irradiation spot, it is evaluated that there is little color unevenness on the skin. When the light diffusion is smaller than the threshold value prepared in advance for the irradiation spot, the skin color unevenness evaluation method includes an evaluation step for evaluating that the skin color unevenness is large.

  According to the present invention, it is possible to provide a new method for estimating the internal structure of the skin and a method for evaluating skin color unevenness, which can be used for counseling and the like, thereby contributing to appropriate skin care and selection of cosmetics.

It is a figure which shows the increase in the light diffusion resulting from the teat structure performed in the test example. It is a schematic diagram which shows the outline | summary of a test example. It is a graph which shows the correlation of the number of nipple structures and color nonuniformity (r = -0.35).

  Hereinafter, although the estimation method of the skin internal structure of this invention and the skin color nonuniformity evaluation method are demonstrated, the technical scope of this invention is not limited only to the following specific embodiments.

The first embodiment of the present invention is a method for estimating a skin internal structure.
In the present invention, the internal skin structure is a papillary structure that exists in a portion where the epidermis and the dermis constituting the skin are in contact.
The estimation method of the internal structure of the skin includes a measurement step of irradiating light on the skin surface and measuring the light diffusion, and if the light diffusion measured in the above step is equal to or greater than a threshold prepared in advance for the irradiation spot, Estimating that the number of nipples inside the skin is large, and estimating the number of nipples inside the skin when the light diffusion is smaller than a threshold prepared in advance for the irradiation spot, the method for estimating the internal structure of the skin It is.
The present invention is based on the discovery of a new relationship between the nipple structure and light diffusion. Hereinafter, test examples conducted by the present inventors will be described.

<Test Example 1>
Using a 3D printer, a concavo-convex mold simulating the nipple structure of the skin was produced. Next, based on the Haze value, which is an indicator of light diffusion, a solution prepared with distilled water to 10% agar (W / V) and skim milk 1% (W / V) is poured into a mold and cooled and solidified. An epidermis model was prepared. The prepared epidermis model is placed with the uneven surface that is the joint surface with the dermis facing upward, and the dermis is considered as a reflector, so that the agar is prepared with only milk so that it becomes 10% (W / V) Poured onto the epidermis model and cooled and solidified to produce an epidermis model.
The prepared epidermal dermis model was placed so that the epidermis was on top, and a diffusion sheet (D123 manufactured by Tsujiden Co., Ltd.) was placed as a pseudo-horny layer to form a skin model. Laser light was incident on the skin model with a laser pointer (red laser pointer manufactured by KOKYOYO) from above 15 cm, and the state was photographed with a digital camera fixed 9 cm obliquely above the skin model. Using the image analysis software (NS2K-Pro Nanosystem Co., Ltd.), the extracted red area is extracted and binarized, and the number of pixels is calculated for the photographed image. The diffusion state was quantified.

  As a result of the above test, the diffusion region increased by about 20% when the nipple structure protrusion was present, compared to the case where the nipple structure protrusion was not present. From this result, it was found that light diffusion was large when the number of teats was large, and light diffusion was small when the number of teats was small. That is, it is understood that the nipple process in the nipple structure causes light diffusion. Therefore, by measuring the light diffusion, it is possible to estimate the nipple structure inside the skin.

In the measurement step, the light for causing light diffusion is preferably monochromatic light in the visible light region, and more preferably laser light, since the spread of light is small and improvement in measurement accuracy can be expected.
In addition, the light diffusion measurement method is not particularly limited as long as light diffusion can be measured. For example, light diffusion is measured by performing binarization processing using an image obtained by imaging a skin irradiated with light with a digital camera. be able to. The binarization process is a process for facilitating measurement of light diffusion and is not essential.

In the estimation step, based on the new knowledge, if the light diffusion measured in the measurement step is equal to or greater than the threshold value prepared in advance for the irradiation spot, it is estimated that the number of nipples inside the skin is large, and the light diffusion is irradiated. This is a step of measuring that the number of nipples inside the skin is small when the spot is smaller than a threshold value prepared in advance.
The irradiation spot is a portion where light is actually irradiated on the skin before the irradiated light is diffused. In order to accurately measure the size of the irradiation spot, it is preferable to acquire an image of the irradiated part and binarize the image.

In the estimation step, a threshold value for presuming that the number of nipples in the skin is large or small is prepared in advance. The threshold can be prepared, for example, by the following procedure, but is not limited thereto.
i) Prepare multiple subjects.
ii) Measure the skin of a plurality of subjects with an in vivo confocal laser and grasp the number of nipples of the subjects.
iii) Light is irradiated on the skin surfaces of a plurality of subjects, and the light diffusion is measured.
iv) The results of ii) and iii) are plotted, and the light diffusion corresponding to the average value of the number of nipples is set as a threshold value.
When such a method is adopted, the number of subjects is usually 5 or more, 20 or less, and preferably 10 or more.

Although the above threshold value varies depending on the age and number of subjects for determining the threshold value, the light diffusion area when the spot area, which is the irradiation range of monochromatic light, is set to 100, is set in the range of approximately 110 to 120. Is done. It may be set at 112 or more and 118 or less, may be set at 114 or more and 116 or less, and may be set at 115.
The threshold value may be changed according to the age of the subject or may be changed according to the living area of the subject. The threshold value is usually an integer, but may be a decimal number.

Further, in the estimation step, a plurality of regions are set in advance according to the light diffusion area when the light diffusion area is 100 or more and 150 or less when the spot area that is the irradiation range of monochromatic light is set to 100. It is preferable to include a step of setting the score so that the score increases in descending order of the light diffusion area and determining that the number of nipples increases in descending order of score.
For example, a light diffusion area of 100 or more and less than 110 is score 1, 110 or more and less than 120 is score 2, 120 or more is score 3, and a light diffusion area of score 3 or more is 120 or more, and the number of nipples is large. Assuming that the number of nipples is normal, it is possible to determine that the number of nipples is less than 100 and less than 110. For example, when the measurement result of the light diffusion area is 118, it can be estimated that the number of teats is normal.

  In this way, by setting a plurality of regions (N regions) in advance by the light diffusion area and setting scores for the plurality of regions, it is possible to estimate the internal structure of the subject's skin by N-stage evaluation Become. N is usually 2 or more and preferably 3 or more. Moreover, it is 10 or less normally, and it is preferable that it is 5 or less.

The second embodiment of the present invention is a method for evaluating skin color unevenness.
The skin color unevenness evaluation method includes a measurement step of irradiating light on the skin surface and measuring the light diffusion, and if the light diffusion measured in the step is equal to or greater than a threshold value prepared in advance for the irradiation spot, An evaluation step of evaluating that the color unevenness of the skin is small, and if the light diffusion is smaller than a threshold value prepared in advance for the irradiation spot, the color unevenness of the skin is evaluated to be large.

  As described above, the present inventors have obtained new knowledge about the relationship between the number of teats and light diffusion. On the other hand, the present inventors have revealed that the number of nipples is correlated with color unevenness. This will be described below.

<Test Example 2>
A skin image is imaged with a digital video microscope on the same measurement site of the subject who measured the number of nipple structures with an in vivo confocal laser microscope or the like. For a captured image, for example, color measurement is performed in units of one dot in the captured image using a color system such as the HIS color system. Thereafter, the degree of variation in the entire captured image for each color system index such as H, S, and I was calculated using the standard deviation as an index.

  As a result of the above test, it can be understood that there is a correlation between the number of nipples and skin color unevenness (r = −0.35). From the fact that the number of nipples can be estimated by combining the results of Test Examples 1 and 2 above and measuring light diffusion, the present inventors correlate the nipple and skin color unevenness. It was conceived that skin unevenness can be evaluated by measuring diffusion.

  In the evaluation step of this embodiment, the light for causing the light diffusion is preferably a laser beam because the spread of the light is small and an improvement in measurement accuracy can be expected. The light diffusion measurement method is not particularly limited as long as the light diffusion can be measured. For example, the light diffusion can be measured using an image obtained by capturing an object with a digital camera.

  In the evaluation step, based on the new comprehensive knowledge, if the light diffusion measured in the measurement step is equal to or greater than a threshold value prepared in advance for the irradiation spot, the skin color unevenness is evaluated to be small. On the other hand, when it is smaller than the threshold value prepared in advance, it is a step of evaluating that there is much skin color unevenness.

The threshold value preparation in the evaluation step can refer to the threshold value preparation method in the estimation step of the first embodiment.
Similarly, the description of the irradiation spot can be referred to the description of the irradiation spot in the estimation step of the first embodiment.

Although the threshold value in the evaluation step varies depending on the age and number of subjects for determining the threshold value, the light diffusion area when the spot area that is the irradiation range of monochromatic light is set to 100 is approximately 110 or more and 120 or less. Set by range. It may be set at 112 or more and 118 or less, may be set at 114 or more and 116 or less, and may be set at 115.
The threshold value may be changed according to the age of the subject or may be changed according to the living area of the subject. The threshold value is usually an integer, but may be a decimal number.

Further, in the estimation step, a plurality of regions are set in advance according to the light diffusion area when the light diffusion area is 100 or more and 150 or less when the spot area that is the irradiation range of monochromatic light is set to 100. It is preferable to include a step of setting the score so that the score increases in order of increasing light diffusion area, and determining that the color unevenness of the skin is less in order from the highest score.
For example, if the light diffusion area is 100 or more and less than 110, the score is 1, 110 or more and less than 120 is the score 2, 120 or more is the score 3, and the light diffusion area of the score 3 or more is 120 or less and the skin color unevenness is small. It can be determined that skin color unevenness is normal, and skin color unevenness of 100 to less than 110 is large. For example, when the measurement result of the light diffusion area is 118, it can be estimated that the skin color unevenness is normal.

  In this way, by setting a plurality of regions (N regions) in advance by the light diffusion area and setting scores for the plurality of regions, it is possible to evaluate the skin color unevenness of the subject by N-level evaluation. Become. N is usually 2 or more and preferably 3 or more. Moreover, it is 10 or less normally, and it is preferable that it is 5 or less.

The present invention can be applied to skin counseling in cosmetics departments and beauty salons. In addition, it can be applied to selection of cosmetics suitable for a subject and selection of esthetic methods at a cosmetics department or an esthetic.
According to the present invention, it is possible to estimate and evaluate the internal structure of the skin and the color unevenness of the skin, which are not normally visually recognized, by a simple method, and thus can be applied to skin care advice.

Claims (8)

The light irradiated on the skin surface, the number of the measurement step of measuring a light amount of diffusion, and wherein when the measurement light diffusion amount measured in step is prepared in advance threshold above with respect to the irradiation spots, skin inside the papilla Estimation of the internal structure of the skin for cosmetic purposes, including an estimation step that estimates that the number of nipples inside the skin is small if the amount of light diffusion is less than a threshold prepared in advance for the irradiation spot Method.   The skin internal structure estimation method according to claim 1, wherein the light to be irradiated is monochromatic light. The light diffusion amount is a light diffusion area;
The skin internal structure estimation method according to claim 2, wherein the threshold value prepared in the estimation step is a numerical value having a light diffusion area of 110 or more and 120 or less when a spot area that is an irradiation range of monochromatic light is set to 100.   In the estimation step, a plurality of regions are set in advance according to a light diffusion area when the spot area that is an irradiation range of monochromatic light is set to 100, and the score increases in descending order of the light diffusion area with respect to the plurality of regions. The method for estimating a skin internal structure according to claim 2, further comprising: setting a score and determining that the number of nipples increases in descending order of score.   5. The skin internal structure estimation method according to claim 4, wherein the plurality of regions based on the light diffusion area include at least a region having a light diffusion area of 120 or more, a region of 110 to 120, and a region of less than 110. 6. The light irradiated on the skin surface, measuring step measures the light amount of diffusion, and when the light diffusion amount measured in step is prepared in advance threshold above with respect to the irradiation spots, the skin color unevenness is small A skin color unevenness evaluation method performed for cosmetic purposes, including an evaluation step of evaluating that the amount of light diffusion is smaller than a threshold prepared in advance for an irradiation spot, and evaluating that there is a lot of skin color unevenness.   The skin color unevenness evaluation method according to claim 6, wherein the irradiation light is monochromatic light. The light diffusion amount is a light diffusion area;
The skin color unevenness evaluation method according to claim 7, wherein the threshold value prepared in the evaluation step is a numerical value of a light diffusion area of 110 or more and 120 or less when a spot area which is an irradiation range of monochromatic light is set to 100.