JP7749366B2 - How to evaluate chapped lips - Google Patents

Description

The present invention relates to a method for evaluating chapped lips.

Lips contribute greatly to a person's impression and are an important part of daily life and beauty, but they have a weak barrier function and are prone to roughness such as dryness and peeling.

Conventionally, methods for evaluating chapped lips are known, such as those described in Non-Patent Documents 1 to 3.

Tatsuya Himeno et al., "Development of a new evaluation method for chapped lips," Abstracts of the 56th SCCJ Research Symposium, 2005, pp. 20-23 Ikuko Ueda et al., "Research on Chapped Lips and Carbonylation-Modified Proteins in Lip Corneal Cells," Abstracts of the 62nd SCCJ Symposium, 2008, pp. 21-24 "Objective evaluation method for dry lips and its causes," by Eriko Tomoki et al., Journal of the Japanese Society of Cosmetic Chemistry, 2018, Vol. 42, No. 1, pp. 1-8

Lip balms and other products are used to reduce chapped lips, but there are cases where the improvement effect is not satisfactory. The inventors conducted a more detailed study of chapped lips to see if a more detailed classification of chapped lips would allow them to propose an appropriate improvement method for each condition. They discovered that even lips that are free of peeling and have a clean appearance can be classified into several types of chapped lips. They also found that the conventional methods described in Non-Patent Documents 1 to 3 are not suitable for classifying chapped lips without peeling.

Accordingly, the object of the present invention is to provide a method for classifying the condition of chapped lips that is free of peeling and has a clean appearance.

That is, the present invention is as follows.
[1]
Step 1: Evaluating the presence or absence of lip peeling from the visible light irradiation image;
Step 2: Evaluating the luminance value of the lips from the UV-illuminated image;
A method for evaluating chapped lips, comprising:
[2]
The method for evaluating chapped lips according to [1], wherein step 2 is carried out after step 1.
[3]
The method for evaluating chapped lips according to [1] or [2], wherein an image of the lower lip exposed to ultraviolet light is used in step 2.
[4]
The method for evaluating chapped lips according to any one of [1] to [3], wherein the ultraviolet irradiation image is an image obtained by irradiating ultraviolet light containing 365 nm light.
[5]
The method for evaluating chapped lips according to any one of [1] to [4], wherein in step 2, the brightness value is evaluated from the ultraviolet irradiation image of the lower lip of the subject who did not have peeling in step 1.
[6]
The method for evaluating chapped lips described in [5], wherein in step 2, the luminance value of the lips is evaluated using a luminance area ratio, which is the ratio of the area showing a luminance value equal to or greater than a luminance threshold to the total area of the lower lip.
[7]
The method for evaluating chapped lips according to [6], wherein in step 2, the luminance value of the lips is evaluated based on the magnitude of the luminance area ratio relative to a luminance area ratio threshold.
[8]
The method for evaluating chapped lips according to [6] or [7], wherein the brightness threshold is any one point in a range of 70 to 80.
[9]
The method for evaluating chapped lips according to any one of [6] to [8], wherein the brightness threshold is 75 and the brightness area ratio threshold is any one point in a range of 5 to 15%.
[10]
A method for determining a brightness threshold value for the method for evaluating chapped lips according to [6] or [7].
[11]
A method for determining a luminance area ratio threshold for the lip chapped mouth evaluation method described in [7].
[12]
A lip counseling method comprising the method for evaluating chapped lips according to any one of [1] to [11].
[13]
The lip counseling method according to [12], which comprises recommending a lip cosmetic and/or topical preparation following the method for evaluating chapped lips according to any one of [1] to [11].

The present invention provides a method for classifying the condition of chapped lips that are free of peeling and have a clean appearance.

1 is a schematic diagram showing an example of a method for evaluating chapped lips according to the present embodiment, and is an explanatory diagram of the evaluation of chapped lips in Example 1. FIG. 1 is a diagram illustrating the evaluation of the presence or absence of peeling in step 1. 10A and 10B are diagrams illustrating evaluation of the luminance value of the lips from the ultraviolet irradiation image in step 2. (a) is the acquired ultraviolet irradiation image, (b) is an image with the lower lip cut out, and (c) is an image binarized using a luminance threshold value. 10A and 10B are diagrams illustrating evaluation of the luminance value of lips from an ultraviolet light irradiation image in step 2. (a) is an image of the subject's lips irradiated with visible light, (b) is an image irradiated with ultraviolet light, and (c) is an image binarized using a luminance threshold value. 10A and 10B are diagrams illustrating evaluation of the luminance value of lips from an ultraviolet light irradiation image in step 2. (a) is an image of the subject's lips irradiated with visible light, (b) is an image irradiated with ultraviolet light, and (c) is an image binarized using a luminance threshold value. 10 is a table showing the results of Example 2. It is a table showing the agreement rate between the luminance threshold and the luminance area ratio threshold and the evaluation by the expert evaluator. 1 is a table showing the results of Example 3. 1 is a table showing the results of Example 6.

The method for evaluating chapped lips of this embodiment includes step 1, which evaluates the presence or absence of chapped lips from an image illuminated with visible light, and step 2, which evaluates the luminance value of the lips from an image illuminated with ultraviolet light. The evaluation method of this embodiment may further include other steps, such as measuring lip parameters.

The order of Step 1 and Step 2 above is not particularly limited, but it is preferable to perform Step 2 after Step 1, as the analysis to determine whether or not the skin has peeled is easier in Step 1.

(Step 1)
In the above step 1, the presence or absence of chapped lips is determined from the visible light irradiation image. Note that the presence or absence of chapped lips may be determined in addition to visual determination.

In step 1, if peeling is found in even one spot on the lip in the visible light irradiation image, it is determined that peeling is present (FIG. 2).
Normally, old keratinocytes remain on the lips without peeling, resulting in thickened areas, which then peel. Peeling refers to a state in which even a portion of the skin on the lip surface has peeled, including complete peeling and peeling only at the edges. In the three circular lines in Figure 2, the area within the large central circular line is the area where the skin has completely peeled, and the area within the small circular line on the right is the area where only the edges have peeled.
The assessor who judges whether or not peeling occurs may be, for example, a specialist assessor of lips. For example, when the assessment is performed by three assessors (preferably specialist assessors), peeling may be determined to occur if all assessors judge that peeling occurs.

The visible light irradiation image is not particularly limited as long as it is an image that can be used to evaluate chapped lips, and may be an image taken using a digital camera or the like under appropriate lighting.
The visible light irradiation image may be an image captured under the same conditions as the ultraviolet light irradiation image described below, except for changing the illumination conditions. For example, the visible light irradiation image and the ultraviolet light irradiation image may be acquired using different devices, or may be acquired using the same device (e.g., VISIA-CR (manufactured by Canfield Scientific)).

The brightness during shooting is preferably 500 to 2000 lux. The image is preferably an image of 3 million pixels or more (preferably 15 million pixels or more) (for example, an image of 2736 pixels or more horizontally and 1824 pixels or more vertically, with the face occupying 50 to 90% (preferably 60 to 80%) of the 100% image area).
When multiple subjects are evaluated, it is preferable that the images of all subjects are taken under the same conditions.

The visible light irradiation image is not particularly limited, and can be, for example, an image taken in the past, an image taken at a location different from the location being evaluated, an image containing multiple people, etc.

Subjects are not particularly limited as long as they are humans, and can be male or female. There are also no particular limitations on the age of the subject.

(Step 2)
In step 2, the luminance value of the lips is evaluated from the ultraviolet light irradiation image. Step 2 may be performed on subjects who are determined not to have peeling in step 1.
In the ultraviolet irradiation image, it can be evaluated that areas with high brightness indicate chapped lips, and areas with low brightness indicate no chapped lips.

The ultraviolet irradiation image may be an image captured under moderate ultraviolet irradiation. The ultraviolet light preferably contains at least a wavelength of 400 nm or less, and more preferably contains a wavelength of 365 nm.

In step 2 above, it has been reported that chapped lips occur specifically on the lower lip, so it is preferable to use an ultraviolet image of the lower lip to enable more accurate classification.

The above brightness values can be determined by converting the UV-irradiated image into a 256-level image. Specifically, they can be determined using the method described in the Examples below.

When capturing UV-illuminated images, a brightness reference scale is placed near the lips to capture the images, reducing blurring between subjects and enabling more accurate analysis of brightness values.

In step 2, the ultraviolet light image is analyzed to evaluate the luminance value of the lips. A preferred method for evaluating the luminance value is to use the luminance area ratio (area showing luminance values above the luminance threshold/total area of the lower lip x 100) (%) as an index, which is the ratio of the area showing luminance values above the luminance threshold to the total area of the lower lip. The higher the luminance area ratio, the more chapped the lips can be evaluated to be.
For example, by analyzing the luminance area ratio of lips from UV-illuminated images of multiple subjects and comparing the luminance area ratio values, it is possible to compare the degree of lip chappedness. This makes it possible to evaluate the degree of chapped lips even among subjects with clean, unpeeled lips, and to propose lip beauty methods and moisturizers that are suitable for each subject.
The area showing a luminance value equal to or greater than the luminance threshold is the total area of the sections of the lower lip that show a luminance value equal to or greater than the luminance threshold when the luminance value is measured for each section of the lower lip. Note that in the above analysis, one section may be one pixel of the lower lip image, or multiple pixels (for example, 2 to 100 pixels).
The brightness values may be measured in the same manner for all subjects, by cutting out a target area (e.g., the lower lip) from the ultraviolet light image and measuring the brightness value of each section using image analysis software. ImageJ is preferably used as image processing software for analyzing brightness values.

In step 2, the method for evaluating the luminance value is preferably to evaluate the luminance value of the lips from the magnitude of the luminance area ratio relative to a luminance area ratio threshold.
For example, a one-variable scatter plot can be created in which the luminance area ratios of multiple subjects are plotted on the vertical axis, and the subjects can be divided into a group with higher values than the luminance area ratio threshold and a group with lower values. By adjusting the luminance area ratio threshold, it becomes possible to classify the subjects into groups with less roughness and groups with more roughness, and it becomes possible to classify the lips according to the proposed lip beauty method, moisturizer, etc.

The method for determining the brightness threshold value of this embodiment is the method for determining the brightness threshold value in the method for evaluating chapped lips of this embodiment described above.The method for determining the brightness area ratio threshold value of this embodiment is the method for determining the brightness area ratio threshold value in the method for evaluating chapped lips of this embodiment described above.The brightness threshold value and the brightness area ratio threshold value may be determined separately or simultaneously.
The luminance threshold and/or the luminance area ratio threshold may be determined based on characteristics related to the lips.

If the brightness threshold is set low, the brightness area ratio will be calculated including small brightness values, and the subject can be classified based on the brightness area ratio calculated including relatively low brightness values in the ultraviolet irradiation image. For example, when proposing a beauty treatment that can be applied to a wide range of lips, from those with severe chapped lips to those with almost healthy lips, the target subject can be classified by setting the brightness threshold low.
On the other hand, if the brightness threshold is set high, subjects can be classified based on the brightness area ratio calculated from only the significantly high brightness values in the ultraviolet irradiation image. For example, when proposing a cosmetic treatment that can be applied to a clean, unpeeled lip with severe chapped lips, the target subjects can be classified by setting the brightness threshold high.
Furthermore, if there is a beauty treatment method to be proposed to a subject who has a high proportion of area showing brightness values in a specific range, it is possible to set two brightness thresholds and classify only subjects who show a brightness area proportion between the thresholds.
The brightness threshold may be one or more. By providing a plurality of brightness thresholds, the state of chapped lips without peeling can be classified in more detail.

The brightness threshold is preferably any point in the range of 60 to 90, more preferably any point in the range of 70 to 80, and even more preferably 75, from the viewpoint of being able to more accurately distinguish between classifications based on visual and palpation evaluations of "lips that are taut, dry to the touch, and not moist," and classifications based on the fact that moisture content remains the same but the amount of moisture evaporation differs.

By lowering the brightness area ratio threshold, it is possible to classify subjects into a range of subjects having a relatively low brightness area ratio in the ultraviolet irradiation image to subjects having a high brightness area ratio. For example, when proposing a beauty treatment that can be applied to a wide range of lips, from those with severe chapped lips to those with almost healthy lips, it is possible to classify the target subjects by lowering the brightness area ratio threshold.
By increasing the brightness area ratio threshold, it is possible to classify subjects with a significantly high brightness area ratio in the ultraviolet irradiation image. For example, when proposing a cosmetic treatment applicable to a clean, unpeeled lip with severe chapped lips, it is possible to classify the target subject by increasing the brightness area ratio threshold.
Furthermore, if there is a beauty method that is recommended to subjects whose brightness area ratio falls within a specific range, it is possible to set two brightness area ratio thresholds and classify only subjects whose brightness area ratio falls between the thresholds.
The brightness area ratio threshold may be one or more. By providing a plurality of brightness area ratio thresholds, the state of chapped lips without peeling can be classified in more detail.

The brightness area ratio threshold is preferably any one point in the range of 5 to 20%, more preferably any one point in the range of 5 to 15%, and even more preferably 10%, from the viewpoint of being able to more accurately distinguish between classifications based on a visual and palpation evaluation of "lips that are taut, dry to the touch, and not moist" and classifications based on the fact that the moisture content remains the same but the amount of moisture evaporation is different.
It is also preferable that the brightness threshold is 75 and the brightness area ratio threshold is any one point in the range of 5 to 15%.

The sum of the brightness threshold and the brightness area percentage threshold (%) is preferably 65 to 110, more preferably 75 to 95, and even more preferably 80 to 90, from the perspective of being able to more accurately classify the condition of chapped lips that have a clean, unpeeled appearance.

As a criterion for determining the brightness threshold and/or the brightness area ratio threshold, for example, parameters of the lips can be used.
The following are examples of decisions:

The present inventors have investigated the classification of lips with a clean appearance by expert evaluators, and have found that by combining visual evaluation and palpation evaluation, even among lips with a clean appearance, there is a tendency for lips to be divided into those in a chapped state (state B) and those in a healthy state (state C).The inventors have found that the criteria for this classification are "lips that are taut, dry to the touch, and do not feel moist."
Then, by comparing a one-variable scatter diagram in which the luminance area ratio of multiple subjects is plotted on the vertical axis with the classification based on the above criteria, it was found that the luminance area ratio was high in condition B and low in condition C. In other words, the luminance area ratio tended to be higher the more taut and dry the lips were.
The brightness threshold and the brightness area ratio threshold can be determined so as to increase the coincidence rate with the classification of condition B and condition C by a specialist lip evaluator using the above criteria.
By setting this threshold, it becomes possible to suggest lip cosmetic methods, moisturizers, etc. that are suitable for each condition based on the image alone, without the need for visual or tactile evaluation by a specialist evaluator.

The inventors further investigated the characteristics of lips that are free of peeling and have a clean appearance, and found that although the moisture content is the same between the group with a high luminance area ratio and the group with a low luminance area ratio, the group with a high luminance area ratio tends to have a high TEWL rate, while the group with a low luminance area ratio tends to have a low TEWL rate. They also found that a positive correlation was observed in a scatter diagram in which the luminance area ratio was plotted on the vertical axis and the TEWL rate on the horizontal axis.
The brightness threshold and the brightness area ratio threshold can be set based on the value of the amount of water evaporation. For example, the amount of water evaporation of lips with a clean appearance and no peeling of a plurality of people (e.g., 100 people) can be measured, a standard of the amount of water evaporation that shows a significant difference between a group with high water evaporation and a group with low water evaporation can be set, and a brightness value or a brightness area ratio corresponding to the standard can be set as the threshold.
By setting this threshold, it is possible to classify subjects who have the same moisture content but high moisture evaporation rates from images alone, without measuring moisture content or moisture evaporation rates, and to suggest appropriate lip beauty methods, moisturizers, etc.
The moisture content and evaporation rate of moisture on the lips can be measured by the method described in the Examples below.

The inventors further investigated the characteristics of lips that are free of peeling and have a clean appearance, and found that the group with a high luminance area ratio tends to have high elasticity (Δf), and the group with a low luminance area ratio tends to have low elasticity (Δf).
The brightness threshold and the brightness area ratio threshold can be set based on the value of elasticity (Δf). For example, the elasticity (Δf) of lips with a clean appearance and no peeling of multiple people (e.g., 100 people) can be measured, a standard of elasticity (Δf) that shows a significant difference between a group with high elasticity (Δf) and a group with low elasticity (Δf) can be set, and a brightness value or brightness area ratio corresponding to the standard can be set as the threshold. Alternatively, a standard can be set so that the difference in Δf value between a group with high elasticity (Δf) and a group with low elasticity (Δf) is 20 or more (preferably 30 or more), and a brightness value or brightness area ratio corresponding to the standard can be set as the threshold.
By setting this threshold, subjects with high elasticity (Δf) can be classified from images alone without measuring elasticity (Δf), making it possible to suggest appropriate lip beauty methods, moisturizers, etc.
The elasticity (Δf) can be measured by the method described in the examples below.

The lip chappedness evaluation method, brightness threshold determination method, and brightness area ratio threshold determination method of this embodiment can be used, for example, to classify lips that are free of peeling and have a clean appearance, and to suggest beauty treatments and cosmetic products that are suitable for the subject.

The above-described method for evaluating chapped lips may involve, for example, determining a brightness threshold and a brightness area ratio threshold in advance from UV-irradiated images of multiple subjects (e.g., 100 subjects), and then evaluating the subject's chapped lips using the method for evaluating chapped lips of this embodiment. The subject's measurements and photographed images may be input into a database, and the measurements and photographed images may be added to the database each time a new subject is measured. By determining the thresholds in advance, it becomes possible to evaluate the lips of even remotely located subjects using only images irradiated with visible light and UV light. A system for processing measurements may be created, and the measurements and photographed images may be stored in a database, improving the accuracy of lip classification. The measurement values of a remotely located subject may be evaluated using the database and system, and the association data between the previously determined chapped lip classification and lip cosmetics and/or topical preparations may also be used to display recommended lip cosmetics and/or topical preparations that can be recommended to the remotely located subject, enabling counseling suggestions, including recommendations for beauty treatments and beauty products.
Furthermore, lip chappedness trends can vary by region and time of year. For example, by changing the threshold for each region and time of year, it becomes possible to suggest beauty methods and beauty products that are appropriate for each region and time of year.
Furthermore, in the method for evaluating chapped lips of this embodiment, one type of evaluation may be performed using one combination of a brightness threshold and a brightness area ratio threshold from one visible light irradiation image and one ultraviolet light irradiation image, or multiple types of evaluation (e.g., evaluation of water evaporation rate and elasticity) may be performed simultaneously using multiple combinations of brightness thresholds and brightness area sum thresholds.
Furthermore, as for the recommended lip cosmetics and topical preparations, for example, for subjects in the group in which peeling is observed in visual and palpable evaluation, the surface is hard, and the moisture content is low, it is preferable to apply a preparation or drug that replenishes moisture; specifically, it is preferable to apply an aqueous component, a water-retaining substance, or a substance that has high lip permeability; and for example, for subjects in the group in which a slight dry feeling is felt in visual and palpable evaluation and the amount of moisture evaporation is high, it is preferable to apply a preparation or drug that has high moisture occlusion properties in order to suppress the amount of moisture evaporation; specifically, it is preferable to apply a preparation composed of an oil or film that is difficult for water to pass through, or a substance that does not easily absorb water, although these are not particularly limited.

The lip counseling method of this embodiment includes the above-described lip chapped evaluation method of this embodiment. For example, after evaluating lip chappedness, a lip counseling method may be proposed based on the evaluation result of lip chappedness.
The above-mentioned counseling method includes suggesting lip cosmetics and topical preparations, etc., explaining the subject's current lip condition, giving advice on improving the lip condition, etc. The above-mentioned counseling may be carried out in the same place as the subject or from a remote location.

The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

Example 1
The three subjects, A, B, and C, were evaluated for lip chappedness using the following method.
Visible light and ultraviolet light images of each subject were obtained using a VISIA-CR (manufactured by Canfield Scientific). The images were acquired with the lighting mode set to Standard 1 or UV Fluorescence and a resolution of approximately 20 million pixels.
The presence or absence of peeling was determined from the obtained visible light irradiation image. "Peeled" refers to a state in which even a portion of the skin on the surface of the lips has peeled. The circled areas in Figure 2 are areas where peeling has occurred. Peeling was observed in subject A, while subjects B and C did not have peeling (Figure 1). Figure 2 is an enlarged view of the lips of subject A with peeling.
Next, for two subjects B and C without peeling, brightness values were evaluated using UV-irradiated images as follows. The lower lip portion was cut out from the UV-irradiated image, and the brightness of each pixel was measured using the image analysis software "ImageJ" (Figures 1 and 3). Brightness was determined by converting the brightness of the image into a 256-level grayscale image. Specifically, analysis was performed using the Color Threshold function of ImageJ.
The brightness values were then binarized using a brightness threshold of 75 (Figure 3). The brightness area ratio for each subject was then calculated using the following formula:
Brightness area ratio (%) = area showing a brightness value of 75 or more / total area of lower lip × 100
The subjects were then classified into Subject B (Fig. 4) with a high luminance area ratio (35.04%) and Subject C (Fig. 5) with a low luminance area ratio (0.09%).

After classification, a professional evaluator visually evaluated the lips of the three subjects and confirmed that peeling was only observed in subject A. Furthermore, the professional evaluator conducted visual and palpation evaluations and found that subject B's lips were taut, dry to the touch, and not moist, while subject C's lips were healthy. Based on the above evaluations, lips with a clean appearance and no peeling could be classified.
Furthermore, when the transpiration water loss (TEWL) and elasticity (Δf) of subjects B and C were measured using the methods described below, subject B had higher values in both cases.

Example 2
The lip chapping of 57 subjects (25 men and 32 women) in their 20s to 50s was evaluated four times at different times.
In the same manner as in Example 1, images of each subject exposed to visible light and ultraviolet light were obtained, and the presence or absence of peeling was determined from the images exposed to visible light.
The luminance values of the lips of a total of 141 subjects who did not have peeling in the visible light irradiation images were evaluated in the same manner as in Example 1.
The brightness threshold was set to 55, 60, 70, 75, 80, and 90, and the brightness area ratio threshold was set to 2.5%, 5%, 7.5%, 10%, 12.5%, 15%, 17.5%, and 20%, and analysis was performed for each. After analysis at each threshold, subjects were classified into a group whose brightness area ratio was equal to or greater than the brightness area ratio threshold and a group whose brightness area ratio was less than the brightness area ratio threshold. Furthermore, all subjects who did not experience peeling underwent visual and tactile evaluation by a specialist evaluator, and were classified into a group whose "lips were taut, dry to the touch, and not moist" (condition B) and a group whose lips were in a healthy condition (condition C).
The agreement rate, which is the ratio of the total number of subjects who had peeling above the brightness area ratio threshold and who were evaluated by the expert evaluator as being in condition B to the total number of subjects who had peeling below the brightness area ratio threshold and who were evaluated by the expert evaluator as being in condition C, was calculated using the following formula.
Matching rate (%) = {(Number of subjects whose brightness area ratio is equal to or greater than the threshold and whose expert evaluator's evaluation is condition B) + (Number of subjects whose brightness area ratio is less than the threshold and whose expert evaluator's evaluation is condition C)} / Total number of subjects without peeling × 100
The results are shown in Figure 6. In the figure, "-" indicates that the evaluation was not performed.
The highest agreement rate with the expert evaluator's condition B-C classification was achieved when the luminance threshold was 75 and the luminance area ratio threshold was 10%. In particular, when the sum of the luminance threshold and the luminance area ratio threshold was 82.5 to 90, the agreement rate was extremely high at 83% or more.

Example 3
Except for setting the brightness threshold to 75 and the brightness area ratio threshold to 10%, subjects were classified in the same manner as in Example 2. They were then classified into those with peeling (Group A), those without peeling and a brightness area ratio threshold of 10% or more (Group B), and those without peeling and a brightness area ratio of less than 10% (Group C).
In addition, visual evaluation, palpation evaluation, moisture content, transpiration water loss (TEWL), and elasticity (Δf) were measured for all subjects using the methods described below. The results are shown in Figure 7.
Although the average moisture content of Group B was the same as that of Group C, the average water loss was significantly higher. Although no significant difference in elasticity (Δf) was confirmed between B and C, a tendency of Group A > Group B > Group C was observed.

Example 4
For subjects who did not have peeling in the visible light irradiation image of Example 2, the moisture content and moisture evaporation rate were measured using the same method as in Example 3. Then, the brightness threshold and brightness area ratio threshold were set so that there was no change in moisture content and a significant difference in moisture evaporation rate, and the brightness threshold was 75 and the brightness area ratio threshold was 10%.

Example 5
For subjects who did not have peeling in the visible light irradiation image of Example 2, Δf was measured in the same manner as in Example 3. Then, the brightness threshold and brightness area ratio threshold were set so that there would be a significant difference in Δf between the group with brightness area ratio equal to or greater than the threshold and the group with brightness area ratio less than the threshold, and the brightness threshold was found to be 80 and 15%.

Example 6
Six subjects were evaluated for chapped lips for 12 consecutive days.
For the evaluation of chapped lips, subjects were classified in the same manner as in Example 2, except that the brightness threshold was set at 75 and the brightness area percentage threshold was set at 10%. Subjects were then classified into those with peeling (Group A), those without peeling and a brightness area percentage threshold of 10% or more (Group B), and those without peeling and a brightness area percentage of less than 10% (Group C).
The results are shown in Figure 8. In the figure, "-" indicates that the evaluation was not performed.

[evaluation]
The evaluations in each example were carried out by the following methods.

(1. Visual Evaluation)
After the three expert evaluators shared a baseline lip condition in advance, they visually evaluated the subject's lips based on their impression when visually inspecting them, using the following criteria. The scores were determined through discussion between the three expert evaluators.
It should be noted that visual evaluation can miss some marks, so even if the method for evaluating lip peeling from an image irradiated with visible light shows "peeling present," the visual evaluation may result in a rank of 4 or lower. Therefore, even if peeling is present in the image irradiated with visible light, the visual evaluation value is ranked 5 or lower (FIG. 7).
-standard-
1: No dryness is observed, moisturized feeling, no roughness is observed 2: No dryness is observed, slight moisturized feeling, no roughness is observed 3: No dryness is observed, no roughness is observed 4: Slight dryness is observed, but no roughness is observed 5: Slight peeling is observed, and roughness due to dryness is observed 6: Peeling is observed, and more severe dryness and roughness are observed 7: Clear peeling is observed, and even more severe dryness and roughness are observed

(2. Palpation Evaluation)
After three expert evaluators shared the standard lip surface smoothness in advance, they evaluated the smoothness of the lips by palpation based on the impression they got when touching the lip surface of the subject, using the following criteria. The scores were determined after consultation between the three expert evaluators.
-standard-
1: Moisture-rich, chewy texture, but not dry and smooth 2: Moisture-rich, moist texture, but not dry and smooth 3: No dryness, not dry and smooth 4: Slight dryness, but not dry and smooth 5: Slight dryness, with a rough, flaky texture 6: Dryness, with a rough, flaky texture 7: Very dryness, with a rough, flaky texture

(3. Moisture content)
The moisture content of the central part of the lower lip was measured using a Skin Moisture Sensor MY-808S (manufactured by Scalar Corporation) under the conditions of a temperature of 22±2°C and a humidity of 50% RH.
The measurement was carried out five times, and the average value of three measurements excluding the maximum and minimum values was used.

(4. Water Evaporation Amount)
The amount of water loss from the center of the lower lip was measured using a VAPOMETER (Delfin) in STD mode with a nail probe at a temperature of 22±2°C and a humidity of 50% RH.
The measurement was carried out five times, and the average value of three measurements excluding the maximum and minimum values was used.

(5. Elasticity Evaluation)
The elasticity of the center of the lower lip was measured using a VENUSTRON (manufactured by AXIOM). The frequency change (Δf) when the device was penetrated 2 mm at 2 mm/s was measured.
The measurement was carried out 10 times, and the five measured values were selected so as to minimize the standard deviation, and the average value was adopted.

Claims (7)

Step 1: Evaluating the presence or absence of lip peeling from the visible light irradiation image;
Step 2: Evaluating the luminance value of the lips from the ultraviolet irradiation image of the lower lip of the subject who did not have peeling in Step 1 ;
and
In step 2 , a method for evaluating chapped lips is characterized in that the brightness value is evaluated from the ultraviolet irradiation image, and the brightness value of the lips is evaluated using a brightness area ratio, which is the ratio of the area showing a brightness value equal to or greater than a brightness threshold to the total area of the lower lip. The method for evaluating chapped lips according to claim 1, wherein the ultraviolet irradiation image is an image acquired by irradiating the skin with ultraviolet light containing 365 nm light. A method for evaluating chapped lips according to claim 1 or 2, wherein in step 2, the lip luminance value is evaluated based on the magnitude of the luminance area ratio relative to a luminance area ratio threshold. The method for evaluating chapped lips according to any one of claims 1 to 3, wherein the brightness threshold is any one point in the range of 70 to 80. The method for evaluating chapped lips according to claim 3 or claim 4 that cites claim 3, wherein the brightness threshold is 75 and the brightness area ratio threshold is any one point in a range of 5 to 15%. A method for determining a brightness threshold for the method for evaluating chapped lips according to any one of claims 1 to 5, comprising any one of the following methods (i) to (iii):
(i) The amount of water evaporation from lips with a clean appearance and no peeling was measured on multiple subjects, a standard for the amount of water evaporation that shows a significant difference between a group with high water evaporation and a group with low water evaporation was set, and the brightness value corresponding to this standard was set as the threshold value. Here, the amount of water evaporation was measured at the center of the lower lip using a VAPOMETER (registered trademark) in STD mode with a nail probe under conditions of a temperature of 22±2°C and a humidity of 50% RH.
(ii) The elasticity (Δf) of lips with a clean appearance and no peeling was measured on multiple subjects, and a standard for elasticity (Δf) that resulted in a significant difference between a group with high elasticity (Δf) and a group with low elasticity (Δf) was set, and the brightness value corresponding to this standard was used as the threshold value. Here, the elasticity (Δf) was defined as the value measured for the change in frequency (Δf) when a VENUSTRON (trademark ) probe (manufactured by AXIOM) was inserted 2 mm into the center of the lower lip at a speed of 2 mm/s.
(iii) The elasticity (Δf) of lips with a clean appearance and no peeling was measured for multiple subjects, and a standard was set so that the difference in Δf values between a group with high elasticity (Δf) and a group with low elasticity (Δf) was 20 or more, and the brightness value corresponding to this standard was used as the threshold value. Here, the elasticity (Δf) was defined as the value measured for the change in frequency (Δf) when a VENUSTRON (trademark) ( manufactured by AXIOM) was inserted 2 mm into the center of the lower lip at 2 mm/s. A method for determining a luminance area ratio threshold for the lip chapped evaluation method according to any one of claims 1 to 5, comprising any one of the following methods (i) to (iii):
(i) The amount of water evaporation from lips with a clean appearance and no peeling was measured on multiple subjects, a standard for the amount of water evaporation that resulted in a significant difference between a group with high water evaporation and a group with low water evaporation was set, and the brightness area ratio corresponding to this standard was set as the threshold value. Here, the amount of water evaporation was measured at the center of the lower lip using a VAPOMETER (registered trademark) in STD mode with a nail probe under conditions of a temperature of 22±2°C and a humidity of 50% RH.
(ii) The elasticity (Δf) of lips with a clean appearance and no peeling was measured on multiple subjects, and a standard for elasticity (Δf) that resulted in a significant difference between a group with high elasticity (Δf) and a group with low elasticity (Δf) was set, and the brightness area ratio corresponding to this standard was used as the threshold value. Here, the elasticity (Δf) was defined as the value measured for the frequency change (Δf) when a VENUSTRON (trademark ) probe (manufactured by AXIOM) was inserted 2 mm into the center of the lower lip at a speed of 2 mm/s.
(iii) The elasticity (Δf) of lips with a clean appearance and no peeling was measured for multiple subjects, and a standard was set so that the difference in Δf values between a group with high elasticity (Δf) and a group with low elasticity (Δf) was 20 or more, and the brightness area ratio corresponding to this standard was used as the threshold. Here, the elasticity (Δf) was defined as the value measured for the change in frequency (Δf) when a VENUSTRON (trademark) ( manufactured by AXIOM) was inserted 2 mm into the center of the lower lip at 2 mm/s.