JP2008029578A - Skin character evaluation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate the evaluation of the surface hardness and internal hardness of the skin mechanically and objectively, which can be conducted independent of a cosmetic expert. <P>SOLUTION: A recess is generated on the skin by pressurizing the skin surface by external force such as the jetting of a compressed gas; the spread of the recess is measured by photographing it with a camera; the depth is measured by a displacement gauge, and thus the surface hardness and internal hardness of the skin are evaluated. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a skin property evaluation method for independently evaluating the surface hardness and internal hardness of skin.

  In order to evaluate the surface characteristics against skin stress, a method is proposed in which compressed gas is injected into the measurement area of the skin surface, the surface displacement is measured optically, and the relationship between the time since injection and the surface displacement is examined. (Patent Document 1, Patent Document 2).

  According to this method, compared to the conventional method for evaluating the elasticity of the skin, in which the mechanical stress is directly applied to the skin and the displacement is measured, the skin is not in contact with the subject without causing discomfort. It is possible to evaluate the elasticity, flexibility, slackness, etc. of the skin.

Japanese Patent Laid-Open No. 61-238224 JP 2004-108794 A

  Conventional methods for evaluating skin surface characteristics against stress include skin elasticity, flexibility, looseness, etc., combining the skin surface from the outermost surface of the skin to the dermis and the inside of the subcutaneous tissue side. It was something to evaluate.

  On the other hand, the present inventors, when a skin care beauty specialist examines the skin hardness of an unspecified number of subjects by palpation, the skin hardness is determined by sliding the finger on the skin surface. There are skin surface hardness evaluated by pressing and skin internal hardness evaluated by pushing the skin surface with a finger, and FIGS. 3A to 3F and these are superimposed on one figure, As shown in FIG. 4, which shows the average values for each age, teenagers tend to have harder surfaces and interiors than older people, and tend to become softer as they age. In addition, it was found that the surface becomes harder than the inside as the aging progresses. Here, these figures show that three skin care beauty professionals have 110 subjects in their teens to 60s as subjects, and for each subject, the surface hardness and the internal hardness are 5 grade scores of 1 to 5, respectively. In this case, the average of the scores of three people is plotted.

  The tendency of the surface and the interior to soften with age is that the skin in the 60s with a surface hardness score of 4 and an internal hardness score of 4 in contrast to the skin in the 20s with a surface hardness score of 2 and an internal hardness score of 2 Then, when the compressed gas is blown onto the cheek, the dent is large, the elasticity is poor, and this corresponds to the slack. In addition, skin in the 60s having a surface hardness score of 2 and an internal hardness score of 4 has hardness less than that of the inside, and at the same time, the texture disappears and the skin surface tends to have gloss.

  Therefore, it is desirable to analyze from the two aspects of surface hardness and internal hardness even in the case of mechanically objectively evaluating the surface characteristics of the skin against stress for cosmetic purposes.

  Therefore, an object of the present invention is to make it possible to independently evaluate the surface hardness and the internal hardness of a skin mechanically and objectively without depending on a skin care beauty specialist.

  The present inventors measured the spread and depth of the dent of the skin that occurs when the skin is momentarily pressed with an external force such as compressed gas, and based on the measurement value, the skin care beauty specialist The present inventors have found that evaluation values corresponding to the evaluation of surface hardness and internal hardness can be calculated.

  That is, the present invention generates a dent in the skin by pressing the skin surface with an external force, and calculates the evaluation value of the skin surface hardness and the evaluation value of the internal hardness based on the spread and depth of the dent. To provide a skin property evaluation method for cosmetic purposes.

Further, as a system for suitably carrying out this method, the present invention provides an external force applying means for pressing an evaluation site of the skin with an external force,
At least when the skin is pressed, a camera that captures an image of the evaluation site of the skin, a displacement meter that measures the surface displacement of the skin, and image processing of the image captured by the camera, and measures the spread of the skin dent caused by the pressing And a skin property evaluation system comprising a computing means for calculating an evaluation value of the surface hardness and internal hardness of the skin based on the measurement value of the spread of the skin dent and the measurement value of the depth of the dent of the skin by a displacement meter. provide.

  According to the skin property evaluation method of the present invention, the hardness of the skin can be mechanically and objectively evaluated from two surfaces of the surface hardness and the internal hardness, regardless of a skin care beauty specialist. Therefore, it is possible to analyze in more detail skin properties important for cosmetics such as elasticity, flexibility, looseness, tension, wrinkles, texture, etc. from young to old.

  Further, according to the skin property evaluation system of the present invention, in the skin property evaluation method of the present invention, the skin dent caused by pressing is taken with a camera, and the skin dent is measured by image processing of the photographed image. Moreover, since the depth of the dent of the skin at that time is measured with a displacement meter, it becomes possible to implement the skin property evaluation method of this invention more simply.

  Hereinafter, the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an example of an evaluation system 100 that implements the evaluation method of the present invention. The evaluation system 100 includes an injection nozzle 1 as one of external force applying means for applying an external force to the evaluation site S on the skin surface. In addition, the high-speed camera 11 that images the evaluation site S, the laser displacement meter 12 that measures the surface displacement of the evaluation site S, and the measurement unit 10 that incorporates the illumination means 13, and the operation timing thereof are controlled. Computation means 20 for calculating evaluation values of the surface hardness and internal hardness of the skin, and a face fixing means 30 as the evaluation site S, the computation means 20 includes images taken by the high-speed camera 11, A display 21 for displaying calculation processing results and the like is connected.

  Here, as the illuminating means 13, in order to avoid an increase in skin temperature, it is preferable to use one that does not easily transmit heat to the skin. In this evaluation system 100, a metal halide can be used as a light source. Further, the illumination means 13 preferably has a higher illuminance than the case of shooting with a normal camera in response to the fast shutter speed by the high-speed camera 11, and the illumination direction is the normal direction of the evaluation part S It is preferable that

  The fixing means 30 comprises a chin rest and a forehead.

  In this evaluation system, the evaluation site S is not particularly limited as long as it is a skin surface, and may be bare skin or makeup skin depending on the evaluation purpose, and even on the face, arms, shoulders, chest, back, abdomen, thighs. Part, calf part and other parts.

  The injection nozzle 1 injects a compressed gas that does not harm the body such as air, nitrogen, carbon dioxide, etc. to such an extent that the skin surface as the evaluation site S is temporarily recessed. A storage chamber 2 for storing, a limiter 3 for adjusting the pressure in the storage chamber 2 to a predetermined pressure, and an operation switch 5 are provided. By turning on the operation switch 5, the pressure of the compressed gas increases, It is ejected from the ejection nozzle 1.

  It is preferable that the pressure of the compressed gas in the air storage chamber 2 and the opening area of the injection nozzle 1 are appropriately changed according to the evaluation site S. For example, when the cheek of a human face is used as the evaluation site S, the gas pressure in the air storage chamber 2 is preferably 0.01 to 0.5 MPa, and the opening diameter of the injection nozzle 1 is preferably 0.5 to 10 mm. In addition, when the body part such as the arm, shoulder, chest, back, abdomen, thigh, calf or the like is used as the evaluation site, it is preferable to increase the gas pressure and the opening diameter of the injection nozzle 1.

  Since the injection nozzle 1 injects the compressed gas to the evaluation site S without diffusing as much as possible, the tip has a throttle structure. The installation angle of the injection nozzle 1 is preferably such that the compressed gas is injected from the normal direction with respect to the evaluation site S.

  The distance between the injection nozzle 1 and the evaluation site S is preferably 0.5 to 100 mm, although it depends on the evaluation site and the injection pressure. The injection time is preferably 0.1 to 0.5 seconds.

  In the evaluation system of the present invention, as an external force applying means for pressing the evaluation site S of the skin, instead of the injection nozzle 1 for injecting compressed gas, the injection nozzle for injecting water and the skin with a predetermined pressure by a spring are used. You may provide the rod-shaped body etc. which enabled it to press.

  The high-speed camera 11 continuously takes high-speed images immediately before the injection nozzle 1 injects the compressed gas to the evaluation site S, during and after the injection, and applies the compressed gas to the evaluation site S. Appears by spraying, and disappears immediately or quickly when the spraying is stopped (usually within 0.2 seconds after stopping the spraying). The preferred shooting timing after the start of jetting of compressed gas is the state where the dent of the skin is maximized, and at least when the compressed gas is jetted, the compression is performed to find the state where the dent of the skin is maximized. It is preferable to take images before and after gas injection. According to the high-speed camera, the change of the skin dent can be easily tracked, and an image in a state where the dent is maximized can be easily taken. On the other hand, it is possible to take an image at the timing using a normal camera by checking in advance the preferable shooting timing after the start of the injection of the compressed gas.

  In addition, in order to take a dent on the skin surface in an image, a reference point or a reference line may be attached to the skin surface in advance so that the spread of the dent on the skin surface can be measured by their movement or distortion. As described above, when measuring the spread of a dent from a ring-like gloss caused by a dent on the skin surface, a high-speed camera capable of capturing such a gloss on an image is used. More specifically, the high-speed camera 11 is preferably a digital camera having a resolution of 100 to 150 pixels / inch and a shutter speed of 60 frames / second or more, and preferably capable of taking both still images and moving images.

  A plurality of high-speed cameras 11 may be provided as necessary, and three-dimensional information may be obtained regarding the shape of the dent due to the injection of compressed gas.

  The laser displacement meter 12 is preferably one that uses a laser of CLASS 2B or lower as a light source from the viewpoint of less injuries to the skin. For example, a red LED can be used as the light source. Also, a high-precision CCD type is desirable because of its high measurement accuracy.

  In the present invention, as a displacement meter, in addition to a laser displacement meter, a displacement meter using ultrasonic waves, a displacement meter using infrared rays, or the like may be used.

  The imaging direction of the high-speed camera 11 is preferably the normal direction of the evaluation region S, the laser displacement meter 12 is preferably directly facing the displacement surface of the evaluation region S, and the above-described injection of the injection nozzle 1 Since it is preferable that all of the direction and the illumination direction of the illumination means 13 be the normal direction of the evaluation site S, it is preferable to integrate them in the measurement unit 10.

  The calculation means 20 controls the operation timing of the high-speed camera 11 and the laser displacement meter 12 and starts the high-speed camera 11 and the laser displacement meter 12 in synchronization before and after the injection of the compressed gas from the injection nozzle 1.

  Further, the calculation means 20 performs image processing on the image taken by the high-speed camera 11 and measures the spread of the dent of the evaluation part S caused by the pressing, and the measurement value and the evaluation part S of the evaluation part S by the laser displacement meter 12 are measured. Based on the measurement value of the depth of the dent, evaluation values of the surface hardness and internal hardness of the skin are calculated.

  As image processing of an image taken by the high-speed camera 11, for example, as shown in FIG. 2A, when a ring-like gloss appears in the evaluation site S by pressing, first, the image is converted to gray scale, Remove noise as needed. Next, the luminance distribution is measured as shown in FIG. 2 (b), and the distance between two points where the luminance change greatly changes due to the ring-like gloss as the diameter of the dent by pressing as shown in FIG. 2 (c). Measure and set the area of the circle corresponding to this diameter as the recessed area. In addition, when the magnitude | size of ring-shaped glossiness changes during injection of compressed gas, it is desirable to use the maximum value as a diameter and an area of a dent. When the ring-like gloss appears in an elliptical shape, the distance between two points on the ring-like gloss is measured from a plurality of directions.

  As the measured value of the depth of the skin dent by the laser displacement meter 12, for example, the maximum amount of dent displacement or the amount of displacement for a predetermined time from the injection of compressed gas is used as the measured value.

  Evaluation value of skin surface hardness and evaluation of internal hardness from measured value of spread of skin dent by image taken by high speed camera 11 and measured value of skin dent depth measured by laser displacement meter 12 As an analysis method for calculating the value, for a plurality of subjects, a score value of surface hardness and a score value of internal hardness are obtained in advance by palpation of a skin care beauty specialist, Measure the skin dent spread and skin dent depth as described above, and use the surface hardness score value and internal hardness score value as objective variables. The multivariate analysis is performed using the measured depth value as an explanatory variable. In this case, as the explanatory variable, in addition to the diameter, area, and depth of the recess, a variable related to the shape change such as the recess volume derived from these may be used.

  The evaluation value of the surface hardness of the skin thus calculated corresponds to a hardness of about 2 mm from the outermost surface of the skin to the dermis, and the internal hardness is the hardness on the dermis side. However, it does not mean the hardness when the skin surface and the inside are strictly separated by a certain depth, and when skin care beauty professionals evaluate skin hardness by palpation It corresponds to subjective surface hardness and internal hardness.

  This skin hardness evaluation value and internal hardness evaluation value are completely new evaluation indices for skin surface properties that have not been known so far, and are used to investigate the effects of cosmetics and skin care techniques on the skin. It is also useful for developing cosmetics and skin care techniques and for applying to beauty advice.

Example 1
110 subjects in their 10s to 60s were subjects, and the face was washed with water, and then the cheeks with lotion applied were used as evaluation sites. The surface hardness and internal hardness of this evaluation site were evaluated by 5 skin care beauty professionals in 5 stages of 1 to 5, respectively, and the average of the 3 evaluation values was used as a score by palpation of the evaluation site. .

  On the other hand, the evaluation system shown in FIG. 1 injects compressed gas to each evaluation site, and images the dent produced by that with a high-speed camera (NAC MEMRECAMfxRX-5, 512x484pixel, 500fps) and a laser displacement meter (KEYENCE LK -G157) measured the amount of dents. In this case, the diameter of the injection nozzle was 1.5 mm, the pressure of the compressed gas in the storage chamber was 0.8 atm (0.08 MPa), and the distance between the evaluation site and the injection nozzle was 65 mm.

  In the calculation means, the image taken with the high-speed camera is converted to gray scale, and it is confirmed that the ring-like gloss is generated on the depressed skin by the injection of the compressed gas, and the image at the time when the ring-like gloss is maximized. The diameter of the dent was measured based on the luminance above, and the area of the dent was calculated from the obtained diameter.

  The skin surface hardness score and the internal hardness score by palpation are the objective variables, and the maximum diameter of the dent, the area, the maximum displacement of the depth, the area of the circle ÷ the maximum displacement is explained by the stepwise method. A random analysis was performed.

  as a result,

A highly reliable multiple regression equation was obtained.

  Thereby, it can be seen that, for each of the surface hardness and the internal hardness, the score by the beauty specialist can be predicted from the measurement of the expansion (diameter, area) and the depth of the dent caused by the injection of the compressed gas.

Apart from the above-mentioned test subjects, as shown in Table 1, the surface hardness score and the internal hardness score are obtained by a beauty specialist for the five test subjects A to E in their respective ages from 10 to 50 in the same manner as described above. The surface hardness score and the internal hardness score were calculated from the obtained regression equations. The results are shown in Table 1.

  From Table 1, it can be seen that, for each subject, the magnitude relationship based on the palpation value of the surface hardness and the internal hardness matches the magnitude relationship based on the calculated value.

Comparative Example 1
In Example 1, a regression equation was obtained using only the depth of the recess as an explanatory variable. As a result, the regression equation is

Thus, the reliability of the regression equation was greatly reduced.

Comparative Example 2
In Example 1, the regression equation was obtained using only the expansion of the dent as an explanatory variable. As a result, the regression equation is

Thus, the reliability of the regression equation was greatly reduced.

  The skin property evaluation method and system of the present invention enables mechanical and objective numerical evaluation of the surface hardness and internal hardness of the skin, and is useful for the development and promotion of cosmetics and skin care methods.

It is a schematic block diagram of the evaluation system of skin surface property. It is explanatory drawing of the measuring method of the diameter of the dent of skin. It is a scatter diagram of surface hardness and internal hardness by palpation of teenage skin. It is a scatter diagram of surface hardness and internal hardness by palpation of skin in 20s. It is a scatter diagram of surface hardness and internal hardness by palpation of 30's skin. It is a scatter diagram of surface hardness and internal hardness by palpation of skin in 40s. It is a scatter diagram of surface hardness and internal hardness by palpation of skin in the 50s. It is a scatter diagram of surface hardness and internal hardness by palpation of skin in the 60s. It is a scatter diagram of surface hardness and internal hardness by palpation of skin of teens to 60s.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Injection nozzle 2 Air storage chamber 3 Limiter 5 Operation switch 6 Cylinder part 10 Measuring part unit 11 High speed camera 12 Laser displacement meter 13 Illumination means 20 Calculation means 21 Display 30 Fixing means 100 Evaluation system S Evaluation part

Claims (4)

  Skin property for cosmetic purposes, where the skin surface is dented by pressing the skin surface with external force, and the evaluation value of the surface hardness of the skin and the evaluation value of the internal hardness are calculated based on the spread and depth of the dent Evaluation methods.   The external force is a compressed gas, the spread of the dent generated in the skin when the compressed gas is injected is measured by photographing with a camera, and the depth of the dent generated in the skin when the compressed gas is injected is measured with a displacement meter. Skin property evaluation method.   The skin property evaluation method according to claim 1 or 2, wherein the skin hardness and internal hardness scores obtained by palpation correspond to the evaluation values of the skin hardness and internal hardness, respectively. An external force applying means for pressing the evaluation site of the skin with an external force,
At least when the skin is pressed, a camera that captures an image of the evaluation site of the skin, a displacement meter that measures the surface displacement of the skin, and image processing of the image captured by the camera, and measures the spread of the skin dent caused by the pressing A skin property evaluation system comprising a computing means for calculating evaluation values of the surface hardness and internal hardness of the skin based on the measured value of the spread of the skin dent and the measured value of the depth of the dent of the skin by a displacement meter.