JP3236731B2 - Skin surface analysis system and skin surface analysis method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skin surface analysis system and a skin surface analysis method, and more particularly, to a method for detecting the characteristics of the skin surface and analyzing and inspecting the unevenness of the skin surface and the reflection of light. The present invention relates to an analysis system and an analysis method.

[0002]

2. Description of the Related Art From the viewpoints of beauty and makeup, it is extremely important to evaluate and quantify skin properties and skin quality such as wrinkles and textures. Conventionally, as a method of detecting the skin surface shape, a replica method of transferring the skin surface using an appropriate material, a method of directly enlarging the skin surface with a camera or the like, and adopting an image obtained by these methods. Was visually observed and evaluated. These methods are often used because of their simplicity and convenience, but it has been difficult to capture complex skin surface shapes to minute points and objectively identify and quantify them. .

[0003] In recent years, in order to further extract the characteristics of the skin surface shape, various techniques for processing the skin surface information using a computer or the like and for digitizing or patterning the same have been developed. That is, image information obtained by imaging the skin surface or a replica thereof with an appropriate photoelectric conversion means is analyzed using a pattern processing program, and the skin surface shape and the like are objectively and quantitatively evaluated. For example, JP-A-60-
No. 53121 and JP-A-61-64232 disclose an apparatus that illuminates a skin replica with a plurality of light sources, extracts a pattern of the skin groove, and analyzes the skin groove interval and the skin groove direction. . Japanese Patent Application Laid-Open No. 64-59145 discloses a method of directly capturing an image from the skin surface without using a replica, binarizing the image, and performing pattern analysis. Japanese Patent Application Laid-Open Publication No. H11-163873 discloses a method in which a replica photographed image is subjected to gradation processing, and then subjected to image processing to obtain data on skin depth. Furthermore, Japanese Patent Application Laid-Open No. Sho 60-63030 discloses a method of monitoring a binarized image while changing a threshold level for a skin image and measuring a skin groove or wrinkle depth.

[0004]

The form of the skin is as follows:
There are wrinkles and textures (fine irregularities called skin crevices and skin crevices), and a number of conventional techniques are known for their morphological evaluation methods as described above. In these conventional techniques, the form of wrinkles, crevices, and crevices is directly measured or analyzed. On the other hand, what we perceive as wrinkles and textures with the naked eye is the difference in brightness between the bright and dark areas created by light hitting the unevenness of the skin, not the fine form itself. . However, none of the conventional skin surface analysis methods described above digitizes this sensory wrinkle or texture.

FIG. 1 schematically shows the appearance of unevenness on the skin surface. As shown in the figure, when light 102 from a certain direction hits the surface irregularities of the skin 101,
There is a portion 103 that is exposed to light and a portion 104 that is not exposed. Then, it is considered that a human recognizes a visual difference between the bright portion 103 to which the light hits and the dark portion 104 to which the light does not hit, that is, a difference in brightness as unevenness.

[0006] Generally, in order to make the skin look beautiful and healthy, wrinkles and textures are made fine and inconspicuous,
It is important to prevent sebum secreted on the skin surface from appearing as shiny. However, on the other hand, it is known that wrinkles and textures are also noticeable depending on the raw materials to be incorporated, even for foundations for adjusting skin color and covering spots and freckles. That is, in a foundation using a large amount of pigment having a high regular reflectance, when light is irradiated from one direction, a bright portion and a dark portion are clearly separated, and conversely, a large amount of a pigment having a large diffuse reflection is used. In the foundation, dark parts are also brightened by diffuse reflection, and the difference between light and dark is reduced, so that wrinkles and textures can be made inconspicuous.

Further, it is known that a problem of "makeup loss" occurs when a foundation is used. This “make-up loss” is mainly caused by sebum secreted on the skin surface, and can be roughly divided into four phenomena as follows. First, when sebum is secreted to the skin surface over time, the surface of the pigment is wetted by the sebum, the reflection of the pigment is lost, and the complexion feels dark. This is the first stage of "makeup loss",
It is called "color sinking" or "dullness." As described above, when the reflection of the pigment is eliminated, wrinkles and textures become noticeable. Then, as the sebum secretion further proceeds, the sebum itself causes specular reflection, creating a state called “shininess”. As the sebum is further secreted, the pigment on the skin sinks into the sebum or floats on the sebum. This is a state called “fat floating”. Further, in a moving part such as the outer corner of the eye or the mouth, a phenomenon called “sway” occurs. This is a state in which the pigment is partially removed and offset due to movement added to the “fat floating” state. As described above, the “makeup loss” includes the above 4
There are two phenomena, and among them, "shininess" and "fat float" are said to be the most important factors in making a user of the foundation recognize "makeup loss".

However, in order to develop a foundation that makes the skin look beautiful and healthy continuously, a new evaluation method for evaluating the foundation is required in addition to accurately grasping the characteristics of each raw material. Become. Therefore, the present invention objectively and quantitatively evaluates the visual roughness of the unevenness of the skin and the uniformity of the lightness distribution on the skin surface of “shininess” and “fat float” due to sebum secretion, that is, the optical beauty of the skin. An object of the present invention is to provide a skin surface analysis system and a skin surface analysis method to be quantified.

[0009]

In order to achieve the above object, the present invention takes the following measures. That is, a skin surface analysis system according to the present invention is a light-dark enhanced image capturing apparatus that captures a two-dimensional sample image in which the fine light-dark distribution of the sample skin surface is enhanced, and processes the two-dimensional sample image to process each pixel of the image. The lightness is compared with a predetermined threshold to separate white and black, and a high-luminance portion, which is a particle of a white portion, is extracted, and the particle analysis for measuring the total area and the number of the extracted particles is performed. The image processing device to be executed, the particle analysis results are totaled, arithmetic processing is performed, and the particle area ratio of the high-brightness portion is a characteristic value correlated to the uniformity of lightness on the skin surface, which is the optical beauty of the sample skin surface. a high-luminance portion area ratio of the area) × 100 or particles one per of the total area or measurement specified area in total) ÷ (the input image of the area of the extracted particles, the (extracted particles Is composed of a computation device for calculating the total) ÷ (total area or the number of measurements specified area of the area) ÷ (extracted particles of the input image) × 100 of the product. Further, the skin surface analysis method according to the present invention includes a procedure of capturing a two-dimensional sample image in which the fine light-dark distribution of the sample skin surface is emphasized, processing the two-dimensional sample image, and setting the brightness for each pixel of the image. Is compared with a predetermined threshold to separate into white and black, the procedure of extracting the high-brightness part which is the white part of the particle and performing the particle analysis, the particle analysis result is aggregated, arithmetically processed, and the sample skin surface Measuring the particle area ratio of the high-brightness portion, which is a characteristic value correlating to the brightness uniformity on the skin surface, which is optical beauty, or the high-brightness portion area ratio per particle described above. It is.

[0010]

According to the present invention having the above-described structure, a two-dimensional sample image in which even a slight contrast difference that cannot be captured by the naked eye is enhanced can be captured using the light-dark enhancement imaging apparatus. Then, by using this light-dark enhancement imaging device, a sample image can be obtained in which the difference between a bright part and a dark part formed by minute unevenness of the skin, that is, the appearance of wrinkles and textures is enhanced. In addition, since the light-dark enhancement imaging device is used, if there is a portion where the sebum secreted on the skin surface causes a glow or greasy glow, a sample image in which the glow or greasy glow is emphasized is also obtained. You can do it. Then, the two-dimensional sample image is processed, a high-luminance portion is extracted and subjected to particle analysis, and the particle analysis result is arithmetically processed to calculate a characteristic value correlated with the optical beauty of the sample skin surface. Therefore, the obtained characteristic value has a very high correlation with the sensory evaluation of the appearance of the skin, and it is possible to objectively quantify the appearance of the skin. It becomes.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 2 is a block diagram showing a basic configuration of the skin surface analysis system according to the present invention. As shown in the figure, this skin surface analysis system includes a light-dark enhancement imaging device (1), and captures a two-dimensional sample image in which a fine light-dark distribution on the surface of a sample skin (2) is enhanced. ing. This contrast enhancement imaging device (1)
Consists of a camera head (3) and a controller (4), and for example, "Super Eye C2847 (manufactured by Hamamatsu Photonics)" can be used. The camera head (3) is composed of an imaging tube having a wide dynamic range,
The controller (4) performs a differentiation process on the image pickup signal output from the camera head (3).
In other words, only the high frequency components are amplified so that fine details that cannot be normally observed with the naked eye can be clearly displayed. The differential time constant can be variably adjusted in multiple stages, and an optimal mode can be selected according to the spatial frequency of the subject.

An image recording device (5) such as a still video recorder is connected to the light / dark enhancement image pickup device (1), and two-dimensional image sample image data is recorded and stored by the image recording device (5). It has become. A signal conversion device (6) is connected to the image recording device (5). The signal conversion device (6) converts the two-dimensional sample image data recorded as a video signal into a graphic display of a computer. Is converted into an RGB signal suitable for the image processing.

Further, an image processing device / arithmetic device (7) is connected to the signal conversion device (6). The image processing device / arithmetic device (7) processes a two-dimensional sample image input in the form of an RGB signal, extracts a high-brightness portion, performs particle analysis, and performs arithmetic processing on the particle analysis result. To calculate a characteristic value correlated with the optical beauty of the surface of the sample skin (2). The characteristic value includes a high-luminance portion area ratio and a high-luminance portion area ratio per particle. More specifically, the image processing device / arithmetic device (7) comprises a combination of an image processor (8) and a host computer (9). The image processor (8) is, for example, an image analyzer NEXUS6.
800 (manufactured by NEXUS), which performs smoothing processing and the like for reducing noise of an input image, and extracts a high-luminance portion of the image to perform particle analysis. The host computer (9) controls the entire system, and also performs arithmetic processing of particle analysis results, data collection, and the like.

FIG. 3 shows an example of a two-dimensional sample image obtained by photographing the forehead portion after makeup is applied by the foundation with the light-dark enhancement image pickup device (1). As is clear from this figure, by performing differentiation processing on the video signal obtained from the camera head, it is possible to emphasize even a subtle difference in contrast that cannot be captured by the naked eye. Therefore, by using the light-dark enhancement imaging device (1), it is possible to obtain an image in which the appearance of wrinkles and textures, and the shine and oil floating due to sebum are enhanced.

For reference, FIG. 4 shows an example of an image obtained by normally photographing the surface of a sample skin. As is clear from the comparison of FIG. 3 with FIG. 3, in a normal photographed image, fine contrast of the skin surface cannot be recognized, and therefore, the appearance of wrinkles and texture and the appearance of shininess and oil floating due to sebum can be suppressed. No useful information can be obtained.

Next, the operation and use of the skin surface analysis system shown in FIG. 2 will be described in detail with reference to FIG. First, in step S1, a light-dark enhanced image of the surface of the sample skin (2) is captured by the light-dark emphasized imaging device (1). At this time, since the illuminance and the incident angle of the illumination light greatly affect the brightness of the captured image, it is preferable to perform the imaging after optimizing the illumination conditions for the surface of each sample skin (2). Next, in step S2, the two-dimensional sample image in which the fine light-dark distribution is emphasized is temporarily recorded and stored in the image recording device (5) as needed. Then, in step S3, the original video signal is converted to a signal conversion device (6).
After that, in step S4, a two-dimensional sample image is input to the image processor (8). Next, step S5
In, processing of the input two-dimensional sample image is performed, and smoothing processing and the like for reducing noise of the image are performed.

Next, in step S6, a measurement area is designated as required. The designation of the measurement area is performed when, for example, performing measurement on the same part of a two-dimensional sample image taken in time series, and using a keyboard or digitizer while observing the monitor of the image processor (8). Using it. For example, when investigating how the appearance of the skin to which the foundation has been applied changes over time, the detection sensitivity can be increased by specifying a completely overlapping area and performing measurement. is there.

Thereafter, in step S7, a binarizing process or a thresholding process is performed to extract a bright portion caused by minute irregularities and a high-brightness portion corresponding to a portion in which shine or grease is floated. This binarization process is performed by the image processor (8), and the brightness of each pixel of the image is compared with a predetermined threshold value to separate the pixel into white and black. Then, by this separation, individual high-luminance portions are emphasized and extracted, and so-called particles are obtained. FIG. 6 shows an example of an image of particles obtained by the binarization process. FIG. 6A is an image before the binarization process is performed, and a bright portion indicates a measurement region. FIG. 6B is a result of performing the binarization process on the above-described FIG. 6A, and a white portion is obtained by extracting a high luminance portion called a particle.

Next, a particle analysis is performed in step S8. That is, the total and number of the areas of the particles extracted as described above are measured, and when the measurement area is designated, the area of the measurement designated area is also measured.
Then, in step S9, the host computer (9) fetches the above-described measurement data from the image processor (8), and the ratio of the total area of the extracted particles to the entire area of the input image or the area of the measurement designated area ( Hereinafter, the area ratio of the high-luminance portion will be calculated. This high-luminance part area ratio is obtained by (total area of extracted particles) / (total area of input image or area of measurement designated area) × 100. In addition, an average ratio of the area per extracted particle to the entire area of the input image or the area of the measurement designated area (hereinafter, referred to as a high-luminance portion area ratio per particle) is calculated. The ratio of the high-luminance part area per particle is:
(Total area of extracted particles) ÷ (total area of input image or area of measurement designated area) ÷ (number of extracted particles) × 100.

Finally, in order to evaluate the skin surface analysis system and the skin surface analysis method according to the present invention, actual measurement data and evaluation results obtained by intuitively evaluating the degree of makeup loss by visual observation and actual feeling are used. The correlation was examined. First, two types of foundations, a commercial product and a prototype, were given to female subjects 5
It was applied to the left and right sides of the face of the name, and immediately after the application, 90 minutes after the application, and 3 hours after the application, a light / dark emphasized image of the forehead was taken. Canon macro lens FD10 as lens
A photographic illuminator using a 575 W metal halide lamp as a light source was used as illumination light.
The illuminance of the imaging part at this time was about 5000 lux.

At the same time as the photographing of the light-dark emphasized image, a questionnaire survey was conducted on the subject regarding makeup loss, and the degree of makeup loss was scored. The items used in the questionnaire survey were four phenomena indicating the state of makeup loss, and the respective items and scores indicating the degree were as shown in Table 1.

[0022]

[Table 1]

The above-mentioned various characteristic values were measured for the photographed differential weighted image of the forehead, and the correlation with the above-mentioned sensory evaluation was obtained. Table 2 shows the results.

[0024]

[Table 2] *: Significant with a risk factor of 5% or less

On the left side of Table 2, questionnaire items are shown, and on the right side, correlation coefficients between two characteristic values are shown. As can be seen from this table, the measured two characteristic values have a significantly higher correlation with the items of “shininess” and “fat lifting”, and therefore, have a correlation with the item related to the light reflection of the pigment. Was high. "Sinking" is a smaller change than "shine" and "fat float".
It is probable that the correlation was low because the item was hard to be recognized by the subject, and because "skew" was not an item related to the reflection of light of the pigment.

Next, from the correlation equation between “shininess” and “high-brightness area ratio”, which were particularly highly correlated in the above results, the “optical beauty of the skin surface” as a measure of “makeup loss” was obtained. Calculated. The correlation equation is given by 2.487 × (high-brightness area ratio) −0.6718.

The results of comparative evaluation of the above two types of foundations using this correlation formula are shown in the graph of FIG. In this graph, the horizontal axis represents the elapsed time after application of the foundation, and the vertical axis represents the “ratio of the optical beauty of the skin surface”. This ratio of optical beauty, for each foundation,
Images are taken immediately after the application and over time, and the “optical beauty of the skin surface” is calculated based on the above correlation equation, and then the ratio between the two is calculated. Therefore, this value represents the amount of change in the optical beauty of the skin surface immediately after the application of the foundation.

According to this graph, the change in the optical beauty of the skin surface immediately after the application is larger in the prototype than in the commercial product, and therefore, the "prototype" is larger in the prototype than in the commercial product. It can be seen that they tend to perform easily. This result was consistent with the result of the questionnaire survey described above.

[0029]

As described above, the present invention captures a two-dimensional sample image in which the fine light-dark distribution on the surface of the sample skin is emphasized, processes the image, and extracts a high-brightness portion to perform particle analysis. Is performed, and a predetermined characteristic value is calculated by performing arithmetic processing on the particle analysis result. However, regarding "shininess" and "fat lifting" in "makeup loss", since a significant correlation is recognized between the analysis result of the differential weighted image and the sensory evaluation, the present invention has Obviously, it is extremely useful as a means for objectively quantifying the optical beauty and as a means for objectively quantifying the effect of cosmetics on "make-up loss".

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating the appearance of wrinkles and textures on the skin surface.

FIG. 2 is a block diagram showing a basic configuration of a skin surface analysis system according to the present invention.

FIG. 3 is a photograph showing an example of a two-dimensional sample image in which light and dark fine distribution on the surface of a sample skin is emphasized.

FIG. 4 is a photograph showing an example of a normally photographed two-dimensional sample image of the sample skin surface.

FIG. 5 is a flowchart illustrating a procedure of a skin surface analysis method according to the present invention.

FIG. 6 is a photograph showing an example of an image before binarization processing and an image after binarization processing of a two-dimensional sample image in which the light and dark fine distribution on the sample skin surface is emphasized.

FIG. 7 is a graph showing the results of calculating changes in the optical beauty of the skin surface after application for two types of foundations.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Contrast-enhanced imaging device 2 Sample skin 3 Camera head 4 Controller 5 Image recording device 6 Signal conversion device 7 Image processing device / arithmetic device 8 Image processor 9 Host computer

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) A61B 5/107 H04N 7/18

Claims (3)

(57) [Claims] 1. A light-and-shade-enhanced image pickup apparatus for picking up a two-dimensional sample image in which a fine light-dark distribution on a sample skin surface is emphasized, processing the two-dimensional sample image, and setting the lightness of each pixel of the image to a predetermined threshold value An image processing apparatus that performs a particle analysis that separates into white and black in comparison with and extracts a high-brightness portion, which is a particle of a white portion, and measures the total area and the number of the extracted particles; The analysis results are tabulated and calculated, and the characteristic area that correlates to the uniformity of lightness on the skin surface, which is the optical beauty of the sample skin surface, is the particle area ratio of the high-brightness area. A skin surface analysis system comprising: an arithmetic unit that calculates (total) ÷ (total area of input image or area of measurement designated area) × 100 . 2. A light-dark emphasized image pickup device for picking up a two-dimensional sample image in which a fine light-dark distribution on a sample skin surface is emphasized, processing the two-dimensional sample image, and setting a lightness of each pixel of the image to a predetermined threshold value. An image processing apparatus that performs a particle analysis that separates into white and black in comparison with and extracts a high-brightness portion, which is a particle of a white portion, and measures the total area and the number of the extracted particles; The analysis results are tabulated and processed, and the characteristic value correlating with the uniformity of brightness on the skin surface, which is the optical beauty of the sample skin surface, is the ratio of the high-brightness area per particle. A skin surface analysis system comprising an arithmetic unit that calculates (total area) ÷ (total area of input image or area of designated measurement area) ÷ (number of extracted particles) × 100 . 3. A procedure for capturing a two-dimensional sample image in which the fine light-dark distribution on the surface of the sample skin is emphasized, processing the two-dimensional sample image, and comparing the brightness of each pixel of the image with a predetermined threshold value. The procedure to extract white and black parts and extract the high-brightness parts, which are white parts, to perform particle analysis.Then, the particle analysis results are aggregated, processed, and the skin, which is the optical beauty of the sample skin surface The characteristic value correlated with the uniformity of the brightness on the surface is the particle area ratio of the high-brightness part. (Total area of the extracted particles) / (the total area of the input image or the area of the designated measurement area) × 100 Or, the ratio of the high-luminance portion area per particle (total area of extracted particles) ÷ (total area of input image or area of measurement designated area) ÷ (number of extracted particles) × 100 To Skin surface analysis method comprising a step of measuring.