WO2007096812A1

WO2007096812A1 - A method of evaluating skin radiance

Info

Publication number: WO2007096812A1
Application number: PCT/IB2007/050488
Authority: WO
Inventors: Jérôme Senee; Camille Amar; Sophie Veyrat; Delphine Compan-Zaouati
Original assignee: L'oreal
Priority date: 2006-02-24
Filing date: 2007-02-14
Publication date: 2007-08-30

Abstract

The present invention relates to a method of evaluating the skin radiance of at least a portion of a subject's skin, the method comprising: i) determining at least first data relating to the level of saturation of at least one hue of the portion of the subject's skin; ii) determining at least second data relating to at least one first non-tinctorial characteristic of the skin of said subject; and iii) determining the skin radiance as a function at least of the first data and the second data.

Description

A METHOD OF EVALUATING SKIN RADIANCE

The present invention relates to evaluating skin radiance and to applications thereof.

European patent EP 0 655 221 Bl discloses an appliance that enables the internal color of the skin to be measured.

European patent applications EP 1 277 436 Al and EP 1 277 437 Al disclose devices that can be useful in evaluating characteristics associated with the radiance of the complexion.

Amongst other things, exemplary embodiments of the invention provide a method enabling skin radiance to be determined in a manner that is relatively precise and reproducible . Exemplary embodiments of the invention provide a method of evaluating the radiance of the complexion of a subject, comprising: i) determining at least first data relating to the level of saturation of at least one hue of at least a portion of the subject's skin; ii) determining at least second data relating to at least one first non-tinctorial characteristic of the skin of said subject; and iii) determining skin radiance as a function at least of the first data and the second data.

The term "data" should not be understood restrictively, and it covers any type of information, e.g. one or more numerical values and/or one or more digital and/or analog signals. The invention relies on the observation that combining at least first data relating to the level of saturation of at least one hue with second data relating to at least one non-tinctorial characteristic of the skin may provide information about skin radiance. Preferably, at least third data is determined relating to at least one second non-tinctorial characteristic of the portion of the subject's skin is determined, the second characteristic being different from the first characteristic.

Also preferably, at least fourth data is determined relating to at least one third non-tinctorial characteristic of the portion of the subject's skin is determined, the third characteristic being different from the first and second characteristics.

The first, second, and third non-tinctorial characteristics may advantageously be selected from the transparency, the brightness, and the uniformity of the skin .

The first, second, third, and fourth data may optionally be evaluated by means of at least one instrument . The evaluation may be carried out with the help of at least one expert, for example with a plurality of experts .

Hues The first data concerning color may relate to the level of saturation of at least two distinct hues of at least a portion of the subject's skin, and better at least three distinct hues.

These hues may be selected from pale pink, beige, and olive green.

Advantageously, the first data relates to the saturation levels of at least the pale pink hue, the olive green hue, and the beige hue.

The hues are characterized by the following L*a*b* values (given to within 15%) .

Using the beige and olive green saturation levels, a so-called pretty hue score can be calculated.

By way of example, this score is calculated as a linear combination of the saturation levels of the beige hue and of the olive green hue, using the following formula :

Score ',pretty hue a - b saturation levelolive green + c saturation levelbeige where a, b, and c are positive constants.

Using the saturation level of the pale pink hue, a so-called freshness score can be calculated. By way of example, this score is calculated by the formula :

^{S c o re} _{fre Shne S S} = s aturat i on_leve l_{pale pink}

The first data may be determined by visually observing the skin of the subject in comparison with a scale of hues, with evaluation being performed, for example, by at least one expert or by a panel of experts.

As a variant, or in addition, the first data relating to color can be determined automatically by image analysis, preferably after colorimetric calibration .

Preferably, when the evaluation is carried by at least one expert, it is carried out under predefined conditions, in particular in an air-conditioned atmosphere and with diffuse lighting.

Transparency

Transparency is defined as the ability to perceive small veins through the skin. High transparency is to be found with skins that are very fine.

Transparency can be measured at specific zones of the face, such as the forehead, the temples, the lower eyelids, and/or the oval portion of the face. Skin that is very transparent may present transparency like tracing paper or a baby's skin.

Skin that is not transparent is thicker and does not enable the underlying small veins to be seen.

By way of example, transparency can be quantified by a number level_transparency lying in the range 0 to 100, where 100 corresponds to maximum transparency.

Transparency may be evaluated by at least one practiced expert.

Transparency may also be evaluated by image analysis, or in a variant, optionally by means of an atlas having a plurality of images representative of different degrees of transparency.

Brightness Brightness is defined as being the intensity of highlights on projecting zones of the face such as cheek bones, the forehead, the nose, and the chin.

Brightness may be evaluated by at least one expert practiced in carrying out this evaluation. Brightness may also be measured by image analysis or by other methods involving instruments, e.g. by quantifying the specular reflection of light on certain zones of the image.

By way of example, brightness is quantified by a number level_brightness lying in the range 0 to 010, where 100 corresponds to maximum brightness.

Skin uniformity

Skin uniformity corresponds to the uniformity of the color and the texture of the skin. Skin uniformity can be evaluated by at least one expert or by image analysis, e.g. by analyzing the distribution of the intensity and of the color of reflected light.

Skin that is uniform in color does not present marks or red patches.

Texture uniformity corresponds to the extent to which the grain of the skin is more or less regular.

By way of example, skin uniformity is quantified by a number level_uniformity lying in the range 0 to 100, where 100 corresponds to skin that is very uniform, having no defects and presenting skin grain that is very regular.

Texture score

Using the transparency, brightness and uniformity scores, a so-called texture score can be calculated, e.g. using the following formula:

Score_texture = α level_{brightnes s} + β level_uniformity + γ level_transparency where CC, β, and γ are pos itive constants . For example CC > β > γ.

Skin radiance score

A skin radiance score (also called complexion radiance score) may be calculated for example from the various scores determined using the first, second, third, and optionally fourth data. The scores Score_texture, Score_{pretty hue}, Score_freshness can be plotted respectively on three axes of a rectangular frame of reference, defining the vertices of a triangle. This can make it possible to produce a representation that gives information quickly about the radiance of the complexion .

Such a representation of skin radiance can be used to reveal the effect of treatment on the radiance of the skin . The effect of the treatment can be determined for example by comparing triangles associated respectively with skin radiance before and after treatment.

A score Score_radiance can be calculated as being the area of the triangle whose vertices lie respectively to the coordinates Score_freshness, Score_{pretty hue}, and Score_texture .

Exemplary embodiments of the invention also provide a method enabling the effectiveness of a treatment and/or a composition to be revealed, the method comprising:

^• evaluating skin radiance of a subject by means of the evaluation method as defined above;

^• carrying out the treatment; and

^• evaluating skin radiance after the treatment by using the evaluation method as defined above.

The treatment may be a cosmetic treatment involving applying a cosmetic, or it may comprise taking food supplements .

The method may comprise supplying the subject with a medium carrying at least a first message relating to complexion radiance before treatment and at least a second message relating to complexion radiance after treatment, the second message serving, for example, to reveal a change in a skin radiance score before and after the treatment.

The medium may carry at least one message relating to the first, second, third, and optionally fourth data used for determining skin radiance. By way of example, the medium may have a reproduction of a hue scale, and markers indicating the saturation level of each hue.

The medium may also carry a brightness scale and a marker identifying a brightness score.

The medium may also carry a transparency scale and/or a skin uniformity scale, and markers identifying the transparency and uniformity scores.

Where appropriate, the medium may also carry a representation of the radiance of the complexion in the form of a triangle having its vertices with respective coordinates Score_freshness, Score_texture, and Score_{pretty hue} as defined above.

The medium may be a printed document or a computer medium, with the subject him- or herself viewing the content of the medium, e.g. at home.

Exemplary embodiments of the invention also provide a method of prescribing a cosmetic treatment and/or composition, the method comprising: i) evaluating skin radiance of a subject by implementing the method as defined above; and ii) prescribing at least one treatment and/or composition to the subject as a function of the evaluation carried out at i) . The prescription may be accompanied by sending or handing over a sample of the composition or the composition to the subject.

Exemplary embodiments of the invention also provide a product, e.g. a cosmetic, in packaging carrying at least one message relating to the effectiveness or incidence of the product on complexion radiance, for example as revealed by an evaluation method as defined above .

In another of its aspects, the invention also provides a method of promoting the sale of a cosmetic product or of tracking a treatment, the method consisting in establishing the incidence on complexion radiance of said product or treatment as revealed by an evaluation method as defined above.

The invention can be better understood on reading the following detailed description of non-limiting implementations thereof, and on examining the accompanying drawings, in which:

^• Figure 1 is a block diagram showing the different steps of an example of the method of the invention;

^• Figure 2 shows an example of representative scores that can be calculated during an evaluation;

• Figure 3 is a block diagram showing an example of a system suitable for use in implementing the method of the invention;

^• Figures 4 and 5 are views analogous to Figure 1, showing other implementations of the invention;

^• Figures 6 and 7 show examples of how the effects of a treatment on the radiance of the complexion can be represented;

^• Figure 8 shows a scale of hues that can be used for evaluating complexions;

^• Figure 9 shows an example of a medium that can be used for promoting a composition or a treatment, and/or that can be handed to a person being evaluated; and

^• Figure 10 shows an example of packaging including information relating to radiance of complexion.

Figure 1 shows different steps in an example of the method of the invention for evaluating the radiance of the complexion.

The method may comprise, in a step 10, acquiring first data concerning the level of saturation of at least one hue of at least a portion of the skin of a subject, in particular of the face, preferably the levels of saturation of a plurality of hues, which in the example under consideration are pale pink, beige, and olive green. The level of saturation can be determined by means of a hue evaluation system 11 shown diagrammatically in Figure 3.

By way of example, the evaluation system 11 includes a scale of hues 12 as shown in Figure 8, including a plurality of color charts corresponding respectively to the different hues, and for each color chart to increasing levels of saturation for the hue in question. The scale 12 may have graduations 13 specifying the level of saturation.

When a scale of hues 12 as shown in Figure 8 is used, evaluation may be carried out under predefined conditions, for example in an air-conditioned cabin with lighting adapted to the subject, in particular diffuse lighting of the daylight type, by one or more experts who can determine the level of saturation for each of the hues while having the scale of hues visible and while observing the subject.

In a variant, or in addition, hues may be evaluated by means of a device for acquiring and analyzing at least one digital image of at least a portion of the skin of the subject under conditions that enable colorimetric measurement to be performed.

At the end of step 10, three numerical values may be determined in the range 0 to 100, for example, quantifying respectively the saturation levels of the various hues.

Starting from those numerical values, at least two scores can be calculated, in particular, for example: -a Score_freshness equal to the level of saturation of the pale pink hue on the hue scale; and

^• a Score_{pretty hue} equal to: a - b saturation_level_{ollve green} + c saturation_level_beige where a, b, and c are positive constants. When the saturation levels vary over the range 0 to 100, the following apply, for example: a = 101.420 b = 0 . 4 6 c = 0 . 539

The method may also include a step 20 of acquiring second data relating to a characteristic of the skin that is not tinctorial, e.g. its transparency. This characteristic may be evaluated by at least one practiced expert and/or with a system 21 for evaluating transparency, e.g. relying on image analysis, with the color of pixels being analyzed in order to detect the presence of small veins in particular.

At the end of step 20, a transparency score can be determined.

In the example described, the method further includes a step 30 of acquiring third data, relating to brightness.

This third data may be determined by at least one practiced expert or by means of a brightness evaluation system 31.

The evaluation system 31 may rely on image analysis, in particular in order to detect and possibly quantify the presence of bright zones on projecting portions of the face .

The method may also include a step 40 of acquiring fourth data, relating to the uniformity of the skin. Skin uniformity may be evaluated by means of at least one expert or by a skin uniformity evaluation system 41, e.g. based on image analysis.

Thus, at the end of step 40, a texture score can be determined in a step 50 as follows: Score_texture = α level_brightness + β level_uniformity + γ level_transparency where CC, β, and γ are positive constants.

When the brightness, transparency, and uniformity levels vary over the range 0 to 100, then the following can apply, for example:

CC = 4.354 β = 3.768 γ = 1.856

The various scores may be calculate by means of a processor unit 80, for example, which unit may be associated where appropriate with display means 81, printer means 82, and a server 83.

By way of example, the processor unit 80 comprises a microcomputer or a portable terminal, suitable for running a program for calculating the various scores.

Where appropriate, the processor unit 80 performs a portion only of the operations, with the remainder of the operations being performed by the server 83.

By way of example, the processor unit 80 can act as a user interface for inputting observed data, which data is then transmitted to the server 83 that returns information relating to the radiance of the complexion. Where appropriate, the system for evaluating hues, transparency, brightness, and uniformity of the skin can be integrated with the processor unit within a microcomputer or a special appliance. The result of evaluating skin radiance may be delivered in a step 60 to the user in a variety of forms.

In an exemplary implementation of the invention, a score representing skin radiance is determined as being the area of a triangle whose vertices have respective coordinates Score_freshness, Score_{pretty hue}, and Score_texture in a rectangular frame of reference, as shown in Figure 2.

Skin radiance can thus be evaluated in step 70 as a numerical value, however in a variant information relating to skin radiance can be delivered to the user in some other form, e.g. an alphanumeric character or a pictogram or in some other way.

Once skin radiance has been determined, treatment can be prescribed in a step 100, as shown in Figure 4.

By way of example, the treatment may consist in proposing one or more kinds of makeup and/or care products to a subject, or one or more food supplements and/or one or more treatments such as massaging. Determining skin radiance can also be useful for determining the effectiveness of a treatment, as shown in Figure 5.

Under such circumstances, in a first step 110, the radiance of the skin is determined, and than a treatment is performed in a step 120, and the radiance of the skin is determined again in a step 130.

By comparing the results in a step 140, it is possible to reveal the effect of the treatment. The treatment may be cosmetic or dermatological, for example applying makeup or a care product or medication.

By way of example, results may be compared by a representation of triangles that correspond respectively to the radiance of the complexion as evaluated before treatment and after treatment, as shown in Figure 6. Where appropriate, these illustrations can be used as media for promoting a product or a treatment.

It is also possible, as shown in Figure 7, to show the relative change in each of the scores together with the corresponding triangles.

Figure 9 shows a medium 150 that can be used for example in promoting a product or to show the result of evaluation relating to a given subject.

A photograph 151 of the subject, taken at different moments in time, may appear on the medium 150 together with the result of evaluating hue saturation levels, for example by reproducing the hue scale of Figure 8 and using markers 152 to mark the saturation levels for each of the hues. The brightness, transparency, and uniformity levels, and the intermediate pretty hue, texture, and freshness intermediate scores 153 can be marked by markers 154 on scales for each evaluation date, or in a variant they can be marked by numerical values. A skin radiance score 152 can be given, possibly together with information 156 quantifying the variation in skin radiance compared with an initial state and/or an earlier evaluation.

Figure 10 shows a cosmetic, dermatological, or food product in packaging 190 that includes at least one message 191 relating to the change in skin radiance that might be obtained by using the product.

For example this may be in the form of a number relating to the skin radiance score obtained on one or more tested subjects. The invention is not limited to the examples described above.

For example, hues other than those mentioned can be used, for example depending on the illumination to which the subject is exposed while being evaluated. The term "comprising a" should be understood as being synonymous with "comprising at least one", unless specified to the contrary.

Claims

1. A method of evaluating skin radiance of at least a portion of the skin of a subject, the method comprising: i) determining at least first data relating to the level of saturation of at least one hue of the portion of the subject's skin; ii) determining at least second data relating to at least one first non-tinctorial characteristic of the skin of said subject; and iϋ) determining the skin radiance as a function at least of the first data and the second data.

2. A method according to claim 1, the first data relating to the level of saturation of at least two distinct hues of the portion of the subject's skin.

3. A method according to claim 1, the first data relating to the level of saturation of at least three distinct hues of at least a portion of the subject's skin.

4. A method according to claim 2 or claim 3, the hues being selected from pale pink, beige, and olive green.

5. A method according to any preceding claim, at least third data being determined relating to at least one second non-tinctorial characteristic of the portion of the subject's skin.

6. A method according to the preceding claim, at least fourth data being determined relating to at least one third non-tinctorial characteristic of the portion of the subject's skin.

7. A method according to the preceding claim, the first, second, and third non-tinctorial characteristics being selected from the transparency, the brightness, and the uniformity of the skin.

8. A method according to claim 7, transparency being measured on at least one of the forehead, the temples, and/or a bottom eyelid and/or the oval part of the face.

9. A method according to claim 7, brightness being measured on at least one of the following: the cheek bones, the forehead, the nose, and/or the chin.

10. A method according to claim 6, the first, second, third, and fourth data being instrumentally evaluated.

11. A method according to claim 6, the first, second, third, and fourth data being evaluated without using instruments.

12. A method according to the preceding claim, the evaluation being carried out with the help of at least one expert.

13. A method according to claim 1, the first data being determined automatically by image analysis.

14. A method according to claim 1, the first data being determined by observing the skin of the subject and comparing it with a hue scale.

15. A method according to claim 4, in which starting from the saturation levels of beige and olive green hues, a so-called pretty hue score is calculated.

16. A method according to claim 15, in which the pretty hue score is calculated by a linear combination of the saturation levels of the beige and olive green hues, using the following formula:

Score_{pretty hue} = a - b saturation_level_{ollve green} + c saturation_level_beige where a, b, and c are positive constants.

17. A method according to claim 4, in which starting from the saturation level of the pale pink hue, a so-called freshness score is calculated.

18. A method according to the preceding claim, in which the score is calculated using the following formula:

^ScOrefre_Shne_SS = saturation_level_{pale pink}

19. A method according to claim 7, in which starting from the levels of transparency, brightness, and uniformity, a so-called texture score is calculated using the following formula:

^Scθretexture = α level_brightness + β level_uniformity + γ level_transparency

20. A method according to claim 5 or claim 6, in which a skin radiance score is calculated from the various scores determined using the first, second, third, and optionally fourth data.

21. A method according to claims 16, 18, and 19, in which the scores Score_texture, Score_{pretty hue}, and Score_freshness are plotted on three respective axes of a frame of reference.

22. A method according claims 16, 18, and 19, in which a score Score_radiance is calculated as being the area of the triangle whose vertices have respective coordinates

^ScOrefre_Shne_SS' ^ScOre _Pretty hue' ^{and ScOre}texture ^•

23. A method for revealing the effectiveness of a composition and/or a treatment, the method comprising: ^• evaluating the skin radiance of a subject using the evaluation method as defined in any one of claims 1 to 22; ^• carrying out the treatment; and

^• evaluating the skin radiance after the treatment using said evaluation method.

24. A method according to claim 23, including supplying a medium to the subject, the medium carrying at least first information relating to the skin radiance before treatment and at least second information relating to the skin radiance after treatment.

25. A method according to claim 23 or claim 24, in which the medium includes a representation of skin radiance in the form of a triangle whose vertices have respective coordinates Score_freshness, Score_texture, and Score_{pretty hue} .

26. A method of prescribing a cosmetic treatment and/or composition, the method comprising: i) evaluating the skin radiance of a subject by implementing the method as defined in any one of claims 1 to 22; and ii) prescribing at least one treatment and/or composition to the subject as a function of the evaluation undertaken in i) .

27. A cosmetic product in packaging including at least one message relating to the effectiveness of the product on the skin radiance , as revealed by a method as defined in any one of claims 1 to 22.