METHOD FOR CHARACTERIZING THE TONE OF THE SKIN AND INTEGUMENTS

• US 20120300050A1
• Filed: 05/17/2012
• Published: 11/29/2012
• Est. Priority Date: 05/27/2011
• Status: Active Grant

• Current Assignee: Lvmh Recherche
• Original Assignee: Lvmh Recherche
• Inventors: KORICHI, Rodolphe, STEPHAN, Sandrine
• Granted Patent: US 9,064,180 B2
• Time in Patent Office: Days
• US Class Current: 348/77
• CPC Class Codes: A61B 5/0059 using light, e.g. diagnosis by transillumination, diascopy, fluorescence A61B5/0093, A61B5/1455, A61B5/02416 and A61B5/0261 take precedence
• CPC Class Codes: A61B 5/441 Skin evaluation, e.g. for skin disorder diagnosis
• CPC Class Codes: G01J 3/462 Computing operations in or between colour spaces; Colour management systems
• CPC Class Codes: G01J 3/463 Colour matching
• CPC Class Codes: G01J 3/513 having fixed filter-detector pairs
• CPC Class Codes: G06T 2207/10024 Color image
• CPC Class Codes: G06T 2207/30088 Skin; Dermal
• CPC Class Codes: G06T 7/90 Determination of colour characteristics
• CPC Class Codes: G06V 10/56 relating to colour
• CPC Class Codes: H04N 21/40 Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
• CPC Class Codes: H04N 21/42204 User interfaces specially adapted for controlling a client device through a remote control device; Remote control devices therefor constructive details of casings for the remote control device H01H9/0235; user interfaces for controlling a tuning device of a television receiver through a remote control H03J9/00; remote control of peripheral devices connected to a television receiver through the remote control device of the television receiver H04B1/205
• CPC Class Codes: H04N 21/42214 using alphanumerical characters

Abstract

A method and apparatus for characterizing the tone of the skin or integuments uses an apparatus capturing a digital image of a skin zone. The image is defined by a multiplicity of pixels (N) and transmitted to a digital image processing device for splitting the digital image into R, G and B colour planes. The apparatus includes means for extracting each of these planes R, G, B; and on each plane, calculation means for logging the grey level value for each of the pixels, i.e. N values, which are optionally processed to obtain a value characteristic of the grey levels for each plane, corresponding to a value characteristic of the colour; as well as the luminosity value L*. The apparatus also characterizes the tone of the skin or integuments on the basis of the combination of the value characteristic of the colour and of the Luminosity value L*.

Claims

1. A method for characterizing the tone of the skin or integuments of a person, comprising:

capturing a digital colour image of at least one zone of the skin or integuments, said image comprising a number N of pixels, each pixel having a grey level;

extracting the three colour planes from said colour image named Red (R), Green (G), and Blue (B);

evaluating the colour of the skin or integuments from the value of the grey level of each pixel from at least some of the N pixels of the image for each colour plane of at least two colour planes of the three colour planes R, G, B;

evaluating the Luminosity L* from the value of the grey level of each pixel from at least some of the N pixels of the image for each colour plane of at least two colour planes of the three colour planes R, G, B; and

characterizing the tone of the skin or integuments ensuing from both said evaluation of the colour of the skin or integuments and of said evaluation of the luminosity L*.

2. A method for characterizing the one of the skin or integuments of a person, comprising the following steps:

a) capturing at least one digital colour image of at least one determined zone of skin or of integuments, said image being defined by a multiplicity (N) of pixels, each pixel having a grey level, with the aid of a digital camera or a digital photographic apparatus, and transmitting said digital colour image to a digital image processing device for processing and recording said at least one digital image therein;

b) splitting the digital colour image thus recorded into three colour planes;

a red plane R, a green plane G, and a blue plane B, with said digital image processing device;

c) extracting each of these planes R, G, B; and

calculating and logging, with said digital processing device, on each plane the grey level value for each of the N pixels, providing N grey level values, which are optionally processed mathematically by mathematical calculation means, to obtain at least one value selected from a graphical grey value, a statistical grey value, at least one average grey value characteristic of the grey levels for each plane, corresponding to a grey value characterizing the colour of the skin;

d) evaluating the Luminosity L* from the value of the grey level resulting from at least some of the N pixels of the image for each colour plane of at least two colour planes of the three colour planes R, G, B; and

e) characterizing the tone of the skin or integuments from both the combination of the value characterizing the colour of the skin or integuments and of the Luminosity value L*.

3. The method of claim 2, comprising selecting an image zone representative of the tone to be observed and calculating on at least one part of this zone, at least one parameter selected from the mean grey level of the image, the aggregate surface area of the grey levels, and the grey level variance.

4. The method of claim 2, comprising plotting a histogram of each plane R, Plane G, and plane B from the digital image in the form of a curve in a plane, and for which the vertical axis represents the number of pixels or the proportion of pixels in the image for each colour plane R, 6, and B, and the horizontal axis represents the values of the grey levels of the pixels of the image, or vice versa, thereby obtaining respectively a histogram R, a histogram G, and a histogram B.

5. The method of claim 2, comprising determining the colour characteristic of the skin or integuments by calculating the tightness, denoted (Δ

_RGB), of at least two of said histograms R, G, B.

6. The method of claim 2, comprising determining the colour characteristic of the skin or integuments by calculating the tightness, denoted (Δ

_RGB), of the histograms R, G, B furthest apart.

7. The method according to claim 5, comprising determining the more or less saturate/desaturated character of a mean colour, or of a saturation of a mean colour, by calculating from said calculation means:

either the area of overlap of at least two histograms from the three histograms R, G, B,

or the number of pixels for which a single grey level value is logged for the three planes R, G and B.

or the arithmetic mean and optionally the deviation from of the grey levels logged for the three planes,

or any of their combinations.

8. The method of claim 6, comprising calculating a whiteness index (I_w) of the skin according to the formula:

(I_w)=Arc tn(L*/(Δ

_RGB)).

9. The method of claim 2, comprising reproducing aid steps a) to e) on various skin zones of the face of the same individual.

10. The method of claim 9, comprising calculating a value for the luminosity L*, the index (Δ

_RGB) and the index (I_w) for each zone.

11. The method of claim 2, comprising selecting at least one skin zone exhibiting a pigmentation defect including a pigmentary blemish, and at least one other control skin zone naturally pigmented.

12. The method of claim 2, comprising performing said image capture of said at least zone of the skin under illumination with white light.

13. The method of claim 2, comprising using a digital colour camera selected from a TRI-CCD digital camera and from a MOS digital photographic apparatus.

14. The method of claim 2, wherein the calculation means take into account the mean of each parameter obtained on the various images obtained respectively with the various zones of the face or of the integuments considered, thereby obtaining each global mean parameter of the face which is recorded and is used, for each person, to construct a curve for calibrating the tone of the skin or integuments.

15. An apparatus for characterizing the tone of the skin or integuments of a person, comprising:

a) a digital camera or a digital photographic apparatus for the capture of at least one digital colour image of at least one determined skin zone, said image being defined by a multiplicity of pixels (N), each pixel having a grey level, said digital colour image is transmitted to a digital image processing device, said image processing device recording said at least one image;

b) splitting means for splitting the digital image into three colour planes;

a red plane a green plane G, and a blue plane B, with said image processing device;

c) said image processing device comprising extracting means for extracting each of these planes R, G, B; and

on each plane, and calculation means for logging the grey level value for each of the N pixels, providing N grey level values, which are optionally processed mathematically by mathematical calculation means, to obtain at least one value selected from a graphical grey value, a statistical grey value, at least one average grey value characteristic of the grey levels for each plane, corresponding to a grey value characterizing the colour of the skin;

d) said image processing device comprising luminosity evaluating means for evaluating the Luminosity L* from the mean grey value of the grey level resulting from at least some of the N pixels of the image for each colour plane of at least two colour planes of the three colour planes R, G, B; and

e) said image processing device comprising tone characterizing means for characterizing the tone of the skin or integuments on the basis of the combination of the value characterizing the colour of the skin or integuments and of the Luminosity value L.

16. The apparatus of claim 15, wherein the calculation means plot a histogram of each digital image in the form of a curve in a plane having a vertical axis and an horizontal axis, and for which the vertical axis represents the number of pixels or the proportion of pixels in the image for each colour plane R, G and B and the horizontal axis represents the set of values of potential luminosity L* of the image, or vice versa, thereby obtaining a histogram R, a histogram G, and a histogram B.

17. The apparatus of claim 15, wherein the colour characteristic of the skin or integuments is determined by calculating the tightness, denoted (Δ

_RGB), of the histograms R, G, B furthest apart.

18. The apparatus of claim 15, wherein the colour characteristic of the skin or integuments is determined by calculating the tightness, denoted (Δ

_RGB), of at least two histograms from said histograms R, G, B.

19. The apparatus of claim 15, wherein the calculation means determine a more or less desaturated character of the mean colour or a saturation of the mean colour value from the calculation of:

either the area of overlap of at least two histograms, preferably of the three histograms R, G, B,

or the number of pixels for which a single grey level value is logged for the three planes R, G, and B,

or the arithmetic mean and optionally the deviation from the mean, of the grey levels logged for the three planes,

or their combinations.

20. The apparatus of claim 15, wherein the calculation means calculate a whiteness index (I_w) of the skin according to the formula:

(I_w)=Arc tn(L*/(Δ

_RGB)).

21. The apparatus of claim 15, wherein the calculation means calculate, for each selected zone of the skin or integuments, a value for the luminosity L*, the index (Δ

_RGB) and the index (I_w), in particular for several selected zones of the skin or integuments.

22. The apparatus of claim 15, wherein at least one selected zone of skin or integuments exhibits a pigmentation defect including pigmentary blemish, and at least one other control skin zone is naturally pigmented.

23. The apparatus of claim 15, furthermore comprising an illuminating device for illuminating with white light or with ultraviolet light allowing the capture of at least one image of at least one zone of the skin under said illumination.

24. The apparatus of claim 15, wherein the digital colour camera is selected from a TRI-CCD digital camera and from a D70S digital photographic apparatus.

25. The apparatus of claim 15, comprising a computer combined with a monitor comprising a screen a keyboard and a mouse and comprising software integrating all of the said means comprising:

the splitting means for splitting the digital image into three colour planes;

red, green, blue, termed R, G, B;

the extracting means for extracting each of these planes R, G, B;

the calculation means;

the recording means for recording said at least one image or a plurality of images of the skin.

26. The apparatus of claim 15, wherein the calculation means take into account the mean of each parameter obtained on the various images obtained respectively with the various zones of the skin or integuments considered, thereby obtaining each global mean parameter of the face which is recorded and is used, for each person, to construct a calibrating curve for calibrating the tone of the skin or integuments.

27. A method for evaluating the cosmetic efficacy of a cosmetic composition as regards care or make-up on at least one person having need thereof, comprising:

a) capturing at least one first colour digital image before application of said cosmetic product to at least one determined zone of skin or integuments;

b) splitting said first digital colour image into three colour planes red (R), green (G) and blue (B) to determine the colour of the skin or integuments, as well as to determine the value of the luminosity L*, as reference parameters of colour and luminosity L* of the skin or integuments before treatment;

c) undertaking the care or make-up, comprising one or more applications of said cosmetic composition to said at least one zone of skin or integuments over a predetermined period of time;

d) capturing at least one second digital image of said at least one zone of skin or integuments, after said predetermined period of time, and determining the current parameters of colour and luminosity L* after treatment as indicated under b), on said second image;

e) comparing the current parameters of colour and luminosity L* of the second image obtained after treatment with the reference parameters of colour and luminosity L* of the first image before treatment; and

f) concluding the efficacy or the absence of efficacy of said cosmetic composition as a function of the obtaining or of the non-obtaining of current parameters of colour and luminosity L* that are significantly different from the reference parameters of colour and luminosity L*.

28. The method of claim 27, comprising determining the colour parameter on each split digital image into three colour planes respectively a Red plane, R;

a Green plane, G; and

a Blue plane, B.

29. The method of claim 27, comprising plotting a histogram of each digital image in the form of a curve in a plane having a vertical axis and an horizontal axis, and for which the vertical axis represents the number of pixels or the proportion of pixels in the image for each colour plane R, G, and B and the horizontal axis represents the set of values of potential luminosity L* of the image, or vice versa, thereby obtaining a histogram R, a histogram G, and a histogram B.

30. The method of claim 29, comprising determining a mean colour value by calculating the level of overlap of at least two histograms of the three histograms R, G, B.

31. The method of claim 29, comprising determining the efficacy of the cosmetic composition by calculating the tightness, denoted (Δ

_RGB), of the histograms R, G, B furthest apart.

32. The method of claim 29, comprising determining the efficacy of the cosmetic composition by calculating the tightness, denoted (Δ

_RGB) of at least two histograms of said histograms R, G, B.

33. The method of claim 29, comprising calculating a whiteness index (I_w) of the skin according to the formula:

(I_w)=Arc tn(L*/(Δ

_RGB)).

34. The method of claim 29, comprising reproducing said method on various skin zones of the same individual.

35. The method of claim 34, comprising calculating a value for the luminosity L*, the index (I_w) and the index (I_w) for each zone.

36. The method of claim 27, comprising selecting at least one zone of skin or integuments exhibits a pigmentation defect including pigmentary blemish, and at least one other control skin zone naturally pigmented.

37. The method of claim 27, comprising performing a whitening care on said at least one zone of skin or integuments, and applying a cosmetic whitening composition during said predetermined period of time, to conclude as to the efficacy, or the absence of efficacy, of whitening, of said cosmetic composition as a function of the obtaining, or of the non-obtaining, of current parameters of colour and luminosity L* that are significantly different from the reference parameters of colour and luminosity L*.

38. The method of claim 37, comprising calculating the whiteness index according to claim 33 and concluding as to the efficacy, or the non-efficacy, of the cosmetic composition depending on whether the trend in the whiteness index is or is not significantly positive.

39. The method of claim 37, comprising performing a tanning on said at least one zone of skin or integuments, said tanning comprising applying a cosmetic tanning composition, during said predetermined period of time, to conclude as to the efficacy, or the absence of efficacy, of tanning, of said cosmetic composition as a function of the obtaining, or of the non-obtaining, of current parameters of colour and luminosity L* that are significantly different from the reference parameters of colour and luminosity L*.

40. The method of claim 35, wherein the significant difference is obtained when a probability of error is of less than or equal to 5%.

41. The method of claim 27, comprising performing said evaluating of cosmetic efficacy on a panel of people of a group representative of a given age category, to determine the significant character of efficacy of the cosmetic product considered.

42. The method of claim 41, comprising selecting said group of people according to their skin colour representative of their index or Individual Typological Angle, rated respectively as very fair skin, fair skin, medium skin and dividing them into two panels, a first panel ranging from very fair skin to fair skin, and a second panel ranging from fair skin to medium skin;

performing the steps a) to f) on each person of each panel, and

concluding the positive or negative efficacy of the cosmetic composition considered when a similarly evolving trend is found in the 2 panels.