WO2018215671A1 - Probe, system and method for analysing the skin - Google Patents

Abstract

The system (10) for analysing the skin comprises: - a chamber (15) having an opening (16) to be positioned in contact with the skin, and comprising a plurality of light sources (18 to 21) illuminating the opening at different angles of incidence, different wavelengths and/or different polarisations, - means (22) for detecting the contact of the opening with the skin, - an image sensor (23) for consecutively capturing images through the opening of the chamber while the detection means detects that the opening of the chamber is in contact with the skin, - switching means (24) for switching the operation of at least two light sources for a period of time separating two images captured consecutively by the image sensor while the detection means detects that the opening of the chamber is in contact with the skin; - means (25) for selecting at least one pair of images captured consecutively, before and after switching, and - means (26) for combining the two images of a selected pair of images.

Description

 PROBE, SYSTEM AND METHOD FOR ANALYZING THE SKIN

TECHNICAL AREA

 The subject of the invention is a probe, a system and a method for analyzing the skin. It applies, in particular, to dermatology and cosmetology.

STATE OF THE ART

 Skin analyzers are an important element in the diagnosis of skin imbalances and pathologies, especially when it comes to optimally choosing skincare and / or make-up products in line with the characteristics of the skin. skin and their specific needs.

 They complete the visual and tactile diagnosis of the practitioner whether he is a dermatologist, aesthetic doctor or beauty professional.

 There is therefore a need for a system or method for analyzing the skin in a satisfactory manner, in particular to provide consumers with personalized advice, particularly with skincare or make-up products for the skin.

 The main non-invasive technologies used are electronic systems capable of quantifying several physical characteristics, the skin's conductivity for its hydration, the capacitance of the skin to evaluate the secretion of sebum or mechanical devices to evaluate the flexibility of the skin

 Numerous skin characteristic analysis systems have thus already been described, in particular systems comprising an optical probe, such as a camera, having for example a light source, and capable of acquiring an image in form. digital, this probe can be associated with means able to process these digital data remotely to give information in relation to a physical characteristic of the skin.

 Numerous skin characteristic analysis systems comprising an optical probe have already been described, in particular probes that can be associated with means able to process the digital data remotely.

 For example, the following patent documents can be cited:

 EP 1 277 437, which describes a dermatoscope comprising a screen for viewing a cutaneous zone under diffuse or polarized illumination compared to reference images;

 AU 2013 201 634, which discloses a non-invasive imaging device comprising an incident light source for directing light onto the skin and a detector for detecting the degree of polarization of light for a determination system and method a skin condition based on an aspect of the polarization of the reflected light,

EP 1 488 737, which discloses a cutaneous observation apparatus which comprises an image pickup device for capturing images of the skin through an aperture in contact with the skin and a lighting system comprising three systems : a texture observation lighting system to radiate a white light along the axis of the opening, a keratin abrasion illumination system for irradiating a white light to the aperture from a lateral direction and a lighting system observing the subcutaneous pigments for irradiating UV light to the aperture;

 US 6,907,138, which discloses a method of analyzing properties of a surface by taking an image scene with a camera, at least two images being taken with directed and / or diffused light illumination, image information of the individual images being converted to digital signals, and then a three-dimensional image is determined from the digital signals in a computer-assisted manner; and

 document US 2015/223749, which describes a skin condition evaluation method comprising the preparation of a light source comprising one or more LEDs, irradiating the light on the skin using the light source. and receiving the light emitted through the skin using a light detector.

 However, none of these devices and none of these methods can effectively reveal the physical characteristics of the skin of the user.

Presentation of the invention

 The present invention aims to remedy all or part of these disadvantages.

 For this purpose, according to a first aspect, the present invention provides a skin analysis system according to claim 1.

 In embodiments, the plurality of light sources has at least one light source of at least two of the following sets:

 a source of light in predominantly direct lighting,

 a source of light in predominantly indirect lighting,

 polarized light source,

 unpolarized light source,

 - visible light source and

 ultraviolet light source.

 In embodiments, the means for detecting the contact of the opening of the chamber with the skin comprises an electrical contactor on which a movable portion of the face of the chamber surrounding the opening of the chamber is supported.

 In embodiments, the contact sensing means for opening the chamber with the skin includes means for measuring a quantity of light entering the chamber through the opening.

 In embodiments, the switching means is configured to switch the operation of at least two light sources providing illumination having two different angles of incidence, one of the light sources providing direct illumination and another source. of light providing indirect lighting.

In embodiments, the switching means is configured to switch the operation of at least two light sources providing illumination having two different wavelengths, one of the light sources providing illumination in the visible range and another light source providing illumination in the field ultraviolet.

 In embodiments, the switching means is configured to switch the operation of at least two light sources providing illumination having two different polarizations, one of the light sources providing unpolarized light and another light source. providing polarized lighting.

 In embodiments, the switching means is configured to switch the operation of at least two light-emitting diode light sources.

 In embodiments, the switching means is configured to switch the operation of at least two light sources between two frame captures by each image sensor.

 In embodiments, the selection means is configured to select the last pair of captured images preceding an end of detecting the contact of the chamber opening with the skin.

 In embodiments, the selection means is configured to select a pair of captured images according to the sharpness of the captured images.

 In embodiments, the selection means is configured to select a pair of captured images based on the matching of contour positions in the captured images.

 In embodiments, at least one light source emits ultraviolet light rays and at least one image sensor is insensitive to the wavelengths of the ultraviolet light rays emitted by the light source.

 In embodiments, the system comprises skin image analysis means providing a physical characteristic of the skin representative of hydration, sebum secretion, pores, skin texture, wrinkles, dermal spots, skin stains, redness and / or skin tone.

 In embodiments, the system includes:

 a means for detecting the proximity of the skin and the opening of the chamber of the probe and

 image capture control means when the skin is at a distance between one tenth of a millimeter and one millimeter of the opening of the chamber,

 In embodiments, the means for combining the two images of a selected pair of images is configured to make a difference in image values at the same position in both images.

 According to a second aspect, the invention relates to a probe according to claim 17.

 According to a third aspect, the invention provides a method according to claim 18.

 The advantages, aims and particular characteristics of this probe and this process being similar to those of the system object of the invention, they are not recalled here.

BRIEF DESCRIPTION OF THE FIGURES

Other advantages, aims and features of the present invention will become apparent from the description which follows, for the purpose of explanation and in no way limiting with respect to the drawings. annexed, in which:

 FIG. 1 represents, schematically, a skin analysis system which is the subject of the invention,

 FIG. 2 represents, in the form of a logic diagram, steps of a skin analysis method which is the subject of the invention;

 FIG. 3 represents successions of operating commutations of light sources and of image captures,

 FIG. 4 represents, schematically and in section, a first embodiment of a contact detection means,

 FIG. 5 represents, schematically and in section, a second embodiment of a contact detection means,

 FIGS. 6A, 6B and 6C show, schematically and partially, the arrangement of the light sources and

 FIG. 7 illustrates images obtained from the surface of the same area of skin acquired under each of four visible, diffuse visible, polarized visible and UV visible lights.

 DESCRIPTION OF EMBODIMENTS OF THE INVENTION

 It is noted that the figures are not to scale.

 FIG. 1 shows a skin analysis system 10 comprising a skin analysis probe 11 in local communication with a communicating terminal 12 and in remote communication with a remote server 13 via a remote control unit. 14. The communications are preferably carried out wirelessly, for example via a router implementing a WiFi (registered trademark) protocol. The communicating terminal 12, for example a fixed or portable computer, a tablet or a mobile telephone, enables the user of the probe to view images captured with the probe 11, images resulting from the combination or treatment of images captured with the probe 1 1, operating parameter values of the probe 1 1 and / or the system 10 and recommendations for treatment of the skin. The computer network 14 is preferably the internet network or a 3-4G type telephone network. The server 13 carries out image processing picked up by probes 11, comparisons of images captured by probes 11 with image data. reference stored in memory and deduced skin treatment recommendations that the server 13 sends to the computer terminal 14.

 The probe 11 comprises a chamber 15 having an opening 16 to be positioned in contact with the skin 17, and comprising a plurality of light sources 18, 19, 20 and 21 illuminating the opening 16 with different angles of incidence. different wavelengths and / or different polarizations. The light sources 18, 19, 20 and 21 are preferably light-emitting diodes (or "LEDs" or "LEDs" for Light-Emitting Diodes). Figures 6A, 6B and 6C illustrate configurations of light sources in a chamber 15.

Preferably, the plurality of light sources comprises at least one source of light from each of at least two of the following sets:

 a source of light in predominantly direct lighting,

 a source of light in predominantly indirect lighting,

 polarized light source,

 - unpolarized light source,

 visible light source and

 ultraviolet light source.

 For example, the light sources 18 provide direct illumination in unpolarized visible light, the light sources 19 provide indirect lighting in nonpolarized visible light, the light sources 20 provide direct illumination in polarized visible light and the sources of light light 21 provide indirect illumination in unpolarized ultraviolet light.

 Visible light details the surface of the skin (the epidermis). With polarized light, it is possible to discriminate the rays coming from the reflection on the surface of the skin (which preserves the polarization) of those having penetrated into the dermis which lose this polarization. It is possible to distinguish emerging tasks from nascent redness and to quantify them. UV light highlights the fluorescence properties of bacteria that can infect dilated pores.

 With the images thus obtained, one can estimate the hydration of the skin, its secretion of sebum, the presence and the importance of the wrinkles, the grain of the skin, the presence of epidermal spots and the complexion.

 The probe 1 1 also comprises a means 22 for detecting the contact of the opening 16 with the skin 17. Two examples of detecting means 22 are illustrated in FIGS. 4 and 5.

 The probe 11 furthermore comprises at least one image sensor 23 for successively capturing images through the opening 16 of the chamber 15 and supplying a signal representative of the image captured when the detection means 22 detects that the opening 16 of the chamber 15 is in contact with the skin 17. Each image sensor 23 is provided with a lens to take a sharp image of the skin resting on the aperture 16. In the embodiment shown in the figures, the probe 1 1 has only one image sensor 23. However, in other embodiments (not shown), the probe comprises a plurality of image sensors sensitive to light rays of different wavelengths (visible range and ultraviolet range, for example) and / or different polarizations (a polarizing filter then being positioned on the optical path of the light rays reaching at least one of the image sensors). If at least one light source 18, 19, 20 or 21 provides illumination of the skin 17 in polarized light, at least one image sensor 23 is preferably provided with a polarization polarization filter perpendicular to the polarization of each source of polarized light to eliminate glare on the surface of the skin 17.

The probe 1 1 further comprises a switching means 24 for switching the operation of at least two light sources 18, 19, 20 and 21 for a period of time between two consecutive captures of images by each image sensor 23 while the detection means 22 detects that the opening 16 of the chamber 15 is in contact with the skin 17. Generally, the number of images being of the order of 24 to 25 per second, with possibly two fields per image, the The total duration of the two image captures is less than 84 milliseconds, or even 42 milliseconds when each frame is considered an independent image. The switching of the operation of the light sources is illustrated in FIG.

 The system 10 comprises, in the probe 1 1, in the terminal 12 or in the server 13 (in FIG. 1, in the probe 1 1), means 25 for selecting at least one pair of images captured before and after a switching operation of light sources. This pair of images is then stored in a memory 35.

 In embodiments, the selection means is configured to select the last pair of captured images prior to an end of detecting contact of the chamber opening with the skin. The selection means 25 is then controlled by the means 22 for detecting the contact of the opening 16 with the skin 17. The memory 35 is then integrated with the probe 11 and keeps, at all times, the digital data representing the last pair of captured images as the detection means 22 detects the contact of the opening 16 with the skin 17.

 In embodiments, the selection means is configured to select a pair of captured images according to the sharpness of the captured images, choosing the pair of images having, together, the maximum sharpness. This sharpness is measured in known manner, for example by measuring the contrasts between juxtaposed points of the images provided by each image sensor. For example, this measurement is the sum of the absolute values of the differences between the values captured for two consecutive points on lines, diagonals and / or columns of parts of the images.

 In embodiments, the selection means is configured to select a pair of captured images based on the match of contour positions in the captured images, choosing the pair of images having the best match. For example, subtract one of the images from the other, point by point, and measure the sum of the absolute values of the differences thus obtained. Alternatively, we extract the outlines of the two images and subtract their values, point by point.

 The system 10 comprises, in the probe 1 1, in the terminal 12 or in the server 13 (in Figure 1, in the server 14), a means 26 for combining the two images of a selected pair of images. Different combinations of images are explained below.

 FIG. 2 shows steps of a skin analysis method implementing a probe which is the subject of the invention. This process comprises:

 a step 30 of detecting the contact of the aperture with the skin and control of image capture by the image sensor when the contact is detected,

a step 31 of switching the operation of at least two light sources providing illumination having two different angles of incidence, two lengths of different waves and / or two different polarizations for a time separating two consecutive captures of images by each image sensor while the detection means detects that the opening of the chamber is in contact with the skin, a step 32 selecting at least a pair of captured images before and after a switching operation of light sources and

 a step 33 of combining the two images of a selected pair of images. FIG. 3 shows a first curve 41 representing, in time, the contact detection of the opening 16 of the chamber 15 with the skin 17, the high value representing a positive detection. A second curve 42 represents successive image capture times by at least one image sensor, the high value representing an exposure time and the low value a transfer time of the images to a memory. A third curve 43 represents the operation of a first light source, the high value representing the emission of light. The fourth curve 44 represents the operation of a second light source, the high value representing the emission of light. A fifth curve 45 represents the transfer of the images of a selected pair of images to an image combining means.

 As understood, this concerns the case of a means 22 for mechanical detection of the contact of the opening 16 with the skin 17 and a means for selecting the last pair of images formed before this contact is detected as broken. . The image sensor 23 operates as soon as contact is detected and alternately captures images of the illuminated skin 17, through the aperture 16, alternately by two different light sources 18, 19, 20 and 21.

 FIG. 4 shows a means 22 for detecting contact of the opening 16 with the skin 17 comprising an electric contactor 27 on which a movable portion 28 of the face of the chamber 15 surrounding the opening 16 of the chamber is supported. 15. Thus, when the opening 16 bears on the skin 17, the switch 27 detects it.

 FIG. 5 shows a means 22 for detecting contact of the opening 16 with the skin 17, comprising means 29 for measuring a quantity of light entering the chamber through the opening 16. For example, all the light sources 18 to 21 are extinguished as long as there is no detected contact and a photodiode or phototransistor measures the amount of light inside the chamber 15. When the opening 16 bears on the skin 17, the darkness inside the chamber 15 is detected by the means 29 for measuring the amount of light.

 Contact detection can also be achieved by means of various other types of sensors such as: optoelectronic detectors - microswitch or resistive or capacitive detection.

 Technical explanations of the operation of the skin analysis system are given below.

It has been demonstrated here that it is possible to carry out from the same probe direct visible lighting or indirect or diffuse visible lighting, for example by means of white LEDs, without altering the desired illumination by the possible addition of LEDs to illumination UV and LED with polarizer.

 By indirect or diffuse light, is meant a light whose rays illuminate the opening 16 in multiple directions to eliminate the projected shadows and reflections on the reflective parts produced by an excess of sebum of the skin. Such a diffuse light has the advantage of providing, as analysis of at least one characteristic, an information or an analysis result in relation to the colorimetric components of the skin, in particular the complexion and / or the staining density of susceptible stains. to be present on the epidermis of the skin. This diffuse illumination obtained either directs the LEDs towards the walls of the envelope of the light source (see FIG. 6A) which bear a rough white coating, or by providing the white LEDs with an achromatic diffuser filter (see FIG. 6B). .

 By direct light, is meant a light which illuminates the skin in a direct manner with a narrow beam of rays and directed on the opening 16. The angle of illumination of the cutaneous surface is chosen so that the reflected beam is directed in the center of the image sensor (precisely the lens of the image sensor). Such radiation promotes the perception of reflective surfaces. The direct illumination of the skin from different angles highlights the shadows generated by the cutaneous relief and thus makes it possible to measure this relief. Such direct visible light has the advantage of providing, as analysis, information or a result of analysis on characteristics of the epidermis in relation to hydration, sebum secretion, skin texture and wrinkles.

 A differential measurement of the same skin surface, by difference, point by point, of images captured in direct visible light and in indirect visible light, makes it possible to accentuate the shadow effects by eliminating the optical background noise represented by the coloring of the skin and its irregularities. Similarly, a differential measurement of the same skin surface between the dermis (polarized light) and the epidermis (diffuse light) makes it possible to assess the depth of the task.

 Among the means for producing a diffuse visible light by an optical probe for the analysis of the skin, mention may be made but not limited to: LEDs, incandescent lamps, fluorescent lamps, flash xenon lamps.

 Among the means for producing a direct visible light by an optical probe for analyzing the skin, mention may be made but limited thereto: LEDs, incandescent lamps, fluorescent lamps, flash xenon lamps, laser diodes.

 By visible light is meant a radiating light in the visible range (400 to 800 nm). This light can be monochromatic, polychromatic or emit a continuous spectrum of color. This type of light can be used in the analysis of wrinkles or microstructure of the skin.

 By white light is meant a light that emits a continuous color spectrum in the visible range (400-800 nm). This type of light is preferably used in measurements in direct, indirect and / or polarized lighting.

Preferably these two lights, diffuse visible light and direct visible light, may also be produced separately at the request of the user or operator through separate commands or programs.

 It has been shown here that these two lights can be produced separately by the same optical probe, for example in this probe:

 - for diffused light lighting, at least one white LED positioned in such a way that its light is partly directed towards a reflective surface / wall of the probe (see Figures 6A and 6B), preferably the LED has an angle of wide diffusion of at least 40 degrees, even more preferably between 50 and 70 degrees; and

 - for direct light illumination, at least one white LED positioned in such a way that its light is directed / focused towards the probe window in contact with the tissue to be studied, preferably the LED has a narrow diffusion angle of less than 30 degrees, even more preferably between 15 and 25 degrees (see Figure 6B),

each of these two lights can be ordered separately.

 Direct light illumination, unlike diffuse light illumination, controls the incident and reflected light beam.

 In another way, it has been shown that these two lights can be produced separately by the same optical probe, for example by placing in this probe:

 - for diffused light lighting, at least one white LED with an achromatic diffuser filter; and

 - for direct-light lighting, at least one white LED not equipped with a diffuser filter,

each of these two lights can be ordered separately or interlaced.

 In preferred embodiments, there are provided in the probe 1 1:

 a set of means for producing a lighting of the skin by diffuse visible light, comprises at least one visible light source, preferably a white light, preferably a white LED, this source being positioned in such a way that its light is positioned in such a way that its light is directed in part towards a reflecting surface / wall of the probe (see FIGS. 6A and 6B), preferably the light source has a wide diffusion angle of at least 40 degrees, so that more preferred between 50 and 70 degrees; and

 a set of means for producing a lighting of the skin by at least one direct visible light source, preferably a white light, more preferably a white LED, this source being positioned in such a way that its light is directed / focused towards the window of the probe in contact with the tissue to be studied, preferably the light source has a narrow diffusion angle of less than 30 degrees, even more preferably between 15 and 25 degrees (see Figure 6B),

each of these two lights can be ordered separately, or interlaced.

 In preferred embodiments, there are provided in the probe:

as a set of means for producing a lighting of the skin by diffuse light, at least one visible light source, preferably white, preferably at least one a white LED with a wide diffusion angle of at least 40 degrees, even more preferably between 50 and 70 degrees, this source being provided with an achromatic diffuser filter; and

 as a set of means for producing skin illumination by direct light, at least one visible light source, preferably white, more preferably a white LED not provided with a diffuser filter, with a narrow diffusion angle of less than 30 degrees. even more preferably between 15 and 25 degrees.

 In preferred embodiments, in the probe, the set of means for producing a skin illumination by diffuse light and by direct light, comprises a luminous device type LED illuminating in the visible wavelength range, comprises:

 at least two white-light LEDs for diffused lighting, preferably three white LEDs, more preferably between two and six white LEDs; and

 at least two white-light LEDs for direct lighting, preferably three white LEDs, more preferably between two and six white LEDs.

 Among the advantages associated with the presence of these two sources of lighting, diffuse and direct, include the possibility of making a diagnosis on patients regardless of their phototype or skin melanotype.

 Thus, the probe according to the invention can perform skin analyzes, both on white or light skin (Fitzpatrick's phototype I and II), but also on intermediate skin types (phototype III) or matt to very dark brown (phototype III to VI).

 By polarized light is meant a light whose electrical wave properties are ordered on a plane perpendicular to the optical axis. Such polarized light has the advantage of providing information on a physical characteristic of the skin in relation to nascent spots in the dermis and redness.

 Among the means for producing light polarized by an optical probe for the analysis of the skin, there may be mentioned but not limited to a white or monochromatic LED source, with incandescent, fluo or xenon supplemented with a dichroic polarizer filter. achromatic plane. A second polarization filter perpendicular to that of the light sources is positioned in front of the image sensor to isolate the reflected polarized light. By carrying out a progressive rotation of the polarizer of the camera, it is possible to obtain indications on the depth of the phenomena observed.

 By ultraviolet light, or UV, is meant a light emitted in the range of UV wavelengths. To create the required fluorescence, the peak wavelength is preferably between 370 and 400 nm. Such UV light has the advantage of providing information on a physical characteristic of the skin in relation to the amount and nature of the pores present on the skin and the nature, bacterial, or not, of the contents of these pores.

Among the means making it possible to produce a UV light by an optical probe for the analysis of the skin, mention may be made of but not limited to: UV LEDs emitting a spectrum of light radiation in a restricted wavelength range;

 - quartz-halogen lamps or quartz-coated xenon flash lamps. For these two types of broadband emission light sources, it is preferred to reduce the range of wavelengths emitted by a gelatin, color or interference type pass-through optical filter.

 The image sensor is very preferably equipped with a high-pass filter cutting the UV radiation reflected by the skin in order to keep only the signals resulting from the fluorescence phenomenon.

 In the case of UV illumination, the color analysis of the fluorescence emitted by the microorganisms makes it possible to have information on the type of microorganisms present in the pores of the skin.

 In preferred embodiments, the probe comprises:

 a set of means for producing a lighting of the skin by diffuse visible light; a set of means for producing a lighting of the skin by direct visible light;

a set of means for producing a skin illumination by polarized light and

a set of means for producing a lighting of the skin by UV light;

and the probe makes it possible, at the same time, to obtain an information, in particular of quantitative type, on the skin in relation with the hydration, the sebum secretion, the pores, the skin texture, the wrinkles, the dermal tasks , skin stains, redness and complexion.

 The selection of light sources can be made in different ways:

 - by sequential selection of sources; for example, but not limited to, illumination of the skin by direct light then by diffuse light and then polarized and UV light, each of these selections being the subject of a different and successive image;

 - interlacing of the ignitions and synchronization with the image sensor (camera or camera); for example, but not limited to, sequential illumination of diodes or flashlamps for 1/10 of a second, each with an image of the camera and digital sorting of photos corresponding to different sources or

 - By the use of a single source associated with mechanically controlled filters that are positioned in front of the common visible source. This technique does not apply to UV sources.

 It has been demonstrated that the presence of a set of means for obtaining images of the skin under diffuse visible light and, separately, under direct visible light, not only provides information or an analysis result in relation to the specific characteristics associated with these illuminations, but also to be able to establish a more precise general diagnosis when these characteristics were combined with the characteristics of the skin obtained from images produced under light illumination polarized and UV by the same probe.

In preferred embodiments, in the probe, the set of means for producing skin illumination by diffuse light, direct light, polarized light, and UV light, includes:

a) a luminous device type LED illuminating in the visible wavelength range and comprising:

 - at least two white-light LEDs for diffuse lighting,

 - at least two white-light LEDs for direct lighting,

 - at least two white-light LEDs with a polarizer for polarized illumination and

b) a luminous device type LED illuminating in the field of ultra-violet wavelengths (UV) and comprising at least two UV LEDs.

 In embodiments, the probe further includes:

 a set of means for acquiring an image of the skin and, if necessary, producing digital data associated with this image, and

 a set of communication means of this image and, if appropriate of these data, with a terminal 12 of the user.

 It has been noticed that the management of the lighting of lighting sources such as diodes (LED, and the automatic triggering of the shooting of the probe also appear as key elements of image acquisition quality This management is automated for at least two reasons:

 a / In terms of safety: it is advisable not to risk lighting the eyes of the subjects / customers with UV or visible radiation too violent

 b / If the probe is in physical contact with the skin, it undergoes a stress that can disturb the measurement.

 These two phenomena can be avoided on the one hand:

 - by triggering the lighting of the LEDs only near the skin; and - by triggering the measurement at the correct focal length of the camera. The contact of the tip of the probe on the skin being as small as possible.

 Thus, it has been demonstrated that it is possible to overcome these problems by equipping the probe of the invention with:

 - a proximity detector of the skin; and

 - Where appropriate, a set of means for fixing and acquiring the image by moving the probe a few tenths of mm from the skin; and

 if necessary, a set of means making it possible to switch off the lighting device of the probe after about half a second as soon as the image is acquired,

 With these additional means, a following sequence of steps can be performed and is preferred:

 - the choice of the appropriate LED for the measured parameter. This choice can be made manually or ordered directly by the program,

 - the manipulation of the probe to bring it to the part of the face concerned by the parameter to be measured. The LEDs are still off,

- close to the skin, the detector ensures the lighting of the chosen LED allowing the viewing the image of the skin on the user's terminal 12. At this stage, the probe is in contact with the skin,

 when the operator considers that the image is appropriate, the fact of moving the probe a few tenths of a mm from the skin freezes the image and transmits it to the server 13 for exploitation, a half-delay device -second turns off the diode at the end of this sequence.

Thus, the shooting takes place without altering the surface of the skin analyzed.

 This detection can take place by means of different types of sensors such as, for example, but not limited to, an optoelectronic detector, a microswitch detector, a resistivity detector, a detector relaying the 50/60 Hz mains current through the sensor. antenna that represents the human body or a detector by capacitive detection.

 Associated with one of these detectors to ensure the lighting of the chosen light source, the analysis of the sharpness of the image produced can complete and refine this device. The sharpness can be estimated by the analysis of the contrast of the image or its illumination or a detector by capacitive detection.

 In a particularly preferred embodiment, the optical probe 11 according to the present invention further comprises:

 means for detecting the proximity of the skin,

 if necessary, a set of means making it possible to fix and acquire the image by moving the probe a few tenths of a millimeter away from the skin,

 - Where appropriate a set of means to turn off the lighting device of the probe after about 0.5 seconds ± 0.25 seconds upon acquisition of the image. Proximity sensors are well known to those skilled in the art. Examples include microswitches (DH type Sherry, trademarks, or equivalent) - Reed contacts associated with a magnet on the moving part of the PIC-type chamber MS-108-3 MS-108-3 1 filed) - capacitive detectors (using Cl TTP223, trademark or equivalent) - optoelectronic detectors (Fairshild GRE1 1 13 type, registered trademarks, or equivalent) or resistivity detectors (Seeed GSR sensor type, trademarks, or equivalent).

 Preferably, said proximity detector is selected from micro switch or optoelectronic techniques.

 Among the means for fixing and acquiring the image by moving the probe a few tenths of mm away from the skin, mention may be made of time, the mechanical wedge or the optoelectronic detection.

 Among the means for extinguishing the lighting device of the probe after a given time as soon as the image is acquired, mention may be made of timers type 555 (registered trademark) or equivalent as well as microcontrollers.

 Combined, these features have the advantage of:

 - Make manipulations easier because the shooting becomes automated;

- to improve the quality of the shooting by guaranteeing the good focal length and the absence of mechanical stress on the skin (like a warm-up of the skin or a preliminary contact shooting between the skin and the probe; and

 - improve safety by allowing UV LEDs to light up only when in contact with the skin. The risk of affecting the eyes is thus removed. UV light is indeed dangerous for this organ and the exposure of the eyes is framed by the safety regulations.

 In the optical probe 1 1, the set of means for acquiring an image of the skin is an image sensor (camera or, preferably, a camera, preferably digital) with a magnifying lens over 30 times, especially at least 40, preferably 50 times. Such a magnification is suitable for image processing in order to quantify all the targeted parameters such as hydration, the presence of sebum, wrinkles, complexion, stains, redness or even pores, for example .

 This set of means for acquiring an image of the skin makes it possible to take shots of specific areas of skin and to acquire the corresponding images. The digital data associated with these acquired images are obtained in a standard format suitable for image processing, namely:

 - directly by the image sensor, and this data is then transmitted to the terminal

12, such as a smartphone, digital tablet or computer, wired, Bluetooth or WiFi (registered trademarks); or

 directly by the terminal 12 to which these images are transmitted and which retrieves the associated digital data in the format suitable for processing these images. Thus, and preferably, in the optical probe 11 according to the present invention, the means of communication of the data or images acquired by the optical probe with the terminal 12 of the user and remote from this optical probe 11 are chosen from the wired, such as the USB port (acronym for Universal Sériai Bus, registered trademark), Bluetooth and WiFi, or any other means of communications permitting.

 Among the formats in which digital data associated with these acquired images are recovered, there may be mentioned, for example but without limitation, the JPEG or MJPEG format when it comes to the video stream.

 Preferably, the server 13 comprises:

 a set of means for processing this acquired image to, if necessary, produce digital data associated with this image and for the processing of these data,

 a set of means for interpreting these data in order to provide information or an analysis result in relation to this characteristic. The various characteristics of the skin analyzed are among the following: hydration, sebum secretion, pores, skin texture, wrinkles, dermal stains, epidermal stains, redness and complexion.

The processing of the acquired image is performed by the server 13 (or by a resource accessible on this server), which retrieves these data or images acquired and finalizes their processing and returns these processed data to the user, as well as, where appropriate any other information in connection with this analysis. Preferably, this server 13 is capable (or has the necessary resources) also of storing these data or images.

 Preferably, this server 13 has an image database, their digital data and their processing or access to such a database.

 The server 13 further includes:

 a set of means for storing data or reference information or data or information obtained for the skin of the same patient under similar conditions in a previous analysis, and

 a set of means making it possible to compare these data or information. These data or reference information may in particular be obtained from analyzes carried out on a group of individuals, preferably associated with a specific age group, having a skin considered as healthy (healthy control) or having a skin whose least one of the characteristics predisposes the subject to receive or to be advised a care or an adapted makeup.

 The server 13 of the system 10 makes it possible, in a also preferred embodiment, to acquire, or to propose a questionnaire in order to obtain them, information or personal data relating to the subject under examination, such as, for example, its identity, age, pathologies of the skin known, previous prescriptions, habits in the care and / or makeup of the skin.

 The system 10 can be arranged so that the terminal of the server 13 delivers by the results of the analysis on the user's terminal (smartphone, tablet or computer) in the form of a page to be displayed on its screen.

 These results can be represented in the form of the representations usually used in mathematics or statistics for one or more parameters (curve, histogram, sector graph, polar graph ...).

 Thus, the user (for example a beauty center and / or skincare, a beautician, a specialist in dermo-cosmetics, or makeup, a dermatologist) with regard to the results of the measurements displayed on his terminal and of course also in view of the information received directly by exchanges with the subject is able to advise his subject in the choice of skin care products and / or makeup.

 Thus, the server 13 preferably has a set of means for proposing or recommending a dermo-cosmetic treatment or a set of dermo-cosmetic products associated with the diagnosis resulting from this or these characteristic (s) thus obtained.

 Preferably, the acquisition of images is performed when the probe is at least 0.5 mm away from the skin, preferably at least 0.65 mm, 0.75 mm and 1 mm, and preferably at least plus 2 mm, 1, 75 mm, 1, 5 mm and 1, 35 mm, even more preferably when the distance between the skin to be analyzed and the probe is between 0.65 mm and 1.35 mm.

Preferably, the method comprises the following steps prior to acquiring the image: - the choice of the light source or LED appropriate to the characteristic (s) to be evaluated, which choice can be made manually or ordered directly by the program and / or

 the manipulation of the probe to bring it to the part of the face concerned by the parameter to be measured for these characteristics, LED diodes still extinguished, and / or

 - near the skin, by means of a proximity sensor, the automatic lighting of the chosen LED and the visualization of the image of the skin on the operator's terminal, the probe being still in contact with the skin at this stage, and / or

 - Fixing and acquisition of the image if the operator believes that this image is appropriate, moving the probe a few tenths of mm from the skin freezing the image and transmitting it to the server to exploit the data; and

 where appropriate, the repetition of steps a) to d) for each parameter on the same light source and for the other light sources chosen.

 In a mode also preferred, the following steps are carried out in the process according to the present invention:

 the user (beauty center, dermatologist or any skincare and / or make-up specialist) has previously acquired the probe 1 1 and has subscribed to the server 13 (personal access with identifier and word password);

 - Each use, the terminal 12 of the user connected to the probe 1 1 connects to the server 13 which checks the update of the driver of the probe;

 the photos produced and acquired by the user's terminal 12 are sent via a router to the server 13 which interprets and stores the results; and

 these results are transferred to the user's terminal 12, which then defines the skin care, and / or the monitoring of the treatments and / or the make-up adapted to the subject / patient.

 The method which is the subject of the invention makes it possible to determine a skincare or a makeup of the skin adapted to a subject, and comprises the following steps:

 a) providing a user with a probe 1 1 according to the present invention or a system 10 according to the present invention,

 b) analyzing at least one skin characteristic of said subject by an assay method according to the present invention, and

 c) in the light of the results of analyzes or information obtained in step b), the determination of skin care or a make-up of the skin adapted to the subject.

 In the system 10 or method according to the present invention:

 At the terminal 12 of the user:

- The sensor management software including the image acquisition software is preferably downloaded through the portal (website) or server 13 accessible to the user client by a personal identifier and password on the terminal 12 of the user - This terminal 12 performs the interfacing with the optical probe, stores the acquired images and performs a preprocessing to optimize the transmission of photo data.

- This management software is suitable for Windows, Android and IOS environments (brands filed).

 At the level of the server 13:

 the user accesses the portal hosted by the server 13 through his browser and identifies himself with identifier and password.

 the software of this server can display the history of the measurements made by this professional user and the coordinates of the user clients.

 - It ensures the transfer of photos acquired in the central server

 - The professional user can enter the contact information of his new topics or customers or update the old ones.

 The site returns the results of the image analyzes and is able to generate a file of these results enriched with a comment from the professional user.

 On the server 13, storage and archiving of images, call the interpretation routine, put online results in the format described above from the calculations entered on a database, ability to host files to download by the professional, the list of products and treatments available and are provided the detailed screens of the portal.

 The skin analysis system consists of three original elements:

 the optical probe 1 1 used to acquire the images of the skin

 a web portal 13 for transferring the images to a server, the human-machine interface and the interpretation of the results.

 a program for interpreting the images transforming the photos of the camera into a numerical value, according to the physical characteristic of the skin to be evaluated (which can be accessed from the web portal or implanted directly on the computer or smartphone of the camera; 'user)

 As illustrated in FIG. 6C, the LEDs are of four types:

 A) three diodes 18 with direct illumination in unpolarized white light and narrow diffusion cone (15 ° to 25 °) favoring the shadows because of their provisions relative to the skin. This type of illumination is suitable for highlighting the microstructures of the skin and wrinkles. The images of the epidermis benefiting from this illumination are used to estimate the hydration, the sebum secretion, the skin texture and the wrinkles.

 B) three diodes 19 diffuse illumination in unpolarized white light and large scattering cone (45 °) decreasing the shadows and parasitic reflections (photograph 51). This type of illumination is intended to evaluate the color of the skin (complexion) as well as the epidermal tasks.

C) three diodes 20 polarized illuminated with a polarizer to visualize the dermis and intended to highlight emerging tasks in the dermis (melanin concentration) and nascent redness due to defects microcirculation blood (photograph 53 ). The principle of polarized light is based on the transparency of the epidermis. The polarization of the light is conserved for the part reflected on the epidermis but is lost for the waves crossing this layer of the skin and reflecting on the dermis. By filtering the light remained polarized on the camera, only the image of the dermis remains.

 D) six UV diodes 21 highlight the fluorescence of the microorganisms contained in the pores of the skin (photograph 54). Under the action of photons emitted by UV light, the molecules of micro-organisms re-emit light at a characteristic wavelength of the species. Fluorescent light therefore allows the counting of the pores of the skin, their size and the nature of the organic matter developing therein.

 The image processing is, for example, developed with OpenCV (registered trademark) free software. It consists of converting an image into a numerical value that depends on the parameter to be evaluated.

 The input data are:

 at least one image taken by the probe,

 - the type of light used to illuminate the skin during the acquisition and

 the physical characteristic to be processed (provided by the user via the terminal 12)

The output data are:

- a value expressed as a percentage or as a number,

 - an image highlighting the treatment carried out and

 - possibly a treatment recommendation to apply to the skin.

 Concerning the analysis of pores, the image processing relates, for example, to an image taken in UV light. Low-pass filtering, Canny algorithm processing and contour extraction are performed. For each contour, the maximum and minimum radii are calculated. The pores are selected based on at least one of these minimum and maximum radii and an average pore area is determined. From the initial image, an average color of the pores is determined as a function of the color difference between the inside of the contour and the background (part of the image which is not in any contour). The number of pores, the average pore area and the average pore color are the results of this image processing. As regards UV illumination, the color analysis of the fluorescence emitted by the microorganisms makes it possible to have information on the type of microorganisms present in the pores of the skin.

 Table 1: Example of a results and diagnosis sheet

 Title LED Levels Diagnostic message

 1 Good hydration

 2 slight dehydration

 Visible

 Hydration 3 Dehydration

 direct

 4 Dry skin

 5 very dry skin

 1 Good level of sebum

 2 slight excess of sebum

 Visible

 Sebum 3 Excess sebum

 direct

 4 oily skin

 5 very oily skin

 1 normal pore

 UV pores

2 Pores slightly dilated but not infected 3 slightly dilated and infected pores

 4 dilated but uninfected pores

 5 dilated and infected pores

 1 Young skin and fine grain

 2 Young but irregular skin

 Visible 3 normal skin and fine grain

 Skin texture

 direct 4 Normal but irregular skin

 5 mature but fine skin

 6 Mature and irregular skin

 1 No wrinkles

 2 nascent and fine wrinkles

 Visible

 Wrinkles 3 nascent but pronounced wrinkles

 direct

 4 Wrinkles accented but fine

 5 Wrinkles accented and pronounced

 1 No spots

 polarized

 2 Small, slightly colored spots

 Dermal spots 3 Small marked staining spots

 4 little stains

 5 spots with marked staining

 1 No spots

 2 Small, slightly colored spots

 Visible spots

 3 small staining spots marked

 diffuse epidermis

 4 little stains

 5 spots with marked staining

 1 No redness

 2 weak, slightly colored redness

 3 slight redness with marked staining

 Polarized redness

 4 Redness slightly accentuated

 5 Redness accentuated

 6 Redness accentuated with dilated vessels

1 dull complexion

 2 Tanned complexion

 Visible

 Complexion 3 Lightly haired complexion

 broadcasts

 4 Clear complexion

 5 pale complexion

 The following combinations of images taken consecutively with a switching operation of two light sources improve the relevance of analysis.

 Image / Image / combination advantage setting

 illumination 1 illumination 2

 Rides Visible direct Visible diffuse subtraction Eliminates the

 hue of the

 skin

 Skin Grain Direct Visible Visible Diffuse Subtraction Emphasizes

 contrast

 Spots Visible Diffused Visible Polarized Subtraction Estimate

 depth stain

Redness Visible diffuse Visible polarized Subtraction Estimate depth

 rash

 Sebum Visible direct Visible diffuse subtraction Emphasizes the

 contrast of the bright area

 EXPRESSION OF RESULTS

 The skin diagnosis is based on one or more values of physical characteristics of the skin to estimate a parameter of the skin:

 Dermal tasks: result depending on "task" calculation parameters

 Epidermis tasks: result according to the "task" calculation parameters

 Redness: result depending on the calculation parameters "redness"

 Pores: result depending on the output data of the parameter "pores"

 Hydration: result depending on the microstructure of the skin

 Sebum: result of reflection and microstructure

 Complexion: result depends on the output data of the complexion parameter

 Wrinkles: results depending on the output data of the wrinkles and microstructure parameter. One of the novel features of the skin analysis system 10 of the invention relates to the use of several image analysis programs to conclude a result (multivariance). If we take again the example of the rednesses, we will use the surface of this redness, the intensity of the coloring (quantity of blood) and a detection of form informing the professional (the user) of the nature of the redness (diffuse or exploded vessel).

 The diagnosis is therefore more relevant and the treatments put in place more effective. The integration of this multi-parameterization can be done by sorting or with the use of artificial intelligence software with a training performed by dermatologists on selected types of clients.

Claims

1. System (10) for analyzing the skin (17), characterized in that it comprises:  a chamber (15) having an opening (16) to be positioned in contact with the skin, and having a plurality of light sources (18 to 21) illuminating the aperture with different angles of incidence, different wavelengths and / or different polarizations,  means (22, 27, 29) for detecting contact of the opening with the skin,  at least one image sensor (23) for successively capturing images through the opening of the chamber and providing a signal representative of the captured image when the detecting means detects that the chamber opening is in contact with the skin; - switching means (24) for switching the operation of at least two light sources providing illumination having two different angles of incidence, two different wavelengths and / or two different polarizations for a period of time between two consecutive captures of images by each image sensor while the detection means detects that the opening of the chamber is in contact with the skin,  means (25) for selecting at least one pair of images captured consecutively, before and after a switching operation of light sources and means (26) for combining the two images of a selected pair of images. The system (10) of claim 1, wherein the plurality of light sources (18-21) comprises at least one light source of each of at least two of the following sets:  light source (18) with mainly direct lighting,  light source (19) with mainly indirect lighting,  polarized light source (20),  non-polarized light source (18, 19),  visible light source (18, 19, 20) and  ultraviolet light source (21).  3. System (10) according to one of claims 1 or 2, wherein the means (22) for detecting the contact of the opening (16) of the chamber (15) with the skin (17) comprises an electrical contact (27) on which support a movable portion (28) of the face of the chamber surrounding the opening of the chamber.  4. System (10) according to one of claims 1 to 3, wherein the means (22) for contact detection of the opening (16) of the chamber (15) with the skin (17) comprises a means ( 29) measuring a quantity of light entering the chamber through the opening. The system (10) according to one of claims 1 to 4, wherein the switching means (24) is configured to switch the operation of at least two light sources providing illumination having two different angles of incidence, one of the light sources (18) providing direct illumination and another light source (19) providing illumination indirect.  The system (10) according to one of claims 1 to 5, wherein the switching means (24) is configured to switch the operation of at least two light sources providing illumination having two different wavelengths, one of the light sources (18, 19, 20) providing visible light and another light source (21) providing illumination in the ultraviolet range.  The system (10) according to one of claims 1 to 6, wherein the switching means (24) is configured to switch the operation of at least two light sources providing illumination having two different polarizations, one of which light sources (18, 19) providing non-polarized illumination and another light source (20) providing polarized illumination.  The system (10) according to one of claims 1 to 7, wherein the switching means (24) is configured to switch the operation of at least two light emitting diode light sources (18 to 21). The system (10) according to one of claims 1 to 8, wherein the switching means (24) is configured to switch the operation of at least two light sources (18 to 21) between two frame captures per each image sensor (23).  10. System (10) according to one of claims 1 to 9, wherein the means (25) of selection is configured to select the last pair of captured images preceding an end of detection of the contact of the opening (16) of the chamber (15) with the skin (17).  1 1. System (10) according to one of claims 1 to 10, wherein the means (25) for selection is configured to select a pair of captured images according to the sharpness of the captured images.  12. System (10) according to one of claims 1 to 1 1, wherein the means (25) selection is configured to select a pair of captured images according to the correspondence of contour positions in the captured images.  13. System (10) according to one of claims 1 to 12, wherein at least one light source (21) emits ultraviolet light rays and at least one image sensor (23) is not sensitive in the wavelengths of ultraviolet light rays emitted by the light source.  14. System (10) according to one of claims 1 to 13, which comprises means (13, 26) for image analysis of the skin providing a physical characteristic of the skin representative of hydration, secretion sebum, pores, skin texture, wrinkles, dermal spots, skin stains, redness and / or skin tone. 15. System (10) according to one of claims 1 to 14, which comprises:  a means for detecting the proximity of the skin and the opening of the chamber of the probe and  image capture control means when the skin is at a distance between one tenth of a millimeter and one millimeter of the opening of the chamber, The system (10) according to one of claims 1 to 15, wherein the combining means two images of a selected pair of images are configured to make a difference in image values at the same position in both images.  17. Probe (1 1) for a system (10) according to one of claims 1 to 16, characterized in that it comprises:  the chamber (15) having an opening (16) to be positioned in contact with the skin (17), and having a plurality of light sources (18 to 21) illuminating the aperture with different angles of incidence, different wavelengths and / or different polarizations,  means (22, 27, 29) for detecting contact of the aperture with the skin, - each image sensor (23) for successively capturing images through the aperture of the chamber and providing a signal representative of the image captured when the detection means detects that the opening of the chamber is in contact with the skin and  the switching means (24) for switching the operation of at least two light sources providing illumination having two different angles of incidence, two different wavelengths and / or two different polarizations for a period of time between two consecutive catches of light. images by each image sensor while the detection means detects that the opening of the chamber is in contact with the skin. 18. A skin analysis method implementing a probe comprising:  a chamber (15) having an aperture (16) to be positioned in contact with the skin (17), and having a plurality of light sources (18 to 21) illuminating the aperture with different angles of incidence, lengths of d different wave and / or different polarizations,  at least one image sensor (23) for successively capturing images through the opening of the chamber and supplying a signal representative of the captured image, the method being characterized in that it comprises:  a step (30) of detecting the contact of the aperture with the skin and image capture control by the image sensor when the contact is detected, - a step (31) of switching the operation of at least two light sources providing illumination having two different angles of incidence, two different wavelengths and / or two different polarizations for a period of time between two consecutive captures of images by each image sensor while the detection means detects that the opening of the chamber is in contact with the skin,  a step (32) of selecting at least a pair of images captured before and after a light source operation switching and  a step (33) of combining the two images of a selected pair of images.