The present invention relates to the field of determining parameters of the scalp and/or of the hair of a user, which parameters are representative of a state of the scalp and of a state of the hair, in particular for the purpose of recommending hair products suitable for these determined parameters.

The term "cosmetic product" is understood, in particular within the meaning of the present invention, to mean a product as defined in Regulation (EC) No 1223/2009 of the European Parliament and Council of 30 November 2009 relating to cosmetic products.

The number and specificity of cosmetic products, and in particular of hair products, on the market is continuously increasing. Given the diversity of existing hair products, it is preferable to determine the state of the hair and of the scalp and to provide the best possible match in terms of hair products used. Hair products include, for example, shampoos, conditioners, care products, etc.

In order to determine which hair products to apply according to the individual, it is known practice to make use of questionnaires that are answered by users.

In this regard, reference could be made to document US-A1-2014/0216492, which describes a method for determining the state of the hair and a diagnostic system for prescribing a cosmetic product which is personalized according to information obtained by means of a questionnaire.

However, the analysis of these questionnaires is particularly laborious and relatively subjective.

In this regard, reference may be made to document KR-A1-101456942, which proposes a hair analysis tool that aims to determine one or more hair parameters automatically by taking photos and analysing the images, in particular by contrast. The diagnostic data are compared with reference data stored on a server before being sent to a display unit. Suitable products are then recommended.

There is a need to improve, in terms of automation and accuracy, the determination of the state of the scalp and/or of the hair of users in order to deduce the most suitable hair products therefrom. One subject of the invention is a system for automatically and accurately determining one or more parameters of the hair and/or of the scalp of a user, leading to an objective, fast and automatic recommendation of at least one target hair product.

The term "hair parameters" is understood in particular to mean hair density, the mean diameter of the hair, etc.

The term "scalp parameters" is understood in particular to mean its degree of irritation (redness), the presence of dandruff, etc.

One subject of the invention is a system for determining hair and/or scalp parameters for the purpose of recommending at least one hair product comprising:

- an image acquisition module capable of acquiring or taking at least one first photograph of the scalp and of its proximal region under illumination by white light and at least one second photograph of the same zone of the scalp and of its proximal region under illumination by blue-ultraviolet light; and

- an analysis module capable of receiving and analysing said photographs of the scalp and of its proximal region for the purpose of automatically determining the value of one or more parameters of the hair and/or of the scalp.

The image acquisition module is provided with dual illumination by white light and by blue-ultraviolet light.

The term "blue-ultraviolet light" is understood to mean light having a wavelength of between 390 and 500 nm.

The term "photograph of the scalp and of its proximal region" is understood to mean a photograph allowing the lower portion of the hair shafts to be viewed, in particular for the purpose of measuring the diameter thereof.

By virtue of illumination by white light and illumination by blue-ultraviolet light, it is possible to detect both dark-coloured elements (for example black or brown hairs, redness of the scalp) and light-coloured elements (in particular white or blond hairs, dandruff flakes). This dual illumination by white light and by blue-ultraviolet light also makes it possible to analyse both the scalp and the hair.

In one embodiment, the analysis module comprises a module for determining at least two parameters of the hair, to be chosen from between the mean diameter of the hair and the density of the hair.

Advantageously, the module for determining at least two parameters of the hair comprises a module for calculating the density of the hair and a module for calculating the mean diameter of the hair, on the basis of an analysis zone selected in each of said photographs taken by the image acquisition module. The module for calculating hair density comprises a module for counting the number of hairs, which detects hairs by contrasting the two photographs taken under the two different types of illumination, and a module for determining hair density according to the number of counted hairs and the area of each selected analysis zone. For example, in order to calculate hair density, the counting module counts the number of hairs detected by contrasting the two photographs taken under the two different types of illumination and determines the hair density according to the number of counted hairs and the area of each selected analysis zone. For example, the counting module discounts curved hairs and crossing hairs.

The module for calculating the mean diameter of the hair is based on the detection of the hair performed by the module for calculating hair density. The diameter is measured only in those zones where the hair are distinct from one another, i.e. the module for calculating the mean diameter discounts crossing hairs. In order to calculate the mean diameter of the hair, the module for calculating the mean diameter corrects the selected analysis zone in order to obtain the most vertical orientation possible. The module for calculating the mean diameter of the hair additionally comprises a module for calculating the mean width of the hair in terms of number of pixels over a fixed height and for determining the mean diameter of the hair by applying a corrective factor to the calculated mean width. In one embodiment, the analysis module comprises a module for determining at least one parameter of the scalp.

Said module comprises, for example, a module for analysing the degree of irritation of the scalp and/or a module for analysing the number of dandruff flakes present on the scalp. Said analyses may be carried out by comparing the photographs taken by the image acquisition module with a plurality of images taken from a database.

Two parameters of the scalp which are representative of the state of the scalp are thus determined.

Advantageously, the image acquisition module is configured to take photographs of the scalp over an area of between 0.2 cm ² and 0.65 cm ² , for example equal to 0.2 cm ² .

Advantageously, the image acquisition module comprises a means for magnification of between 30x and 40x, for example equal to 35x.

In one embodiment, the analysis module comprises:

- a module for receiving the one or more photographs of the scalp and of its proximal region acquired by the acquisition module; - potentially, a module for producing a general overview grouping together said parameters of the scalp and/or of the hair in order to obtain a general overview of the state of the scalp and/or of the state of the hair; and

- a module for recommending at least one suitable hair product according to said determined parameters and to a list of products contained in a database.

The personalized automatic recommendation of at least one product is faster and more reliable. Moreover, it is able to take the state of both the scalp and the hair of the user into account.

It is thus possible to obtain data on the state of the scalp and/or of the hair and a list of suitable hair products quickly and accurately and at least semi-automatically or indeed fully automatically (redness and the number of dandruff flakes may in particular be determined automatically).

In one embodiment, the system comprises a display device capable of displaying information transmitted by the analysis module.

According to a second aspect, the invention relates to a method for determining parameters of the hair and/or of the scalp of a user for the purpose of recommending at least one hair product comprising:

- a step of acquiring or taking at least one first photograph of the scalp and of its proximal region under illumination by white light and at least one second photograph of the same zone of the scalp and of its proximal region under illumination by blue-ultraviolet light; and

- a step of analysing said photographs of the scalp and of its proximal region in order to determine the value of one or more parameters of the hair and/or of the scalp.

Advantageously, when analysing said photographs of the scalp and of its proximal region, said photographs are received and parameters of the scalp and/or of the hair are determined. A general overview grouping together said parameters of the scalp and/or of the hair may potentially be produced in order to obtain a general overview of the state of the scalp and/or of the state of the hair.

In one embodiment of the invention, when determining parameters of the scalp, said first photograph under illumination by white light is compared with a plurality of images taken from a second database and the image closest to said first photograph is selected.

In another embodiment, the system autonomously evaluates, directly from the one or more photographs, one or more parameters of the scalp such as, for example, the degree of redness, which is an indicator of irritation, and/or the number of dandruff flakes or the area covered by said flakes.

In one embodiment of the invention, when determining the parameters of the hair, the density of the hair is calculated and the mean diameter of the hair is calculated according to the photographs of the scalp under the two types of illumination and its proximal region taken by the image acquisition module.

In order to calculate hair density, the number of hairs is counted by detecting the hairs by contrasting the two photographs taken under the two different types of illumination and the hair density is determined according to the number of counted hairs and the area of each selected analysis zone. For example, curved hairs and crossing hairs are discounted.

In order to calculate the mean diameter of the hair, the detection of the hairs performed by the module for calculating hair density is used as a basis. The diameter is measured only in those zones where the hairs are distinct from one another, i.e. crossing hairs are discounted. For example, in order to calculate the mean diameter of the hair, the selected analysis zone is corrected in order to obtain the most vertical orientation possible. Lastly, the mean width of the hair in terms of number of pixels over a fixed height is calculated and the mean diameter of the hair is determined by applying a corrective factor to the calculated mean width.

The module 26 for determining the parameters of the hair, via the calculation modules 32 and 34, averages the results of the different photographs obtained with each of the types of illumination.

In one embodiment, the method comprises a step of recommending at least one suitable hair product according to said determined parameters and to a list of hair products contained in a database. The method may also comprise a step of displaying the hair and/or scalp parameters and/or of displaying the one or more recommended hair products.

Further aims, features and advantages of the invention will become apparent from reading the following description, which is given only by way of non-limiting example and with reference to the appended drawings, in which:

- Figure 1 is a schematic representation of a system for determining parameters of the scalp and of the hair and for recommending a hair product according to one exemplary embodiment of the invention;

- Figure 2 is a detailed schematic illustration of an analysis module of Figure l; and - Figure 3 is a flowchart illustrating the steps of a method for determining parameters of the scalp and of the hair according to one exemplary implementation of the invention.

A system 10 for determining parameters of the scalp and of the hair and for recommending hair products is illustrated in Figure 1. The hair product may be a cosmetic product such as, for example, a hair dyeing product, a shampoo, a conditioner or a care product that is intended to be applied, for example, to the hair or to the scalp of the user.

The system 10 comprises a module for acquiring images or an image sensor 12, a communication unit 14, an analysis module 16 and a display device 18. The communication unit 14 is capable of transmitting the photographic images taken by the image acquisition module 12 to the analysis module 16 and to the display device 18. By way of non- limiting example, all of the elements of the system 10 may be integrated into a single device 1 1 shown by dashed lines in Figure 1. The device 11 may be, for example, a tablet, a computer or any other means provided with an image sensor, such as, for example, a digital video camera, a processor and a display means such as, for example, a screen.

As will be described in greater detail below, the analysis module 16 receives and analyses said photographic images, and transmits information to the display device 18.

The connections between the various modules of the system 10 are illustrated by dashed lines in Figures 1 and 2.

The image acquisition module 12 is, for example, a digital still camera or a digital video camera and it is provided with dual illumination: a first type of illumination by white light and a second type of illumination by blue-ultraviolet light.

In the example illustrated, the communication unit 14 is separate from the image acquisition module 12. As a variant, provision could be made for the communication unit 14 to be integrated directly into the image acquisition module 12. The communication unit may, for example, be a means for communication by Wi-Fi or infrared radiation, or any other transmission means allowing the photographic images to be transmitted to the analysis module 16.

The image acquisition module 12 is configured to take a first photograph PI of a portion of the scalp and of its proximal region under the first type of illumination and a second photograph P2 of the same portion of the scalp and of its proximal region under the second type of illumination. It is possible to envisage the image acquisition module 12 being configured to take a plurality of photographs of various portions of the scalp under the first type of illumination, for example three photographs, and a plurality of photographs of various portions of the scalp under the second type of illumination, for example three photographs. The first photograph PI taken under the first type of illumination allows dark-coloured hairs, such as, for example, brown hairs or black hairs, to be detected. The second photograph P2 taken under the second type of illumination allows light-coloured hairs, such as, for example, white hairs, blond hairs or bleached hairs, to be detected.

The image acquisition module 12 is configured to take photographs of the scalp over an area of between 0.2 cm ² and 0.65 cm ² , preferably 0.2 cm ² .

The image acquisition module 12 comprises a means for magnification (not shown) of between 30x and 40x, for example 35x.

The display device 18 comprises a screen, for example a touchscreen tablet or any other means allowing both the photographs taken by the image acquisition module 12 and the result of the analysis from the analysis module 16 to be displayed.

The analysis module 16, illustrated in detail in Figure 2, comprises a module 20 for receiving the photographs PI, P2 taken by the image acquisition module 12 and delivered by the communication unit 14 (Figure 1) or directly by the image acquisition module 12.

The analysis module 16 additionally comprises a module 24 for determining parameters of the scalp and a module 26 for determining parameters of the hair.

As illustrated, the module 24 for determining parameters of the scalp comprises a module 28 for analysing the degree of irritation of the scalp and a module 30 for analysing the level of dandruff present on the scalp.

In one variant, the module 28 for analysing the degree of irritation of the scalp displays, on the display device 18, the first photograph taken under one of the types of illumination and at least two images taken from a database Bl that were taken under the same type of illumination, corresponding to two degrees of irritation of the scalp, for example not irritated or very irritated.

As a variant, provision could be made for a number of images taken from the database Bl of greater than or equal to three, for example four, corresponding for example to a scalp that exhibits no irritation, a low degree of irritation, a medium degree of irritation or a high degree of irritation. The user then selects the image taken from the database that is closest to said photograph taken under the first type of illumination. Similarly, the module 30 for analysing the level of dandruff on the scalp displays, on the display device 18, the first photograph taken under one of the types of illumination and at least two images that were taken under the same type of illumination from the database B 1 , corresponding to two levels of dandruff present on the scalp, for example no dandruff or a large amount of dandruff. As a variant, provision could be made for a number of images taken from the database of greater than or equal to three, for example four, corresponding for example to a scalp including no dandruff, a small amount of dandruff, a medium amount of dandruff or a large amount of dandruff. The user then selects the image taken from the database that is closest to said photograph PI taken under the same type of illumination.

The module 26 for determining parameters of the hair additionally comprises a module 32 for calculating the density D of the hair and a module 34 for calculating the mean diameter φ of the hair according to the photographs PI, P2 of the scalp and its proximal region taken by the image acquisition module 12 and from the database Bl .

Each calculation module 32, 34 selects an analysis zone, for example a zone centred on each of the photographs PI and P2 taken by the image acquisition module 12. The analysis zone is between 0.15cm ² and 0.18cm ² , for example equal to 0.16cm ² . The analysis zone allows both the hair density D and the mean diameter φ of the hair to be calculated using a photograph PI, P2 taken under the two types of illumination (white light and blue-ultraviolet light).

In the case that the image acquisition module 12 takes a plurality of photographs of the scalp under white light and under blue-ultraviolet light, there are two possibilities. Either the module 26 for determining the parameters of the hair, via the calculation modules 32 and 34, averages the results of the various photographs obtained under each of the types of illumination, or the module 26 for determining the parameters of the hair transmits all of the photographs taken by the image acquisition module 12 to the display module 18 so that the user manually selects at least one photograph under the white light and at least one photograph under the blue-ultraviolet light. The photographs selected by the user are then transmitted to each of said calculation modules 32, 34.

The module 32 for calculating hair density comprises a module for counting the number of hairs, which detects hairs by contrasting the two photographs taken under the two different types of illumination, and a module for determining hair density according to the number of counted hairs and the area of each selected analysis zone. In order to calculate hair density, it is preferable to count the number of hairs detected by contrast and to determine the hair density according to the number of counted hairs and the area of each selected analysis zone. An effort is also made to discount curved hairs and crossing hairs.

The module 34 for calculating the mean diameter of the hair is based on the detection of the hairs performed by the module 32 for calculating hair density. The diameter is measured only in those zones where the hairs are distinct from one another, i.e. the module 34 discounts crossing hairs. In order to calculate the mean diameter of the hair, it is preferable to correct the selected analysis zone in order to obtain the most vertical orientation possible. The module 34 for calculating the mean diameter of the hair additionally comprises a module (not shown) for calculating the mean width of the hair in terms of number of pixels over a fixed height and for determining the mean diameter of the hair by applying a corrective factor γ to the calculated mean width.

The calculation modules 32, 34 use the photograph of one and the same portion of the scalp and of its proximal region as a basis. As a variant, provision could be made for the calculation modules 32, 34 to use photographs of different portions of the scalp and of its proximal region as bases.

The analysis module 16 preferably additionally comprises a module 36 for producing a general overview grouping together the parameters of the scalp and of the hair in order to obtain a summary of the state of the scalp and of the state of the hair.

The analysis module 16 also comprises a module 38 for recommending products matched to the state of the scalp and/or of the hair determined beforehand according to a list of products contained in a database B2.

In order to recommend a product personalized to the scalp and to the hair of the user, the module 38 for recommending products compares the parameters of the scalp and of the hair, i.e. preferably the degree of irritation of the scalp, the level of dandruff present on the scalp and the hair diameter and density, with parameters of the scalp and of the hair contained in a third database B3 and proposes hair products associated with these parameters.

The databases B2 and B3 may consist of a single database. The databases Bl,

B2 and B3 are, for example, stored locally.

Figure 3 is a flowchart illustrating the main steps of a method 40 for determining parameters of the scalp and of the hair and for providing a personalized recommendation of at least one hair product. The method 40 comprises a step 42 of acquiring or taking at least one first photograph PI of the scalp and of its proximal region under illumination by white light and at least one second photograph P2 of the scalp and of its proximal region under illumination by blue-ultraviolet light using the image acquisition module 12 and a step 44 of receiving said photographs.

Once the photographs have been taken by the image acquisition module 12, said photographs are analysed in order to determine one or more parameters of the scalp and/or one or more parameters of the hair and to deduce a recommendation of at least one suitable hair product therefrom.

The method thus preferably comprises a step 46 of determining two parameters of the scalp that are representative of the state of the scalp such as, for example, the degree of irritation and the number of dandruff flakes present on the scalp.

In one variant of the invention, in order to determine the degree of irritation of the scalp and the level of dandruff present on the scalp, the user compares said first photograph PI taken under illumination by white light with at least two images taken from the database Bl and selects the image closest to said first photograph PI .

In one variant that may be identical to or differ from the preceding variant, the method also comprises a step 48 for determining two parameters of the hair that are representative of the state of the hair such as, for example, hair density and diameter.

By way of non-limiting example, in order to calculate the density of the hair, the number of hairs is counted by detecting the hairs by contrasting the two photographs taken under the two different types of illumination and the hair density is determined according to the number of counted hairs and the area of each selected analysis zone.

By way of non-limiting example, in order to calculate the mean diameter of the hair, crossing hairs are detected and discounted. Curved hairs may also be detected and discounted. Once curved hairs have been discounted, the analysis zone is oriented so that the hair to be analysed is positioned in a vertical plane and the mean width of the hair is calculated in terms of number of pixels over a fixed height. A corrective factor γ may then be applied to the calculated mean width in order to determine the mean diameter of the hair.

Once the state of the hair and of the scalp has been determined, the method preferably comprises a step 50 of producing a general overview of the state of the scalp and of the state of the hair that were determined beforehand and displays this result on the display device 18. Provision is also made for a step 52 of recommending a hair product in order to provide a list of at least one hair product matched to the state of the scalp and/or of the hair determined beforehand according to a list of products contained in the database B2. In the step 52 of recommending a hair product, the parameters of the scalp and/or of the hair that were determined beforehand or the obtained overview are compared with parameters of the scalp and of the hair or with reference overviews contained in a third database B3, which may or may not be merged with the database B2, and hair products associated with these elements are proposed by the system.

By virtue of the system according to the invention, it is possible to carry out a complete diagnosis of the hair and/or of the scalp, preferably of the hair and of the scalp, on the basis of at least one photograph of the scalp and of its region taken under illumination by white light and at least one photograph of the same zone of the scalp taken under illumination by blue-ultraviolet radiation and data provided by a database.