METHOD FOR DETERMINING THE SHINE OF A SECTION OF A USER'S SKIN

Abstract

Method (100) for determining a gloss value of a section (201) of a user's skin (200), the method comprising: - Emitting (110) a polarized light (220) with known properties from a portable light source (211) towards the section of the user's skin, wherein the portable light source is arranged on a mobile device (210), wherein the polarized light is thrown directly from the portable light source onto the section of the user's skin; - Measuring (120) the reflected light (230) that has acted upon the section of the user's skin using a sensor (212) arranged on the mobile device; - Determining (130) a ratio between the properties of the emitted polarized light and the properties of the measured reflected light using a processor of the mobile device; - Determining (140) the gloss value of the section of the user's skin based on the determined ratio, and - Outputting or triggering an output of the specified gloss value, wherein the method is characterized in that the portable light source is part of a display (214) of the mobile device, and wherein the method further comprises: - Activating part (310, 320, 330) of the display of the mobile device to emit polarized light towards the section of the user's skin.

Description

TECHNICAL AREA

[0001] The invention relates to the field of characterizing skin properties, in particular skin luster, in order to determine the most relevant beauty care products suitable for a current skin condition. TECHNOLOGICAL BACKGROUND

[0002] In skincare, it is common to offer a wide range of cosmetic products specifically designed for different skin types. Skin can differ, for example, in color, the presence of wrinkles, pore size, the presence of sweat or oily substances such as sebum or other secretions, and the presence of bacteria, such as those that lead to acne.

[0003] The appearance of the skin can change from day to day and requires regular observation to determine which skincare products are best suited to convey the appearance desired by the user.

[0004] Among the many parameters that influence the appearance of skin before or after applying skincare products, such as creams or dyes, shine is particularly relevant. Skin shine can vary from day to day and is further affected by external conditions such as temperature and humidity. Generally, people consult skincare professionals or visit retail outlets to have their skin shine measured. Specialized portable shine meters have been developed specifically for these professionals. These meters include a light source and two sets of sensing devices to measure light reflected and scattered by the skin. A specific lighting configuration requires mirrors to keep the portable device small enough to be held with one hand.The cost of a dedicated device discourages users from purchasing such a radiance meter and using it regularly at home. As a result, users cannot easily monitor the development of their skin's radiance and cannot easily select the most suitable cosmetic products based on their current radiance.

[0005] Document US 2016 / 098614 A1 describes a gloss determination device that determines a gloss state by processing a photograph of an object illuminated with polarized light.

[0006] Document WO 2018 / 073266 A1 describes a device for a skin image acquisition unit that can determine skin gloss.

[0007] Document WO 2018 / 001727 A1 describes a method and device for determining skin gloss. The determination is based on illuminating the skin with flashes of light. Document DE 691 09 413 T2 describes a device for analyzing the properties of a surface using images taken with light coupled to a polarizer and an analyzer.

[0008] Therefore, a method is being sought to determine the gloss level of a user's skin more easily and cost-effectively. BRIEF SUMMARY OF THE INVENTION

[0009] To overcome the above disadvantages, the invention provides a method for determining a gloss value of a section of a user's skin, the method comprising: -Emitting a polarized light with known properties from a portable light source towards the section of the user's skin, wherein the portable light source is arranged on a mobile device, and wherein the polarized light is projected directly from the portable light source onto the section of the user's skin; -Measuring the reflected light that has acted on the section of the user's skin using a sensor located on the mobile device; -Determining a ratio between the properties of the emitted polarized light and the properties of the measured reflected light using a processor of the mobile device; - Determining the gloss value of the user's skin section based on the specified ratio, and - Outputting or triggering an output of the specified gloss value, wherein the method is characterized in that the portable light source is part of a display of the mobile device, and wherein the method further comprises: - Activating part of the mobile device's display to emit polarized light towards the section of the user's skin.

[0010] The invention makes determining a user's skin gloss more accessible by using a mobile device to process optical information collected from the user's skin. The light source and camera can be integrated into the mobile device and positioned on it, for example, by being glued or clamped to its surface.

[0011] Unlike dedicated devices in the prior art, the method of the invention does not require mirrors to direct light onto the user's skin, but can project light directly onto the user's skin. The angle of incidence of the emitted light on the skin can also be adjusted by changing the orientation of the light source and / or the camera.

[0012] The term “mobile device” preferably refers to, for example, a portable phone, a tablet or a smartwatch.

[0013] The term "properties," when referring to emitted polarized light or reflected light, can typically include the intensity of light, which is generally used in the prior art when determining gloss values. It can also include spectral information about the light.

[0014] The term "gloss value" can refer to a qualitative description of skin gloss (low, medium, high) or correspond to a value on a scale used to measure skin gloss. Gloss units, for example, can be used to express the gloss value. Gloss units might typically correspond to the ratio of reflected to incident light from a section of the user's skin compared to the same ratio obtained for a gloss reference material, such as black glass with a known refractive index. The terms "gloss" and "gloss" are used interchangeably in this description.

[0015] The method for determining gloss is described in the prior art literature; typically, incident light strikes the user's skin at an angle of approximately 60°. Specular reflection is measured, and the ratio of the intensity of the incident light to the reflected light is used as an indicator of gloss. Conversion to units is achieved by comparing this ratio to a reference standard.

[0016] The portable light source is part of a display of the mobile device, the method further comprising: - Activating part of the mobile device's display to emit polarized light towards the section of the user's skin.

[0017] The display of a mobile device, such as a smartphone, tablet, or smartwatch, can be used as a portable light source. A special program can activate the entire display or just a section of it to project light directly onto the user's skin. The properties of the emitted light (intensity, spectrum) can also be adjusted or directed onto the user's skin according to a pre-programmed sequence.

[0018] According to one embodiment, the method may further include: - Activating different parts of the mobile device's display that differ by a distance separating the different parts of the mobile device's display from the sensor.

[0019] The spatial extent of the mobile device's display, which could be, for example, a portable phone, tablet, or smartwatch, allows for the activation of only one or more sections of the display at a time to adjust the angle of incidence of the light projected onto the user's skin. The distance between the camera and the light source can thus be varied to test different lighting configurations and capture multiple comparable measurements of the properties of the light acting on the user's skin.

[0020] In particular, it is possible to program a lighting sequence that, for example, activates sections of the display according to a pattern or sequence, creating different angles of incidence for the light projected onto the user's skin. For this purpose, the activated section of the display is advantageously a point or a narrow band of light. Such sequence activation can also help to reduce the influence of the distance between the mobile device and the user's skin. If a user positions the mobile device's display and camera toward their skin in a configuration similar to a "selfie" mode, they cannot precisely control the distance between the mobile device and their skin.By testing different lighting configurations, the method can overcome this disadvantage and obtain measurements for a range of angles of incidence that remain essentially the same between different uses of the mobile device.

[0021] According to one embodiment, the different parts of the display of the mobile device can be activated one after the other.

[0022] According to one embodiment, the polarized light with known properties can be projected onto the section of the user's skin at an angle of incidence between 10° and 75°.

[0023] According to one embodiment, the method may further include: - Measuring the amount of light scattered through the section of the user's skin.

[0024] According to one embodiment, the scattered light can be measured with a camera of the mobile device.

[0025] Measuring scattered light provides another way to improve the determination of the user's skin radiance. The signal captured from scattered light can, for example, compensate for the influence of skin color. For this purpose, a subtraction between the reflected and scattered light can be performed before determining the radiance of the user's skin section.

[0026] According to one embodiment, the mobile device can be selected from: a portable phone, a tablet or a smartwatch.

[0027] According to one embodiment, the method may further include: - Recording a gloss value determined for the section of the user's skin at a first time point; - Recording a gloss value determined for the section of the user's skin at a second time point, which differs from the first time point; - Outputting an assessment of the gloss of the user's skin section based on the gloss value determined at the first and second time points.

[0028] According to one embodiment, the method may further include: - Determine at least one recommended non-therapeutic skincare product for the user's skin section based on the determined shine value; - Issuing a reference that identifies the specific at least one recommended non-therapeutic skincare product.

[0029] To determine a recommended skincare product, such as cosmetics or creams, that will alter the appearance of the user's skin, the process typically accesses a database containing a correspondence between shine levels and non-therapeutic skincare products considered suitable for a given shine level. The typical effect users seek is to reduce their skin's shine.

[0030] Furthermore, it is possible to ask the user about the desired effect before recommending non-therapeutic skincare products, in case the user wants an effect other than shine reduction. Input provided by the user can be used to access relevant product descriptions in a database.

[0031] The invention also relates to a system for determining the shine of a section of a user's skin, wherein the system comprises: - a portable light source configured to emit polarized light of known properties to the section of the user's skin such that the polarized light is projected directly onto that section of the user's skin by the portable light source; - a sensor configured to measure the reflected light that has acted upon the section of the user's skin; - a mobile device that includes a processor configured as follows: - to determine a relationship between the properties of the emitted polarized light and the properties of the measured reflected light; - to determine the gloss value of the section of the user's skin based on the specified ratio; wherein the sensor is arranged on the mobile device or forms an integral part thereof, wherein the sensor is capable of transmitting information to the mobile device, wherein the portable light source is part of a display of the mobile device, and wherein the display of the mobile device is capable of emitting the polarized light towards the section of the user's skin by activating a part of the display of the mobile device.

[0032] Such a system is particularly suitable for implementing the method described above in such a way that a user can repeatedly assess their skin's shine without the need to visit a retail outlet or consult a skincare expert. The invention makes measuring skin shine more accessible to users. With the system according to the invention, users can therefore regularly collect data on the development of their skin's shine to gain insight into its condition and adjust their daily skincare routine accordingly, for example, by selecting more suitable cosmetics that are compatible with their skin's shine or by choosing specific cleansers, creams, or moisturizing lotions.

[0033] The invention also relates to a non-volatile, computer-readable storage medium with a computer program stored thereon, which includes instructions for carrying out a method for determining a gloss value of a section of a user's skin, as described above.

[0034] In other words, the invention also relates to a computer program product comprising instructions for carrying out a method for determining a gloss value of a section of a user's skin as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present disclosure is described below in conjunction with the following drawing figures, where the same reference numerals denote the same elements, and: Fig. 1. A flowchart that summarizes the steps of a procedure for determining a gloss value of a section of a user's skin; Fig. 2 a schematic representation of a mobile device equipped with a sensor, which is capable of implementing the method of the invention; Fig. 3 is a schematic representation of a mobile device used in a mode that projects light with its display onto the skin of a user and measures reflected and scattered light with the camera of the mobile device.

[0036] For the sake of clarity, the dimensions of the features shown in these figures may not necessarily correspond to the actual size proportion of the corresponding elements. DETAILED DESCRIPTION

[0037] The following detailed description is merely exemplary and is not intended to limit the disclosure, application, or uses of the subject matter described herein. Furthermore, no commitment to any theory set forth in the preceding background or in the detailed description below is intended.

[0038] The invention provides a portable device for easily determining the shine level of a user's skin. This allows users to regularly monitor the shine of their skin (on any part of it), eliminating the need to visit a retail outlet or purchase expensive equipment.

[0039] To determine a user's skin gloss level, it is advantageous to use the flowchart from Fig. to follow 1 summarized steps. Fig. Figure 1 shows a method for determining a user's skin gloss level. The value can be measured on different sections of a user's skin to differentiate between various body or facial areas for more accurate estimates and product recommendations.

[0040] First, the method consists of emitting polarized light with known properties toward a section of the user's skin. 110 This polarized light can have a known intensity and spectrum (generally essentially monochromatic) and is emitted from a portable light source. The portable light source is located on a portable device such as a smartphone, another portable phone, a tablet, or a smartwatch. The portable light source can be an integral part of the mobile device.

[0041] The procedure then continues by measuring reflected light that has acted on the position of the user's skin using a sensor located on the mobile device 120.

[0042] This sensor can typically be a CCD camera and can even be a camera that forms an integral part of the mobile device. Alternatively, the sensor can be mounted on the mobile device using fastening mechanisms: a magnetic mounting mechanism, a clamp, adhesive, or a screw. Advantageously, the sensor is positioned on an opposite edge of the mobile device to measure light reflected at a 60° angle onto the user's skin. A typical gloss measurement would rely on incident light striking the user's skin at an angle of incidence between 5° and 85°, preferably between 40° and 70°.If the mobile device is, for example, a handheld phone, its length separates the light source from the sensor by approximately 15 cm. This creates conditions that allow the area of ​​skin to be illuminated at a 60° angle of incidence and the reflected light to be captured in a close-up selfie configuration. In such a configuration, the user can hold the mobile device a few centimeters above the area of ​​skin to measure the reflected light.

[0043] The light detected by the sensor is then processed to compare its properties with those of the light emitted by the light source in a subsequent step. This step corresponds to determining the ratio of the properties of the reflected light to those of the incident light, and thus the gloss value. Specifically, a ratio between the intensity of the reflected light and the intensity of the incident light can be calculated to establish a gloss value. As is common with available gloss meters, this ratio can also be compared to a reference value, for example, the same ratio obtained on a black glass with a known refractive index. Typically, this black glass might be a highly polished black glass with a refractive index of 1.567 for the sodium D-line, associated with a gloss value of 100.The ratios between incident light and reflected light on other surfaces are compared to this reference ratio and assigned a gloss value higher or lower than 100.

[0044] Other means of defining gloss value can also be used.

[0045] Finally, the process can be completed by outputting or triggering the output of the specified gloss value. This can typically be done by displaying the specified gloss value on a display of the mobile device or by transmitting this value to another device.

[0046] In the embodiment where the sensor is not an integral part of the mobile device, it is possible to transmit the measured reflected light to a processor of the mobile device. For example, if the sensor is the camera of the mobile device, the measured reflected light can be transmitted to a processor of the mobile device to determine the gloss value and display it to the user.

[0047] The mobile device can also output the gloss value by expressing it verbally to the user (for example, speech output via a speaker of the mobile device or another suitable device).

[0048] The procedure described above can be guided by the user using their mobile device and interact with via an app. In particular, such an app can guide the user through the process of emitting polarized light, measuring the reflected light, and specifically by indicating how to position the mobile device over the section of the user's skin.

[0049] The app can advantageously receive user input, information about their age, skin tone, and the type of skincare products used. Furthermore, the app can use local information about weather and location to consider other factors that may influence the user's skin radiance.

[0050] The gloss value can be displayed as a number, for example, in specific gloss units as described above. Alternatively, the gloss value can also be a more qualitative assessment of the gloss of the user's skin area, for example, indicating that the user's skin has a low, medium, or high gloss value.

[0051] In addition to displaying the shine level, the system can also provide product recommendations to the user. Specifically, it can access a database and select a range of non-therapeutic skincare products, such as creams and lotions, to reduce shine. These recommendations can be refined by asking the user via an app about the desired effect (e.g., reducing shine, increasing shine, and the time of day when the effect is desired).

[0052] The app can monitor the development of the user's skin radiance by recording each value and measurement time and comparing it to previous measurements. This can enable more accurate product recommendations or predict the future development of the user's skin radiance and adjust the product recommendation accordingly, further based on existing user input.

[0053] The Fig. Figure 3 shows a possible system arrangement to enable the implementation of the method according to the invention. Fig. 2 is not part of the invention.

[0054] In Fig. Figure 2 depicts a user 200 with a section 201 of skin. A mobile device 210 in the form of a portable telephone is positioned such that its display 214 faces the section 201 of the user 200's skin. A portable light source 211 is attached to an edge of the mobile device 210 and emits polarized light 220 towards the section 201 of the user 200's skin. The angle of incidence 240 of this light is advantageously set to 60°, but other angles are also acceptable, provided that the sensor 212 on another edge of the mobile device allows the measurement of the light reflected onto the section 201 of the user 200's skin.

[0055] The reflected light 230 arrives at the sensor 212.

[0056] The mobile device 210 typically already includes a camera 213, which could also serve as the sensor. In this case, the portable light source could, for example, be located at the lower edge of the mobile device 210, as shown in Fig. Figure 2 illustrates this. The display 214 of the mobile device 210 can also serve as a portable light source or as an additional light source emitting the same light as the portable light source 211. This second light can be used at different angles of incidence to measure the light scattered by the user's skin in order to subtract the contribution of skin color or specific skin features to the gloss value being determined. This feature, which consists of recording light scattered by the skin to measure its gloss value more accurately, is already known from existing gloss meters. Prior art gloss meters typically measure the scattered light at an angle of incidence of 0°. The invention can measure scattered light at different angles depending on the relative position of the light source (a separate element, such as a portable light source 211 or the display 214 of the mobile device 210).

[0057] Fig. Figure 3 shows an embodiment of the invention. Fig.3 The portable light source is located in the display of the mobile device 210. The polarized light is emitted by activating a part 310, 320, 330 of the display. This area is advantageously a strip or a spot, but can also be the entire screen of the mobile device or any other pattern thereon. The app, which can be used to determine the gloss value of the section of the user's skin, can activate parts 310, 320, 330 in a sequence, for example, as a scanner. This illuminates the user's skin section at different angles of incidence, and the reflection point 302, 303, 304 on the skin varies accordingly.This method can be used to determine an average gloss value over a section of a user's skin extending over a few centimeters, thereby avoiding equally inaccurate determinations due to the presence of irregularities on the user's skin.

[0058] The steps of the examples and embodiments described above can be implemented by a processor such as a computer. A computer program product that includes steps of the procedure described above can be used to implement the procedure on a computer.

[0059] Various types of non-volatile, computer-readable storage media, comprising a computer program with instructions for implementing the method according to the invention, can be used. These could, for example, include a processor or chip, an electronic circuit comprising several processors or chips, a hard disk, a flash or SD card, a USB stick, a CD-ROM or DVD-ROM, a Blu-ray disc, or a floppy disk.

[0060] Although at least one exemplary embodiment has been presented in the foregoing detailed description, it should be noted that a large number of variations exist. Furthermore, it is understood that the exemplary embodiment or embodiments are merely illustrative examples and do not in any way limit the scope, applicability, or configuration of the various embodiments. Rather, the foregoing detailed description provides those skilled in the art with practical guidance for implementing an exemplary embodiment in accordance with the present context. It is understood that various modifications to the function and arrangement of elements described in an exemplary embodiment can be made without departing from the scope of the various embodiments set out in the appended claims.

Claims

[1] Method (100) for determining a gloss value of a section (201) of a user's skin (200), the method comprising: - Emitting (110) a polarized light (220) with known properties from a portable light source (211) towards the section of the user's skin, wherein the portable light source is arranged on a mobile device (210), wherein the polarized light is thrown directly from the portable light source onto the section of the user's skin; - Measuring (120) the reflected light (230) that has acted upon the section of the user's skin using a sensor (212) arranged on the mobile device; - Determining (130) a ratio between the properties of the emitted polarized light and the properties of the measured reflected light using a processor of the mobile device; - Determining (140) the gloss value of the section of the user's skin based on the determined ratio, and - Outputting or triggering an output of the specified gloss value, wherein the method is characterized in that the portable light source is part of a display (214) of the mobile device, and wherein the method further comprises: - Activating part (310, 320, 330) of the display of the mobile device to emit polarized light towards the section of the user's skin. [2] The method of claim 1, further comprising: - Activating different parts of the display of the mobile device, wherein the different parts differ by a distance that separates the different parts of the display of the mobile device from the sensor. [3] Method according to claim 2, wherein the different parts of the display of the mobile device are activated one after the other. [4] Method according to one of the preceding claims, wherein the polarized light of known properties is thrown onto the section of the user's skin with an angle of incidence (240) which is between 10° and 75°. [5] Method according to any one of the preceding claims, further comprising: - Measuring the amount of light scattered through the section of the user's skin. [6] Method according to claim 5, wherein the scattered light is measured with a camera (213) of the mobile device. [7] Method according to any of the preceding claims, wherein the mobile device is selected from: a portable phone, a tablet, a smartwatch. [8] Method according to any one of the preceding claims, further comprising: - Recording a gloss value determined for the section of the user's skin at a first time point; - Recording a gloss value determined for the section of the user's skin at a second time point, different from the first time point; - Outputting an assessment of the gloss of the user's skin section based on the gloss value determined at the first and second time points. [9] A method according to any one of the preceding claims, further comprising: - Determine at least one recommended non-therapeutic skincare product for the user's skin area based on the determined shine value; - Issuing a reference that identifies the specific at least one recommended non-therapeutic skincare product. [10] System for determining a gloss value of a section (201) of a user's skin (200), the system comprising: - a portable light source (211) configured to emit polarized light (220) of known properties to the section of the user's skin such that the polarized light is projected directly onto the section of the user's skin by the portable light source; - a sensor (212) configured to measure the reflected light (230) that has acted upon the section of the user's skin; - a mobile device (210) comprising a processor configured as follows: - to determine a relationship between the properties of the emitted polarized light and the properties of the measured reflected light; - to determine the gloss values ​​of the section of the user's skin based on the specified ratio; wherein the sensor is arranged on the mobile device or forms an integral part thereof, wherein the sensor is capable of transmitting information to the mobile device, wherein the portable light source is part of a display (214) of the mobile device, and wherein the display of the mobile device is capable of emitting the polarized light towards the section of the user's skin by activating a part (310, 320, 330) of the display of the mobile device. [11] Non-volatile computer-readable storage medium with a computer program stored thereon, comprising instructions for carrying out a method for determining a gloss value of a section of a user's skin according to any one of claims 1 to 9.

Images