Quantitative assistance in assessing and / or changing a person's skin state

Abstract

The invention relates to a method including a) providing a plurality of indicators (10, 20), the indicators being indicative of a current skin state of the person and / or of an influence on a skin state of the person, and b) determining, for informing the person about the current skin state and / or an expected future skin state, an assistance quantity (61, 62, 63) based on a normalization and a renormalization of the indicators, the renormalization being based on at least one renormalizing feature selected from an age and / or a genetic characteristic of the person. An accordingly determined assistance quantity can be an improved assistance for a person in assessing and / or changing his or her skin state.

Description

[0001] Quantitative assistance in assessing and / or changing a person’s skin state

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a method, a device and a computer program for assisting in assessing and / or changing a skin state.

[0004] BACKGROUND OF THE INVENTION

[0005] The complexity of the human skin makes it difficult for individuals to reliably assess a state of their own skin. In clinical practice, several measures are known for quantifying specific aspects of the human skin. However, even for individuals having access to such measures it will often not be clear how to combine them in order to receive a holistic view on the skin. The difficulty in reliably assessing a skin state can particularly be a hurdle for individuals aiming to improve their skin state. For such individuals, specifically the complexity of the human skin regarding its reactions to influencing factors is of additional relevance. Without being able to reliably assess their skin state and also how their skin might react to changes in influencing factors, it can become practically impossible for individuals to improve their skin state. There is therefore a need for assistance in assessing and / or changing a skin state of a person.

[0006] SUMMARY OF THE INVENTION

[0007] It is an object of the invention to provide assistance in assessing and / or changing a skin state of a person.

[0008] In a first aspect, a computer-implemented method for assisting in assessing and / or changing a skin state of a person is presented, the method including the following steps: a) providing a plurality of indicators, the indicators being indicative of a current skin state of the person and / or of an influence on a skin state of the person, and b) determining, for informing the person about the current skin state and / or an expected future skin state, an assistance quantity based on the indicators. The assistance quantity is preferably determined based on a renormalization of the indicators. The renormalization may be based on at least one renormalizing feature of the person. In particular, therefore, the presented method may additionally include a step of providing the at least one renormalizing feature of the person, wherein then the step of determining the assistance quantity refers to determining the assistance quantity based on the indicators and the provided at least one renormalizing feature. The at least one renormalizing feature may be selected from an age and / or a genetic characteristic of the person.

[0009] The assistance quantity is preferably also determined based on a normalization of the indicators. The normalization may refer to a normalization to a same numerical range. In particular, therefore, the method preferably further comprises a step of normalizing the indicators to a same numerical range.

[0010] Thus, preferably a normalization and a renormalization of the indicators is carried out for determining the at least one assistance quantity. The normalization may be carried out before the renormalization or vice versa, i.e., the renormalization may also be carried out before the normalization. In other words, the indicators may be normalized and the assistance quantity may be determined based on the normalized indicators and the at least one normalizing feature, orthe assistance quantity may be determined by renormalizing at least one of the indicators and thereafter normalizing the indicators, of which at least one may have already been renormalized, to a same numerical range.

[0011] As far as the normalization is carried out before the renormalization, a computer-implemented method for assisting in assessing and / or changing a skin state of a person is presented, the method including the following steps: a) providing a plurality of indicators, the indicators being indicative of a current skin state of the person and / or of an influence on a skin state of the person, b) normalizing the provided indicators to a same numerical range, c) providing at least one renormalizing feature of the person, the at least one renormalizing feature being selected from an age and / or a genetic characteristic of the person, and d) determining, for informing the person about the current skin state and / or an expected future skin state, an assistance quantity based on the normalized indicators and the at least one renormalizing feature of the person.

[0012] In any case, since a plurality of indicators are provided that are indicative of a current skin state of the person and / or of an influence on a skin state of the person, a quantitative basis is provided for assessing the current skin state and / or possible changes thereof. By normalizing the indicators to a same numerical range, their meaning for the assessment can be more easily compared to each other, which can also make it easier to combine them. In other words, differences between the indicators in what constitutes “good and bad” can be taken into account by normalizing the indicators to a same numerical range. The “same” numerical range may be understood as a predefined numerical range being the same for all indicators. Normalizing an indicator to a predefined numerical range may refer to mapping values of the indicator to the predefined numerical range, such as according to a predefined normalization rule. Normalization rules for the indicators may be chosen such that the normalized values of the indicators share a same interpretation regarding the skin state and / or an expected change of the skin state. For instance, different indicators will typically have different non-normalized values signifying the same degree to which the skin state, as indicated by the respective indicator, can be considered good or bad. In contrast, this degree may uniquely correspond to a single normalized value of the different indicators.

[0013] While the normalization can account for differences between the indicators in what constitutes “good and bad”, it has been realized that there will also be differences between individuals, and even over time for a same individual, in what constitutes “good and bad”, and that these differences might also need to be taken into account. It has been found that this can be done by using at least one renormalizing feature being selected from an age and / or a genetic characteristic of the person. If at least one such renormalizing feature of the person is provided and, for informing the person about the current skin state and / or an expected future skin state, an assistance quantity is determined based on the indicators and the at least one renormalizing feature of the person, this assistance quantity can be an improved assistance forthe person in assessing and / or changing the skin state. It has been realized that this is the case irrespective of whether a) the indicators are first normalized and then the at least one renormalizing feature is additionally used to determine the assistance quantity based on the (normalized) indicators, or b) the at least one renormalizing feature is first used to adjust the indicators and then a normalization of the (adjusted) indicators is carried out to determine the assistance quantity.

[0014] The assistance quantity may generally refer to a derived quantitative measure for the person's skin state and / or a change in the person's skin state. The quantitative measure may assist the person in assessing and / or changing his or her skin state. It may be referred to as being derived, since it is determined based on indicators indicative of a current skin state of the person and / or an influence on the skin state of the person. The assistance quantity may also be referred to as a score. It should be noted that a single indicator can be indicative both of the current skin state and of an influence on the skin state. This is because the current skin state can indicate past influences on the skin as well as a susceptibility of the skin to change in response to influences, both of which may also indicate future influences on the skin. For instance, wrinkles or elasticity can indicate a degree to which the skin was subject to environmental influences in the past, and / or a degree to which the skin reacted to such influences, wherein the past environmental influences and the degree to which the skin reacted to those influences can be likely to persist into the future. Similarly, a collagen intensity in the skin measured at some point in time not only indicates the skin state at that point in time, but also indicates how the skin will evolve in the future, i.e., from that point in time onwards. The amount of collagen in the skin determines, among other factors, the skin’s resilience against environmental influences such as UV radiation, and hence the likelihood of the skin to develop wrinkles, for instance.

[0015] Accordingly, the assistance quantity may inform the person both about the current skin state and the expected future skin state, and hence may assist the person both in assessing the current skin state and in changing the skin state.

[0016] Providing the plurality of indicators can include receiving previously acquired indicators via a data interface and thereafter providing the received indicators. Similarly, the plurality of indicators can be provided by retrieving them from a storage.

[0017] Besides the plurality of indicators and the at least one renormalizing feature, a normalization range for each of the indicators may be provided. While the at least one renormalizing feature may be provided for renormalizing at least one of the indicators, the normalization ranges may be provided for normalizing the indicators to the same numerical range. The normalization ranges may be predefined based on observed normal, healthy or possible ranges of a respective indicator in a population or a part thereof. In particular, the normalization ranges may be chosen to correspond to observed normal, healthy or possible ranges of a respective indicator. The renormalization may, on the other hand, refer to an adjustment of a respective indicator which is chosen based on the at least one renormalizing feature such that the influence of the at least one renormalizing feature on the adjusted indicator is decreased. In other words, where a non-renormalized value of an indicator depends on a renormalizing feature such as a person’s sex, age or ethnicity, its renormalized version may depend less or not at all on the sex, age or ethnicity. The normalization and the renormalization may interact or be combined in a combined adjustment of indicator values to a same numerical range. The at least one assistance quantity may thus be determined based on a mapping of indicator values to the same numerical range, wherein the mapping depends on the at least one renormalizing feature. The mapping may correspond to a graph, or curve, which indicates how non-normalized and nonrenormalized values of indicators are mapped to values in the same numerical range.

[0018] Moreover, a weight may be provided for each of the indicators, for weighting the indicators according to a respective relevance for assisting in informing the person about the current skin state and / or the expected future skin state. The relevancies and hence the weights may be predefined. Like the indicators, also the at least one renormalizing feature, the normalization ranges and the weights may be provided based on receiving them via an interface, or by retrieving them from a storage, for instance.

[0019] Hence, in an embodiment, the indicators, a normalization range for each of the indicators, at least one renormalizing feature and a weight for each of the indicators is provided, wherein at least one assistance quantity is determined based on the indicators, the normalization ranges, the at least one renormalizing feature and the weights. It may be preferred to determine the at least one assistance quantity by first renormalizing the indicators, then normalizing the renormalized indicators and subsequently weighting the normalized renormalized indicators.

[0020] One or more of the indicators may indicate at least the current skin state of the person in terms of a measured value associated with at least one of the following: a collagen intensity, a retraction time, hydration, wrinkles. Using values from such measurements has been found to be particularly useful for reliably indicating a skin state. Retraction time and collagen intensity may be viewed as characterizing a firmness of the skin, and may be measured by known mechanical, specifically biomechanical, measurement means. In particular, collagen intensity may be measured using ultrasound, for instance. The hydration of the skin may be measured, for instance, as skin conductivity. Wrinkles may be quantified in terms of their number or density and / or their strength and / or the area of the face they cover. This may be measured visually or by means of optical measurement instruments, including image-based measurements. It should be noted that measurements as referred to herein may include quantitative assessments of respective indicators by an expert such as a clinician, wherein the assessment by the expert may be assisted by measurement means, possibly including optical and / or imaging devices. It may be preferred that the indicators include measured indicators indicating the current skin state of the person in terms of the following: a collagen intensity, a retraction time and a characteristic associated with wrinkles. Hence, particularly each of these indicators may be used, which allows for a particularly reliable assessment of the current skin state of the person. The characteristic associated with wrinkles may, for instance, be a number of wrinkles or area of the face covered by wrinkles.

[0021] The above indicators may be measured in different skin regions, wherein measured values of a respective indicator from the different skin regions may be used for determining the assistance quantity: In particular, the assistance quantity may be determined based on a relation between the measured values from the different skin regions. In this way, an indicator baseline may be maintained for each person individually, wherein the skin state and / or changes in the skin state can be quantified with respect to the baseline. The different skin regions may be chosen such that they differ in environmental influences on the skin in that region. Preferably, the face and another part of the body may be chosen as skin regions. For instance, a collagen intensity may be measured on a forearm, particularly an inner part thereof, and in the face, particularly the forehead, wherein a relation, such as a ratio or relative difference, between the two measured collagen intensities may be used for determining the assistance quantity. The forearm, particularly its inner part, for instance, typically has relatively little UV exposure and thus can serve as a baseline for collagen intensity measurements in the face.

[0022] Furthermore, one or more of the indicators may indicate at least an influence on the skin state of the person by indicating at least one of the following: a general well-being of the person, an own perception of the skin state by the person. These indicators have been found to be particularly useful for reliably indicating an influence on a person’s skin state. While they, particularly a person’s own perception of his or her skin state, may not directly influence the skin state, they have been found to be correlated with and hence indicative of changes of the skin state. Indicators like the general well-being of the person or his or her own perception of the skin state may be provided based on a user input, such as by the person him- or herself indicating his or her general well-being and / or own perception of the skin state via a user interface. The indicators may possibly not be indicated by the user directly, but may optionally be determined based on several inputs provided by the user in response to questions of a questionnaire. If, for instance, the computer implemented method is run on a terminal device such as a smartphone, a touchscreen of the smartphone may serve as the user interface via which the user can provide inputs and via which also the questionnaire may be presented to the user. It may be preferred that the indicators include indicators indicating an influence on the skin state of the person in terms of the following: a general well-being of the person and an own perception of the skin state by the person. Hence, particularly both of these indicators may be used, which allows for a particularly reliable assessment of one or more influences on the skin state of the person and hence of how the skin state of the person may evolve.

[0023] In a further exemplary embodiment, as indicators indicating the current skin state of the person indicators associated with pores, age / lentiginous brown spots, a redness and a roughness are used, wherein roughness could also be referred to in terms of raised and depressed areas, and as indicators indicating the influence on the skin state of the person indicators associated with sleep, nutrition, smoking and alcohol consumption are used. The indicators associated with pores, age / lentiginous brown spots, a redness and a roughness of the skin may be provided based on a visual assessment and / or an optical measurement, and the indicators associated with sleep, nutrition, smoking and alcohol consumption may be provided based on a user input.

[0024] Generally, the indicators being indicative of the current skin state could be regarded as indicating a current phenotype of the skin of the person. Additionally or alternatively, the indicators being indicative of the current skin state could be defined as clinical endpoints and / or outcomes associated with the skin of the person at a current time.

[0025] As mentioned above, it is possible that indicators that are indicative of the current skin state of a person are also indicative of an influence on the skin state. Therefore, in particular, the indicators being indicative of an influence on the skin state of the person could be defined as including all indicators being indicative of an influence on the skin of the person except those that are already indicative of the current skin state of the person. In other words, where reference is made herein to indicators indicative of an influence on the skin of the person, this may particularly refer to further indicators, which are not yet part of the indicators taken into account for indicating the current skin state of the person. Hence, for instance, the indicators being indicative on an influence of the skin could be defined as including all indicators being indicative of an influence on the skin state of the person except those which are indicative of a current phenotype of the skin of the person. However, the present disclosure is not limited by this definition, since it is also possible that indicators of an influence on the skin are also indicative of a current skin state. Possible indicators indicative of an influence on a person’s skin state could be indicative of, for instance, a habit of the person and / or an emotional well-being of the person. Since an influence on the skin state indicates a change of the skin state, the indicators indicative of an influence on the skin state could also be referred to as indicators indicative of a change of the skin state.

[0026] Preferably, after the plurality of indicators have been provided, and optionally after renormalization of at least one of them, they are being normalized to a same numerical range. For instance, the same numerical range can be the range from 0 to 100. Hence, the same numerical range can particularly be dimensionless, i.e., without physical units. Normalizing an indicator may correspond to a division of a range of possible values of the indicator into sub-ranges and assigning a normalized value, i.e., a value in the same numerical range to which the indicators are normalized, to each of the sub-ranges. The range of possible values of a respective indicator may be referred to as a normalization range. Moreover, the assignment may also be referred to as a mapping, as already indicated above. It may be preferred that higher normalized values may be assigned to possible values of the indicators that are associated with a better skin state and / or a positive influence on the skin state and vice versa.

[0027] Besides the normalization, a renormalization of one or more of the indicators is considered. The renormalization can particularly refer to a renormalization of one or more of the previously normalized indicators. However, as mentioned above, it may also be preferred that the renormalization is carried out before the normalization, such that the normalization may refer to a normalization of indicators of which at least one has been renormalized already. For carrying out the renormalization, at least one renormalizing feature of the person is provided, the at least one renormalizing feature being selected from an age and / or a genetic characteristic of the person. Genetic characteristics of a person are understood herein as particularly including a skin type, skin color, eye color, hair color of the person and the sex of the person. For example, an ITA score may be considered as genetic characteristic. The age may particularly refer to a biological or chronological age, specifically a biological or chronological cell age of the person. A further renormalizing feature may be a sex of the person. Renormalizing features like an age, sex and / or skin type of the person may be provided based on a user input.

[0028] Determining the assistance quantity based on the (optionally already normalized) indicators and the at least one renormalization feature can particularly refer to renormalizing at least one of the (optionally already normalized) indicators using the at least one renormalizing feature. Hence, some of the indicators may be renormalized, while others may not be renormalized. Among those one or more indicators which are renormalized, the use of the at least one renormalization feature for renormalizing the respective indicator may differ, particularly if at least two renormalization features are used. For instance, after having normalized or before normalizing the plurality of indicators, among those of them which are being renormalized, different combinations of at least two renormalization features may be used.

[0029] Renormalizing an indicator may refer to renormalizing the normalized value of the indicator, or to renormalizing a value of the indicator which has not yet been normalized. Hence, for instance, if previously a measured value of an indicator indicating a current state of the person’s skin has been assigned a normalized value in a predefined numerical range, wherein this range is the same for all indicators, the normalized value may be adjusted. The renormalization may then also be viewed as a further adjustment of values of one or more indicators. If the value of an indicator which has not yet been normalized is renormalized, on the other hand, the renormalization may refer to a first adjustment of the value, wherein the normalization may referto a further, second adjustment of the value. Moreover, as mentioned above, the normalization and renormalization may form a combined mapping of indicator values, which may be viewed as “raw” or “bare” indicator values, to values in the same predefined numerical range, wherein the mapping may depend on the indicator, the one or more renormalizing features and / or a normalization range as indicated above.

[0030] The adjustment carried out for renormalization is based on the at least one renormalizing feature. The renormalization may hence also be viewed as an adjustment for an age and / or a genetic characteristic of the person. The adjustment of an indicator carried out for renormalization may be chosen based on a known or assumed influence of the age and / or the genetic characteristic of the person on the indicator, preferably such that the influence on the adjusted indicator is decreased. The indicator, particularly also a normalized value thereof, may hence be "put into perspective" in view of the age and / or the genetic characteristic. Therefore, in fact, the renormalization may also be viewed as a kind of normalization. However, in in this kind of normalization it would not be the aim to bring all provided indicator values to a same numerical range in order to make them comparable regarding what constitutes “good and bad”, but instead to “factor out” contributions to the indicators, the current skin state and / or a change in skin state stemming from the age and / or a genetic characteristic of the person, which are outside of the control of the person. In other words, contributions to indicators, the current skin state and / or the change in skin state that are considered normal or naturally expected for a person are preferably not considered in determining the assistance quantity. In this way, the assistance quantity can better assist the person in assessing those aspects of his or her skin for which he or she is likely responsible and hence also in taking meaningful actions to change his or her skin state. For instance, as a person ages, his or her skin state may naturally deteriorate, and the degree to which he or she is able to improve or maintain his or her skin state may be limited by this natural aging process.

[0031] To further illustrate the aspect of renormalization by way of example, the value of an assistance quantity determined for a person based on indicators which are renormalized for age may not change as the person ages, even though the person neither has a lifestyle which would affect the skin state in a particularly negative way nor takes any measures to slow down or even revert the natural ageing process of the skin. In this way, a constant assistance quantity could indicate to the person that he or she takes sufficiently good care of his or her skin. More preferably, the assistance quantity may always increase, in particular as long as the person takes at least some skin care measures. The assistance quantity may increase even if the at least some skin care measures are not sufficient to stop a natural decrease in a skin state of the person over time.

[0032] It may be preferred that more than one assistance quantity is determined. In particular, for informing the person about the current skin state, a first assistance quantity may be determined and / or, for determining the person about an expected future skin state, a second assistance quantity may be determined. Additionally or alternatively, for determining the person about the current skin state and the expected future skin state in combination, a third assistance quantity may be determined. The first assistance quantity, the second assistance quantity and the third assistance quantity may be determined differently based on the indicators, particularly based on differently chosen indicators and / or differently chosen weights. Moreover, the third assistance quantity may be determined based on the first assistance quantity and the second assistance quantity.

[0033] The at least one determined assistance quantity can be presented to a user, such as the person to which the skin state relates. If, for instance, the method is carried out at least in part using a terminal device as indicated above, wherein the terminal device comprises a display, the at least one determined assistance quantity may be presented via the display. The at least one assistance quantity may be presented in terms of a numerical value of the assistance quantity and / or in terms of a visual representation thereof, such as in terms of a diagram and / or other graphical elements.

[0034] In an example, as already indicated above, the first assistance quantity, the second assistance quantity and the third assistance quantity may be determined, wherein the third assistance quantity may be determined based on the first assistance quantity and the second assistance quantity. Therefore, all three assistance quantities may be presented. However, it is also possible in that case that only the third assistance quantity is presented. This may provide sufficient assistance for the user. In fact, it may like this even be easier for him / her to assess his / her current skin state and / or take appropriate actions to change his / her skin state, since ambiguity or at least perceived ambiguity can be avoided.

[0035] The third assistance quantity may be determined based on a weighting of the first assistance quantity and the second assistance quantity, wherein the weighting is defined such that the second assistance quantity is assigned a higher weight than the first assistance quantity for the third assistance quantity. Thus, in arriving at the third assistance quantity, emphasis may be put on the expected future skin state. In this way, an improved assistance in changing the skin state can be achieved. The weighting of the first and the second assistance quantities to determine the third assistance quantity may refer to a further weighting, which may be different from a weighting of indicators carried out to determine any of the first and the second assistance quantity.

[0036] Optionally, one or more of the indicators indicate at least a current skin state of the person and are provided based on at least one of the following: an optical analysis, an ultrasoundbased analysis, a mechanical analysis, a microbiome analysis, a blood analysis. The one or more analyses may be carried out by a medical expert, such as a practitioner.

[0037] Possible indicators that can be acquired in this way can particularly be associated with any of the following: skin color, pigmentation, tone, radiance, age spots / lentiginous brown spots, pores, under-eye circles, wrinkles (incl. crow's feet, furrow lines, forehead wrinkles, under-eye wrinkles, upper lip wrinkles), skin roughness and / or smoothness (e.g., as indicated by raised and depressed areas), red areas / redness, skin thickness, barrier function, skin PH, facial and specific zone volumetries (nasolabial, eyelids, puffiness), collagen intensity, elasticity / laxity, hydration, porphyrins (acne bacteria), sebum intensity (oiliness), sun damage to the skin incl. pigment-dysregulated patches (“sun spots”), skin microbiome (e.g., bacteria, fungi), biochemical diagnostics (blood work incl. e.g., protein nutrition, vitamins, hormones, electrolytes, other biomarkers). All of these indicators are considered as a possible basis for determining the one or more assistance quantities.

[0038] The analyses may include measurements in different regions of the skin, wherein an indicator provided based on a respective analysis may be indicative of a relation between analysis results in the different regions. Equivalently, the assistance quantity may be determined based on a relation between values of an indicator acquired by analysis in different skin regions. For instance, the collagen intensity may be measured on a forearm and in the face of a person, wherein an indicator corresponding to a relative difference between the measured collagen intensity on the forearm and the measured collagen intensity in the face may be provided as a basis for determining the assistance quantity.

[0039] Furthermore, one or more of the indicators may indicate at least an influence on the skin state of the person and may be provided based on a user input indicative of any of the following: an environmental or social context of the person, a habit of the person, a mental state of the person. The user providing the user input may be the person whose skin state is to be assessed and / or changed, or a medical expert such as a practitioner. Habits of a person are considered herein as including nutrition, liquid intake, smoking, alcohol consumption, sleep, physical activity, sunscreen usage. The mental state may, for instance, refer to a general well-being and / or to more specific mental states. Also a person’s perception of his or her skin state is understood herein as a specific mental state.

[0040] More generally, indicators indicating at least an influence on the skin states can be associated with any of the following: general well-being and happiness, feeling beautiful (vs. disfigured), self-perception of the skin, occupation, stress levels / perceived stress, air pollution, place of residence, place of work, nutrition, hydration (as indicated, e.g., by water / liquid consumption), sun exposure incl. history of sun exposure, sunscreen usage, physical activity, alcohol consumption, smoking, sleep, physical activity, skin type, skin, hair, and eye color, ethnicity, geographic origin, geographic origin of biological parents. All of these indicators are considered as a possible basis for determining the one or more assistance quantities. Moreover, some of these indicators may not be provided based on a user input, but based on tracking data acquired using a wearable device.

[0041] The plurality of indicators used for determining a respective assistance quantity may be weighted. Preferentially, the weighting may be carried out after normalization and renormalization. The indicators may be weighted using predefined weights indicative of a respective relevance of the indicators forthe respective assistance quantity. The weights may correspond to respective contributions of the indicators to the respective assistance quantity.

[0042] In particular embodiments, for informing the person about the current skin state, a first assistance quantity is determined based on a weighting of the indicators. More particularly, the provided indicators may include an optically measured texture indicator of a texture of the skin of the person, wherein the texture indicator may be assigned a highest weight among the indicators used for determining the first assistance quantity. The texture of skin could also be referred to as the topography of skin. For example, it may be given in terms of a characteristic associated with wrinkles, pores and / or a skin roughness and / or smoothness. The texture of skin has been found to be most important for a useful assessment of the state of human skin.

[0043] It may be preferred that, for informing the person about the current skin state, a first assistance quantity is determined based on indicators indicative of the following: a texture of the skin of the person, a degree of homogeneity in color of the skin of the person, a hydration of the skin of the person, a past exposure to sunlight. The degree of homogeneity in color of the skin, which may also be referred to as a degree of visual homogeneity of the skin color, may particularly be defined in terms of a base skin color and variations therefrom such as a redness, age / lentiginous brown spots or under-eye circles. The past exposure to sunlight may be determined from a number of sunspots, for instance, but could also be determined based on a corresponding user input, such as an answer to a corresponding question in a questionnaire. The degree of homogeneity in color of the skin of the person, the hydration of the skin of the person and the past exposure to sunlight may each be given a weight in a range below the weight of the texture indicator. These indicators are hence still considered relevant for reflecting the current skin state of the person, and approximately equally so.

[0044] In a further particular embodiment, for informing the person about an expected future skin state, a second assistance quantity is determined based on a weighting of the indicators. More particularly, the indicators may include a mechanically measured firmness indicator of a firmness of the skin of the person, wherein the firmness indicator may be assigned a highest or second highest weight among the indicators used for determining the second assistance quantity. As indicated above, skin firmness may be given, for instance, in terms of a retraction time and a collagen intensity, or collagen density, of skin. The firmness of the skin of a person has been found to be one of the most reliable indicators for how the skin state will evolve.

[0045] Optionally, the indicators used for determining the second assistance quantity include a habit indicator of one or more habits of the person, wherein the habit indicator is assigned a highest or second highest weight among the indicators used for determining the second assistance quantity. Also habits of the person have been found to be among the most reliable indicators for how the skin state of the person will evolve. The habit indicator may therefore be given a similarly high weight as the firmness indicator. As mentioned above, indicators of an influence on the skin state such as the habit indicator may be provided based on a user input and / or based on tracking data acquired by one or more wearable devices, i.e., devices wearable by the person.

[0046] In an embodiment, the habit indicator is determined based on a weighted combination of a plurality of habit sub-indicators being provided based on respective user inputs, each of the habit sub-indicators indicating one of the following: a) a frequency and / or intensity of the person exposing herself / himself to the sun, the associated habit sub-indicator being assigned a highest weight, b) a sleep habit of the person, an eating and / or drinking habit of the person, a smoking habit of the person, a physical activity level of the person.

[0047] It may be preferred that the second assistance quantity is determined based further on indicators indicative of a barrier function of the skin of the person and an environment of the person. Also a barrier function of the skin of the person and an environment of the person have been found to be relevant for reliable prognoses regarding the future skin state. These further indicators may each be considered with a weight in a range sufficiently high, but below that of the firmness indicator and the habit indicator.

[0048] Generally, the following selection of indicators has been found to be advantageous for determining the one or more assistance quantities:

[0049] - one or more emotional and / or perceptional indicators, in particular being indicative of a general well-being and / or happiness of the person, and whether the person feels beautiful or disfigured,

[0050] - one or more indicators of a tone of the person’s skin, in particular being indicative of a skin color, red areas of the skin and age spots / lentiginous spots,

[0051] - one or more indicators of a skin topography, in particular being indicative of wrinkles and a skin roughness,

[0052] - one or more indicators of biomechanical skin properties, in particular being indicative of

[0053] - a skin elasticity,

[0054] - a collagen intensity in the skin and

[0055] - porphyrins in the skin,

[0056] - one or more contextual and / or habitual indicators, in particular being indicative of a nutrition of the person, sun exposure of the person, an alcohol consumption by the person, smoking habits of the person and sleep habits of the person.

[0057] As mentioned above, indicators measurable on the skin, such as the above indicators of the skin tone, the skin topography and the biomechanical properties, may be measured in different skin regions, wherein measurement results from the different skin regions, particularly a relation between them, may be used for determining the assistance quantity.

[0058] In some embodiments, the assistance quantity is determined based on the indicators and at least the age and the sex of the person as renormalizing features, wherein a), as far as the assistance quantity is determined for informing the person about the current skin state, at least one of the indicators used for determining the assistance quantity is renormalized with respect to an expected current skin state of the person, and wherein b), as far as the assistance quantity is determined for informing the person about an expected future skin state, the renormalization includes a continuously progressing renormalization of at least one of the indicators used for determining the assistance quantity with age and a constant renormalization of at least one of the indicators used for determining the assistance quantity depending on the sex. In the same or other embodiments, a), as far as the at least one assistance quantity is determined for informing the person about the current skin state, the renormalization refers to an adjustment of at least one of the indicators used for determining the assistance quantity based on a value thereof that is expected from the current age and the sex of the person, and b), as far as the assistance quantity is determined for informing the person about an expected future skin state, the renormalization includes a continuously progressing renormalization of at least one of the indicators used for determining the assistance quantity with age and a constant renormalization of at least one of the indicators used for determining the assistance quantity depending on the sex.

[0059] For instance, a measured value of an indicator of a relative difference in collagen intensity between the face and an arm of a person may be normalized according to a first mapping to a range of normalized values, such as 0 to 100, if the person has a first age, which may be an age for which it has been determined that the collagen intensity is expected to decrease from thereon. For a person having a second age, the first mapping may be replaced by a second mapping, wherein if the second age is higher than the first age the second mapping may correspond to the first mapping with an additional increase in the indicator which depends on the difference between the second age and the first age. The additional increase may balance a natural decrease in collagen intensity with age. In this example, the first age may be viewed as a representative reference age. For a person with an age below the first age, a same or similar normalization may be carried out as for the first person. In other words, the first mapping or a mapping similar to the first mapping may also be used for normalizing respective indicator values measured for a person younger than the first age.

[0060] Other indicators such as skin redness may not correlate with age but instead with the sex. Thus, for instance, a measured value of a skin redness may be normalized according to a first mapping to a range of normalized values, such as 0 to 100, if the person is male. For a female person, the first mapping may then be replaced by a second mapping, wherein the second mapping may correspond to the first mapping with an additional decrease in the indicator which accounts for a naturally higher tendency of females, as compared to males, to suffer from hormonal acne after puberty.

[0061] In particular, a number of wrinkles may be renormalized by a predefined negative percentage per year, starting from a predefined age. Collagen intensity may be renormalized by a predefined positive percentage per year and retraction time by again a predefined negative percentage per year, both starting from a predefined age below that where the renormalization for wrinkles starts. Moreover, the number of wrinkles and the retraction time may be renormalized by a constant percentage for men, wherein additionally also a renormalization of collagen intensity may be considered. Indicators indicating hydration of the skin may be renormalized by a predefined positive percentage per year starting at a predefined age, but only for men and not for women.

[0062] Indicators of brown / lentiginous spots, red areas and a pH value of the skin may not be renormalized. Likewise, indicators associated with trans-epidermal water loss, habits, and oiliness of the skin and pores therein may not need renormalization.

[0063] The respective assistance quantity may be determined based on the indicators in terms of a function representing the assistance quantity depending on the indicators. The function may be linear, step-linear (i.e., comprising several lineal segments with different slopes in the respective indicator values) or nonlinear.

[0064] In a further aspect, a data processing device comprising a processor configured to carry out a method as defined above is presented. In yet another aspect, a computer program is presented that comprises instructions which, when the program is executed by a computer, cause the computer to carry out a method as defined above.

[0065] It shall be understood that the method of claim 1 , the device of claim 14 and the computer program of claim 15, have similar and / or identical preferred embodiments, in particular, as defined in the dependent claims.

[0066] It shall be understood that a preferred embodiment of the present invention can also be any combination of the dependent claims or above embodiments with the respective independent claim.

[0067] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

[0068] BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1A shows schematically and exemplarily aspects of a computer-implemented method for assisting in assessing and / or changing a skin state of a person.

[0070] Figure 1 B shows schematically and exemplarily aspects of a computer-implemented method for assisting in assessing and / or changing a skin state of a person, wherein the method is similar to the method shown in Figure 1A.

[0071] Figure 2 shows schematically and exemplarily further aspects of the computer implemented method.

[0072] DETAILED DESCRIPTION OF EMBODIMENTS

[0073] Figure 1 A shows schematically and exemplarily an embodiment of a method for assisting in assessing and / or changing a skin state of a person. In this embodiment, a plurality of indicators 10 of a current skin state of the person are provided that had previously been acquired in the course of clinical measurements. Furthermore, indicators 20 of an influence on a skin state of the person are provided based on corresponding user inputs and / ortrack- ing data acquired by the person of herself / himself using, for instance, wearable devices. The indicators 10, 20 are subsequently normalized to a same numerical range based on a set of predefined normalization rules 30. One or more of the normalized indicators are subsequently renormalized using renormalizing features 40 of the person, which are provided for this purpose, such as based on a user input. Subsequently, the indicators, which have been normalized and subsequently at least partially renormalized, are weighted using predefined weights 50, and based thereon an assistance quantity is determined for informing the person about the current skin state and / or an expected future skin state.

[0074] Figure 1 B shows schematically and exemplarily a variant of the embodiment shown in Figure 1A, wherein in this variant the indicators 10, 20 are initially renormalized based on the renormalizing features 40, and wherein the renormalized indicators are subsequently normalized according to predefined normalization rules 30’. The weighting can be carried out as in the embodiment of Figure 1A. The normalization rules 30’ may substantially correspond or even be equal to the normalization rules 30.

[0075] As seen in Figure 2, a first assistance quantity 61 may be determined in accordance with Figure 1A for informing the person about the current skin state, and a second assistance quantity 62 may be determined in accordance with Figure 1 A for informing the person about the expected future skin state. Furthermore, a third assistance quantity 63 may be determined based on the first assistance quantity 61 and the second assistance quantity 62 by weighting them using predefined assistance quantity weights 70 and thereafter combining them to receive the third assistance quantity 63. The third assistance quantity 63 may be determined for informing the person about the current skin state and the expected future skin state in combination. Notably, while the third assistance quantity 63 may be determined as shown in Figure 2, it may also be determined directly based on the indicators 10, 20 as shown in Figure 1 A.

[0076] It has been realized that existing tools for informing individuals about their skin still have potential regarding comprehensiveness, reliability and retail availability. For instance, some known systems only allow for a visual analysis of the skin and only simulate future skin development based on the current visual state of the skin. Other known systems only provide for a biomechanical analysis of the current state of the skin. This has been found to be not comprehensive enough to reliably assist a person in assessing and / or changing his / her skin state. There also exist artificial intelligence-based tools relying on smartphone front camera images in order to allow users to analyze their skin at home. However, also tools like this have been found to allow for improvements in reliability. On the other hand, clinical grade medical and research-grade solutions are available, which allow to carry out relatively accurate analyses of the skin. However, these solutions tend to either be too expensive and too medically focused or can for other reasons hardly be deployed in a retail setting, such as due to being insufficiently capable of being used on a standalone basis. Simplertools are therefore needed. In view of this, a solution that is both simple and reliable was still needed, and is presented herein.

[0077] The indicators 10, 20 considered as a basis for determining the at least one assistance quantity 61 , 62, 63 can be indicative of any of the following:

[0078] Skin tone / visual properties: Skin color, red areas / redness, pigmentation, tone, radiance, age spots / lentiginous brown spots, under-eye circles; Skin type, eye color, hair color; Geographic origin of the individual, geographic origin of the individual’s biological parents

[0079] Skin surface / topography: Wrinkles (incl. crow’s feet, furrow lines, upper lip, un- der-eye, forehead wrinkles), roughness / raised and depressed areas, open pores Skin vitality / biomechanical properties, e.g.: Elasticity, collagen, hydration, sebum, porphyrins

[0080] Skin shield / structural aspects: Thickness, barrier function, skin PH

[0081] Skin volume: Facial and specific zone volumetries (e.g., nasolabial, eyelids, puffiness)

[0082] Microbiome composition, e.g.:

[0083] Bacteria (e.g., Staphylococcus epidermidis, Streptococcus mitis, Cutibac- terium acnes, Corynebacterium spp., Acinetobacter johnsonii, etc.) Fungi (e.g., yeasts, skin-living fungi / dermatophytes, opportunistic fungi / n o n -d e rmato ph ytes)

[0084] Lifestyle: Context and habits

[0085] Context: Occupation, stress, air pollution

[0086] Habits, e.g.:

[0087] Nutrition: Calorie intake and composition in comparison to activity level, age, sex

[0088] Sun: Sun exposure, sunscreen usage, solarium visits, history of sunburns

[0089] Physical activity: Everyday activity levels and workouts Alcohol consumption and smoking Hydration: Liquid intake Sleep: Amount and regularity

[0090] Blood work / laboratory-chemical diagnostics incl. vitamins, hormones, electrolytes, protein nutrition Emotions and perceptions: Well-being, happiness, feeling beautiful vs. disfigured

[0091] The means considered for acquiring the indicators 10, 20 may include visual analyses, mechanical analyses, analyses carried out in a microbiome laboratory, biochemical analyses carried out in a blood laboratory, as well as contextual / habitual questionnaires. Questionnaires can be provided to a user, which may be the person whose skin state is to be analyzed, via a terminal device such as a smartphone, wherein the user may then be prompted to fill in the questionnaires.

[0092] Some analyses may be deployed in different approaches:

[0093] Visual and mechanical anamnesis, performed by a practitioner

[0094] Visual, using one or more kinds of imaging technology such as, in particular, using optical coherence tomography in addition to imaging using a conventional photographic camera

[0095] Mechanical, using some kind of mechanical analysis device

[0096] Contextual / habitual as questionnaires

[0097] Contextual / habitual via application programming interfaces (APIs) for health tracking

[0098] Skin microbiome, in laboratory analyses Blood work, in laboratory analyses

[0099] Notably, the analyses via which the indicators 10, 20 are acquired are preferably not part of the method presented herein. Instead, the indicators 10, 20, which may previously have been acquired in the course of any of the above analyses, may just be provided via an interface or from a storage. For instance, if the method is carried out on a backend server, analysis results from clinical measurements may be sent to the server from respective clinical analysis sites, filled-in questionnaires may be sent to the server from a user’s smartphone and health tracking data may be sent to the server from wearables of the user. The determined one or more assistance quantities may then be determined on the server and sent to the smartphone of the user or a display device at an analysis site for presentation.

[0100] For further illustration, the following practical example may be considered: A female aged 38 years would like to understand what she can do to maintain a youthful and healthy skin. Today, it is almost impossible for her to know exactly what works best for her skin. She books an appointment for a skin analysis. Before her appointment, she fills in a survey about her habits, for example her sunscreen use. She may do this via her smartphone or using a dedicated device provided for this purpose at the analysis site. During her appointment, high-resolution images of her face are taken and a biomechanical analysis of her face is conducted. A software, which may be run by a computer at the analysis site and / or in the cloud, then analyzes and quantifies her results, such as by deriving a) predefined indicators indicative of the female’s current skin from the high-resolution images taken and the biomechanical analysis conducted, as well as b) indicators indicative of an influence on the female’s skin state from her answers provided in the survey. The derived indicators may be a) visual surrogate markers and biomechanical features, and b) contextual, habitual, perceptional and emotional indicators, respectively, as indicated in the list further above. Furthermore, an assistance quantity in the form of an aggregate score integrating the several indicators may be determined. The assistance quantity may subsequently be shown to the female together with sub-scores for the several indicators individually. In this example, the aggregate score is lower than the average for 38 year-old women and so is the sub-score for collagen intensity. Algorithms based on peer-reviewed literature suggest procedures to be taken to improve the scores. This helps inform the female’s priorities for example as regards to her habits (e.g., applying sunscreen more regularly) and her skin treatment routine (e.g., consider a micro-needling treatment). She then proceeds to have one or more micro-needling treatments performed. Some time after the treatments), survey and analysis are conducted again. Again, the results are quantified, potentially showing an improvement of the collagen intensity and, hence, the aggregate score.

[0101] Preferably, the indicators 10, 20 actually to be used are selected based on a trade-off between their relevance for the respective assistance quantity to be determined and the ease of availability of the analysis needed for the respective indicator 10, 20. It has been found that a good trade-off can be achieved for indicators indicative of the following: wrinkles, redness and age spots / lentiginous brown spots, roughness / raised and depressed areas, UV spots, pH value, elasticity and collagen, hydration, as well as selected contextual and habitual factors.

[0102] To illustrate the considerations relevant for the selection of suitable indicators 10, 20, it may be noted that some of the indicators 20 can be the main external drivers of skin aging, but can at the same time be very hard to change for a person. An example of such an indicator 20 would be one that is indicative of a sun exposure of the person. Moreover, indicators 10 indicative of wrinkles of a person have been found to be very strongly associated with human aging, wherein indicators 10 of redness, age spots / lentiginous brown spots, a rough- ness / raised and depressed areas of the skin have also been found to significantly matter. On the other hand, volume loss of the skin is considered to be too individual to infer therefrom a quantifiable, reliable trend. Indicators of a hydration of the skin can matter for both the perception of the skin at a current time as well as for the future development of the skin. Hydration can in so far be regarded as being both an indicator 10 as well as an indicator 20. Firmness of the skin, followed by the skin’s barrier function, has been found to be a particularly important indicator 10. The skin microbiome may also play a very relevant role in skin aging. Indicators thereof may be technologically less easily accessible (both regarding their measurement as well as regarding how they can be influenced to change the skin state), but may nevertheless be preferred.

[0103] A good composition of indicators for determining based thereon an assistance quantity informing a person about his or her current skin state (first assistance quantity) has been found to include indicators of the following: texture (e.g., wrinkles, pores, smoothness, raised and depressed areas), homogeneity (e.g., brown / lentiginous spots, red areas, hydration), sun situation (e.g. existing pigment-dysregulated patches (“sun spots”), UV index). Also a skin color indicator may be included. Additionally, an oiliness of the skin may be measured to include this in a database, where this may however not be used for determining the assistance quantity.

[0104] Moreover, a good composition of indicators for determining based thereon an assistance quantity informing a person about an expected future skin state (second assistance quantity) has been found to include indicators of the following: firmness (e.g., retraction time, collagen intensity), skin barrier (e.g., pH value, wherein additionally a trans-epidermal water loss may be measured to include this in the database without using it for determining the assistance quantity), habits, particularly regarding sun protection (e.g., regular sun exposure, use of sunscreen), physical activity, sleep, nutrition, hydration (liquid intake), smoking and alcohol consumption, and living context (e.g., urban or rural).

[0105] Indicators of wrinkles, pores and smoothness may be defined as the number of or area covered by wrinkles, pores and raised and / or depressed areas respectively. In otherwords, respective features on the skin may be counted or the area covered by them estimated in order to quantitatively arrive at these indicators. The count or estimate may be limited to particular areas in the person’s face, such as to the forehead, regions underthe eyes and / or an upper lip region. Similarly, indicators of homogeneity of the skin may be defined. For instance, a number or area of brown spots and / or red areas of the skin may be counted or the area covered by them measured, and the respective number or area size may be used as the homogeneity indicator. Also, a skin color indicator may correspond to a measured value of skin color in terms of the CIELAB scale, for instance. These indicators may be normalized to, for instance, the range from 0 to 100 based on a statistically observed range thereof (normalization range), wherein lower numbers may be mapped to higher normalized values and vice versa. For some indicators, a value considered optimal may lie further within the statistically observed range. For those indicators, the mapping between indicator values and normalized values may first rise and thereafter fall again. This will be exemplified in the following for some of the possible indicators.

[0106] Skin hydration indicators may specifically be defined in terms of skin conductivity on a person’s forehead. Where, for instance, the conductivity is measured on some total, physically possible scale, a typically actually measured range, which may also be regarded as a healthy range, may only be a fraction thereof, wherein within this typical, healthy range, which may be viewed as normalization range, higher values might be considered better, i.e., as indicating a better skin state. Therefore, for normalizing a respective hydration indicator, the normalization rules 30 may be predefined such that conductivity values above the typically measured range (normalization range) may be assigned a normalized value of 100, conductivity values in the typically measured range to normalized values from 1 to 99, respectively, i.e. using a linear function, and conductivity values below the typically measured range to a normalized value of zero. When measured in terms of the skin conductivity on a respective person’s forehand, the skin hydration range considered typical, or healthy, may correspond to 100 to 300 microsiemens.

[0107] Indicators of a sun history may be defined in terms of a counted number of pigment-dysreg- ulated patches (“sun spots”) on the skin or a measurement of the area these cover, i.e. again based on a feature count or area size as indicated above for exemplary indicators associated with the skin texture. Also this counted number or area size may be normalized to the range from 0 to 100 based on a statistically observed range (normalization range) thereof, wherein lower number may be mapped to higher normalized values and vice versa.

[0108] Indicators of a sun exposure may be defined in terms of a UV index associated with a place of residence of the respective person, which can be measured on a scale from 1 to 1 1 or more, wherein a UV index of 1 corresponds to the lowest degree of sun exposure. Since a lower sun exposure is considered advantageous, a healthy subrange (normalization range) of the full UV index scale may be mapped to the normalized range of values from 0 to 100 in a monotonically decreasing manner. The range of UV indices from 1 to 5 may be assumed as healthy subrange. Indicators of an oiliness of the skin may be defined in terms of a degree of light ray reflection off a testing strip with which a probe from the skin has been taken. The degree of light reflection may be measured on a scale from 0 to 100%. Light reflection percentages towards the middle of this range are considered more optimal, while only very low or high light reflection percentages are considered unhealthy. For instance, the range from 20 to 70% light reflection may be considered healthy and hence used as normalization range. Thus, for instance, the scale of percentages indicating the degree of light reflection from the testing strip may be normalized by use of a function that, as the degree of light reflection increases, is first zero for some interval (e.g., up to 20% light reflection), then rises to 100 and subsequently falls off again (e.g., in the range considered healthy) until again being zero for an interval (e.g., above 70% light reflection).

[0109] Indicators of the firmness of the skin can include a collagen intensity and / or a retraction time. The collagen intensity, which may also be regarded as a measure of collagen density, may be defined in terms of a degree to which sound waves, particularly ultrasound waves, are reflected by the skin, and may again be measured on a percentage scale from 0 to 100. Again, a healthy range of percentages may be defined, wherein, within this range, which may be considered as normalization range, higher values may be considered as indicating a better skin status. Thus, for instance, the normalization rules 30 may indicate a mapping function that monotonically increases in the healthy range and is zero below. The healthy range may be taken to lie between 20 and 50% ultrasound wave reflection.

[0110] The retraction time may be measured in milliseconds. Moreover, again a healthy range (normalization range) of typically observed retraction times may be defined. Within this range, shorter times can be considered indicating a better skin state. Thus, the normalization rules 30 may be predefined such that they map retraction times to normalized values according to a function that is maximal below the healthy range, monotonically decreasing in the healthy range, and zero above. The healthy range may be defined to correspond to retraction times from 100 to 1500 milliseconds.

[0111] Besides using collagen intensity and retraction time, a vitality of the skin may also be indicated in terms of a number of porphyrins in the skin. This number may be counted, for instance, in a predefined skin region, and thereafter normalized.

[0112] A pH value may be measured on a scale from 1 to 14, wherein ideal pH values of skin are considered to lie not far from, but below the middle of this range, with some still healthy range around. Accordingly, the normalization rules 30 may be predefined such that pH values below the healthy range (normalization range) are assigned normalized values of 0, pH values in the healthy range are assigned monotonically increasing normalized values until the end of the optimal range of pH values, pH values above but still in the healthy range are assigned again monotonically decreasing normalized values and pH values above the healthy range are assigned normalized values of zero again. In total, the healthy range may extend from a pH value of 4.75 to a pH value of 5.75, for instance.

[0113] Indicators 20 associated with habits of the person include indicators of a physical activity of the person, the sleep of the person, the nutrition of the person, the hydration (i.e., liquid intake) of the person, smoking habits of the person, an alcohol consumption of the person and a sunscreen usage of the person. Each of these particular habit indicators may be provided on an individual scale and may also be normalized differently.

[0114] Physical activity may be quantified on a scale from 1 to 5, wherein an increasing number indicates an increasing level of physical activity. On this scale, values from 3 to 5 may be considered healthy, wherein in this healthy range (normalization range) increasing values may be assigned monotonically decreasing normalized values. Alternatively, the scale from 1 to 5 may be normalized such that the normalized values peak at the number 3 of the scale and fall off asymmetrically from there on such that a physical activity of 5 is assigned a higher normalized value than a physical activity of 0.

[0115] Sleep quality may be quantified in terms of hours of sleep per night, such as in terms of average hours sleep per night. Normalized values may be determined from the typically observed range of hours of sleep (normalization range) by assigning values from the lower and from the upper end of the range to relatively low normalized values, while assigning one or more values in the middle of the range, which may be considered optimal, to the maximum normalized value. The typically observed range, which may be considered as healthy range, can correspond to the range from 6 to 9.5 hours of sleep per night.

[0116] Nutrition may be quantified in terms of calorie intake per day, wherein again averages may be considered. A predefined calorie intake range for males (e.g., 2200 to 2400 kcal per day) and a further predefined calorie intake range for females (e.g., 1700 to 1900 kcal per day) may be considered healthy for moderately active individuals, wherein these ranges, which could be considered as normalization ranges, may be adjusted for a level of physical activity in several steps. Hence, different “optimal” calorie range steps may be defined depending on a level of physical activity. The normalized value assigned to a given actual calorie intake, or its deviation from the maximum normalized value possibly being 100, may be chosen depending on a number of steps which the actual calorie intake lies away from the “optimal” calorie intake.

[0117] Hydration of a person may be indicated in terms of liquid intake per day (excluding alcohol, and again possibly referring to an average), wherein a predefined volume per day (e.g., 1 to 3.7 liters) may be considered healthy (without physical workouts), and thus considered as normalization range. The normalized values assigned to the liquid intakes may be chosen to monotonically increase with liquid intake, with liquid intakes above the predefined volume possibly all being assigned a maximum normalized value.

[0118] Also sunscreen usage may be quantified, although possibly only based on a subjective indication by a person of how regularly and / or comprehensively / carefully he or she applies sunscreen if exposed to the sun. Such indications, which may be provided on a predefined numerical scale, may then be normalized, wherein increasingly high normalized values may be assigned to increasing degrees of regularity and / or comprehensiveness / careful- ness of the sunscreen usage.

[0119] In order to quantify smoking habits in terms of a normalized value, a value of 100 may be assumed for somebody who has never smoked or has not smoked for more than a predefined number of months, wherein the normalized values may then decrease monotonically with increasing intensity of smoking. Generally, smoking habits may quantified based on occasions at which and a regularity with which a person smokes, wherein the normalized values assigned may be the higher the less the person smokes.

[0120] Alcohol consumption may be quantified (again by using averages, for instances) by using normalization rules 30 indicating a highest normalized value, i.e., for instance, a value of 100, if the alcohol intake is limited to a predefined number of standard glass(es) of alcohol a week, wherein a distinction between men and women may be made. Furthermore, account may be taken of a number of days of a week on which alcohol is consumed. For instance, the highest normalized value may be assigned if alcohol consumption is limited to one or two days in a week and, on each of the one or two days, to two standard glasses for men and to one standard glass for women. With increasing consumption of alcohol, the normalized value may then decrease. Regarding the living context of a person, for instance, an air pollution where the person lives may be quantified in terms of the Common Air Quality Index (CAQI), which generally ranges from 0 to values of 100 and above, wherein the CAQI value increases with increasing degrees of air pollution. A CAQI subrange from 0 to 50 may be considered healthy, wherein this subrange (normalization range) may be normalized such that a value of 0 is assigned the highest normalized value, a value of 50 is assigned the lowest normalized value and the normalized values are monotonically decreasing in between.

[0121] When indicating the living context additionally or alternatively using a stress indicator, this indicator may result from a subjective assessment by a person regarding his or her own stress level. Irrespective on the particular scale used for this purpose, a value resulting from the assessment, i.e., the respective stress indicator, may be mapped to a corresponding normalized indicator value such that higher perceived stress levels map to lower normalized indicator values.

[0122] For quantitatively capturing indicators related to emotions and perceptions, further particular scales may be defined. User inputs with respect to these scales may then again be normalized, although this might not always be necessary. For instance, a person’s wellbeing may be indicated by him or her using the WHO-5 index scale, which already ranges from 0 to 100, with 0 representing the worst imaginable well-being and 100 representing the best imaginable well-being. On the other hand, whether a person rather feels beautiful or disfigured may be indicated by him or her based on a questionnaire resulting in values on a scale that still requires normalization.

[0123] Hence, generally, the normalization of the indicators may be carried out such that a respective range of indicated values that is considered healthy, which may be considered as normalization range, is mapped to a same range of normalized indicator values for each of the indicators. Within the range of indicator values considered healthy (normalization range), values that are considered optimal, which may either lie well inside the range, such as in its center, or at one of its boundaries, may be assigned the highest normalized value, and wherein the normalized values may fall off from there on monotonically within the range considered healthy (normalization range), and be zero outside. It will be understood that, although in the above examples the range of normalized numerical values was the range from 0 to 100, any other range could be used.

[0124] The renormalization using the renormalizing features 40, in turn, may be carried out to further adjust how the respective indicators enterthe respective assistance quantity 61 , 62, 63. In particular, the renormalizing features 40 can include an age, such as the biological or chronological cell age, and the sex of the respective person. These features are considered outside of a person's control and are therefore preferably "factored out" from the assistance quantity. This is particularly relevant for features such as age, sex and also skin type, since all of them significantly influence skin states, particularly how fast human skin ages. By use of renormalization for at least some of the indicators 10, 20, it can be achieved that the respective assistance quantity 61 , 62, 63 always increases over time. Without renormalization, even persons trying vigorously to improve their skin state might not succeed since they may not be able to keep up with a natural decrease in skin state as caused by their progressing age, their sex, their general skin type, particularly their natural skin color, and / or other genetic characteristics such as, for instance, their eye or hair color. The renormalization may be implemented as an adjustment to one or more of the above outlined mappings from normalization ranges to the range of normalized numerical values, for instance.

[0125] Measured indicators such as, for instance, a number of pores are not considered renormalizable (100 pores will always be 100 pores). The measured numerical values and / or scales of such indicators might differ depending on the measure used, but not depending on the renormalizing features 40. For instance, extremely high and low values of skin oiliness should reduce the respective indicator value, but this is the same regardless of whether the respective person is 35 or 45 years old.

[0126] However, at least the indicators associated with wrinkles, collagen intensity and retraction time might preferably be renormalized depending on the age of the person. Since the number of wrinkles naturally increases with age, for instance, the indicator associated with wrinkles is preferably numerically decreased by a small yearly rate from some minimum age on. Likewise, since collagen intensity naturally decreases and retraction time naturally increases with age, the respective indicators are preferably increased and decreased in value, respectively, by a similarly small yearly rate from some minimum age on.

[0127] Moreover, the indicators associated with wrinkles, hydration and retraction time should be renormalized depending on age and sex of the person. For instance, since men's and women’s skin ages differently, which theoretically impacts all indicators apart from habit indicators, a corresponding constant percentage may be introduced for example for men at least to the numerical values of the indicators associated with wrinkles and retraction time, respectively. Furthermore, young men have been observed to have a higher stratum corneum (SC) hydration in comparison to women, whereas SC has been observed to be stable or even increasing in women over lifetime, and the skin hydration and men is progressively decreasing from age 40 on. Thus, no renormalization of indicators associated with hydration may be applied for women, but for men the indicators associated with hydration may be renormalized by an additional small percentage per year starting at a further predefined age.

[0128] Indicators associated with brown spots, red areas, pores, UV spots, a pH value, trans- epidermal water loss (TEWL) and habits are preferably neither re-normalized for age nor for sex. Brown spots naturally increase with age, but are relatively easy to remove. The likelihood of red areas showing up increases with age, but also these are relatively easy to remove. pH values for men are typically below those for women, but all in a range that may be considered healthy. Hence, no renormalization may be needed in this regard. Moreover the trans-epidermal water loss in middle-aged men can be significantly lower than in women of the same age, regardless of the location. With aging, however, sex-related differences in TEWL are believed to assimilate. Besides, habits are thought to have a same impact on a person's skin overtime. Regarding oiliness, this is generally higher in men than in women and might increase with age for men, whereas it might decrease with age for women. But, it is hypothesized that a healthy level of oiliness is the same for both sexes and all ages. Further regarding pores, men might tend to have larger ones than women, but as long as the associated indicator just indicates a number of pores and not their size, this does not need to be taken into account in terms of renormalization.

[0129] Apart from the above described aspects of normalization and renormalization, it is preferred that an importance of the respective indicators for the respective assistance quantity 61 , 62, 63 can be reflected. This is possible by using a weighting of the indicators, i.e., in addition to the normalization and the renormalization. The weighting may be chosen such that assistance is provided by the respective assistance quantity to take a long-term view on the skin state, without understating short-term results in changing the skin state. The weighting may be defined in terms of the indicator weights 50, as shown in Figure 1A.

[0130] In particular, if the first assistance quantity 61 , i.e., the assistance quantity for informing about the current skin state of the person, is determined based on a texture indicator, a visual homogeneity indicator, a skin hydration indicator and a sun history indicator as already indicated further above, the texture indicator may receive a highest weight, and the visual homogeneity indicator, the skin hydration indicator and the sun history indicator may each receive a lower weight. The weights may be chosen such that they sum up to 100%. Skin texture has been found to play the most important role in how humans perceive each other’s age. When the texture indicator is determined based on an indicator associated with wrinkles, an indicator associated with pores and an indicator associated with raised and / or depressed areas, for determining the texture indicator, the indicator associated with wrinkles may be assigned a highest weight, and the indicator associated with pores and the indicator associated with raised and / or depressed areas may each be assigned a lower weight.

[0131] Visual homogeneity and a skin hydration are believed to have roughly similar effects on skin aging today. Moreover, the sun exposure may also be considered in terms of habit indicators. Therefore, the above weighting has been found suitable.

[0132] When the visual homogeneity indicator is determined based on an indicator associated with yellow colored skin areas and an indicator associated with brown colored skin areas, for determining the visual homogeneity indicator each of the two further (sub-)indicators may be weighted roughly equally and such that the weights sum up to 100%. This is because humans are believed to perceive yellow and brown colors in roughly the same intensity.

[0133] When the sun history indicator is determined based on an indicator associated with sunspots and an indicator associated with a local UV index, the indicator associated with sunspots may receive a highest weight and the indicator associated with the local UV index may receive a lower weight for determining the sun history indicator based on the two.

[0134] If the second assistance quantity 62, i.e., the assistance quantity for informing about an expected future skin state of the person, is determined based on a firmness indicator, a habit indicator, a skin barrier indicator and a context indicator as already indicated further above, the firmness indicator and the habit indicator may each receive a weight that is higher than that of the skin barrier indicator and the context indicator, wherein the weights may be chosen so as to sum up to 100%.

[0135] Among the above-mentioned indicators, habits are considered to have the highest correlation with skin aging. Nevertheless, since the associated indicator may be acquired based on a subjective assessment of the user, it might be preferable to weight it only similarly to the skin firmness. If the habit indicator is determined based on an indicator associated with sun exposure, indicators associated with sleep, nutrition, hydration (liquid intake), smoking, alcohol consumption and physical activity, for determining the habit indicator, the sun exposure indicator may be considered most important and hence may receive a highest weight, wherein the other subindicators are considered to have roughly similar impacts and thus may each be weighted in a same, lower range, wherein the sum of the weights assigned to the subindicators used for determining the habit indicator may be chosen to be 100%.

[0136] Regarding the other, measured indicators 10 for determining the second assistance quantity, firmness has been found to have the highest correlation with skin aging, and thus the weight in the same range as the habit indicator. If the firmness indicator is determined based on a collagen intensity indicator and on a retraction time indicator, the collagen intensity indicator may be weighted higher than the retraction time indicator, with the weights again preferably summing up to 100%, since collagen intensity is believed to have a higher predictive power regarding a future skin state that the (current) retraction time.

[0137] Also a barrier function of the skin is considered relevant to skin aging, even though not as relevant and habits. While the barrier function indicator may be determined based on a pH value, it may prospectively additionally or alternatively be measured in terms of a trans- epidermal water loss.

[0138] Notably, the weighting of indicators 10, 20 carried out for determining the first and / or the second assistance quantities 61 , 62 is to be distinguished from the renormalization. The weights of the indicators 10, 20, which may be regarded as assigning an importance to the indicators, may be defined independently of renormalizing features 40 like the age or a genetic characteristic such as the sex of the person. To illustrate this, skin elasticity would be considered equally important for users of different ages. Likewise, skin firmness would be considered equally important for users of different ages. Also habits are expected to have the same impact on a change in skin state irrespective of the ages of a person. The renormalization can therefore not be understood as a kind of weighting of indicators 10, 20 in the sense described herein. The renormalization may rather be viewed as an adjustment of the normalization of the indicators 10, 20 or, more precisely, an adjustment of the normalized values to which the originally provided indicators values are mapped. The adjusted normalization, however, preferably is still such that the range of normalized values is the same for all indicators 10, 20.

[0139] As shown in Figure 2, although not necessarily, a third assistance quantity 63 may be determined based on the first assistance quantity 61 and the second assistance quantity 62, for informing about the current skin state and the expected future skin state in combination. In doing so, assistance quantity weights 70 may be considered. These may be predefined so as to overweight the second assistance quantity 62 as compared to the first assistance quantity 61 . This may be preferable to ensure proper reflection both of actions taken by the person to change the skin state as well as of the current skin state itself.

[0140] Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims.

[0141] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality.

[0142] A single unit or device may fulfill the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

[0143] Procedures like the providing of indicators, their normalization, the providing of renormalizing features, a weighting of the indicators, the determination of an assistance quantity, et cetera, can be performed by one or several units or devices. For instance, any method steps disclosed herein can be carried out locally, remotely and / or in a computing network. The procedures can be implemented as program code means of a computer program and / or as dedicated hardware.

[0144] A computer program may be stored / distributed on a suitable medium, such as an optical storage medium or a solid-state medium, supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems.

[0145] Any reference signs in the claims should not be construed as limiting the scope.

[0146] The invention relates to a method including a) providing a plurality of indicators, the indicators being indicative of a current skin state of the person and / or of an influence on a skin state of the person, and b) normalizing the provided indicators to a same numerical range. Furthermore, the method includes c) providing at least one renormalizing feature of the person, the at least one renormalizing feature being selected from an age and / or a genetic characteristic of the person, and d) determining, for informing the person about the current skin state and / or an expected future skin state, an assistance quantity based on the normalized indicators and the at least one renormalizing feature of the person. An accordingly determined assistance quantity can be an improved assistance for a person in assessing and / or changing his or her skin state. More generally, the invention relates to a method including a) providing a plurality of indicators, the indicators being indicative of a current skin state of the person and / or of an influence on a skin state of the person, and b) determining, for informing the person about the current skin state and / or an expected future skin state, an assistance quantity based on a normalization and a renormalization of the indicators, the renormalization being based on at least one renormalizing feature selected from an age and / or a genetic characteristic of the person. An accordingly determined assistance quantity can be an improved assistance for a person in assessing and / or changing his or her skin state.

Claims

Claims1 . A computer-implemented method for assisting in assessing and changing a skin state of a person, the method including: providing a plurality of indicators (10, 20), the indicators (10, 20) being indicative of a current skin state of the person and of an influence on a skin state of the person, the indicators (10, 20) including i) an optically measured texture indicator of a texture of the skin of the person, which is given in terms of a characteristic associated with at least one of wrinkles, pores and a skin roughness and / or smoothness, and ii) a firmness indicator of a firmness of the skin of the person, the firmness indicator being given in terms of at least one of a collagen intensity in the skin, which has been measured using ultrasound, and a mechanically measured retraction time, and determining, for informing the person about the current skin state and an expected future skin state, at least one assistance quantity (61 , 62, 63) based on a normalization, a renormalization and a weighting of the provided indicators (10, 20), wherein a) the normalization refers to a normalization of the indicators (10, 20) to a same numerical range, b) the renormalization refers to an adjustment of at least one of the indicators (10, 20) for an age and / or a genetic characteristic of the person, the adjustment being chosen based on a known or assumed influence of the age and / or the genetic characteristic of the person on the indicator such that the influence on the adjusted indicator is decreased, and c) the weighting refers to a weighting of the indicators according to a respective relevance of the indicators (10, 20) for the assistance quantity (61 , 62, 63), wherein the weighting is carried out after normalization and renormalization.

2. A method as defined in claim 1 , wherein the indicators (10, 20) include indicators (20) indicating an influence on the skin state of the person in terms of the following: a general well-being of the person and an own perception of the skin state by the person.

3. A method as defined in any of the preceding claims, wherein one or more of the indicators (10) indicate a current skin state of the person and are provided based on at least one of the following: a microbiome analysis, a blood analysis.

4. A method as defined in any of the preceding claims, wherein one or more of the indicators (20) indicate an influence on the skin state of the person and are providedbased on a user input indicative of any of the following: an environmental or social context of the person, a habit of the person, a mental state of the person.

5. A method as defined in any of the preceding claims, wherein, for informing the person about the current skin state, a first assistance quantity (61) is determined based on a weighting of the indicators (10, 20).

6. A method as defined in claim 5, wherein the texture indicator is assigned a highest weight among the indicators used for determining the first assistance quantity (61).

7. A method as defined in any of the preceding claims, wherein, for informing the person about the current skin state, a first assistance quantity (61) is determined based on the indicators (10, 20), wherein the indicators (10, 20) include one or more further indicators (10, 20) indicative of the following: a degree of visual homogeneity in color of the skin of the person, a hydration of the skin of the person and a past exposure to sunlight.

8. A method as defined in any of the preceding claims, wherein, for informing the person about an expected future skin state, a second assistance quantity (62) is determined based on a weighting of the indicators (10, 20).

9. A method as defined in claim 8, wherein a) the firmness indicator is assigned a highest or second highest weight among the indicators (10, 20) used for determining the second assistance quantity, and / or wherein b) the indicators (10, 20) used for determining the second assistance quantity (62) include a habit indicator indicative of one or more habits of the person, wherein the habit indicator is assigned a highest or second highest weight among the indicators (10, 20) used for determining the second assistance quantity.

10. A method as defined in any of the preceding claims, wherein, for informing the person about an expected future skin state, a second assistance quantity (62) is determined based on the firmness indicator and indicators (10, 20) indicative of the following: a barrier function of the skin of the person, habits of the person and an environment of the person.

11. A method as defined in any of the preceding claims, wherein the indicators (10, 20) include:one or more emotional and / or perceptional indicators (10, 20), in particular being indicative of a general well-being and / or happiness of the person, and whether the person feels beautiful or disfigured, one or more indicators (10, 20) of a tone of the person’s skin, in particular being indicative of a skin color, red areas of the skin and age spots / lentiginous brown spots, the texture indicator the firmness indicator one or more contextual and / or habitual indicators (10, 20), in particular being indicative of a nutrition of the person, sun exposure of the person, an alcohol consumption by the person, smoking habits of the person and sleep habits of the person.

12. A method as defined in any of the preceding claims, wherein a), as far as the at least one assistance quantity (61 , 62, 63) is determined for informing the person about the current skin state, the renormalization refers to an adjustment of at least one of the indicators (10, 20) used for determining the assistance quantity (10, 20, 30) based on avalue thereof that is expected from the current age and the sex of the person, and wherein b), as far as the assistance quantity (61 , 62, 63) is determined for informing the person about an expected future skin state, the renormalization includes a continuously progressing renormalization of at least one of the indicators (10, 20) used for determining the assis- tance quantity (61 , 62, 63) with age and a constant renormalization of at least one of the indicators (10, 20) used for determining the assistance quantity (61 , 62, 63) depending on the sex.

13. A data processing device comprising a processor configured to carry out a method as defined in any of claims 1 to 12.

14. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out a method as defined in any of claims 1 to 12.

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