UV-BODYGUARD

Description

[0001] The present invention relates to a system comprising a UV detection unit and a method for adapting UV forecast data.

[0002] Without the sun, life on Earth would be impossible. In addition to visible light and infrared radiation, which we perceive as heat, the sun also emits ultraviolet (UV) radiation. UV radiation is electromagnetic radiation in the wavelength range from 100 nm to 400 nm. UV radiation is invisible and is further divided according to wavelength into the sub-ranges UVA (315-400 nm), UVB (280-315 nm), and UVC (100-280 nm). While UVC radiation cannot normally reach the Earth's surface due to absorption in the ozone layer and by the molecular oxygen in the Earth's atmosphere, UVA and a small amount of UVB radiation penetrates to the Earth's surface and can have biological effects on human health.

[0003] UVB radiation stimulates the production of vital vitamin D3, which plays a key role in the development and maintenance of bones in the human body. Vitamin D deficiency is usually caused by insufficient sun exposure. However, UV radiation can also have significant negative effects on the human body, especially on the skin. Exceeding a certain threshold of UV radiation can cause acute skin damage and even skin cancer.

[0004] Against this background, products are known in the state of the art that are designed to measure UV radiation and, on the basis of the measured data, to carry out an analysis, to issue a warning when limit values ​​are exceeded or to create a forecast of a future permissible duration of exposure to the sun.

[0005] From the document WO 2018 / 208166 A2 a device for determining UV exposure according to the preamble of the main claim 1 is known.

[0006] The problem with measuring UV radiation is that conventional UV measuring devices are only capable of detecting a spectral sum of the incident radiation (an integral across all wavelengths within the sensor's sensitivity range). However, different parts of the spectrum pose varying degrees of exposure to human skin, so the same sensor readings can correspond to different exposure values ​​for the skin. UVA radiation (UV radiation with a wavelength > 315 nm) penetrates deep into the skin and causes long-term damage. UVB radiation (UV radiation with a wavelength < 315 nm) causes short-term effects such as sunburn.

[0007] To account for these varying skin exposures, the internationally recognized UV index has been established as the physical unit for quantifying UV radiation. The UV index is defined as the integral of the product of the erythema function s er (λ) and the spectral irradiance E(λ) in the wavelength range from approximately λ=250 to approximately λ=400 nm. A factor of k=40 m 2 < / W makes the UV index dimensionless: I UV = k ∗ ∫ 250 nm 400 nm E λ ∗ s er λ d

[0008] The erythema function represents a measure of the stress on human skin (erythema: dermatological term for skin reddening or inflammation). The erythema function can also be understood as the spectral sensitivity of the skin and can be based, for example, on IEC 60335-2-27 of DIN 5050, Part 1, or DIN EN 60335-2-27.

[0009] Forecast data from a weather service, for example, is used for a forecast. However, such a forecast may need improvement because the forecast data can deviate significantly from the UV radiation actually measured at the time of the forecast. This is partly because many forecast data on UV radiation are created solely for a clear sky, whereby the influence of clouds is not taken into account. On the other hand, even if the UV forecast data is created using the cloud cover forecast by the weather model, many other factors such as the specific cloud cover, the soil type, or the elevation of the location where the user is located can influence the UV radiation.The grid resolution of weather models, typically 10 or more kilometers in mesh size, does not allow for a spatially resolved UV forecast, as, for example, broken clouds are smeared into a medium cloud density across an entire grid cell and thus cannot be adequately represented. With elevation, UV radiation increases by approximately 10 percent per 1,000 meters. In addition, the ground partially reflects UV radiation, with the albedo, a measure of reflectivity, varying greatly depending on the ground type. For example, certain ground types, such as snow or sand, have a higher albedo, so UV radiation can be amplified in this way.

[0010] It is therefore an object of the present invention, according to the following aspects, to provide an improved system and an improved method that address one or more of the aforementioned disadvantages of the prior art. This object is achieved by a system for determining UV exposure according to the subject matter of main claim 1 and by a method for determining UV exposure according to the subject matter of claim 2.

[0011] According to a first aspect of the invention, this object is achieved by a system for determining UV exposure, comprising: a portable device comprising a UV detection unit which is configured to detect UV radiation irradiated onto the UV detection unit, a data processing unit which is configured to receive at least one measured value of the detected UV radiation from the device, wherein the data processing unit is further configured to receive an ozone value related to an ozone situation for a location at which the UV detection unit is located from a remote server, wherein the data processing unit is configured to detect a sun elevation value and to determine a UV exposure value based on the detected UV radiation and the ozone value and to process it for information of a user.By measuring the ozone value (e.g., the amount of ozone or the thickness of the ozone layer, measured in the "Dobson" unit), the measured UV radiation can be used to determine the spectral distribution of UV radiation, which in turn allows the determination of a UV exposure value based on the UV index mentioned above. The UV exposure value is therefore significantly more informative about the exposure to human skin at a given location than the UV radiation measurement alone.

[0012] A transfer function is stored in the data processing unit by which the UV exposure value at a predetermined time can be determined from the UV radiation at the predetermined time, the ozone value at the predetermined time and / or the sun elevation value at the predetermined time.

[0013] According to a second aspect of the invention, there is provided a method for determining UV exposure, preferably using a system of the first aspect of the invention, the method comprising the following steps: Detecting incident UV radiation at a location, receiving an ozone level related to an ozone situation for the location from a remote server, determining the solar elevation at the current location, determining a UV exposure level based on the detected UV radiation and the ozone level.

[0014] This method achieves the advantages described above with respect to the system of the first aspect.

[0015] The invention according to the first and second aspects further comprises the generation of a transfer function by which the UV exposure value can be determined from the UV radiation, the ozone value, and / or the solar elevation value. The transfer function is determined using a trained neural network, wherein the neural network was trained using a plurality of training data sets, each training data set containing a UV radiation value, an associated ozone value, an associated solar elevation value, and an associated UV exposure value or UV index for a predetermined irradiation situation. The neural network can be a multilayer perceptron (MLP).

[0016] The invention will be explained in more detail below using a preferred embodiment with reference to the accompanying drawings. They show: Fig. 1 is a schematic representation of a UV bodyguard system according to an embodiment of the present invention, Fig. 2 is a spectral sensitivity of a UV sensor of the embodiment, an erythema function and a radiation flux with the sun high and low in the sky, Fig. 3 is a representation of a modulation of the solar radiation flux due to different ozone amounts in the stratosphere, Fig. 4 is a sensor count and UV index as a function of the solar zenith angle (SZW) for different stratospheric ozone amounts (250, 300 and 550 Dobson units).

[0017] In Fig. 1A UV bodyguard system is schematically illustrated, wherein the system comprises a portable device 10 and a data processing unit 20, wherein the data processing unit 20 is preferably a smartphone. Communication between the device 10 and the data processing unit 20 can be wired or wireless, with communication preferably taking place via Bluetooth. The smartphone can include a GPS module for position determination. Position determination can alternatively be performed by other technical means (e.g., GSM positioning) or by manual position input by the user.

[0018] The portable device 10 comprises at least one UV sensor, which is configured to detect at least one UV radiation irradiated onto the device 10. The portable device 10 preferably further comprises a housing, wherein the housing contains the UV detection unit, preferably also a Bluetooth interface, a microprocessor with a radio module, a rechargeable battery, a solar cell, and an LED module with, for example, a two-color LED for displaying information (e.g., battery charge level), wherein the above-mentioned components are preferably integrated into a circuit board. To measure the UV radiation, the microprocessor communicates with the UV sensor, preferably via the I2C protocol. The microprocessor can switch the UV sensor on and off, as well as adapt the exposure time for each individual measurement to the detected UV radiation intensity.

[0019] The housing is preferably made of a UV-permeable plastic and an elastomer, which serve as fastening and sealing. The housing is preferably created in a target group-specific design, e.g. in the shape of a turtle for children, with the housing having, for example, a length of approximately 5 cm, a width of approximately 4.5 cm and a height of approximately 1.3 - 1.5 cm. The housing can be formed in two parts with a top and a bottom that are clipped together. On the back of the housing there is preferably a micro-USB plug for charging the battery. Alternatively or additionally, the battery can also be charged by the solar cell. The housing preferably has at least one opening through which, for example, a Velcro strap or clip can be pulled for further attachment to a sun hat or backpack. Alternative attachments such as sewing or tying are also conceivable.To reduce the directional dependence of the UV sensor and to ensure unobstructed exposure of the sensor, the housing is preferably provided with a large opening in the form of a window or lens on the top. The portable device 10 can be attached to a backpack or sun hat, whereby the orientation of the device relative to the sun should be taken into account during attachment.

[0020] The portable device 10 is preferably coupled to the smartphone 20 via Bluetooth and transmits the measured UV values ​​to the smartphone 20 in real time at a frequency defined by the manufacturer or user.

[0021] Should the connection be lost, for example, due to excessive distance between device 10 and smartphone 20, this connection will be automatically restored as soon as device 10 and smartphone 20 are within a range of less than 10 meters, for example, and the missing data will be transferred. Depending on the storage capacity, a certain amount of data can be stored in the device 10 on the UV sensor or the associated microprocessor, preferably for a measurement time of up to 2.5 hours.

[0022] Application software, a so-called app, is preferably installed on the smartphone 20. The app is preferably configured to evaluate received UV measurements and visualize the evaluation results and other information for the user. The evaluation results include, for example, the current UV intensity, the previous UV dose, the current position of the sun and any further development of the sun's position, as well as the remaining time in the sun to avoid exceeding the permitted UV dose. If defined limits are exceeded, the app can warn the user.

[0023] It should be noted that the threshold values ​​can be user-specific and influenced by many factors, such as the user's skin type, the sun protection factor of the sunscreen used, etc. Therefore, the app is preferably configured to receive user-specific data (e.g., through an input window), whereby the forecast or threshold values ​​can further be created based on the user-specific data.

[0024] To create a forecast of the remaining time in the sun, the smartphone is preferably configured to receive UV forecast data from the Copernicus Atmosphere Monitoring Service (CAMS) 30. However, the received UV forecast data can deviate significantly from the actually measured UV radiation due to many factors such as cloud cover, soil type, and terrain elevation. To improve the forecast, the smartphone is preferably configured to derive a correction function based on the UV radiation received in the past up to the current time and the corresponding past UV forecast data, so that future UV forecast data can be adjusted using the correction function.

[0025] A measured UV radiation value and the UV forecast data corresponding to the UV radiation are preferably only used to derive the correction function if the current generated by the solar cell exceeds a certain threshold at the time the measured value is recorded. This avoids the use of measured data and corresponding forecast data when the user is inside a building or in heavy shade at the time of the measurement. Such measured data can, of course, deviate significantly from the forecast data and thus lead to an incorrect correction function.

[0026] Alternatively or additionally, the smartphone can also be configured to receive further information about, for example, cloud model, soil types and terrain heights, and to adjust the received UV forecast data exclusively or additionally based on such information.

[0027] A transfer function can be stored in the smartphone 20, by which a UV exposure value, in particular a UV index or a value indicating the UV index, can be determined from an ozone value and a solar elevation value. The smartphone can receive the ozone value from the Copernicus Atmosphere Monitoring Service (CAMS) 30. The smartphone can calculate the solar elevation value, for example, based on the current position, the date, and the time, or can also receive it from a remote server, the Internet, or from the Copernicus Atmosphere Monitoring Service (CAMS) 30.

[0028] An example of a UV sensor and a transfer function is described below.

[0029] For example, the UV sensor of the portable device 10 may have a maximum spectral sensitivity to incident electromagnetic waves at 315 nm with a half-width of 60 nm. This half-width may be distributed asymmetrically and cover a range from -20 nm to +40 nm around the peak sensitivity. Thus, the UV sensor used may respond differently, partially to the UVB spectrum (280-315 nm) and partially to the UVA spectrum (315-400 nm).

[0030] Figure 2 shows the spectral profile of the relevant parameters, namely the sensor sensitivity, the erythema function, and the solar radiation fluxes at two different positions of the sun. The sensor sensitivity takes into account the optical effect of the housing of the device 10, in particular the protective cover of the UV sensor.

[0031] The part of the electromagnetic spectrum relevant for an erythema reaction covers the wavelength range below 315 nm. The erythema function is an exponential function that extends over a wide range of magnitudes.

[0032] The spectral sensitivity distribution of the UV sensor is significantly broader than the erythema response function. In particular, the sensor's sensitivity is strongly influenced by UV-A. While UV-B is responsible for sunburn and vitamin D production in the skin, UV-A primarily causes long-term effects, such as skin aging.

[0033] Due to this broad sensitivity distribution of the UV sensor, differences in the thickness of the ozone layer - which are highly weighted by the erythema function - are not resolved or only weakly. Figure 3illustrates this relationship for high ozone levels (e.g. 550 Dobson units) and low ozone levels (e.g. 250 Dobson units) in the stratosphere, with the same position of the sun at the current position of the smartphone 20.

[0034] Quantitatively, this is as in Figure 4 Shown here are the simulated sensor counts (the UV radiation measured by the UV sensor of device 10) for solar elevations from 90° (sun at its zenith) to 0° (sun at the horizon) for stratospheric ozone values ​​(ozone layer thicknesses) of 200, 300, and 550 Dobson units. Regardless of the ozone value, the sensor counts exhibit values ​​that are barely distinguishable from one another. The UV index, however, varies considerably and, for example, is approximately 7 (550 DE), 13 (300 DE), or 21 (200 DE) in the case of the sun at its zenith (SZA=0°).

[0035] To derive the correct erythema-effective UV index, according to the exemplary embodiment of the invention, a transfer function is provided that incorporates the current ozone situation (ozone value) and the current solar elevation. The transfer function can be generated by training a multilayer perceptron (MLP). Output data can be simulated spectral intensities for the UV sensor and for the erythema response function. The transfer function thus determined can be tabulated and integrated into the app on the smartphone 20. This enables an efficient, particularly power-saving, translation of the measured UV sensor data from the device 10 into the actual skin-relevant UV exposure value, in particular the UV index.

Claims

1. System for determining UV-exposure, comprising: - a portable device (10) comprising a UV detection unit configured to detect UV radiation irradiated onto the UV detection unit, - a data processing unit (20) configured to receive at least one measurement value of the detected UV radiation from the device, wherein the data processing unit is further configured to receive from a remote server an ozone value related to the stratospheric ozone situation for a location at which the UV detection unit is positioned, wherein the data processing unit (20) is further configured to detect a solar elevation value, wherein the data processing unit (20) is further configured to determine a UV evaluation value based on the detected UV radiation and the ozone value and to process it for informing a user, wherein in the data processing unit (20) a transfer function is stored, by means of which the UV exposure value can be determined at a predetermined time from the UV radiation at the predetermined time, the ozone value at the predetermined time and the solar elevation value at the predetermined time, characterized in that the transfer function is determined using a trained neural network, wherein the neural network is trained using a plurality of training datasets, wherein each training dataset for a predetermined irradiation situation has a UV radiation value, an associated ozone value, an associated solar elevation value and an associated UV exposure value.

2. Method for determining UV-exposure, wherein the method comprises the following steps: - detecting an irradiated UV radiation at a location, - receiving an ozone value for the location related to an ozone situation from a remote server, - determining the solar elevation value at the current location, - determining a UV exposure value at a predetermined time from the UV radiation at the predetermined time, the ozone value at the predetermined time and the solar elevation value at the predetermined time by means of a transfer function, characterized in that the transfer function is determined using a trained neural network, wherein the neural network is trained using a plurality of training datasets, wherein each training dataset for a predetermined irradiation situation has a UV radiation value, an associated ozone value, an associated solar elevation value and an associated UV exposure value.