Multispectral images, including ultraviolet light and its interactions with ultraviolet light-interactive compounds, can be captured, processed, and represented to a user. Ultraviolet-light related information can be conveniently provided to a user to allow the user to have awareness of UV characteristics and the user's risk to UV exposure.

A method for determining natural illumination duration and an electronic device are provided, to more accurately determine a scenario in which a user is located and effectively determine natural illumination duration, to help the user improve vision. The method is applied to an electronic device having a display screen and includes: determining a current scenario based on a preset reference factor (S901), where the preset reference factor includes any one or more of ultraviolet intensity, illumination intensity, and locating signal strength; and counting current natural illumination duration towards cumulative natural illumination duration if the current scenario is a preset scenario (S902), where the preset scenario includes any one or more of an outdoor scenario, an indoor near-window scenario, and an outdoor blocked scenario.

A tool for recommending proper sun block use. The tool receives, by one or more computer processors, a first image of a user captured by a camera, and a second image of a user captured by a camera, wherein the first image is an ultraviolet image, and the second image is a digital color image. The tool determines, by one or more computer processors, areas of ultraviolet radiation vulnerability for the user captured in the first and second image. The tool determines, by one or more computer processors, a level of ultraviolet radiation vulnerability for the determined areas. The tool determines, by one or more computer processors, a recommendation for proper sun block use based, at least in part, on the level of ultraviolet radiation vulnerability.

A tool for recommending proper sun block use. The tool receives, by one or more computer processors, a first image of a user captured by a camera, and a second image of a user captured by a camera, wherein the first image is an ultraviolet image, and the second image is a digital color image. The tool determines, by one or more computer processors, areas of ultraviolet radiation vulnerability for the user captured in the first and second image. The tool determines, by one or more computer processors, a level of ultraviolet radiation vulnerability for the determined areas. The tool determines, by one or more computer processors, a recommendation for proper sun block use based, at least in part, on the level of ultraviolet radiation vulnerability.

There is described a method of determining the UV fluence received by a fluid. The method comprises the steps of: (a) irradiating the fluid at an unknown UV fluence; (b) measuring the fluorescence of a test sample of the fluid after irradiation in Step (a) to produce a test signal proportional to the concentration of a prescribed fluorescent composition of matter comprised in the test sample; and (c) determining the value of the unknown UV fluence by comparing the test signal to a calibration curve of a control signal proportional to concentration of the prescribed fluorescent composition of matter in the fluid as a function of applied UV fluence. There is also described a system for determining the UV fluence received by a fluid being treated in UV fluid treatment system comprising at least one UV source. The system comprises: (a) a radiation-transparent vessel for receiving a test sample of the fluid after irradiation of the fluid at an unknown UV fluence; (b) a fluorometer for measuring the fluorescence of the test sample received in the radiation-transparent vessel to produce a test signal proportional to the concentration of a prescribed fluorescent composition of matter comprised in the test sample; and (c) a controller configured to determine the value of the unknown UV fluence by comparing the test signal to a calibration curve of a control signal proportional to concentration of the prescribed fluorescent composition of matter in the fluid as a function of applied UV fluence.

A light receiver capable of detecting the intensity of light in a certain wavelength range is provided. The light receiver includes a first light receiving element (PD1) and a second light receiving element (PD2) that have an identical spectral sensitivity characteristic, and a UV cut filter (11). Light that has passed through the UV cut filter (11) enters the first light receiving element (PD1). A subtractor is provided that calculates a difference between a photocurrent of the first light receiving element (PD1) and a photocurrent of the second light receiving element (PD2).

Provided are an ultraviolet-sensing sheet, an ultraviolet-sensing set, and an ultraviolet-sensing method, in which color gradation properties which are suitable for detecting an ultraviolet dose are obtained and in which the coloring of an ultraviolet-sensing layer caused by the effect of light other than ultraviolet light is prevented.

An ultraviolet-sensing sheet 1 includes: a filter layer 10 that selectively allows transmission of light having a specific wavelength; and an ultraviolet-sensing layer 20 that includes a capsule including a color-forming dye and a photooxidant. It is preferable that the filter layer 10 has a maximum value of the transmittance in a wavelength range of 300 nm or longer and shorter than 380 nm.

In embodiments, a control system for a UV air treatment system, especially one used for cleaning a fume stream such as in a kitchen exhaust system, detects a need for cleaning maintenance on the UV light source based on changes in light intensity. The system further detects the light intensity each time the UV light source is cleaned to determine if the drop in intensity after cleaning indicates that the UV light source should be replaced. The cleaning and replacement requirements are indicated automatically by a user interface.

A sensor circuit includes a transistor comprising an oxide semiconductor; a first circuit which supplies one of a first potential and a second potential; a first switch; a second switch; and a second circuit to which a current flowing between a source and a drain of the transistor is applied via the second switch when the first potential is applied to a gate of the transistor. The first potential is lower than a potential of the source or a potential of the drain of the transistor, and the second potential is higher than the potential of the source or the potential of the drain of the transistor. The first switch electrically connects the source and the drain of the transistor when the second potential is applied to the gate of the transistor, and electrically isolates them when the first potential is applied to the gate of the transistor.

Disclosed herein are a system and method for controlling the temperature of a user. The wearable device may include a first temperature measurement unit configured to measure a temperature of a user and a control unit configured to calculate a temperature difference by comparing the temperature measured by the first temperature measurement unit with a previously stored temperature of the user at normal times, provide temperature measurement information to an external device if the calculated temperature difference is more than a reference temperature difference for a predetermined time, and receive service information for controlling the temperature of the user based on the temperature measurement information from the external device.