Dynamic visualization of ultraviolet dose on skin with sunscreen applied using minimum erythema dose

BACKGROUND: Visualizing the ultraviolet (UV) dose on skin serve as an intuitive approach to ensure appropriate sunscreen usage and reduce the risk of erythema. UV dose is determined by a number of external factors, such as properties of sunscreens, weather, and type of outdoor activity. We propose a framework for visualizing UV doses that considers various external factors. MATERIALS AND METHODS: First, the skin of a three‐dimensional human model was represented using triangular meshes, and various static postures and dynamic motions were simulated to express outdoor activities. Then, we evaluated the persistency and insufficiency properties of sunscreen, which are time dependent and directly affect the effectiveness of the sunscreen skin protection factor (SPF) during UV exposure. Finally, to calculate the UV dose in real time, we tracked the trajectory of the sun and motion of the skin while considering the time‐dependent properties of sunscreen. RESULTS: An S/W system was implemented based on the proposed framework to visualize the distribution of UV doses through dynamic color changes in exposed skin areas. The color types include true colors, which represent the minimum erythema dose (MED), and pseudo colors representing states before 1 MED is reached. We devised various examples to discuss the usability of the proposed framework. CONCLUSION: The system conveniently displays the MED according to an individual's skin phototype. When the properties of a wide range of commercial sunscreens are added to the system database, it is expected that the rate of appropriate sunscreen usage by customers will increase.