Abstract
This paper addresses an easy-to-handle technique to visualize the risk of the hot environment in outdoor surroundings. The authors surveyed the use of the public spaces and nearby greenways. Then we modeled the hot environment by estimating wet-bulb globe temperature (WBGT) based on a computer graphics (CG) technique. We focus on the global illumination (GI) technique, which performs the computation of the energy transfer between object surfaces to simulate the light behaviors of multi-reflection, penetration and their multi-path combinations to render photo-realistic imageries. Then we expected that the correlation between WBGT and the visible light environment which can be simulated by the GI-based CG. Also, we acquire a relationship between intensities between solar radiation and the observed pixels in an image captured by a camera. This correlation allows us to use computer-generated realistic pixel values for estimating solar radiation in the CG scene, and thus WBGT can be calculated by additional information of dry and wet bulb temperatures, without specific devices to measure WBGT. This paper also shows the applicability of the proposed method by 3D modeling of the actual public green way at Settsu-city in Osaka Pref. By using this measurement-based model and actual geodetic coordinates, WBGT distribution on an arbitrary date and time can be visualized in the 3D scene. This method has the advantage to predict planting effects on mitigating hot environment from the planning stages as well as the visualizing the risk of existing hot environment one time to another.
