著者

池野 和之介 福田 知弘 矢吹 信喜

出版者

日本建築学会

雑誌

日本建築学会環境系論文集 (ISSN:13480685)

巻号頁・発行日

vol.85, no.776, pp.757-765, 2020 (Released:2020-10-30)

参考文献数

38

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The importance of the administrative authorities communicates information about disaster prevention is increased. When a natural disaster occurs in Japan, administrative authorities communicate this information using disaster administrative radio system. Ministry of Internal Affairs and Communications recommends distribution individual house receivers to all family, however, many municipalities use not individual house receivers but outdoor loudspeakers due to financial matters and limited cost-effectiveness. There is a problem that some regions don’t receive the information from outdoor loudspeakers. Municipalities need to reconsider the placement of outdoor loudspeakers, but it is difficult to confirm audibility intuitively and there are few cases that experts and non-experts such as government and citizens share and consider acoustic analytic results. High-precision outdoor acoustic analysis method is proposed. Virtual Reality (VR) and Mixed Reality (MR) System for visualizing simulation of environmental circumstances are developed. However, these simulation need many computer resources and take a long time. Therefore this study aims to develop an interactive visualization system for simulations of sound circumstance from outdoor loudspeakers using MR. By using an optical see-through Head Mounted Display (HMD) and tablet terminal, users can view the acoustic analytic results of the simulation. Sound simulation is carried out on PC. Furthermore, when users change the simulation condition such as sound source positions, users can view the results of the simulation immediately. It is necessary to create three-dimensional model of the object region and input our system preliminarily. This system uses the Ray-Tracing Method which is a type of geometric acoustic simulation method because this method can reduce calculation load. And, using the approximate of Maekawa Chart, this system can handle transmission of diffracted sound which cannot be handled in geometric acoustic simulation method. This system converts simulation results into sound pressure level (SPL) and shows heatmap and bar histogram by using MR. Our proposed system can reduce calculation load by using Sound Ray-Tracing Method. Our system is appropriate for an interactive system. However, when users view the acoustic analytic results of simulation by using HoloLens which is one of the optical see-through Head Mounted Display, this system needs time for rendering objects such as sound receiver and heatmap because of too many objects. The cause of this problem is the data transmission speed between PC and HoloLens. By reducing drawn objects and improving transmission speed, this problem is solved. We set coordinates of the sound source at the same place as the current position of one of the outdoor loudspeakers and simulated by using our system. We tested the effectiveness of our system by comparing the simulation results to more detailed simulation results and actual measurement value. The conclusions of the present study are shown below. ● Develop the groundwork of interactive visualization system for sound environment simulation using MR. ● Reduce calculation load by using Ray-Tracing Method which is a type of geometric acoustic simulation method. ● Confirm audibility intuitively by heatmap and bar histogram by using MR. The future prospect is to enable simulation in consideration of plural sound sources, wind and temperature.