Case study: OtologMap: a case study on the construction of an environmental sound map recorded by smart devices at Okayama and Kurashiki

We present a case study on the visualization of environmental sound signals collected using a cloud sensing approach; in particular, participatory sensing and opportunistic sensing. The proposed environmental sound visualization map features two major extra functions compared with a simple noise map, which only visualizes sound levels. The first is the overlay visualization of sound-type icons on the noise map, resulting in information enrichment. The second is the transition animation of sound levels on this map and their variation with time during a day. We conduct several experiments and use the results to construct the proposed sound map and develop its functions. Initially, we develop a sound collection system to simultaneously collect physical sound signals, their statistics, and their subjective impressions. Next, we conduct sound collection experiments using the developed system for Okayama and Kurashiki. By performing data analysis, we compare sound-level transitions in bustle areas and cities, with noise maps aligned in a time-series order during days with unusual events. Then, we introduce subjective sound levels on the map and its predicted form for further investigation. Finally, we discuss the results to gain insight into the advantages and limitations of the proposed method.