Mixed Reality Visualization System for the 3D sound intensity using PAGE method and spatial interpolation

In the our previous study, we proposed the visualization system of three-dimensional sound intensity measured by handy 4-ch microphones using Mixed Reality. In the previous system, since the sound intensity was estimated by the cross-spectrum method. the error at the higher frequency than the spatial Nyquist frequency becomes larger due to the microphone intervals. In addition, visibility of sound intensity map was degraded because the microphone array was moved by hands and the intervals of measurement points for sound intensity map are irregular. In this study, we improve the previous mixed reality system for sound intensity by applying the PAGE method (Phase and Amplitude Gradient Estimation), which can accurately estimate the sound intensity up to higher frequencies. Furthermore, by using spatial interpolation of an irregularly-sampled intensity map, we improve visibility of sound intensity map with mixed reality. The proposed system interpolates sound intensities at equal intervals from the sound intensities measured at irregular intervals. For evaluation, we conducted visualization experiments of sound intensities surrounding single loudspeaker.