SOUND FIELD THREE-DIMENSIONAL IMAGE MEASUREMENT METHOD BY DIGITAL HOLOGRAPHY, AND SOUND REPRODUCTION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a sound field image measurement method/device and a sound reproduction method/device that records a sound field as a three-dimensional field as a hologram and can perform reproduction of a sound field (reproduction of sound).SOLUTION: Object light passing a sound field and reference light are superimposed non-coaxially to be made interference light, the interference light is imaged time-serially, the object light is reconfigured by each interference intensity distribution, time serial phase distribution data is acquired from a time serial reconfiguration image, and sound information in a three-dimensional field is reconfigured. Imaging of the interference light is performed in a sampling cycle by twice or more frequency of sound to be measured. Reconfiguration of the sound information is performed by acquiring phase time waveform from the time serial phase distribution data. It is possible to identify a sound source position from the three-dimensional sound field data as well. Moreover, the phase time waveform is available for speech recognition and extraordinary noise measurement by acquiring a frequency spectrum of the sound field by Fourier transformation.