PURPOSE: To narrow down a place required for measurement by varying the position relation between a body to be measured and a sensor array so that the sensor array covers the external surface of the body to be measured and the distance from the body to be measured is nearly equal.
CONSTITUTION: Sensor arrays 2W4 using a microphone 5 are at distance lfrom respective surfaces of a sound source 1. When data are collected by the sensor arrays, the sensor arrays 2W4 are moved in parallel to the surface of the sound source that the sensor arrays face. Then, the respective sensor arrays collect data in a space 6. The data collected as mentioned above are processed by a data processor to obtain an image showing the three-dimensional information on the sound source 1.