When inspecting an internal state of a tree in a nondestructive manner, high-frequency acoustic waves whose amplitudes and frequencies are accurately controlled are made incident on the inside of the tree from a plurality of positions, acoustic waves that are propagated inside the tree are received at a plurality of positions, and based on the received signals, the internal state of the tree is visualized, whereby the state including hollows and decay inside the standing tree is efficiently diagnosed in a nondestructive manner.
Internal tree nondestructive inspection method and apparatus using acoustic tomography