PROBLEM TO BE SOLVED: To derive an estimated value of a sound velocity in a subject at a high degree of accuracy without reference to an imaging region.SOLUTION: Reception signals in a plurality of frequency bands different from one another are acquired by transmission/reception of ultrasonic waves into/from a subject. The degree of strain, which indicates the magnitude of the strain of each of the reception signals in the plurality of frequency bands, is derived. The reception signal in one frequency band is selected from among the reception signals in the plurality of frequency bands on the basis of the degree of the strain. An estimated value of a sound velocity in the subject is derived on the basis of the selected reception signal.COPYRIGHT: (C)2014,JPO&INPIT【課題】撮像部位によらず被検体内の音速の推定値を高い精度で導出する。【解決手段】被検体内への超音波の送受信によって互いに異なる複数の周波数帯域の受信信号を取得する。複数の周波数帯域の受信信号の各々の歪みの大きさを示す歪み度を導出する。歪み度に基づいて複数の周波数帯域の受信信号の中から1の周波数帯域の受信信号を選択する。選択された受信信号に基づいて被検体内の音速の推定値を導出する。【選択図】図1
