PROBLEM TO BE SOLVED: To find an accurate local sonic speed even if a convex probe is used of if a scan line is refracted.SOLUTION: Ultrasonic waves are transmitted and focused on at least two points (grid points B1i and Ai+1) with different depths within a subject from an ultrasonic probe to obtain each element reception signal of ultrasonic waves reflected at each grid point. The spacial position (depth D[0]) of the shallower point (Ai+1) of the at least two points with different depths is computed, and an average sonic speed (local sonic speed) in a region from the deeper point to the shallower point is computed based on the obtained each element reception signal and the computed spacial position of the shallower point.COPYRIGHT: (C)2014,JPO&INPIT【課題】コンベックスプローブの場合や走査線が屈折する場合でも正しい局所音速を求めることができるようにする。【解決手段】超音波探触子から被検体内の2以上の深さの異なる点(格子点B1i,Ai+1)に超音波を送信フォーカスし、各格子点で反射した超音波の各素子受信信号を取得する。2以上の深さの異なる点のうちの浅い点(Ai+1)の空間位置(深さD[0])を算出し、取得した各素子受信信号と算出した浅い点の空間位置とに基づいて、深い点から浅い点までの領域の平均音速(局所音速)を算出する。【選択図】 図6
