When the gap occurs with organizational displacement direction and the displacement search direction which are expected, the error which originates in the gap is made small, the ultrasonic image pickup system whose precision improvement of the elastic picture is possible is offered. From the ultrasonic propagation direction component map of the pressure which uses the revision angular map which was requested from the vector displacement map which was requested with block matching during RF displacing and two dimensional video pictures regarding the ultrasonic propagation direction which was calculated with the cross correlation between the RF signals, erasutogurahui where the gap of displacement direction is revised is made. With this method, slipping from direction of normal vector of the sending wave front of the ultrasonic probe of displacement vector of organization, without dropping precision, picture conversion of hardness ratio is possible.予想される組織変位方向と、変位探索方向との間にずれが生じる場合に、ずれに起因した誤差を小さくし、弾性画像の精度向上が可能な超音波撮像システムを提供する。RF信号間の相互相関により算出した超音波伝播方向に関するRF変位と、二次元ビデオ画像間のブロックマッチングにより求めたベクトル変位マップから求めた補正角マップを用いた圧力の超音波伝播方向成分マップから、変位方向のずれが補正されたエラストグラフィを作る。この方法により、組織の変位ベクトルの超音波探触子の送波面の法線ベクトルの向きからずれても、精度を落とさずに硬さ率の画像化が出来る。
