PROBLEM TO BE SOLVED: To provide an ultrasound signal processing device capable of reducing the amount of computation in phasing addition while suppressing the degradation of spatial resolution and S/N ratio in a synthetic aperture method using conversing transmission beam forming.SOLUTION: Provided is an ultrasound signal processing device, comprising: a transmitter for transmitting an ultrasound beam to a target region inside a subject, while changing the focus point for each transmission event； a phasing adder for generating linear-region acoustic line signals by performing, for each transmission event, weighted phasing addition including delay processes based on a distance between an observation point and the focus point and a distance between the focus point and an oscillator with respect to a plurality of observation points on a straight line passing through the focus point； and a synthesizer for generating sub-frame acoustic line signals from the linear-region acoustic line signals and performing weighted synthesis of the sub-frame acoustic line signals to synthesize frame acoustic line signals； the ultrasound signal processing device being characterized in that, in at least one of weighting processes, weight sequences for observation points deeper than the focus point have a larger dispersion than weight sequences for observation points shallower than the focus point.SELECTED DRAWING: Figure 8【課題】集束型の送信ビームフォーミングを用いた合成開口法において、空間分解能及びＳ／Ｎ比の低下を抑制しながら整相加算の演算量を削減することのできる超音波信号処理装置を提供する。【解決手段】フォーカス点を送信イベントごとに変更しながら被検体内の対象領域に超音波ビームを送信させる送信部と、送信イベントごとに、フォーカス点を通る直線上に存在する複数の観測点について、観測点とフォーカス点、フォーカス点と振動子の距離に基づく遅延処理を含む重みづけ整相加算をして線領域音響線信号を生成する整相加算部と、線領域音響線信号からサブフレーム音響線信号を生成し、サブフレーム音響線信号を重みづけ合成しフレーム音響線信号を合成する合成部とを備える超音波信号処理装置において、重みづけ処理の少なくとも一方で、フォーカス点より深い観測点に対する重み数列は、フォーカス点より浅い観測点に対する重み数列より、分散が大きい。【選択図】図８
