PROBLEM TO BE SOLVED: To reduce a computation amount in a technology to perform aperture synthesis while weighting a phasing signal using a coherence value of a reception signal after phasing.SOLUTION: A delay addition part includes a delay processing part for delaying a plurality of reception signals, an addition part for adding the reception signals after the delay and generating signals after phasing addition, and an evaluation index calculation part for calculating an evaluation index for the reception signals delayed by the delay processing part. The evaluation index calculation part calculates an evaluation index using the reception signals delayed for a reception scan line for only partial reception scan lines of a plurality of reception scan lines. A multiplication part uses the evaluation index calculated by the evaluation index calculation part as a weight.SELECTED DRAWING: Figure 3COPYRIGHT: (C)2019,JPO&INPIT【課題】整相後の受信信号のコヒーレンス値を用いて、整相信号を重み付けしつつ、開口合成も行う技術において、演算量を低減する。【解決手段】遅延加算部は、複数の受信信号を遅延させる遅延処理部と、遅延後の受信信号を加算して整相加算後信号を生成する加算部と、遅延処理部が遅延させた受信信号について評価指標を算出する評価指標算出部とを含む。評価指標算出部は、複数の受信走査線のうち一部の受信走査線についてのみ、その受信走査線のために遅延させた受信信号を用いて評価指標を算出する。乗算部は、評価指標算出が算出した評価指標を重みとして用いる。【選択図】図3
