中文摘要：

与传统的延时叠加法相比,Capon自适应波束形成算法,在医学超声成像中具有更好的空间分辨率。但是超声回波信号的强相关性以及Capon算法对方向向量误差的敏感性,限制了其广泛应用。本研究介绍一种改进方案,采用空间平滑法去除回波信号的相关性,通过对角线加载法增强Capon算法的稳健性,并针对合成发射孔径数据的特点,提出双次稳健Capon算法处理。仿真和实验结果表明,改进后的Capon算法在成像的空间分辨率上有很大提高。

英文摘要：

Compared with classical delay-and-sum beamforming, Capon adaptive beamforming can perform better spatial resolution in medical ultrasonic imaging. The standard capon beamforming （SCB） can not be directly applied to ultrasonic imaging because it＇ s too sensitive to steering vector error and fail to work with coherent or highly correlated echo signals. In this paper, we introduced an improved method, in which we used spatial smoothing and diagonal loading to decorrelated the echo signals and robust capon beamforming （RCB）. According to the characteristic of synthetic aperture, we processed the multistatic data using twice robust capon beamforming （RCB2）. The excellent performance of the improved capon beamformer was demonstrated via some simulated and experimental examples.