相干系数与幅度相位估计融合的医学超声成像算法

Amplitude and Phase Estimation Combined Coherence Factor Applied to Medical Ultrasound Imaging

在医学超声成像中,最小方差(MV)自适应波束形成算法虽能有效地提高成像分辨率,但牺牲了成像对比度和算法稳健性。针对此问题,提出一种基于幅度相位估计(APES)并引入相干系数(CF)的自适应波束形成算法。首先通过APES根据接收信号自适应的计算出初步结果;然后再通过接收信号的相干性计算出相干系数作为加权系数;最后对APES算法计算出的结果进行加权来进一步抑制噪声和干扰,改善成像分辨率和对比度。仿真实验结果表明,该算法在成像分辨率和对比度方面都要优于传统的延时叠加(DAS)法、最小方差法和原始的幅度相位估计法。

In medical ultrasound imaging,the minimum variance( MV) adaptive beamforming method can improve the imaging resolution at the expense of imaging contrast and robustness. In order to overcome this drawback,the amplitude and phase estimation( APES)adaptive beamforming method combined coherence factor( CF) was introduced. Firstly,preliminary result was adaptively computed using the APES based on the received signals,and then the CF was computed as weighted factor by the coherence in the signals. Finally,the preliminary result was weighted by the CF for reducing the level of noises and interferences which led to improve the imaging resolution and contrast ratio. The simulated results showed that the proposed method in the aspects of imaging resolution and contrast was better than the conventional delay and sum( DAS),MV and original APES beamforming method.