Department of Electronic Engineering, Fudan University, Shanghai 200433, China.
Department of Electronic Engineering, Fudan University, Shanghai 200433, China; Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention (MICCAI) of Shanghai, Shanghai 200232, China.
Ultrasonics. 2021 May;113:106373. doi: 10.1016/j.ultras.2021.106373. Epub 2021 Jan 28.
Plane wave compounding (PWC) is a valid method for ultrafast ultrasound imaging. Its imaging quality depends on the beamforming method. The coherence factor (CF) and Wiener postfilter are effective signal processing schemes for aberration correction. However, the CF usually causes over-suppression and brings artifacts. Additionally, the conventional CF and Wiener postfilter cannot fully utilize the spatial coherence in the PWC, which limits the imaging performance and increases the computation. In this paper, we propose a united Wiener postfilter specially for the PWC. The signal and noise power are both estimated through the echo signal matrix, rather than array signal vectors. The method also accords with the theoretical relationship between the CF and Wiener. To evaluate the performance of the proposed method, we conduct simulations, phantom and in vivo experiments and make comparisons with the delay-and-sum (DAS), the CF, the generalized coherence factor (GCF), the conventional Wiener and the scaled Wiener beamformers. Results indicate that our method can offer the better resolution and contrast than the DAS and Wiener. It also solves the over-suppression drawback of the CF. Specifically, the contrast ratio and contrast-to-noise ratio achieve 26.7% and 25.2% improvements in simulations, 28.7% and 32.4% in phantom experiments, respectively. The proposed method also performs well in terms of the speckle signal-to-noise ratio and the generalized contrast-to-noise ratio. Consequently, we believe that the proposed method is effective in enhancing the imaging quality of the PWC.
平面波复合（PWC）是一种用于超快超声成像的有效方法。其成像质量取决于波束形成方法。相干因子（CF）和维纳后滤波器是用于像差校正的有效信号处理方案。然而，CF 通常会导致过度抑制并带来伪影。此外，传统的 CF 和维纳后滤波器不能充分利用 PWC 中的空间相干性，这限制了成像性能并增加了计算量。在本文中，我们提出了一种专门用于 PWC 的联合维纳后滤波器。信号和噪声功率都是通过回波信号矩阵估计的，而不是通过阵列信号向量。该方法还符合 CF 和维纳之间的理论关系。为了评估所提出方法的性能，我们进行了模拟、体模和体内实验，并与延迟和求和（DAS）、CF、广义相干因子（GCF）、传统维纳和比例维纳波束形成器进行了比较。结果表明，与 DAS 和维纳相比，我们的方法可以提供更好的分辨率和对比度。它还解决了 CF 的过度抑制问题。具体来说，在模拟中对比度比和对比度噪声比分别提高了 26.7%和 25.2%，在体模实验中分别提高了 28.7%和 32.4%。该方法在斑点信号噪声比和广义对比度噪声比方面也表现良好。因此，我们认为该方法在提高 PWC 的成像质量方面是有效的。
