IEEE Trans Ultrason Ferroelectr Freq Control. 2022 Feb;69(2):489-499. doi: 10.1109/TUFFC.2021.3123079. Epub 2022 Jan 27.
Efficient ultrasound (US) systems that produce high-quality images can improve current clinical diagnosis capabilities by making the imaging process much more affordable and accessible to users. The most common technique for generating B-mode US images is delay-and-sum (DAS) beamforming, where an appropriate delay is introduced to signals sampled and processed at each transducer element. However, sampling rates that are much higher than the Nyquist rate of the signal are required for high-resolution DAS beamforming, leading to large amounts of data, making remote processing of channel data impractical. Moreover, the production of US images that exhibit high resolution and good image contrast requires a large set of transducer elements, which further increases the data size. Previous works suggest methods for reduction in sampling rate and in array size. In this work, we introduce compressed Fourier domain convolutional beamforming, combining Fourier domain beamforming (FDBF), sparse convolutional beamforming, and compressed sensing methods. This allows reducing both the number of array elements and the sampling rate in each element while achieving high-resolution images. Using in vivo data, we demonstrate that the proposed method can generate B-mode images using 142 times less data than DAS. Our results pave the way toward efficient US and demonstrate that high-resolution US images can be produced using sub-Nyquist sampling in time and space.
高效的超声（US）系统能够生成高质量的图像，可以通过降低成像过程的成本和提高用户的可及性，来提高当前的临床诊断能力。生成 B 模式 US 图像最常用的技术是延迟求和（DAS）波束形成，其中在每个换能器元件处对采样和处理的信号引入适当的延迟。然而，对于高分辨率的 DAS 波束形成，需要比信号奈奎斯特率高得多的采样率，这会导致大量的数据，使得通道数据的远程处理变得不切实际。此外，产生具有高分辨率和良好图像对比度的 US 图像需要大量的换能器元件，这进一步增加了数据量。先前的工作提出了降低采样率和阵列尺寸的方法。在这项工作中，我们引入了压缩的傅里叶域卷积波束形成，结合了傅里叶域波束形成（FDBF）、稀疏卷积波束形成和压缩感知方法。这使得在实现高分辨率图像的同时，能够减少阵列元件的数量和每个元件的采样率。使用体内数据，我们证明了该方法可以使用比 DAS 少 142 倍的数据生成 B 模式图像。我们的结果为高效 US 铺平了道路，并证明了可以使用时间和空间上的亚奈奎斯特采样来生成高分辨率 US 图像。
