IEEE Trans Ultrason Ferroelectr Freq Control. 2018 Jul;65(7):1133-1140. doi: 10.1109/TUFFC.2018.2831789.
The filtered delay multiply and sum (F-DMAS) beamformer has recently been presented in the context of medical ultrasound image formation. This nonlinear beamformer produces images with improved contrast resolution and noise rejection when compared with the delay and sum (DAS) beamformer. In an attempt to better understand the origin of the improved image quality, this paper shows a theoretical study of the image amplitude statistics backed up by numerical simulations. The results show that the difference in image amplitude using the DAS or F-DMAS beamformers can be partly explained by the way signal coherence influences both beamformers. When using the F-DMAS compared with the DAS beamformer, the image amplitude is shown to be more dependent on the signal coherence. Experimental ultrasound images of a phantom confirm our findings.
滤波延迟相乘和求和（F-DMAS）波束形成器最近在医学超声成象的背景下被提出。与延迟求和（DAS）波束形成器相比，这种非线性波束形成器在对比度分辨率和噪声抑制方面产生的图像质量得到了改善。为了更好地理解图像质量提高的原因，本文通过数值模拟对图像幅度统计进行了理论研究。结果表明，使用 DAS 或 F-DMAS 波束形成器的图像幅度差异可以部分解释为信号相干性对两种波束形成器的影响方式。与 DAS 波束形成器相比，F-DMAS 波束形成器的图像幅度更依赖于信号相干性。对一个体模的实验性超声图像证实了我们的发现。
