Frequency-Domain Synthetic Aperture Focusing Techniques for Imaging with Single-Element Focused Transducers

Q4 Physics and Astronomy
Elyas Shaswary, J. Tavakkoli, Carl Kumaradas
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引用次数: 0

Abstract

Synthetic aperture focusing techniques (SAFT) make the lateral spatial resolution of the conventional ultrasound imaging from a single-element focused transducer more uniform. In this work, two new frequency-domain SAFT (FD-SAFT) algorithms are proposed, which are based on 2D matched filtering techniques. The first algorithm is the FD-SAFT virtual disk source (FD-VDS) that treats the focus of a focused transducer as a finite sized virtual source and the diffraction effect in the far-field is accounted for in the image reconstruction. The second algorithm is the FD-SAFT deconvolution (FD-DC) that uses the simulated point spread function of the imaging system as a matched filter kernel in the image reconstruction. These algorithms were implemented for pulsed and linear frequency modulated chirp excitations. The performance of these algorithms was studied using a series of simulations and experiments, and it was compared with the conventional B-mode and time-domain virtual point source SAFT (TD-VPS) imaging techniques. The image quality was analyzed in terms of spatial resolution, sidelobe level, signal-to-noise ratio (SNR), contrast resolution, contrast-to- speckle ratio, and ex vivo tissue image quality. The results showed that the FD-VDS had the highest spatial resolution and FD-DC had the second highest spatial resolution. In addition, FD-DC had generally the highest SNR. The computation run time of the proposed methods was significantly lower than the TD-VPS. Furthermore, chirp excitation improves the SNR of all methods by about 8 dB without significantly affecting the spatial resolution and sidelobe level. Thus, the FD-VDS and FD-DC methods offer efficient solutions to make the spatial resolution of conventional B-mode imaging more uniform.
单元件聚焦传感器成像的频域合成孔径聚焦技术
合成孔径聚焦技术(SAFT)使单元件聚焦换能器的传统超声成像的横向空间分辨率更加均匀。本文基于二维匹配滤波技术,提出了两种新的频域SAFT算法。第一种算法是FD-SAFT虚拟盘源(FD-VDS),它将聚焦换能器的焦点视为有限大小的虚拟源,并在图像重建中考虑远场中的衍射效应。第二种算法是FD-SAFT反褶积(FD-DC),它使用成像系统的模拟点扩散函数作为图像重建中的匹配滤波器核。这些算法被用于脉冲和线性调频啁啾激励。通过一系列仿真和实验研究了这些算法的性能,并与传统的B模式和时域虚拟点源SAFT(TD-VPS)成像技术进行了比较。从空间分辨率、旁瓣电平、信噪比、对比度分辨率、对比散斑比和离体组织图像质量等方面分析了图像质量。结果表明,FD-VDS具有最高的空间分辨率,FD-DC具有第二高的空间分辨率。此外,FD-DC通常具有最高的SNR。所提出的方法的计算运行时间显著低于TD-VPS。此外,啁啾激励使所有方法的信噪比提高了约8dB,而不会显著影响空间分辨率和旁瓣水平。因此,FD-VDS和FD-DC方法提供了使传统B模式成像的空间分辨率更加均匀的有效解决方案。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Canadian Acoustics - Acoustique Canadienne
Canadian Acoustics - Acoustique Canadienne Physics and Astronomy-Acoustics and Ultrasonics
CiteScore
0.50
自引率
0.00%
发文量
1
期刊介绍: The CAA is the professional, interdisciplinary organization that : - fosters communication among people working in all areas of acoustics in Canada - promotes the growth and practical application of knowledge in acoustics - encourages education, research, protection of the environment, and employment in acoustics - is an umbrella organization through which general issues in education, employment and research can be addressed at a national and multidisciplinary level
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