Frequency-sum beamforming for passive cavitation imaging.
Frequency-sum beamforming for passive cavitation imaging.
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DOI：
10.1121/1.5045328
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发表时间：
2018-07
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影响因子：
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通讯作者：
Shima Abadi;K. Haworth;Karla P. Mercado-Shekhar;D. Dowling
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文献类型：
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作者：
Shima Abadi;K. Haworth;Karla P. Mercado-Shekhar;D. Dowling
波束形成包括可用于根据近场传感器阵列记录确定声源位置的各种空间滤波技术。对于这种情况，波束形成分辨率取决于声频、阵列几何形状和目标位置。源和阵列之间的介质中的随机散射可能会降低波束形成分辨率，而较高的频率更容易受到降低的影响。本文报告了频率和 (FS) 波束成形的性能，可降低对轻微散射的敏感性，同时提高分辨率。 FS 波束成形与数据相关的 [最小方差 (MV)] 或数据无关的（延迟求和，DAS）权重向量一起使用，通过复信号幅度的二次乘积从低频信号分量产生高频信息。目前的发现和比较基于使用 128 元件线性阵列记录的 3 MHz 和 6 MHz 发射进行的模拟和被动空化成像实验。使用四个指标将 FS 波束成形结果与传统 DAS 和 MV 波束成形进行比较：点扩散函数 (PSF) 大小、轴向和横向对比度以及计算时间。在自由空间和轻度散射环境中，FS 波束形成比传统 DAS 波束形成产生更小的 PSF，且计算时间比 MV 波束形成更少。然而，当存在多个未知声源时，它可能会失败。
Beamforming includes a variety of spatial filtering techniques that may be used for determining sound source locations from near-field sensor array recordings. For this scenario, beamforming resolution depends on the acoustic frequency, array geometry, and target location. Random scattering in the medium between the source and the array may degrade beamforming resolution with higher frequencies being more susceptible to degradation. The performance of frequency-sum (FS) beamforming for reducing such sensitivity to mild scattering while increasing resolution is reported here. FS beamforming was used with a data-dependent [minimum variance (MV)] or data-independent (delay-and-sum, DAS) weight vector to produce higher frequency information from lower frequency signal components via a quadratic product of complex signal amplitudes. The current findings and comparisons are based on simulations and passive cavitation imaging experiments using 3 MHz and 6 MHz emissions recorded by a 128-element linear array. FS beamforming results are compared to conventional DAS and MV beamforming using four metrics: point spread function (PSF) size, axial and lateral contrast, and computation time. FS beamforming produces a smaller PSF than conventional DAS beamforming with less computation time than MV beamforming in free space and mild scattering environments. However, it may fail when multiple unknown sound sources are present.