Sum-of-harmonics method for improved narrowband and broadband signal quantification during passive monitoring of ultrasound therapies.
Sum-of-harmonics method for improved narrowband and broadband signal quantification during passive monitoring of ultrasound therapies.
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DOI：
10.1121/1.4958991
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发表时间：
2016-07
期刊：
影响因子：
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通讯作者：
Erasmia Lyka;C. Coviello;R. Kozick;C. Coussios
中科院分区：
文献类型：
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作者：
Erasmia Lyka;C. Coviello;R. Kozick;C. Coussios
被动声学测绘(PAM)通过波束形成超声焦点发出的声发射，实现了对超声治疗的实时监测。窄带或宽带声发射分量的重建能够映射不同的物理现象，其中窄带发射由非线性传播和散射、非惯性空化或组织沸腾产生，而宽带(通常，幅度显著较低)指示惯性空化。目前，基于预定义的频域梳状滤波器的接收信号的准确分类不能得到保证，因为作为信号幅度和加窗函数的选择的函数而发生不同程度的泄漏。本文提出了一种时域参数模型，其目的是在宽带信号存在的情况下准确估计时变窄带分量的幅度。相反，该方法使得在存在主次谐波或其他窄带分量的情况下恢复微弱的宽带信号成为可能。与传统的梳状滤波相比，本文提出的谐波和法能够更好地反映空化源的物理位置和范围。
Passive Acoustic Mapping (PAM) enables real-time monitoring of ultrasound therapies by beamforming acoustic emissions emanating from the ultrasound focus. Reconstruction of the narrowband or broadband acoustic emissions component enables mapping of different physical phenomena, with narrowband emissions arising from non-linear propagation and scattering, non-inertial cavitation or tissue boiling, and broadband (generally, of significantly lower amplitude) indicating inertial cavitation. Currently, accurate classification of the received signals based on pre-defined frequency-domain comb filters cannot be guaranteed because varying levels of leakage occur as a function of signal amplitude and the choice of windowing function. This work presents a time-domain parametric model aimed at enabling accurate estimation of the amplitude of time-varying narrowband components in the presence of broadband signals. Conversely, the method makes it possible to recover a weak broadband signal in the presence of a dominant harmonic or other narrowband component. Compared to conventional comb filtering, the proposed sum-of-harmonics method enables PAM of cavitation sources that better reflect their physical location and extent.