Mean-scatterer spacing estimates with spectral correlation.
Mean-scatterer spacing estimates with spectral correlation.
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DOI：
10.1121/1.410611
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发表时间：
1994-12
期刊：
影响因子：
--
通讯作者：
T. Varghese;K. D. Donohue
中科院分区：
文献类型：
--
作者：
T. Varghese;K. D. Donohue
由准周期散射体组成的材料的超声背散射信号在其相位谱和幅度谱上都表现出冗余。本文提出了一种利用谱自相关函数（SAC）估计后向散射超声信号的平均散射体间距的方法。平均散射体间距估计进行比较的技术，使用倒谱和SAC功能。A -扫描模型是由一组间距为Gamma分布的规则散射体组成，这些规则散射体嵌入间距为均匀分布的漫散射体中。该模型通过将随时间变化的系统响应与频率相关的散射中心进行卷积来考虑衰减。仿真结果表明，基于SAC的估计收敛更可靠，在更少量的数据比基于倒谱的估计。性能优势的一个主要原因是SAC函数使用相位信息，而倒频谱使用直接受系统响应和漫散射（散斑）存在影响的无相位功率谱密度。最后给出了一个估算肝组织中平均散射元间距的例子。
An ultrasonic backscattered signal from material comprised of quasiperiodic scatterers exhibit redundancy over both its phase and magnitude spectra. This paper addresses the problem of estimating mean-scatterer spacing from the backscattered ultrasound signal using spectral redundancy characterized by the spectral autocorrelation (SAC) function. Mean-scatterer spacing estimates are compared for techniques that use the cepstrum and the SAC function. A -scan models consist of a collection of regular scatterers with Gamma distributed spacings embedded in diffuse scatterers with uniform distributed spacings. The model accounts for attenuation by convolving the frequency dependent scattering centers with a time-varying system response. Simulation results indicate that SAC-based estimates converge more reliably over smaller amounts of data than cepstrum-based estimates. A major reason for the performance advantage is the use of phase information by the SAC function, while the cepstrum uses a phaseless power spectral density that is directly affected by the system response and the presence of diffuse scattering (speckle). An example of estimating the mean-scatterer spacing in liver tissue also is presented.