title: Mean-scatterer spacing estimates with spectral correlation.
abstract: 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.
authors: Department of Electrical Engineering, University of Kentucky, Lexington 40503.
authors: T
authors: T
authors: Varghese
authors: K D
authors: KD
authors: Donohue
mesh_terms: D046508:Culture Techniques; D006801:Humans; D008099:Liver / Q000000981:diagnostic imaging; D008962:Models, Theoretical; D014465:Ultrasonics; D014463:Ultrasonography