Ultrasonic Signal Processing for <u>in Vivo</u> Attenuation Measurement: Short Time Fourier Analysis

TLDR

Short‑time Fourier analysis is well suited for processing nonstationary tissue echographic signals. The study investigates using short‑time Fourier analysis to estimate the time‑varying spectral composition of echographic signals, enabling inference of frequency‑dependent attenuation via the spectral centroid. The method corrects diffraction‑induced filtering bias and is validated on simulated 1‑D tissue models before application to real echo data. Experimental results on a tissue‑like phantom and in‑vivo liver tissue demonstrate the expected effects of diffraction and attenuation.

Abstract

Short-time Fourier analysis is well suited for processing tissue echographic signals which are nonstationary. We have investigated the use of short-time Fourier analysis to provide an estimation of the echographic spectral composition as a function of time. It will be shown that the time dependence of the spectral centroid of this representation allows one to deduce easily the frequency-dependent attenuation. A simple correction of the noninvariant filtering effect due to diffraction is used to unbias the attenuation slope estimation. This new signal processing technique was first tested on simulated echographic data from a 1-D tissue model. Experimental results obtained from echo signals on a tissue-like phantom and on in vivo liver tissue show the influence of diffraction and attenuation respectively.