Methods of analysis for backscattering from tissues

Two techniques for tissue characterization by ultrasonic analysis are described. In the first, using narrow-band pulses, the angular variation I (theta) of the ultrasonic intensity back-scattered by vegetal or animal targets is analysed. We examine how it is possible to estimate the surface roughness and the average spatial periodicity d characteristic of the tissues, by calculating the Fourier transform or the autocorrelation function of I (theta). In the second technique the sample is insonified with a broadband pulse at a fixed angle. A value of the mean periodicity can be obtained directly from the frequency spectrum of the echo for tissues of fairly regular structure.