Acoustic nonlinearity parameter tomography via a parametric array

This paper presents a new acoustic nonlinear imaging method via a sound par ametric array. The principle of this method is to generate a secondary wave with sum or difference frequency due to the nonlinear interaction of two p rimary waves. For some lossless and attenuating media, computer simulation for B/A tomography from calculated sound pressure of difference-frequency w ave is studied using filtered convolution method. An experimental imaging s ystem is set up land several B/A images for some liquids and biological tis sues are obtained in this paper.