ESTIMATION OF ACOUSTIC PARAMETERS OF TISSUE USING ULTRASONIC ECHO.

This paper describes a method to estimate the attenuation of tissue from echo signals. Since the echo signals possess attenuation and reflectance characteristics to estimate the attenuation of tissue from echo signals, the separation of them in echo signals is necessary. Then, in order to separate the attenuation characteristic, this method uses the extraction of the Gaussian component from the power spectrum of the echo signals, under the assumption that the spectrum of the echo still retains the Gaussian shape, shifting only in center frequency if the power spectrum of the input signal is Gaussian in shape and the attenuation coefficient is a linear function of frequency. The Gaussian component is extracted by examining the coefficients of orthogonal expansion of the echo signals, and the attenuation coefficient is estimated by determining the center frequency shift. Experimental results obtained from the echo on in vivo human liver show that the method is fruitful for the estimation of attenuation.