Abstract: Ultrasonographic means and method for visualizing the internal structure and composition of an in vivo soft tissue specimen as a function of its effect on the frequency spectrum of an applied complex wave pulse of short duration provided by a single wideband, shock-excited transducer utilized in the pulse-echo mode. Echo trains spatially related to the specimen structure are bandpass filtered to provide a plurality of spectrum signals indicative of the frequency content of each echo train as a function of time. In a first display mode a plurality of three spectrum signals are primary color-coded and combined to present a multicolor B-scan ultrasonogram permitting characterization of tissue specimen locations in terms of their frequency response as related to the color spectrum correlated to the frequency spectrum.