Abstract: A contour map underwater ultrasonic image system simultaneously uses a la time-bandwidth product signal waveforms for extremely fine range resolution, and an image memory organized as a three-dimensional data base of object reflectivity. The transmitted waveform is a pseudo-random coded signal. A plurality of correlator receivers produce a time-compressed pulse for each angular resolution cell. An image memory receives the output of the correlator receivers and builds up a three-dimensional data base of echoes in the form of a set of contour lines for each range cell. Standard computer-graphic techniques are used to accept the three-dimensional data base and generate displays to assist an operator in identifying the object.