An ultrasonic diagnostic imaging system processes echo information signals by means of detecting, for different regions of the patient's anatomy, the actual noise present for that particular examination, under existing environmental conditions, and in imaging system itself. The noise detected is used to create an actual noise signature for the actual noise present in that particular examination under existing environmental conditions and in the imaging system itself, and the noise signature is used to maximize available dynamic range to create the highest resolution scan images possible while rejecting noise. In a preferred embodiment the dynamic range and noise rejection level are varied for different regions of a patient's anatomy as a function of all scanning coordinates being used, including varying depths, steering angles, and linear positions for both sector-type and linear-type scans.