Peak detector for resolution enhancement of ultrasonic visualization

Abstract

A digital electronic system for improving the resolution and dynamic range-handling capacity for received ultrasound in reflection or transmission imaging system. This system provides a means for preventing loss of structural detail in the display by minimizing the overlapping of signals resulting from the transducer bandwidth and pulse length. It also makes use of a (positive or negative) peak detector to recognize and print as a single point the presence of point targets. With the present technology, a point target may be represented in a B-mode display on several successive scan lines resulting in an abnormally large representation on the display. The actual target is represented by the peak point of the envelope of a series of scan lines in which the point target is displayed. The objective is to print only one point which corresponds with the actual position of the point target and with an intensity that corresponds to the intensity of the received signal. In general, dynamic range compression is required to prevent the wide intensity range of the received ultrasound from either saturating or overdriving the display. To accomplish this objective the received signal amplitudes are continually digitized and stored so that three successive lines of data can be compared. At any given instant of time, three resolution elements from each of these three successive lines are compared. A signal to print is transmitted to the display if the center resolution element of the three-by-three array is equal to or in excess of the surrounding eight resolution elements. The amplitude of the displayed point is established by a transfer function programmed into the system.