| 摘要 |
<p>A method for producing cross-sectional images using an ultrasonic imaging unit operating on the pulse-echo principle, which unit includes a transducer system having a stationary elongated array of adjacent transducer elements with transverse electrode segments adjacent one another on one side of the array. Successively and cyclically selected groups of adjacent elements are energized to produce an ultrasonic beam as a result of pulsed signals being applied to the corresponding electrode segments. Focussing of the ultrasonic beam produced by each group of the transducers is effected by having the transmitter signals applied to the electrode segments or subgroups thereof, and/or the echo-signals derived by the electrode segments from the reflected energy, time shifted relative to one another, in which each transmitter or echo-signal has a time shift associated thereto which is a function of the distance between the corresponding electrode segments (or subgroups of segments) and the center of the group of transducers.</p> |
