| 摘要 |
The present invention relates to an ultrasonic imaging apparatus comprising a transducer array having a plurality of ultrasonic transducer elements. The outer transducer element from the central axis of said array is thicker to produce lower ultrasonic frequency. A drive means (12) supplies drive pulses to the transducer elements (E1-En) to cause an ultrasonic beam to be emitted from said transducer elements towards an object. A summing means (16) sums echo signals received by said transducer elements, and a time variable band pass filter means (7) reduces low cutoff frequency according to the time elapsed from the preceding pulse of said drive means, for passing echo signals received by outer transducer elements from said axis of the array as the depth of the object from which echo signals are received is increased. A display means (19) displays echo signals provided from said time variable band pass filter means. |
