| 摘要 |
PCT No. PCT/AU88/00181 Sec. 371 Date Mar. 28, 1989 Sec. 102(e) Date Mar. 28, 1989 PCT Filed Jun. 10, 1988 PCT Pub. No. WO88/09939 PCT Pub. Date Dec. 15, 1988.In ultrasonic echoscopy, when an object to be examined has overlying layers of a medium (for example, fat, muscle, skin or bone) which have different ultrasonic transmission characteristics from those of the object, the echogram of the object is usually distorted. To reduce that distortion, the present invention uses a transducer comprising an array of ultrasonic transducer elements operated in a higher resolution mode than its normal imaging mode, to obtain information about the geometry of the overlying layers. Using this information and a knowledge of the transmission characteristics of the overlying layers, amplitude and phase corrections are calculated, to enable the transducer, when operated in its normal imaging mode, to generate a required beam of ultrasound. The corrections are then applied and an echogram of the object, with reduced distortion, is obtained while operating the transducer in its normal imaging mode. |
