| 摘要 |
System comprising at least one ultrasonic transducer (3) outside a room like a tube or vessel. The transducer is fit for transmitting and/or receiving an ultrasonic beam (6) into respectively from the interior of said room through the room's wall (2). The system comprises a matching element (5) at the interior's side of the wall, fit for matching the acoustic impedance and/or the sound speed of the wall material (2) and the those of the medium residing (1) within said room. The matching element may be mounted within a cavity in said wall, and may have a shape, at the side of the room, conforming to the room's inside shape. The matching element may have, at the side of the transducer, an arbitrarily curved shape, designed to obtain a certain desired beam directivity and/or to compensate for diffraction effects. The transducer may be mounted under an angle of less than 90 degrees vis-à-vis the room's wall or axis, and the matching element's cross section may have more or less the shape of a wedge. |
