| 摘要 |
A system for detecting defects in a pipe wall (1), comprisesan ultrasonic transducer (2)which is arranged for emitting, via an exit opening, ultrasonic signals from the interior of thepipe towards its wall and for receiving, via an entrance opening, backscattered signals from the wall. The system is arranged to emit and receive a multitude of signals havingtheir main directions within a plane (4) mainly perpendicular to the pipe axis. The openings are configured to make the ultrasonic transmission signal diverge and/or to receive back signals from a diverging range of angles over a large area of the pipe wall, by using openings with a diameter with magnitude of thewavelength of the ultrasonic signals. Sets of emitted and backscattered signalsfor different emission and reception positions areprocessed, in processing means (5), to form an image based on transmission times between emission and reception of backscattered signals. |
