| 摘要 |
PURPOSE:To calibrate the sensitivity of an echo and a time axis, which are displayed on a display device automatically, when a defect is detected by using an ultrasonic wave probe. CONSTITUTION:A multiple-gate circuit 30 comprising a plurality of gates, which are divided into the different time zones, is provided. An ultrasonic wave probe is made to scan (move) with an echo comparing and selecting part 32 under the state, wherein the probe is in contact with a standard test piece. In this process, the maximum echo and the elapsed time, which are outputted from each gate, are detected. A in-wedge (shoe) delay time DELTAt is computed basing on the elapsed time of the maximum echo with a delay-time computing part 33. The zero point of the time axis is adjusted basing on the in-wedge (shoe) delay time with an automatic time-axis calibrating part 29. A beam path is obtained with a refractive-angle computing part 36 basing on the elapsed time of the maximum echo. The refractive angle theta is computed basing on the beam path and the shape of the standard test piece. Furthermore, the sensitivity of a received signal is adjusted so that the height of the maximum echo agrees with the specified echo height with an automatic sensitivity calibrating part 25. |
