| 摘要 |
PROBLEM TO BE SOLVED: To accurately determine where the subject of reflection is located in a pipeline by classifying reflection signals from sound waves sent out into the pipeline, when investigating the pipeline using the sound waves. SOLUTION: The timing of reception of the input signal of a reflected sound wave obtained by sending out a sound wave from an end P1 located in the area of a pipeline for investigation and the timing of reception of a reflected sound wave obtained by sending out a sound wave from an end P2 different from the end P1 are reversed in terms of time to set a condition in which the timing of reception of the latter reflected sound wave has the same starting point on a time axis as the time of transmission of the sound wave from the end P1, and then the latter timing of reception is compared with the former timing of reception. If the comparison results shows that the reflected sound waves exit at the coincident timing, the subject of reflection is determined to be located within the area between the ends P1, P2. |
