| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce influence of reverberation superposed on a received ultrasonic signal with a less number of times of averaging when an ultrasonic wave is transmitted to and received from an object of inspection repeatedly, and ultrasonic signals having been received repeatedly are averaged. <P>SOLUTION: A repetition interval setting part 41 increases or decreases a repetition time interval T by a constant trigger shift quantity α each time transmission of an ultrasonic wave by an ultrasonic wave transmission device 10 is repeated. Denoting an angular frequency of the ultrasonic wave as ω, the number of times of averaging by an averaging processing part 43 as N, and m, n is an integer equal to or greater than 1, the trigger shift quantity α is determined to be a value satisfying α×ω/(2×π)=n/(m×N) so that a reverberation superposition index E<SB POS="POST">m</SB>representing the absolute value of the ratio of reverberation components by an ultrasonic wave of m-th times before an ultrasonic wave to be inspected, before and after averaging by the averaging processing part 43 becomes minimum. <P>COPYRIGHT: (C)2013,JPO&INPIT |
