Patent ID: 6886412
Filing Date: 2005-05-03
Classification: G01N

Abstract:
1. An ultrasonic-wave propagation-time measuring method in which an ultrasonic wave is transmitted by use of an ultrasonic element, a reflection wave of the transmission wave is received as a reception wave by use of the same ultrasonic element or a different ultrasonic element, and a period of time between transmission of the ultrasonic wave and reception of the reception wave is measured as a propagation time, the method comprising: a reference-value setting step which comprises subjecting a reception wave to full-wave rectification to obtain a full-wave-rectified wave, integrating the full-wave-rectified wave or a portion thereof in order to obtain an integral value, and setting a reference value on the basis of the integral value; and a propagation time measurement step which comprises determining an arrival time of the reception wave by use of the reference value when the propagation time is measured.