| 摘要 |
<p>in a method and apparatus for ultrasonic measurement, there are provided first and second ultrasonic transducers arranged to directly oppose each other across a object interposed therebetween, and a third ultrasonic transducer, the transducers being so arranged that a ray from the third ultrasonic transducer intersects, internally of the object, a rayconnecting the first and second ultrasonic transducers. A first period of time required for an ultrasonic wave emitted by first ultrasonic transducer to be received by the second ultrasonic transducer through the object is measured, as well as second and third periods of time respectively required for an ultrasonic wave emitted by the third ultrasonic transducer to be received by the first and second ultrasonic transducers following scattering of the ultrasonic wave from within the object. Mean propagation velocity of sound or a distribution of propagation velocity of sound internally of the object is measured on the basis of the first, second and third periods of time.</p> |
