Patent ID: 6829940
Filing Date: 2004-12-14
Classification: G01H,G01N

Abstract:
A method of measuring the surface travel time of a wave between first and second points on a surface of a specimen, comprising:providing first and second ultrasonic transducers each having a longitudinal axis, said ultrasonic transducers being acoustically coupled to said surface and disposed in a spaced-apart relationship so that said longitudinal axes are substantially perpendicular to said surface; transmitting a first wave from said first ultrasonic transducer and determining a first direct travel time for said first wave to travel from said first ultrasonic transducer to said first point on said surface; transmitting a second wave from said second ultrasonic transducer and determining a second direct travel time for said second wave to travel from said second ultrasonic transducer to said second point on said surface; transmitting a third wave and measuring a total time for said third wave to travel along a path from said first ultrasonic transducer through said first and second points to said second ultrasonic transducer; and determining said surface travel time by subtracting said first and second direct travel times from said total time.