
Apparatus for detecting an abnormality such as a discontinuity in a predetermined region of a material by directing an elastic mechanical wave, such as an ultrasonic or other acoustic wave, in a series of pulses to portions of the region and providing response to the wave pulses reflected therefrom. The amplitudes of pulses reflected from a normal portion of the region may approximate the amplitudes of pulses reflected from a portion where an abnormality is present and thus make it difficult to ...











