| 摘要 |
PURPOSE:To improve the measuring accuracy of the frequency characteristic of the true ultrasonic attenuation in a body to be inspected by accurately obtaining the ultrasonic attenuation caused by factors other than the body to be inspected when the ultrasonic wave is transmitted on the body to be inspected and the frequency characteristic of the ultrasonic-wave attenuation at the body do be inspected is quantitatively measured. CONSTITUTION:An attenuating-amount memory means for the surface of a body to be inspected 7, an attenuated-correcting-amount operating means 8 and an attenuation- correcting amount memory means 9 are provided. The attenuations alphas(f), alphai(f) and alphad(f) at the surface of the body to be inspected, the boundary of the body to be inspected and an ultrasonic wave diffusion are quantitatively obtained. The sum of the values is stored and held as the attenuation correcting amount alphac(f). An attenuation correcting amount alphac(f) is subtracted from an attenuation alpham(f) of the ultrasonic pulses, which are measured and operated with an ultrasonic transceiver means 4, a gate means 5 and an ultrasonic-pulse-attenuation operating means 6. Thus, the frequency characteristic alpha(f) at the body to be detected is obtained. The approximation expression alphaa(f) of the measured ultrasonic attenuation alpha(f) is computed with an ultrasonic-attenuation approximating means 12. |
