| 摘要 |
PROBLEM TO BE SOLVED: To provide a method capable of reducing the noise caused by the reflected echo at a crystal grain boundary and capable of detecting a flaw accurately by suppressing the disappearance of the reflected echo from the flaw even if there is the flaw in the vicinity of the side end portion of a specimen. SOLUTION: When the signal from an edge echo large in amplitude is obtained before SSP(split spectrum) processing is performed, amplitude restraining processing suppressing the amplitude to a certain constant value forcibly is executed. By performing amplitude restraint with respect to the signal from the edge echo, though the flaw in a specimen is positioned in the vicinity of the side end portion of the specimen, the reflected echo from the flaw remains without disappearance even after the SSP processing is executed and the presence of the flaw can be detected highly accurately. |
