METHODS FOR DETECTING DEFECT OF MATERIAL USING ULTRASONIC GUIDED WAVE

摘要

The present invention provides a method for detecting the defect of materials using guided waves capable of obtaining the accuracy and reliability of defect detection. The method for detecting the defect of materials using guided waves comprises a step of calculating a pixel value at each coordinate of chromaticity according to the mode of a first time-frequency section formed by performing the short time Fourier transform of a signal receiving guided waves that a reference test sample transmits; a step of calculating a pixel value at each coordinate of the chromaticity according to the mode of a second time-frequency section by performing the short time Fourier transform of the signal receiving the guide waves that the target test sample transmits; and a step of determining whether the target test sample has a defect by expressing the absolute value of difference between the pixel value of the first time-frequency section and the corresponding pixel value of the second time-frequency section as the chromaticity of a third time-frequency section.