The Distance of Lance and Angle Cosine for the Ultrasonic Guided Wave Signal Processing

In this paper, it is suggested that the ultrasonic guided wave signal processing based on the distance of lance or angle cosine. In those schemes, the excitation signal is defined as the active detected signal, while the receiving signals is treated as the passive detection signal. The similarity coefficients between the excitation signal and the receiving signals with the help of a sliding window are calculated with the distance of lance or angle cosine, which are screened with a proper threshold. And then the receiving signals are reconstructed with the superposition principle. Through the ultrasonic guided wave signal of the 3% defects pipeline are processed with the two schemes, which show that the schemes are able to reduce the noise and modal transformation to affect the defect location and have high precision defect location recognition ability. The two schemes of implementation in the program have very little time complexity and space complexity, and are good for locating defects in a pipe on line detection.