Research on frequency domain synthetic aperture focusing pipeline guided wave imaging based on phase migration

In order to overcome the limitations of traditional ultrasonic imaging methods, which cannot directly give the imaging results of defects in a pipeline and have low imaging quality, a frequency domain synthetic aperture focusing pipeline imaging method based on phase migration is proposed. The measured data were reconstructed by frequency domain synthetic aperture focusing, and the results were compared with those of time-domain synthetic aperture focusing imaging. The results show that the frequency domain synthetic aperture imaging method is more accurate for the location and quantification of defects in a pipeline, the influence of noise waves on the imaging transverse resolution is reduced, and the imaging resolution is increased by nearly 30%. It was found that the quantitative errors of axial double defects are 5.2% and 17.9%, and that of circumferential defects is 7.5%. These results show that the frequency domain synthetic aperture focusing pipeline imaging algorithm based on phase migration can achieve the accurate determination of multiple defects in pipelines.