Research on imaging and reconstruction of hole defects based on ultrasonic synthetic aperture

WU Jing; LIN Zeyu; YANG Yingfeng; LIU Yang; ZHENG Mingfang; ZHANG Weiwei

doi:10.16579/j.issn.1001.9669.2026.07.017

Abstract：[Objective]Ultrasonic wave attenuation during propagation leads to reduced defect echo amplitude and increased missed detection rate.Meanwhile,traditional synthetic aperture imaging quality is constrained by hardware costs and data processing methods.A defect imaging and three-dimensional reconstruction method based on ultrasonic synthetic aperture was proposed to provide reference for internal hole defect detection of metal components.[Methods]Firstly,a single circular straight probe combined with synthetic aperture focusing technology was used to realize two-dimensional imaging of defects,so as to reduce hardware cost and system complexity.Secondly,an adaptive time gain compensation curve based on signal intensity variation was constructed to perform gain processing on echo signals at different depths,so as to compensate for acoustic wave attenuation.Then,bilinear interpolation was adopted to improve image resolution,and-6 dB threshold segmentation combined with Canny edge detection algorithm was applied to complete quantitative analysis of defects.Finally,dynamic threshold was introduced to improve the Marching Cubes algorithm for three-dimensional reconstruction of defects.[Results]The results show that the proposed method can reduce the relative error of hole defect diameter detection from 40％and 74％to 9％and 8.5％,and improve the axial resolution by 24.7％～32.5％.The operation efficiency of two-dimensional imaging and three-dimensional reconstruction is increased by 16.9％and 3.2％respectively,which can complete internal defect detection of metal components quickly and with high quality.