合成孔径聚焦技术在TOFD检测中的应用

摘要

为了准确定位和测量在低合金厚板对接焊缝中的缺陷,对超声衍射时差法的D扫描图像进行了处理。为了提高图像的横向分辨率,准确识别缺陷的位置和尺寸,引入了D扫描图像的合成孔径聚焦算法（SAFT-D）。根据缺陷端部和换能器之间的几何关系,建立了D扫描图像SAFT-D处理的数学模型,实现了D扫描图像的SAFT重建。试验结果表明,SAFT-D算法有效地提高了图像的分辨率,增强了缺陷识别的能力,能够准确地定位和定量工件中的缺陷。%In order to accurately locate and measure the defects in low-alloy plate butt weld,the D-scan image obtained by the time of flight diffraction method was processed.In order to improve the horizontal resolution of the image,accurately recognize the position and size of the defects,the synthetic aperture focusing algorithm（SAFT-D,synthetic aperture focusing algorithm-D） was introduced.Based on the geometric relationship between the defects edge and the transducers,the mathematical model of SAFT-D processing on the D-scan image was build,the SAFT reconstruction of the D-scan image was achieved.The results showed that,by the SAFT-D algorithm,the resolution of the D-scan image was effectively improved,the capacity of the defect recognition was enhanced,the defect in material could be accurately located and quantified.