超声频域合成孔径聚焦技术在主轴缺陷检测技术中的应用

Application of Ultrasonic Frequency Domain Synthetic Aperture Focusing Technique in Defect Inspection for Spindle

以钢制主轴为研究对象,将线性超声阵列探头置于主轴端面采集超声阵列信号。基于相位迁移(PSM)成像算法对采集到的超声阵列信号进行傅里叶变换,并通过角谱运算对频域内声场进行重建,最后通过反傅里叶变换即可实现整个成像区域的聚焦。成像结果表明:将主轴中宽度0.5 mm、深度1 mm表面切槽半波高横向水平宽度范围由23~29 mm缩小到19~22 mm,分辨率可提高的范围至少为17%~24%。此算法计算效率高,充分满足实时成像要求。

In this paper,taking the steel spindle as the research object,a linear ultrasonic array transducer was placed on the end of the spindle to collect the ultrasonic array signals.The phase shift migration（PSM） imaging algorithm was used to perform Fourier transform on the collected ultrasonic array signal,and the frequency domain wave field was reconstructed by using the angular spectrum equation.Finally,the entire imaging area can be focused by the inverse Fourier transform.The imaging results show that the frequency domain SAFT can effectively improve the defect resolution of the image.For surface groove with 0.5 mm width and 1 mm depth,the half lateral width of defect were reduced from 23 ~ 29 mm to 19 ~ 22 mm,and the resolution can be increased by at least 17% ~ 24%.It also proves that this algorithm has high computational efficiency and fully satisfices real-time imaging requirements in the application.