| Ultrasonic testing technology is a non-destructive testing technology that has received widespread attention from scholars both at home and abroad in the field of non-destructive testing.Currently,time-domain ultrasonic imaging algorithms are commonly used for imaging the detection of holes and defects in steel blocks.However,the delay stacking process in timedomain imaging algorithms requires repetitive and tedious iterative operations,which cannot meet the requirements of high-quality real-time imaging.In contrast,frequency domain ultrasound imaging algorithms have higher imaging resolution and faster imaging speed.This article has conducted research on both time-domain and frequency-domain imaging algorithms,with a focus on frequency-domain imaging algorithms.Based on the frequencydomain PSM(Phase shift migration)and frequency-domain FMC-PSM(Full Matrix Capture Phase shift migration)imaging algorithms,a radix 2-FFT(Fast Fourier Transformation)input hierarchical truncation algorithm is proposed for ultrasonic imaging of hole defects in steel blocks.Experiments have shown that this method further improves imaging quality and imaging speed.The main research content of this article is as follows:In response to the problem of zero value redundancy calculation in two-dimensional Fourier transform in frequency domain ultrasound imaging algorithms,a radix 2-FFT input hierarchical truncation algorithm that supports any non zero value input is proposed.This algorithm has a computation speed 27% faster than the standard radix 2-FFT algorithm.The experimental results demonstrate that the fixed threshold processing operation in this algorithm can remove image background noise and further improve image resolution.At the same time,the improved frequency domain PSM algorithm using the radix 2-FFT input hierarchical truncation improves the imaging speed by 13% compared to the standard frequency domain PSM algorithm.Applying the radix 2-FFT input hierarchical truncation algorithm to the frequency domain FMC-PSM ultrasound imaging algorithm,an improved frequency domain FMC-PSM algorithm is obtained.The experimental results show that compared to the standard FMCPSM algorithm,the improved frequency domain FMC-PSM algorithm can present higher quality images while increasing the imaging speed by 15%.Experimental results have shown that the improved frequency domain PSM and FMCPSM imaging algorithms proposed in this article can both improve image quality and imaging speed.Compared to the improved frequency domain PSM algorithm,the improved frequency domain FMC-PSM algorithm requires a large amount of data,resulting in lower imaging speed.However,it can present high-quality images and is expected to solve the problem of difficult balance between imaging quality and imaging efficiency in ultrasound imaging. |
