Abstract

Over the past few years, the use of ultrasonic arrays for nondestructive testing (NDT) applications has grown rapidly and led to use new algorithms of signal processing. The present paper’s main objective is to improve the resolution of defect detection and make the detection process as fast and accurate as possible. This paper introduces a novel method to improve the resolution of ultrasonic phased array. The proposed method is based on the variational decomposition of signal and on a deconvolution method. To reduce the level of signal’s noise, a method based on the variational mode decomposition (VMD) is used and to improve the resolution, a sparse deconvolution algorithm optimized using the majorization-minimization (MM) method is used. A simulation study has been carried out simulating a block of stainless steel containing several defects in different positions. Experimental tests were performed on a sample of stainless steel containing several defects. The obtained results show that the proposed method can improve the quality of ultrasonic data which enhances the localization of defects.

中文翻译：

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稀疏卷积和变分模式分解算法提高超声信号的分辨率

摘要

在过去的几年中，超声阵列在无损检测（NDT）应用中的使用迅速增长，并导致使用新的信号处理算法。本文的主要目的是提高缺陷检测的分辨率，并使检测过程尽可能快速准确。本文介绍了一种提高超声相控阵分辨率的新方法。所提出的方法基于信号的变分分解和反卷积方法。为了降低信号的噪声水平，使用了基于变分模式分解（VMD）的方法，并且为了提高分辨率，使用了使用最小化最大化（MM）方法优化的稀疏反卷积算法。已经进行了模拟研究，以模拟在不同位置包含多个缺陷的不锈钢块。对包含多个缺陷的不锈钢样品进行了实验测试。所得结果表明，该方法可以提高超声数据的质量，增强缺陷的定位。