Tarpara Eaglekumar G, Patankar V H
Homi Bhabha National Institute (HBNI), Mumbai 400094, India.
Rev Sci Instrum. 2018 Dec;89(12):125118. doi: 10.1063/1.5074152.
A real time empirical mode decomposition (EMD) algorithm based ultrasonic imaging system has been developed for non-destructive testing (NDT) applications. It is difficult to implement the EMD based signal processing algorithm in real time because it is totally a data-driven process which comprises numerous sifting operations. In this paper, the EMD algorithm has been implemented in the visual software environment. The EMD implementation encompasses two types of interpolation methods: piecewise linear interpolation (PLI) and cubic spline interpolation (CSI). The cubic spline tridiagonal matrix has been solved by using the Thomas algorithm for real time processing. The total time complexity functions for both the implemented PLI and CSI based EMD methods have been computed. For the signal filtering, the partial reconstruction algorithm has been adopted. The baseline correction and noise filtering applications have been presented using an EMD based visual software. The real time practicability and the efficiency of this method have been validated through ultrasonic NDT experimentation for improvement in the time domain resolution of the ultrasonic A-scan raw data. The practical results show that in the noisy environment, it is possible to enhance the signal-to-noise ratio for the visualization and identification of ultrasonic pulse-echo signals in real time.
一种基于实时经验模态分解（EMD）算法的超声成像系统已被开发用于无损检测（NDT）应用。基于EMD的信号处理算法难以实时实现，因为它完全是一个数据驱动的过程，包含大量的筛选操作。本文在可视化软件环境中实现了EMD算法。EMD的实现包括两种插值方法：分段线性插值（PLI）和三次样条插值（CSI）。通过使用托马斯算法求解三次样条三对角矩阵以进行实时处理。已计算出基于PLI和CSI实现的EMD方法的总时间复杂度函数。对于信号滤波，采用了部分重构算法。使用基于EMD的可视化软件展示了基线校正和噪声滤波应用。通过超声无损检测实验验证了该方法的实时实用性和效率，以提高超声A扫描原始数据在时域的分辨率。实际结果表明，在噪声环境中，能够实时提高超声脉冲回波信号可视化和识别的信噪比。
