Applying sub-band energy extraction to noise cancellation of ultrasonic NDT signal

作者：Zhang, Qi^*; Que, Pei wen; Liang, Wei

来源：Journal of Zhejiang University-Science A(Applied Physics & Engineering), 2008, 9(8): 1134-1140.

DOI：10.1631/jzus.A0720072

• empirical mode decomposition (EMD)
• signal-to-noise ratio (SNR)
• de-noising
• non-destructive testing (NDT)
• intrinsic mode IMF)

In ultrasonic non-destructive tests, the echo signal at the flaw is highly complex due to the interference of multiple echoes with random amplitudes and phases, and is disturbed by all kinds of noises, such as thermal noise, digitalization noise, and structure noise. In this paper, the ultrasonic signal was decomposed by empirical mode decomposition (EMD) to obtain the intrinsic mode IMF) components according to ultrasonic defect echo signals occuring at the corresponding time, and the energy of the ultrasonic signal was concentrated. The IMF component selection criterion based on sub-band energy extraction was proposed to extract the ultrasonic signal component accurately and automatically from IMF components. When the selected IMF components were filtered by a band pass filter, the signal-to-noise ratio (SNR) was enhanced greatly.

• 出版日期2008-8
• 单位上海交通大学