Novel Signal Denoising Approach for Acoustic Leak Detection

Abstract

If noise easily interferes with acoustic pipeline leak detection technology, false alarms and missing alarms result. This paper proposes a denoising method for the acoustic leak signal sensed by a dynamic pressure transducer (DPT), which is a kind of widely used acoustic sensor. Compared with the normal signal, the leak signal detected by the DPT has stronger energy in low-frequency components. Based on this observation, a numerical integrator was added to the wavelet denoising method for acoustic signal denoising. The numerical integrator can enhance the low-frequency component of a signal. When used for denoising, the wavelet low-pass filter can remove the high-frequency noise first, and then the numerical integrator can enhance the low-frequency leak signal. Therefore, the signal-to-noise ratio (SNR) of the leak signal can be improved. Based on the analysis of the amplitude frequency response of several common numerical integrators, the trapezoidal integrator was selected, which is easy to achieve in engineering. The field experiments show that the method can help reduce the sensitivity of the signal preprocessing result to key parameters of the denoising method including the wavelet basis function and the decomposition scale. Therefore, the stability of signal denoising result can be increased and the robustness of the pipeline leak detection system can be improved.