Signal-Noise Separation of Sensor Signal Based on Variational Mode Decomposition
Bin He, Yanping Bai
School of Science
North University of China
Shanxi, China
e-mail: aihebin19@163.com
Abstract—For the problem of strong noisy interference in the
data acquisition of the micro electro mechanical system
(MEMS) hydrophone, signal-noise separation of the MEMS
hydrophone receiving signal make use of the variational mode
decomposition (VMD), which is a completely non-recursive
variational method. The frequency of the signal is segmented
by the default parameters, then the center frequency and the
intrinsic mode function (IMF) are obtained. Firstly, the
empirical mode decomposition (EMD), the ensemble empirical
mode decomposition (EEMD) and the VMD are regarded as a
bandpass filter, respectively. And the simulation signal of
different signal-to-noise ratio is going to be denoised.
According to the denoising effect and performance index, the
experiment shows that the denoising effect of the VMD is much
better than the previous two methods. Secondly, the VMD is
applied to the Fenji experimental data of the North University
of China in the lake trial. Finally, the results show that the
VMD is one of the best estimation algorithms of MEMS
hydrophone original signal.
Keywords-VMD; sensor signal; EMD; EEMD; signal-noise
separation
I. INTRODUCTION
According to various energy forms of ocean exploration,
acoustic waves have the most distant transmission
performance in the ocean. Therefore, underwater acoustic
waves have become the main carrier of information
transmission in the ocean and underwater acoustic
technology has become the main method about research and
exploration. An acoustic source launches an acoustic wave
which carries the acoustic source. The acoustic waves arrive
in acoustic receivers or hydrophone array through the sea.
Due to the complex ocean environment, the acoustic waves
are mixed with different noise in the process of transmitting
and receiving, which affects the analysis of acoustic source
information, the position and number of acoustic source.
While the researchers are analysing the acoustic source
information, they should denoise the received signal
primarily [1-3]. Nowadays, there are a lot of methods being
used to deal with the noise reduction of underwater acoustic
signals, such as fouier filtering, wavelet transform, adaptive
filtering and empirical mode decomposition et al. Although
these methods have some noise reduction effect, there are
some shortcomings. The known frequency signal processing
has obvious denoising effect in the Fourier filtering method,
but denoising effect of some multi frequency signal is
insufficient. Donoho and other scientists have proposed
wavelet transform method, which has good effect on non-
stationary signal denoising [4]. But the shortcoming of
wavelet transform is the choice of wavelet base and
decomposition level. An empirical mode decomposition
method is proposed by Norden E. Huang et al. Empirical
mode decomposition is based on the characteristics of
adaptive basis selection of the signal decomposition in order
to overcome the deficiency of the basis selection and the
mode mixing of intrinsic mode component [5-6]. To reduce
the mode mixing, Zhaohua Wu and other scientists proposed
ensemble empirical mode decomposition method, which
achieved good results in the experiments. The method is the
way to use the added auxiliary white noise to reduce the
impact of the mode mixing, but the mode mixing of EEMD
is serious in the case of low signal-to-noise ratio [7].
Konstantin Dragomiretskiy and Dominique Zosso have
proposed VMD to solve the influence of mode mixing well
in 2014. Aiming at the problem of strong noise interference
in the data acquisition of MEMS hydrophone, we use the
VMD to separate the signal and noise of the MEMS
hydrophone signal [8-10]. In the simulation experiment, this
method is superior to the signal-noise separation of EMD
and EEMD in the noise reduction effect and the performance
index. And the method is applied to the Fenji experiments of
the North University of China. The results show that the
method has good feasibility and superiority.
The paper is organized as follows. In Section 2, the
principle and procedure of the EMD, EEMD and VMD are
introduced in the experiment. In Section 3, the EMD, EEMD
and VMD are used to separate the signal and noise of the
simulated signal, and the comparison of the denoising effect
and the performance index is also carried out. In Section 4,
we apply the VMD algorithm to denoise the Fenji lake trial
data of the North University of China. In Section 5, the
conclusion is explained.
II. B
ASIC PRINCIPLE AND PROCESS
A. Empirical Mode Decomposition
EMD algorithm was firstly proposed by Norden E.Huang
in 1998, which is a good method to deal with nonlinear and
non-stationary signals [11-12]. The method is based on the
time scale characteristics of complex signal and the noisy
signal is decomposed into a set of data series which retain
the local feature information, namely IMF. Then, the
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