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| Centroid-based sifting for empirical mode decomposition |
| Hong Hong*,1, Xin-long Wang1, Zhi-yong Tao1, Shuan-ping Du2 |
| 1 Key Laboratory of Modern Acoustics and Institute of Acoustics, Nanjing University, Nanjing 210093, China 2 State Key Laboratory of Ocean Acoustics, Hangzhou Applied Acoustics Research Institute, Hangzhou 310012, China |
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Abstract A novel sifting method based on the concept of the ‘local centroids’ of a signal is developed for empirical mode decomposition (EMD), with the aim of reducing the mode-mixing effect and decomposing those modes whose frequencies are within an octave. Instead of directly averaging the upper and lower envelopes, as suggested by the original EMD method, the proposed technique computes the local mean curve of a signal by interpolating a set of ‘local centroids’, which are integral averages over local segments between successive extrema of the signal. With the ‘centroid’-based sifting, EMD is capable of separating intrinsic modes of oscillatory components with their frequency ratio ν even up to 0.8, thus greatly mitigating the effect of mode mixing and enhancing the frequency resolving power. Inspection is also made to show that the integral property of the ‘centroid’-based sifting can make the decomposition more stable against noise interference.
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Received: 25 February 2010
Published: 08 February 2011
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Centroid-based sifting for empirical mode decomposition
A novel sifting method based on the concept of the ‘local centroids’ of a signal is developed for empirical mode decomposition (EMD), with the aim of reducing the mode-mixing effect and decomposing those modes whose frequencies are within an octave. Instead of directly averaging the upper and lower envelopes, as suggested by the original EMD method, the proposed technique computes the local mean curve of a signal by interpolating a set of ‘local centroids’, which are integral averages over local segments between successive extrema of the signal. With the ‘centroid’-based sifting, EMD is capable of separating intrinsic modes of oscillatory components with their frequency ratio ν even up to 0.8, thus greatly mitigating the effect of mode mixing and enhancing the frequency resolving power. Inspection is also made to show that the integral property of the ‘centroid’-based sifting can make the decomposition more stable against noise interference.
关键词：
Sifting,
Empirical mode decomposition (EMD),
Mode mixing effect,
Frequency resolution,
Local centroids,
Noise resistance
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