emd.sift.ensemble_sift#

emd.sift.ensemble_sift(X, nensembles=4, ensemble_noise=0.2, noise_mode='single', noise_seed=None, nprocesses=1, sift_thresh=1e-08, max_imfs=None, verbose=None, imf_opts=None, envelope_opts=None, extrema_opts=None)[source]#

Compute Intrinsic Mode Functions with the ensemble EMD.

This function implements the ensemble empirical model decomposition algorithm defined in [1]. This approach sifts an ensemble of signals with white-noise added and treats the mean IMFs as the result. The resulting IMFs from the ensemble sift resembles a dyadic filter [2].

Parameters:
Xndarray

1D input array containing the time-series data to be decomposed

nensemblesint

Integer number of different ensembles to compute the sift across.

ensemble_noisefloat

Standard deviation of noise to add to each ensemble (Default value = .2)

noise_mode{‘single’,’flip’}

Flag indicating whether to compute each ensemble with noise once or twice with the noise and sign-flipped noise (Default value = ‘single’)

noise_seedint

seed value to use for random noise generation.

nprocessesint

Integer number of parallel processes to compute. Each process computes a single realisation of the total ensemble (Default value = 1)

sift_threshfloat

The threshold at which the overall sifting process will stop. (Default value = 1e-8)

max_imfsint

The maximum number of IMFs to compute. (Default value = None)

Returns:
imfndarray

2D array [samples x nimfs] containing he Intrisic Mode Functions from the decomposition of X.

Other Parameters:
imf_optsdict

Optional dictionary of keyword options to be passed to emd.get_next_imf.

envelope_optsdict

Optional dictionary of keyword options to be passed to emd.interp_envelope

extrema_optsdict

Optional dictionary of keyword options to be passed to emd.get_padded_extrema

verbose{None,’CRITICAL’,’WARNING’,’INFO’,’DEBUG’}

Option to override the EMD logger level for a call to this function.

References

[1]

Wu, Z., & Huang, N. E. (2009). Ensemble Empirical Mode Decomposition: A Noise-Assisted Data Analysis Method. Advances in Adaptive Data Analysis, 1(1), 1–41. https://doi.org/10.1142/s1793536909000047

[2]

Wu, Z., & Huang, N. E. (2004). A study of the characteristics of white noise using the empirical mode decomposition method. Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences, 460(2046), 1597–1611. https://doi.org/10.1098/rspa.2003.1221