Name

boundary_conditions_emd — extends an extrema set to limit edge effects on the interpolations

Calling Sequence

   [TMIN,TMAX,ZMIN,ZMAX,EMODE] = boundary_conditions_emd(INDMIN,INDMAX,T,X,Z,NBSYM)
   [TMIN,TMAX,ZMIN,ZMAX,EMODE] = boundary_conditions_emd(INDMIN,INDMAX,[],X,Z,NBSYM)
   

Parameters

inputs:

- INDMIN, INDMAX:

indices of minima and maxima in the real signal X

- T:

sampling times. If emtpy, then t is set to t = 1:length(x);

- X:

real signal in which INDMIN and INDMAX are the indices of extrema

- Z:

signal which values are interpolated in the final envelope

- NBSYM:

number of points added to each end

outputs:

- TMIN, TMAX:

extended sampling times

- ZMIN, ZMAX:

extended "extrema" set

- EMODE:

0 means the signal has not enough extrema. 1 means x has enough extrema.

Description

defines new extrema points to extend the interpolations at the edges of the signal (mainly mirror symmetry)

- for a real signal X:

[TMIN,TMAX,ZMIN,ZMAX] = boundary_conditions_emd(INDMIN,INDMAX,T,X,X,NBSYM)

- for a complex signal Z and a direction PHI:

X = exp(-i*PHI)*Z;

[TMIN,TMAX,ZMIN,ZMAX] = boundary_conditions_emd(INDMIN,INDMAX,T,X,Z,NBSYM)

TODO: it has to be noted that this function was originally written for the classical EMD and adapted to the bivariate case without a proper study of its effects. The edge effects problem for the bivariate EMD has not been studied yet.

See also

local_peaks

Authors

H. Nahrstaedt
G. Rilling, last modification 3.2007
gabriel.rilling@ens-lyon.fr