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wenergy

Energy for 1-D wavelet or wavelet packet decomposition

    Description

    example

    [Ea,Ed] = wenergy(c,l) returns, for a 1-D wavelet decomposition, Ea, the percentage of energy corresponding to the approximation, and Ed, the percentages of energies corresponding to the details. c and l are outputs of wavedec.

    E = wenergy(wpt) returns the percentages of energy corresponding to the terminal nodes of the wavelet packet tree wpt (see wptree, wpdec, and wpdec2). In this case, wenergy is a method of the wptree object wpt, which overloads the previous wenergy function.

    Examples

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    Load a 1-D signal.

    load noisbump

    Obtain the 4-level wavelet decomposition of the signal using the sym4 wavelet.

    wv = "sym4";
    [c,l] = wavedec(noisbump,4,wv);

    Obtain the percentages of energy in the approximation and details coefficients.

    [Ea,Ed] = wenergy(c,l)
    Ea = 88.2860
    
    Ed = 1×4
    
        2.1560    1.2286    1.4664    6.8630
    
    

    Obtain the wavelet packet tree corresponding to the 3-level wavelet packet decomposition of the signal using the sym4 wavelet.

    t = wpdec(noisbump,3,wv);

    Obtain the percentages of energy in the terminal nodes.

    e = wenergy(t)
    e = 1×8
    
       95.0329    1.4664    0.6100    0.6408    0.5935    0.5445    0.5154    0.5965
    
    

    Input Arguments

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    Wavelet decomposition, specified as a vector. The vector contains the wavelet coefficients. The bookkeeping vector l contains the number of coefficients by level. See wavedec.

    Data Types: single | double
    Complex Number Support: Yes

    Bookkeeping vector, specified as a vector of positive integers. The bookkeeping vector is used to parse the coefficients in the wavelet decomposition c by level. See wavedec.

    Data Types: single | double

    Wavelet packet tree, specified as a wptree object. See wptree, wpdec, and wpdec2.

    Output Arguments

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    Percentage of energy corresponding to approximation coefficients, returned as a positive scalar.

    Data Types: single | double

    Percentage of energy corresponding to details coefficients, returned as a vector.

    Data Types: single | double

    Percentage of energy corresponding to the terminal nodes, returned as a vector.

    Data Types: single | double

    See Also

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    Introduced before R2006a