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Multisignal 1-D wavelet decomposition


DEC = mdwtdec(DIRDEC,X,LEV,LoD,HiD,LoR,HiR)
DEC = mdwtdec(...,'mode',EXTMODE)


DEC = mdwtdec(DIRDEC,X,LEV,WNAME) returns the wavelet decomposition at level LEV of each row (if DIRDEC = 'r') or each column (if DIRDEC = 'c') of matrix X, using the wavelet WNAME.

The output DEC is a structure with the following fields:


Direction indicator: 'r' (row) or 'c' (column)


Level of the DWT decomposition


Wavelet name


Structure with four fields LoD, HiD, LoR and HiR


DWT extension mode (see dwtmode)


DWT shift parameter (0 or 1)


Size of X


Approximation coefficients at level LEV


Cell array of detail coefficients, from level 1 to level LEV

Coefficients cA and cD{k} (for k = 1 to LEV) are matrices and are stored in rows if DIRDEC = 'r' or in columns if DIRDEC = 'c'.

DEC = mdwtdec(DIRDEC,X,LEV,LoD,HiD,LoR,HiR) uses the four filters instead of the wavelet name.

DEC = mdwtdec(...,'mode',EXTMODE) computes the wavelet decomposition with the EXTMODE extension mode that you specify (see dwtmode for the valid extension modes).


% Load original 1D-multisignal.
load thinker

% Perform a decomposition at level 2 using wavelet db2.
dec = mdwtdec('r',X,2,'db2')
dec = 
        dirDec: 'r'
         level: 2
         wname: 'db2'
    dwtFilters: [1x1 struct]
       dwtEXTM: 'sym'
      dwtShift: 0
      dataSize: [192 96]
            ca: [192x26 double]
            cd: {[192x49 double]  [192x26 double]}

% Compute the associated filters of db2 wavelet.
[LoD,HiD,LoR,HiR] = wfilters('db2');

% Perform a decomposition at level 2 using filters.
decBIS = mdwtdec('r',X,2,LoD,HiD,LoR,HiR)

decBIS = 
        dirDec: 'r'
         level: 2
         wname: ''
    dwtFilters: [1x1 struct]
       dwtEXTM: 'sym'
      dwtShift: 0
      dataSize: [192 96]
            ca: [192x26 double]
            cd: {[192x49 double]  [192x26 double]}


Daubechies, I. , Ten lectures on wavelets, CBMS-NSF conference series in applied mathematics. SIAM Ed., 1992.

Mallat, S., “A theory for multiresolution signal decomposition: the wavelet representation,” IEEE Pattern Anal. and Machine Intell., vol. 11, no. 7, 1989, pp. 674–693.

Meyer, Y. , Ondelettes et opérateurs, Tome 1, Hermann Ed. (English translation: Wavelets and operators, Cambridge Univ. Press. 1993.)

See Also


Introduced in R2007a

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