dwt.q

Computation of 1D and 2D discrete wavelet transforms

Summary
dwt.qComputation of 1D and 2D discrete wavelet transforms
Constants
Wavelets
Functions
orthogonal_waveletComputes filter coefficients for an orthogonal wavelet
dwt2d_untiledUntiled inplace version of the dwt2d
idwt2d_untiledUntiled inplace version of the idwt2d
pdwt2d_untiledUntiled inplace version of the 2d wavelet packet transform
ipdwt2d_untiledUntiled inplace version of the 2d inverse wavelet packet transform
dwt2dComputes the 2D DWT.
idwt2dComputes the inverse 2D DWT.

Constants

Wavelets

haarAnalysis scaling coefficients for the haar wavelet
db2Analysis scaling coefficients for Daubechies’ wavelet of length 4 (2 vanishing moments)
db3Analysis scaling coefficients for Daubechies’ wavelet of length 6 (3 vanishing moments)
db4Analysis scaling coefficients for Daubechies’ wavelet of length 8 (4 vanishing moments)
db5Analysis scaling coefficients for Daubechies’ wavelet of length 10 (5 vanishing moments)
db6Analysis scaling coefficients for Daubechies’ wavelet of length 12 (6 vanishing moments)
db7Analysis scaling coefficients for Daubechies’ wavelet of length 14 (7 vanishing moments)
db8Analysis scaling coefficients for Daubechies’ wavelet of length 16 (8 vanishing moments)
db10Analysis scaling coefficients for Daubechies’ wavelet of length 20 (10 vanishing moments)
db12Analysis scaling coefficients for Daubechies’ wavelet of length 24 (12 vanishing moments)
db14Analysis scaling coefficients for Daubechies’ wavelet of length 28 (14 vanishing moments)
db16Analysis scaling coefficients for Daubechies’ wavelet of length 32 (16 vanishing moments)
sym2Analysis scaling coefficients for Daubechies’ symmlet of length 4 (2 vanishing moments)
sym3Analysis scaling coefficients for Daubechies’ symmlet of length 6 (3 vanishing moments)
sym4Analysis scaling coefficients for Daubechies’ symmlet of length 8 (4 vanishing moments)
sym5Analysis scaling coefficients for Daubechies’ symmlet of length 10 (5 vanishing moments)
sym6Analysis scaling coefficients for Daubechies’ symmlet of length 12 (6 vanishing moments)
sym7Analysis scaling coefficients for Daubechies’ symmlet of length 14 (7 vanishing moments)
sym8Analysis scaling coefficients for Daubechies’ symmlet of length 16 (8 vanishing moments)
sym10Analysis scaling coefficients for Daubechies’ symmlet of length 20 (10 vanishing moments)
sym12Analysis scaling coefficients for Daubechies’ symmlet of length 24 (12 vanishing moments)
sym14Analysis scaling coefficients for Daubechies’ symmlet of length 28 (14 vanishing moments)
sym16Analysis scaling coefficients for Daubechies’ symmlet of length 32 (16 vanishing moments)
coif1Coiflet of length 1
coif2Coiflet of length 2
coif3Coiflet of length 3
coif4Coiflet of length 4
coif5Coiflet of length 5
all_waveletsA cell array containing all wavelets defined in this module
all_wavelet_namesA cell array containing the names of all wavelets defined in this module

Functions

orthogonal_wavelet

Computes filter coefficients for an orthogonal wavelet

function [wc,ctd,ctr] = orthogonal_wavelet(w)

Parameters

worthogonal wavelet (see Wavelets)
wcmatrix with wavelet filter coefficients
  • row 0 - analysis scaling filter coefficients
  • row 1 - analysis wavelet filter coefficients
  • row 2 - synthesis scaling filter coefficients
  • row 3 - synthesis wavelet filter coefficients
ctdorigin of the analysis filter
ctrorigin of the synthesis filter

dwt2d_untiled

Untiled inplace version of the dwt2d

function [] = dwt2d_untiled(x, w, J)

Parameters

xthe input data
wthe filters being used (see orthogonal_wavelet)
Jthe number of scales

idwt2d_untiled

Untiled inplace version of the idwt2d

function [] = idwt2d_untiled(y, w, J)

Parameters

ythe input data
wthe filters being used (see orthogonal_wavelet)
Jthe number of scales

pdwt2d_untiled

Untiled inplace version of the 2d wavelet packet transform

function [] = pdwt2d_untiled(x, w, J, rev=0)

Parameters

xthe input data
wthe filters being used (see orthogonal_wavelet)
Jthe number of scales
revtime reversal the wavelet filter coefficients

ipdwt2d_untiled

Untiled inplace version of the 2d inverse wavelet packet transform

function [] = ipdwt2d_untiled(y, w, J)

Parameters

ythe input data
wthe filters being used (see orthogonal_wavelet)
Jthe number of scales

dwt2d

Computes the 2D DWT.

function bands = dwt2d(x, w, J)

Parameters

xthe input data
wthe filters being used (see orthogonal_wavelet)
Jthe number of scales
bandsan output cell array containing the wavelet subbands
  • bands[0..J-1][0..2]: wavelet subbands for orientations HL,LH,HH
  • bands[J]: scaling coefficients

See also

idwt2d

idwt2d

Computes the inverse 2D DWT.

function y = idwt2d(bands, w, J)

Parameters

bandscell array containing the wavelet subbands
wthe filters being used (see orthogonal_wavelet)
Jthe number of scales
ythe output data

See also

dwt2d

Computes the 2D DWT.
Computes the inverse 2D DWT.
Computes filter coefficients for an orthogonal wavelet
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