Plot dual-tree or double-density wavelet transform

- example
`plotdt(wt)`

Plot the complex dual-tree wavelet transform of the noisy Doppler signal.

Load the noisy Doppler signal. Obtain the complex dual-tree wavelet transform down to level 4.

load noisdopp; wt = dddtree('cplxdt',noisdopp,4,'dtf1');

Plot the coefficients.

plotdt(wt)

Plot the complex oriented dual-tree wavelet transform of an image.

Load the "xbox" image. Obtain the complex oriented dual-tree wavelet transform down to level 3.

load xbox; wt = dddtree2('cplxdt',xbox,3,'dtf1');

Plot the coefficients.

plotdt(wt)

Select the level-one detail coefficients from the drop-down list in the lower left corner.

`wt`

— Wavelet transformstructure Wavelet transform, returned as a structure from `dddtree`

or `dddtree2`

with
these fields:

`type`

— Type of wavelet decomposition (filter bank)`'dwt'`

| `'ddt'`

| `'realdt'`

| `'cplxdt'`

| `'realdddt'`

| `'cplxdddt'`

Type of wavelet decomposition (filter bank), specified as one
of `'dwt'`

, `'ddt'`

, `'realdt'`

, `'cplxdt'`

,, `'realdddt'`

,
or `'cplxdddt'`

. `'realdt'`

and `'realdddt'`

are
only valid for the 2-D wavelet transform. The type, `'dwt'`

,
is a critically sampled (nonredundant) discrete wavelet transform
for 1-D data or 2-D images. The other decomposition types are oversampled
wavelet transforms. For details about transform types see `dddtree`

for 1-D wavelet transforms and `dddtree2`

for 2-D wavelet transforms.

`level`

— Level of the wavelet decompositionpositive integerLevel of the wavelet decomposition, specified as a positive integer.

`filters`

— Decomposition (analysis) and reconstruction (synthesis) filtersstructureDecomposition (analysis) and reconstruction (synthesis) filters, specified as a structure with these fields:

`Fdf`

— First-stage analysis filtersmatrix | cell arrayFirst level decomposition filters specified as an *N*-by-2
or *N*-by-3 matrix for single-tree wavelet transforms,
or a 1-by-2 cell array of two *N*-by-2 or *N*-by-3
matrices for dual-tree wavelet transforms. The matrices are *N*-by-3
for the double-density wavelet transforms. For an *N*-by-2
matrix, the first column of the matrix is the scaling (lowpass) filter
and the second column is the wavelet (highpass) filter. For an *N*-by-3
matrix, the first column of the matrix is the scaling (lowpass) filter
and the second and third columns are the wavelet (highpass) filters.
For the dual-tree transforms, each element of the cell array contains
the first-stage analysis filters for the corresponding tree.

`Df`

— Analysis filters for levels > 1matrix | cell arrayAnalysis filters for levels > 1, specified as an *N*-by-2
or *N*-by-3 matrix for single-tree wavelet transforms,
or a 1-by-2 cell array of two *N*-by-2 or *N*-by-3
matrices for dual-tree wavelet transforms. The matrices are *N*-by-3
for the double-density wavelet transforms. For an *N*-by-2
matrix, the first column of the matrix is the scaling (lowpass) filter
and the second column is the wavelet (highpass) filter. For an *N*-by-3
matrix, the first column of the matrix is the scaling (lowpass) filter
and the second and third columns are the wavelet (highpass) filters.
For the dual-tree transforms, each element of the cell array contains
the analysis filters for the corresponding tree.

`Frf`

— First-level reconstruction filtersmatrix | cell arrayFirst-level reconstruction filters, specified as an *N*-by-2
or *N*-by-3 matrix for single-tree wavelet transforms,
or a 1-by-2 cell array of two *N*-by-2 or *N*-by-3
matrices for dual-tree wavelet transforms. The matrices are *N*-by-3
for the double-density wavelet transforms. For an *N*-by-2
matrix, the first column of the matrix is the scaling (lowpass) filter
and the second column is the wavelet (highpass) filter. For an *N*-by-3
matrix, the first column of the matrix is the scaling (lowpass) filter
and the second and third columns are the wavelet (highpass) filters.
For the dual-tree transforms, each element of the cell array contains
the first-stage synthesis filters for the corresponding tree.

`Rf`

— Reconstruction filters for levels > 1matrix | cell arrayReconstruction filters for levels > 1, specified as an *N*-by-2
or *N*-by-3 matrix for single-tree wavelet transforms,
or a 1-by-2 cell array of two *N*-by-2 or *N*-by-3
matrices for dual-tree wavelet transforms. The matrices are *N*-by-3
for the double-density wavelet transforms. For an *N*-by-2
matrix, the first column of the matrix is the scaling (lowpass) filter
and the second column is the wavelet (highpass) filter. For an *N*-by-3
matrix, the first column of the matrix is the scaling (lowpass) filter
and the second and third columns are the wavelet (highpass) filters.
For the dual-tree transforms, each element of the cell array contains
the first-stage synthesis filters for the corresponding tree.

`cfs`

— Wavelet transform coefficientscell array of matricesWavelet transform coefficients, specified as a 1-by-(`level`

+1)
cell array of matrices. The size and structure of the matrix elements
of the cell array depend on the type of wavelet transform and whether
the decomposition is 1-D or 2-D. For a 1-D wavelet transform, the
coefficients are organized by transform type as follows:

`'dwt'`

—`cfs{j}`

j = 1,2,...

`level`

is the level.`cfs{level+1}`

are the lowpass, or scaling, coefficients.

`'ddt'`

—`cfs{j}(:,:,k)`

j = 1,2,...

`level`

is the level.k = 1,2 is the wavelet filter.

`cfs{level+1}(:,:)`

are the lowpass, or scaling, coefficients.

`'cplxdt'`

—`cfs{j}(:,:,m)`

j = 1,2,...

`level`

is the level.m = 1,2 are the real and imaginary parts.

`cfs{level+1}(:,:)`

are the lowpass, or scaling, coefficients.

`'realdddt'`

—`cfs{j}(:,:,d,k)`

j = 1,2,...

`level`

is the level.d = 1,2,3 is the orientation.

k = 1,2 is the wavelet transform tree.

`cfs{level+1}(:,:)`

are the lowpass, or scaling, coefficients.

`'cplxdddt'`

—`cfs{j}(:,:,d,k,m)`

j = 1,2,...

`level`

is the level.k = 1,2 is the wavelet transform tree.

m = 1,2 are the real and imaginary parts.

`cfs{level+1}(:,:)`

are the lowpass, or scaling, coefficients.

For a 2-D wavelet transform, the coefficients are organized by transform type as follows:

`'dwt'`

—`cfs{j}(:,:,d)`

j = 1,2,...

`level`

is the level.d = 1,2,3 is the orientation.

`cfs{level+1}(:,:)`

are the lowpass, or scaling, coefficients.

`'ddt'`

—`cfs{j}(:,:,d)`

j = 1,2,...

`level`

is the level.d = 1,2,3,4,5,6,7,8 is the orientation.

`cfs{level+1}(:,:)`

are the lowpass, or scaling, coefficients.

`'realddt'`

—`cfs{j}(:,:,d,k)`

j = 1,2,...

`level`

is the level.d = 1,2,3 is the orientation.

k = 1,2 is the wavelet transform tree.

`cfs{level+1}(:,:)`

are the lowpass, or scaling, coefficients.

`'cplxdt'`

—`cfs{j}(:,:,d,k,m)`

j = 1,2,...

`level`

is the level.d = 1,2,3 is the orientation.

k = 1,2 is the wavelet transform tree.

m = 1,2 are the real and imaginary parts.

`cfs{level+1}(:,:)`

are the lowpass, or scaling, coefficients.

`'realdddt'`

—`cfs{j}(:,:,d,k)`

j = 1,2,...

`level`

is the level.d = 1,2,3 is the orientation.

k = 1,2 is the wavelet transform tree.

`cfs{level+1}(:,:)`

are the lowpass, or scaling, coefficients.

`'cplxdddt'`

—`cfs{j}(:,:,d,k,m)`

j = 1,2,...

`level`

is the level.d = 1,2,3 is the orientation.

k = 1,2 is the wavelet transform tree.

m = 1,2 are the real and imaginary parts.

`cfs{level+1}(:,:)`

are the lowpass, or scaling, coefficients.

Was this topic helpful?

You can also select a location from the following list:

- Canada (English)
- United States (English)

- Belgium (English)
- Denmark (English)
- Deutschland (Deutsch)
- España (Español)
- Finland (English)
- France (Français)
- Ireland (English)
- Italia (Italiano)
- Luxembourg (English)

- Netherlands (English)
- Norway (English)
- Österreich (Deutsch)
- Portugal (English)
- Sweden (English)
- Switzerland
- United Kingdom (English)