DWILT2 2D Discrete Wilson transform
Usage: c=dwilt2(f,g,M);
c=dwilt2(f,g1,g2,[M1,M2]);
c=dwilt2(f,g1,g2,[M1,M2],[L1,L2]);
[c,Ls]=dwilt2(f,g1,g2,[M1,M2],[L1,L2]);
Input parameters:
f : Input data, matrix.
g,g1,g2 : Window functions.
M,M1,M2 : Number of bands.
L1,L2 : Length of transform to do.
Output parameters:
c : array of coefficients.
Ls : Original size of input matrix.
DWILT2(f,g,M) calculates a two dimensional discrete Wilson transform
of the input signal f using the window g and parameter M along each
dimension.
For each dimension, the length of the transform will be the smallest
possible that is larger than the length of the signal along that dimension.
f will be appropriately zero-extended.
All windows must be whole-point even.
DWILT2(f,g,M,L) computes a Wilson transform as above, but does
a transform of length L along each dimension. f will be cut or
zero-extended to length L before the transform is done.
[c,Ls]=dwilt(f,g,M) or [c,Ls]=dwilt(f,g,M,L) additionally returns the
length of the input signal f. This is handy for reconstruction.
c=DWILT2(f,g1,g2,M) makes it possible to use a different window along the
two dimensions.
The parameters L, M and Ls can also be vectors of length 2. In
this case the first element will be used for the first dimension and the
second element will be used for the second dimension.
The output c has 4 or 5 dimensions. The dimensions index the
following properties:
1. Number of translations along 1st dimension of input.
2. Number of channels along 1st dimension of input
3. Number of translations along 2nd dimension of input.
4. Number of channels along 2nd dimension of input
5. Plane number, corresponds to 3rd dimension of input.
Examples:
---------
The following example visualize the DWILT2 coefficients of a test
image. For clarity, only the 50 dB largest coefficients are show:
c=dwilt2(cameraman,'itersine',16);
c=reshape(c,256,256);
figure(1);
imagesc(cameraman), colormap(gray), axis('image');
figure(2);
cc=dynlimit(20*log10(abs(c)),50);
imagesc(cc), colormap(flipud(bone)), axis('image'), colorbar;
Url: http://ltfat.github.io/doc/gabor/dwilt2.html
See also: dwilt, idwilt2, dgt2, wildual.
Package: ltfat