cwtstruct = cwtft2(x) returns
the 2-D continuous wavelet transform (CWT) of the 2-D matrix, x. cwtft2 uses
a Fourier transform-based algorithm in which the 2-D Fourier transforms
of the input data and analyzing wavelet are multiplied together and
inverted.

Shows how an isotropic wavelet does not discern the orientation of features while an anisotropic wavelet does. The example uses the Mexican hat isotropic wavelet and the directional (anisotropic) Cauchy wavelet.

Load and view the hexagon image.

Im = imread('hexagon.jpg');
imagesc(Im); colormap(jet);

Obtain the scale-one 2-D CWT with both the Mexican hat and Cauchy wavelets. Specify a vector of angles going from 0 to 15π/8 in π/8 increments.

Input data, specified as a 2-D matrix or 3-D array. If the input
data is a 3-D array, the input matrix is a truecolor image.

Example: X = imread('stars.jpg');

Data Types: double | uint8

Name-Value Pair Arguments

Specify optional comma-separated pairs of Name,Value arguments.
Name is the argument
name and Value is the corresponding
value. Name must appear
inside single quotes (' ').
You can specify several name and value pair
arguments in any order as Name1,Value1,...,NameN,ValueN.

Example: 'wavelet','paul','scales',2^(0:5) specifies
to use the Paul wavelet and a vector of scales.

Analyzing wavelet, specified as a comma-separated pair consisting
of 'wavelet' and a character vector, a structure,
or a cell array. cwtftinfo2 provides
a comprehensive list of supported wavelets and associated parameters.

If you specify 'wavelet' as a structure,
the structure must contain two fields:

name — the character vector
corresponding to a supported wavelet.

param — a cell array with
the parameters of the wavelet.

If you specify 'wavelet' as a cell array, wav,
the cell array must contain two elements:

wav{1} — the character vector
corresponding to a supported wavelet.

wav{2} — a cell array with
the parameters of the wavelet.

The 2-D CWT, returned as a structure with the following fields:

wav — Analyzing wavelet and parameters structure

Analyzing wavelet and parameters, returned as a structure with
the following fields:

wname — name

param — parameters

wav_norm — Normalization constants matrix

Normalization constants, returned as a M-by-N matrix
where M is the number of scales and N is
the number of angles.

cfs — CWT coefficients array

CWT coefficients, returned as an N-D array. The row and column
dimensions of the array equal the row and column dimensions of the
input data. The third page of the array is equal to 1 or 3 depending
on whether the input data is a grayscale or truecolor image. The fourth
page of the array is equal to the number of scales and the fifth page
of the array is equal to the number of angles.