2d dual tree discrete wavelet transform

sir/madam can you please explain the basic operations of 2d dual tree discrete wavelet transform with source code and explain with an example(for both real and imaginary trees).Please consider this request and give reply as soon as possible.

Answer 1

[Hari]

Hi Maha Lakshmi,

In order to perform a 2D Dual-Tree Discrete Wavelet Transform, you can follow the below steps:

Load the Image:

Read the image that you want to process. Convert it to grayscale if it is in color, as wavelet transforms are typically applied to single-channel images.

I = imread('example.jpg');
if size(I, 3) == 3
    I = rgb2gray(I);
end
I = double(I);

Set Up Wavelet Filters:

Define or load the wavelet filters for the dual-tree DWT. The transform uses two sets of filters: one for the real part and another for the imaginary part.

[Faf, Fsf] = FSfarras(); % Filters for the first stage
[af, sf] = dualfilt1();  % Filters for subsequent stages

Perform the 2D Dual-Tree DWT:

Apply the dual-tree transform to the image. This involves decomposing the image using both the real and imaginary filter sets.

J = 3; % Number of decomposition levels
[realTree, imagTree] = dddtree2('cplxdt', I, J, Faf, af);

Visualize the Decomposition:

Display the wavelet coefficients for both the real and imaginary trees at a specific level.

level = 2; % Choose a level to visualize
figure;
subplot(1, 2, 1), imshow(realTree{level}, []), title('Real Tree');
subplot(1, 2, 2), imshow(imagTree{level}, []), title('Imaginary Tree');

Interpret the Results:

Analyze the results to understand the frequency and orientation information captured by the wavelet coefficients.

Refer to the documentation of "dualtree" function to know more about the properties supported: https://www.mathworks.com/help/wavelet/ref/dualtree.html

Hope this helps!