How to scramble an image using Gyrator transform? matlab code?

 Accepted Answer

Hi
Though the gyrator transform is not directly available in MATLAB. You could use the FFT and permutation matrix.
Find the attached code to scramble an Image using the Gyrator transform.
Hope this helps!
% Read the input image
img = imread('1680714900716.jpg');
% Convert the input image to grayscale
if size(img, 3) == 3
img = rgb2gray(img);
end
% Generate a random permutation matrix
N = size(img, 1);
P = eye(N);
ind = randperm(N);
P = P(ind,:);
% Compute the Fourier transform of the input image
F = fft2(img);
% Compute the gyrator transform matrix
G = diag(exp(2*pi*1i*(0:N-1)/N));
G = P*G*P';
% Apply the gyrator transform to the Fourier coefficients of the input image
F_scrambled = G*F*G';
% Compute the inverse Fourier transform of the scrambled Fourier coefficients
img_scrambled = ifft2(F_scrambled);
% Display the input and scrambled images
figure;
subplot(1, 2, 1); imshow(img); title('Input image');
subplot(1, 2, 2); imshow(abs(img_scrambled),[]); title('Scrambled image');

2 Comments

Thanks! Is there any way to calculate the permutation matrix according to the rotation angle?
Thank you so much nayan...how to perform inverse process of it?

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Asked:

on 10 Jan 2023

Commented:

on 21 Apr 2023

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