How to change the graph of frequency domain

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Dear all,
I have coding to convert from spatial domain to frequency domain. Below is my coding.
Z = zeros(99); % create square matrix of zeroes
origin = [round((size(Z,2)-1)/2+1) round((size(Z,1)-1)/2+1)]; % "center" of the matrix
radius = round(sqrt(numel(Z)/(2*pi))); % radius for a circle that fills half the area of the matrix
[xx,yy] = meshgrid((1:size(Z,2))-origin(1),(1:size(Z,1))-origin(2)); % create x and y grid
Z(sqrt(xx.^2 + yy.^2) <= radius) = 1; % set points inside the radius equal to one
Z = im2double(Z)
imshow(Z); % show the "image"
%spatial domain
figure, imtool(Z)
%Frequency Domain
j = fftshift(fft2(Z));
figure, imshow(j)
j1 = log(1+abs(j));
figure ,imshow(j1)
j2 = bar(j1);
My graph frequency domain like this
How to make the graph like below

Accepted Answer

Hassaan
Hassaan on 20 May 2024
% Create a square matrix of zeroes
Z = zeros(99);
origin = [round((size(Z,2)-1)/2+1) round((size(Z,1)-1)/2+1)]; % "center" of the matrix
radius = round(sqrt(numel(Z)/(2*pi))); % radius for a circle that fills half the area of the matrix
[xx,yy] = meshgrid((1:size(Z,2))-origin(1),(1:size(Z,1))-origin(2)); % create x and y grid
Z(sqrt(xx.^2 + yy.^2) <= radius) = 1; % set points inside the radius equal to one
Z = im2double(Z);
imshow(Z); % show the "image"
% Spatial domain
figure, imtool(Z)
% Frequency Domain
j = fftshift(fft2(Z));
j1 = log(1 + abs(j));
% Display the frequency domain image using imagesc
figure;
imagesc(j1);
colormap('jet'); % You can choose a different colormap if you prefer
colorbar;
title('Frequency Domain Representation');
% Extract a line profile through the center of the frequency domain representation
center = round(size(j1, 2) / 2);
lineProfile = j1(center, :);
% Plot the line profile
figure;
plot(lineProfile);
title('Line Profile of Frequency Domain');
xlabel('Frequency');
ylabel('Magnitude');
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It's important to note that the advice and code are based on limited information and meant for educational purposes. Users should verify and adapt the code to their specific needs, ensuring compatibility and adherence to ethical standards.
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