How to create and plot a Gaussing function?

Question

Gn Gnk 2020-12-7

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/683458-how-to-create-and-plot-a-gaussing-function

评论： Gn Gnk 2020-12-7

采纳的回答： VBBV

在 MATLAB Online 中打开

Hello ,

i want to create a 2D Gaussian function 9x9 and sigma =0.7 using this type :

Here is my code:

sigma=0.7;
nx=9;
ny=9;
[x,y]=meshgrid(1:nx,1:ny);
G=(0.5/(pi.*(sigma.^2))).*exp(-0.5.*((y.^2+x.^2)./(sigma.^2)));

Then i was asked to take the Gaussian function G and compute its fast fourier transform by using fft2()

G_fft=fft2(G);

Finally by using mesh() i was asked to compare the 2 results .

figure();
mesh(G);
figure();
mesh(G_fft);

The problem here is that in the first case (mesh(G)) i am getting a big edge(which i dont know if its right) and in the second case i am getting this error : X, Y, Z, and C cannot be complex. (problem in the line mesh(G_fft) because G_fft has complex numbers due to fourier transform).

Can comeone tell me what is wrong here?

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Gn Gnk 2020-12-7

gaussian_using_mesh.fig

This is what i get using mesh() for ploting the Gaussian function

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Answer 1

VBBV 2020-12-7

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/683458-how-to-create-and-plot-a-gaussing-function#answer_567408

编辑：VBBV 2020-12-7

在 MATLAB Online 中打开

%true
sigma=0.7;
nx=9;
ny=9;
[x,y]=meshgrid(-nx:0.5:nx,-ny:0.5:ny);
G=(0.5./(pi.*(sigma.^2))).*exp(-0.5.*((y.^2+x.^2)./(sigma.^2)));  
G_fft=fft2(G);
figure(1);
mesh(x,y,G);
figure(2);
mesh(x,y,abs(G_fft));