Diffraction pattern manipulation.

I want to know how to take only the right part of a diffraction pattern matrix. Here is the diffraction pattern in a 1000x1000 matrix :

Here is the code I am using to take only the part from the center to the first 0 of the 'sinc like' pattern

 Mask_radius = 0.431*dx;
 Mask = sqrt(X.^2 + Y.^2) < Mask_radius;

 S1 = abs(U_real.^2);
 S2 = abs((Mask.*abs(fft_U)).^2);

It works but it is not very classy :s.

Result with the code :

[Ali Dordaee]

Could you please send me the whole coding if you have fixed it? I really appreciate it. this is my Email:

[e-mail]

If you want, you can also send the coding as my answer on this website. thanks so much.

Answer 1

[Image Analyst]

There is nothing wrong or unclassy about that code, except that you don't need the outer abs on S2. There are alternative ways of getting the same thing but they're not necessarily better, like

S2 = abs(fft_U); % Initialize
S2(~Mask) = 0;   % Erase outside Mask
S2 = S2 .^ 2;    % Square.

[Regis Robles]

Yes, it is another way to do the same thing. But I want to know if it is possible to take only the center part of the fft_I = abs(fft_U.^2) matrix.

I want this because when I change some parameters in my program, the Mask matrix does not change and thus S2 = abs((Mask.*abs(fft_U)).^2) gives the wrong result. And in your way, it will be the same wrong result.

[Image Analyst]

What does "take" mean? I can think of only two things: erase outside of it (which we've done), or to crop it out to its own image, which you can do by indexing or by using imcrop().

Answer 2

[Tanweepriya Das]

was the problem solved finally?

[Image Analyst]

Evidently not or else he would have marked my answer as "Accepted". Plus he never answered my question about what he means by take. However I doubt he's still working on it after 2 years.