How do I generate a two dimensional Fourier Transform with a given image in a .mat file?

I don't even know how to start. Help will be much appreciated.

Thank you

[David Young]

The documentation for fft2 and save will help you get started.

Answer 1

[Konstantinos Sofos]

Hi,

Mathworks documentation is excellent and is always a good point to start. Have a look here Fourier Transform and Image Transforms

Assuming that I is your input image and F is its Fourier Transform (i.e. F = fft2(I))

You can use this code:

F = fftshift(F); % Center FFT

F = abs(F); % Get the magnitude
F = log(F+1); % Use log, for perceptual scaling, and +1 since log(0) is undefined
F = mat2gray(F); % Use mat2gray to scale the image between 0 and 1

imshow(F,[]); % Display the result

Regards

[sean darmadi]

Hi, I am given a mat file called A.mat. So I am assuming I need to first open the file first. So i wrote,

fid=load('A.mat');

After that, I am not sure what to do with the opened file. I am confused on how to use the fft2 function cause every time I tried it says undefined function 'fttn' for input arguments of type 'struct'.

Am I doing something wrong?

Answer 2

[Image Analyst]

Attached are two of my FFT2 demos for you.

[sean darmadi]

Hi,

I am just given a file in the .mat format. When I try to do ftt2, I am unable to convert the file. When I use the load function, it says that I have a 300x300 double.

[Image Analyst]

You forgot to attach your .mat file and your .m file so I'm unable to do anything to help you (yet).