2D DFT of an image

Hi, how do we perform the 2D DFT of an image without using the built-in function fft2?

Please help with the algorithm giving in detail the steps that have to be performed.

Thanks

[Bjorn Gustavsson]

Why would you want to do that?

If it is for learning and understanding the FFT algoritm, then why don't you want to do it yourself? If you use someone elses code as a black-box you will learn about as little as using the built-in fft.

[Jake Cooper]

I appreciate your concern. However, it would of help if you could answer my query.

Answer 1

[Bjorn Gustavsson]

OK, here's a solution that's computationally useless since 1965:

szIm = size(Im);
M1 = dftmtx(szIm(1));
M2 = dftmtx(szIm(2));
sft2Im = (M1*Im)*M2;

HTH