CODEWITHSUNDEEP
c#matlabfft
Md Sifatul Islam
Md Sifatul Islam

Reputation: 854

AForge FFT2 and matlab FFT2 results dont match

I tried using Aforge.Math for doing FFT2 on 2D complex matrix and tried the same on matlab

On C#, for AForge:

Complex[,] array2D = new Complex[,] { {  (Complex)1,  (Complex)2 }, {  (Complex)3,  (Complex)4 }, {  (Complex)5, (Complex) 6 }, {  (Complex)7,  (Complex)8 } };
FourierTransform.FFT2(array2D,FourierTransform.Direction.Forward);

On Mathlab:

x =[1 2; 3 4; 5 6; 7 8]
fft2(x)

but unfortunately the results are not the same for c#: enter image description here

for mathlab:

  36.0000 + 0.0000i  -4.0000 + 0.0000i
  -8.0000 + 8.0000i   0.0000 + 0.0000i
  -8.0000 + 0.0000i   0.0000 + 0.0000i
  -8.0000 - 8.0000i   0.0000 + 0.0000i

I have no clue why the results are different, btw I can just use tools , don't know details about FFT2. Update: AForge result is scaled according to the input matrix size!

Upvotes: 2

Views: 194

Answers (1)

Evk
Evk

Reputation: 101453

To get the same result as in matlab, change direction to Backward:

FourierTransform.FFT2(array2D,FourierTransform.Direction.Backward);

Upvotes: 1

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