Intel® Integrated Performance Primitives
Deliberate problems developing high-performance vision, signal, security, and storage applications.

fftshift

siddy
Beginner
1,396 Views

Hi all,

     Again, trying to transcode some matlab ideas to IPP based C++ : is there a similar function in IPP that

performs the fftshift operation, as in Matlab? (shift zero frequence to the center of the space). Or, if someone can confirm that the FFTFwd etc.

already result in transforms in this format, and that fftshift operation is not required. 

Thanks,

Sid.

0 Kudos
5 Replies
Chuck_De_Sylva
Beginner
1,396 Views
Can you submit a sample of what you are trying to do in Matlab code? Thanks.
0 Kudos
siddy
Beginner
1,396 Views
F = fftshift(fft2(I)) where I is MxN image. Q: is fftshift needed for IPP fft, and if yes, how to do it? Sid.
0 Kudos
John_M_1
Beginner
1,396 Views

Ever got an answer to your question, siddy?

0 Kudos
Chao_Y_Intel
Moderator
1,396 Views

Hello,

When I check the fftshift function here:  http://www.mathworks.com/help/matlab/ref/fftshift.html

For vectors, fftshift(X) swaps the left and right halves of X. For matrices, fftshift(X) swaps the first quadrant with the third and the second quadrant with the fourth.

Could you try to use the ippiCopy_xxx function to swaps these data one by one block?

Regards,
Chao

0 Kudos
Royi
Novice
1,396 Views

@Chao,

It would be great to have something like that out of the box.
Mainly that it is crucial when visualizing the Spectrum.

Thank You.

0 Kudos
Reply