CODEWITHSUNDEEP
opencvimage-processingfft
Navdeep
Navdeep

Reputation: 863

Translation of a Fourier Image

I know that DC component in Frequency Domain is always at F(0,0) i.e at TOP LEFT. If I want to bring it to centre, they say we need to multiply the image, f(x,y), with (-1)^(x+y) and it will take the DC component to centre. I am not able to understand it, how this happens. Also if DC component is brought to the centre then what value has gone to F(0,0)? I read this in Gonzalez, Please explain me with the help of an example so that I can understand it that how F(0,0) is brought to centre and what value moves to F(0,0).

Upvotes: 0

Views: 667

Answers (1)

Dennis
Dennis

Reputation: 521

I had the same problem of understanding until I read this OpenCV tutorial (focus on point 6.):
http://docs.opencv.org/doc/tutorials/core/discrete_fourier_transform/discrete_fourier_transform.html
So if you divided your frequency domain image into four quadrants, then:

  • Swap top-left quadrant with bottom-right quadrant
  • Swap top-right quadrant with bottom-left quadrant

Upvotes: 3

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